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1.
Zhonghua Zhong Liu Za Zhi ; 42(2): 133-138, 2020 Feb 23.
Artigo em Chinês | MEDLINE | ID: mdl-32135648

RESUMO

Objective: To evaluate the long-term effect and safety of chrono-chemotherapy combined with intensity modulated radiotherapy (IMRT) in locally advanced nasopharyngeal carcinoma (NPC). Methods: 160 patients with locally advanced NPC were randomly divided into a chrono group and conventional group according to random number table. In the first stage, all patients underwent two cycles of induced chemotherapy, consisting of docetaxel, cisplatin and 5-Fu every 21 days. Notably, patients received chrono-moduated chemotherapy according to circadian rhythm in the chrono group, and conventional chemotherapy in the conventional group. Then, 21 days after the completion of first stage, three cycles of concurrent cisplatin chemotherapy every 21 days were given to all patients during IMRT. The median follow-up after the completion of radiotherapy was 31 months. Long-term side effects and the survival of patients were observed. Results: Patients in the chrono group had significantly lower rates of hearing loss (22.72%), dysphagia (0) and neck fibrosis (4.54%) compared with those in the conventional group (39.13%、8.69%, 15.94%, respectively, all P<0.05). Meanwhile, the 1- year overall survival rates (97.0% vs 92.8%), 3-year overall survival rates (80.3% vs 81.2%), 1-year progression free survival rates (95.5% vs 87.0%), 3-year progression free survival rates (71.2% vs 73.9%), 1-year locoregional relapse-free survival rates (97.0% vs 95.7%), 1-year locoregional relapse-free survival rates (92.4% vs 92.8%), 1-year distant metastasis-free survival rates (97.0% vs 98.6%) and 3-year distant metastasis-free survival rates (90.9% vs 91.3%) between the chrono group and the conventional group were not statistically significant (all P>0.05). Conclusions: Compared with conventional chemotherapy, chrono-chemotherapy combined with IMRT didn't affect long-term survival, but reducing the incidence of adverse events in patients with locally advanced NPC.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Nasofaríngeo/tratamento farmacológico , Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/radioterapia , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Quimiorradioterapia/métodos , Cisplatino/administração & dosagem , Terapia Combinada , Docetaxel/administração & dosagem , Cronoterapia Farmacológica , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Carcinoma Nasofaríngeo/patologia , Neoplasias Nasofaríngeas/patologia , Radioterapia de Intensidade Modulada/métodos , Resultado do Tratamento
2.
Cancer Radiother ; 24(1): 53-59, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32046915

RESUMO

PUPOSE: To compare dosimetric plans for the treatments of oligobrains metastases (2-6) using mono-isocentric arc therapy and multi-isocentric volumetric modulated arc therapy (VMAT). MATERIAL AND METHODS: A total of sixteen patients with multiple brain metastases were selected. Prescription dose was between 24 and 15Gy depending on the tumor size. For every patient,arctherapy and VMAT plans were generated respectively, with Elements Multiple Brain Mets SRS version 2.0 (BrainLab) and Eclipse SRS Treatment Planning Systeme version 15.5. The conformity index (CI), homogeinity index (HI), gradient index (GI), dose volume histogram for each organs at risk, total Monitor Units were evaluated. RESULTS: For coverage of the PTV, mono-isocentric plans showed a better CI and a better GI than multi-isocentric plans, respectively CI of 1.18±0.11 vs 1.41±0.20 (P<0.01), and GI of 3.55±0.59 vs 4.03±1.20 (P<0.01). Homogeneity index was not better with mono-isocentric plans, with respectively HI 24.32±3.87 vs 14.05±4.46 (P=1). For organs at risk, there were no statistical differences between mono and multi-isocentric plans for both eyes, both lenses, both optic nerves, chiasma, brainstem, and hippocampi.V12Gy and V10Gy of normal brain were statistically lower with mono-isocentric plans than with multi-isocentric plans, respectivellyV12Gy of 3.06Gy 95%CI [2.25;3.86]vs 5.18Gy 95%CI [3.43;6.93] (P<0,01) and V10Gy 4.66Gy 95%CI [3.33;5.98] vs7.30Gy 95%CI [4.73;9.87] (P<0.03). Total number of MU was significantly lower with mono-isocentric plans than with multi-isocentric plans, respectively 6668±1463 vs 12403±4941 (P<0.01), then treatment time was lower with mono-isocentric plans. CONCLUSION: Mono-isocentric plans had a better conformity index and gradient index than multi-isocentric plans for the treatment of multiple brain metastases. Moreover, mono-isocentric techniques gave fewer doses to normal brain and used less monitor units than multi-isocentric techniques.


Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/efeitos da radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Planejamento da Radioterapia Assistida por Computador
3.
Cancer Radiother ; 24(1): 28-37, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32007370

RESUMO

PURPOSE: To guide parotid gland (PG) sparing at the dose planning step, a specific model based on overlap between PTV and organ at risk (Moore et al.) was developed and evaluated for VMAT in head-and-neck (H&N) cancer radiotherapy. MATERIALS AND METHODS: One hundred and sixty patients treated for locally advanced H&N cancer were included. A model optimization was first performed (20 patients) before a model evaluation (110 patients). Thirty cases were planned with and without the model to quantify the PG dose sparing. The inter-operator variability was evaluated on one case, planned by 12 operators with and without the model. The endpoints were PG mean dose (Dmean), PTV homogeneity and number of monitor units (MU). RESULTS: The PG Dmean predicted by the model was reached in 89% of cases. Using the model significantly reduced the PG Dmean: -6.1±4.3Gy. Plans with the model showed lower PTV dose homogeneity and more MUs (+10.5% on average). For the inter-operator variability, PG dose volume histograms without the optimized model were significantly different compared to those with the model; the Dmean standard deviation for the ipsilateral PG decreased from 2.2Gy to 1.2Gy. For the contralateral PG, this value decreased from 2.9Gy to 0.8Gy. CONCLUSION: During the H&N inverse planning, the optimized model guides to the lowest PG achievable mean dose, allowing a significant PG mean dose reduction of -6.1Gy. Integrating this method at the treatment-planning step significantly reduced the inter-patient and inter-operator variabilities.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Órgãos em Risco , Glândula Parótida , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Carcinoma de Células Escamosas/radioterapia , Humanos , Glândula Parótida/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos
4.
Br J Radiol ; 93(1107): 20190584, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31977241

RESUMO

OBJECTIVE: We compared the sensitivity of intensity modulated proton therapy (IMPT) and photon volumetric modulated arc therapy (VMAT) plans to setup uncertainties in locally advanced non-small cell lung cancer (NSCLC) using probabilistic scenarios. METHODS: Minimax robust (MM) and planning target volume (PTV) optimised IMPT and VMAT nominal plans were created with physical dose of 70 Gy in 35 fractions in 10 representative patients. Using population data of setup errors, a fractionated treatment course was simulated, summed (Dsum) and compared to the nominal plan. Three treatment-course simulations were done for each plan. Target robustness criteria were: dose deviation of ≤5% to clinical target volume (CTV) D98% and CTV V95% ≥ 99.9%. Voxelwise simulation repeatability was analysed using Bland-Altman plots. Acceptable limits of agreement were 2% of the prescription dose. RESULTS: All Dsum met target robustness criteria. While fraction VMAT and MM-IMPT doses were excellent, simulated fraction doses in PTV-IMPT were suboptimal. Almost all (>99%) of VMAT and MM-IMPT fraction doses met both target robustness criteria. For PTV-IMPT, only 96.9 and 80.3% of fractions met CTVD98% and V95% criteria respectively. Simulation repeatability was excellent (limits of agreement range: 0.41-1.1 Gy) with strong positive correlations. CONCLUSION: When considering the whole treatment course, setup errors do not influence robustness irrespective of planning techniques used. However, on a fraction level, VMAT and MM-IMPT plans are superior compared to PTV-IMPT plans. ADVANCES IN KNOWLEDGE: Probabilistic analysis provides a fast and practical method for evaluating VMAT and IMPT plan sensitivity against setup uncertainty. VMAT and robust-optimised IMPT plans have comparable sensitivity to setup uncertainties in conventionally fractionated treatment for NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Fótons/uso terapêutico , Terapia com Prótons/métodos , Erros de Configuração em Radioterapia , Radioterapia de Intensidade Modulada/métodos , Incerteza , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/patologia , Fracionamento da Dose de Radiação , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
Br J Radiol ; 93(1108): 20190792, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31939310

RESUMO

OBJECTIVES: To evaluate the feasibility and optimal restricted angle of the complete-directional-complete block (CDCB) technique in helical tomotherapy (HT) by including regional nodal irradiation (RNI) with the internal mammary node (IMN) in left-sided breast cancer. METHODS: Ten left-sided breast cancer patients treated with 50 Gy in 25 fractions were compared with five-field intensity-modulated radiation therapy (5F-IMRT) and six types of HT plans. In the HT plans, complete block (CB), organ-based directional block (OBDB) and CDCB with different restricted angles were used. RESULTS: The conformity index (CI) between the CDCB0,10,15,20 and 5F-IMRT groups was similar. Compared to CB, OBDB and 5F-IMRT, CDCB20 resulted in a decreased ipsilateral mean lung dose. The low-dose region (V5) of the ipsilateral lung in OBDB (84.0%) was the highest among all techniques (p < 0.001). The mean dose of the heart in CB was significantly reduced (by 11.5-22.4%) compared with other techniques. The V30 of the heart in CDCB20 (1.9%) was significantly lower than that of CB, OBDB and 5F-IMRT. Compared to the mean dose of the left anterior descending (LAD) artery of 5F-IMRT (27.0 Gy), CDCB0, CDCB10, CDCB15, CDCB20 and OBDB reduced the mean dose effectively by 31.7%, 38.3%, 39.6%, 42.0 and 56.2%, respectively. Considering the parameters of the organs-at-risk (OARs), CDCB10,15,20 had higher expectative values than the other techniques (p = 0.01). CONCLUSIONS: HT with the CDCB technique is feasible for treating left-sided breast cancer patients. The CDCB10-20 techniques not only achieved similar planning target volume coverage, homogeneity and dose conformity but also allowed better sparing of the heart and bilateral lungs. ADVANCES IN KNOWLEDGE: For left-sided breast cancer patients whose RNI field includes the IMN, heart avoidance is an important issue. The CDCB technique achieved good PTV coverage, homogeneity and dose conformity and allowed better sparing of the mean dose of the lung, the LAD artery, and the heart and reduced the V30 of the heart.


Assuntos
Coração/efeitos da radiação , Pulmão/efeitos da radiação , Irradiação Linfática/métodos , Órgãos em Risco/efeitos da radiação , Lesões por Radiação/prevenção & controle , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Fracionamento da Dose de Radiação , Estudos de Viabilidade , Feminino , Humanos , Órgãos em Risco/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias Unilaterais da Mama/diagnóstico por imagem
6.
Br J Radiol ; 93(1108): 20190789, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31971829

RESUMO

OBJECTIVE: Prostate stereotactic ablative radiotherapy (SABR) delivers large doses using a fast dose rate. This amplifies the effect geometric uncertainties have on normal tissue dose. The aim of this study was to determine whether the treatment dose-volume histogram (DVH) agrees with the planned dose to organs at risk (OAR). METHODS: 41 low-intermediate risk prostate cancer patients were treated with SABR using a linac based technique. Dose prescribed was 35 Gy in five fractions delivered on alternate days, planned using volumetric modulated arc therapy (VMAT) with 10X flattening filter free (FFF). On treatment, prostate was matched to fiducial markers on cone beam CT (CBCT). OAR were retrospectively delineated on 205 pre-treatment CBCT images. Daily CBCT contours were overlaid on the planning CT for dosimetric analysis. Verification plan used to evaluate the daily DVH for each structure. The daily doses received by OAR were recorded using the D%. RESULTS: The median rectum and bladder volumes at planning were 67.1 cm3 (interquartile range 56.4-78.2) and 164.4 cm3 (interquartile range 120.3-213.4) respectively. There was no statistically significant difference in median rectal volume at each of the five treatment scans compared to the planning scan (p = 0.99). This was also the case for median bladder volume (p = 0.79). The median dose received by rectum and bladder at each fraction was higher than planned, at the majority of dose levels. For rectum the increase ranged from 0.78-1.64Gy and for bladder 0.14-1.07Gy. The percentage of patients failing for rectum D35% < 18 Gy (p = 0.016), D10% < 28 Gy (p = 0.004), D5% < 32 Gy (p = 0.0001), D1% < 35 Gy (p = 0.0001) and bladder D1% < 35 Gy (p = 0.001) at treatment were all statistically significant. CONCLUSION: In this cohort of prostate SABR patients, we estimate the OAR treatment DVH was higher than planned. This was due to rectal and bladder organ variation. ADVANCES IN KNOWLEDGE: OAR variation in prostate SABR using a FFF technique, may cause the treatment DVH to be higher than planned.


Assuntos
Órgãos em Risco/efeitos da radiação , Neoplasias da Próstata/radioterapia , Radiocirurgia/métodos , Radioterapia de Intensidade Modulada/métodos , Reto/efeitos da radiação , Bexiga Urinária/efeitos da radiação , Idoso , Fracionamento da Dose de Radiação , Humanos , Masculino , Próstata , Radiometria , Planejamento da Radioterapia Assistida por Computador/métodos , Reto/diagnóstico por imagem , Estudos Retrospectivos , Bexiga Urinária/diagnóstico por imagem
7.
Medicine (Baltimore) ; 99(2): e18545, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31914029

RESUMO

This study aimed to determine the impact of the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) on the prognosis of nasopharyngeal carcinoma (NPC) before and after intensity modulated radiotherapy (IMRT).Pre/post-treatment and changes in inflammatory biomarker levels of 207 patients who were diagnosed with NPC and received IMRT between January 2012 and December 2014 were analyzed, and the cellular biomarker analyses were from patient blood. ROC (receiver operating characteristic) analysis was used to decide the optimal cutoff values of NLR and changes in NLR (ΔNLR) and PLR (ΔPLR). The Kaplan-Meier and logarithmic rank methods were used to compare overall survival times between groups. Univariate analysis was used to investigate the effects of age, gender, histology, Karnofsky performance score (KPS), TNM stage, clinical stage, course of disease and lymphocyte, neutrophil and platelet counts as well as alkaline phosphatase (ALP) levels on the prognosis of NPC. The independent predictors of OS were determined by Cox multivariate regression analysis.The optimal cut-off values of NLR, PLR, ΔNLR and ΔPLR were 2.49, 155.82, 1.80, and 100.00, respectively. These were used to classify patients into high (NLR > 2.49) and low NLR groups (NLR < 2.49); high (PLR>155.82) and low (PLR < 155.82) PLR groups; high (ΔNLR>1.80) and low ΔNLR groups (ΔNLR < 1.80); high (ΔPLR > 100.00) and low ΔPLR groups (ΔPLR < 100.00). TNM stage, clinical stage and ALP levels were highly correlated with high NLR and PLR. Cox multivariate regression analysis suggested that the ΔNLR (HR = 2.89, 95% CI: 1.33∼2.78) was independent of the characteristics for NPC.As a novel inflammatory index, ΔNLR appears to have some predictive power for the prognosis of patients with NPC.


Assuntos
Linfócitos/efeitos da radiação , Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/radioterapia , Neutrófilos/efeitos da radiação , Radioterapia de Intensidade Modulada/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/sangue , Contagem de Células Sanguíneas , Plaquetas/patologia , Plaquetas/efeitos da radiação , Feminino , Humanos , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo/mortalidade , Carcinoma Nasofaríngeo/patologia , Neoplasias Nasofaríngeas/mortalidade , Neoplasias Nasofaríngeas/patologia , Estadiamento de Neoplasias/métodos , Neutrófilos/patologia , Valor Preditivo dos Testes , Prognóstico , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos
8.
Br J Radiol ; 93(1107): 20190583, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31696729

RESUMO

OBJECTIVE: To identify a subgroup of lung cancer plans where the analytical dose calculation (ADC) algorithm may be clinically acceptable compared to Monte Carlo (MC) dose calculation in intensity modulated proton therapy (IMPT). METHODS: Robust-optimised IMPT plans were generated for 20 patients to a dose of 70 Gy (relative biological effectiveness) in 35 fractions in Raystation. For each case, four plans were generated: three with ADC optimisation using the pencil beam (PB) algorithm followed by a final dose calculation with the following algorithms: PB (PB-PB), MC (PB-MC) and MC normalised to prescription dose (PB-MC scaled). A fourth plan was generated where MC optimisation and final dose calculation was performed (MC-MC). Dose comparison and γ analysis (PB-PB vs PB-MC) at two dose thresholds were performed: 20% (D20) and 99% (D99) with PB-PB plans as reference. RESULTS: Overestimation of the dose to 99% and mean dose of the clinical target volume was observed in all PB-MC compared to PB-PB plans (median: 3.7 Gy(RBE) (5%) (range: 2.3 to 6.9 Gy(RBE)) and 1.8 Gy(RBE) (3%) (0.5 to 4.6 Gy(RBE))). PB-MC scaled plans resulted in significantly higher CTVD2 compared to PB-PB (median difference: -4 Gy(RBE) (-6%) (-5.3 to -2.4 Gy(RBE)), p ≤ .001). The overall median γ pass rates (3%-3 mm) at D20 and D99 were 93.2% (range:62.2-97.5%) and 71.3 (15.4-92.0%). On multivariate analysis, presence of mediastinal disease and absence of range shifters were significantly associated with high γ pass rates. Median D20 and D99 pass rates with these predictors were 96.0% (95.3-97.5%) and 85.4% (75.1-92.0%). MC-MC achieved similar target coverage and doses to OAR compared to PB-PB plans. CONCLUSION: In the presence of mediastinal involvement and absence of range shifters Raystation ADC may be clinically acceptable in lung IMPT. Otherwise, MC algorithm would be recommended to ensure accuracy of treatment plans. ADVANCES IN KNOWLEDGE: Although MC algorithm is more accurate compared to ADC in lung IMPT, ADC may be clinically acceptable where there is mediastinal involvement and absence of range shifters.


Assuntos
Algoritmos , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Método de Monte Carlo , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Análise de Variância , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/patologia , Fracionamento da Dose de Radiação , Tomografia Computadorizada Quadridimensional , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Neoplasias do Mediastino/radioterapia , Análise Multivariada , Órgãos em Risco/efeitos da radiação , Eficiência Biológica Relativa , Incerteza
9.
Int J Radiat Oncol Biol Phys ; 106(2): 340-348, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655197

RESUMO

PURPOSE: Local persistence and relapse of disease in the gross tumor volume (GTV) account for the majority of treatment failures after standard chemoradiation therapy. The primary objective of this phase 1 trial was to define the maximum tolerated dose (MTD) of a hyperfractionated radiation therapy (HFRT) boost to the GTV with concurrent weekly paclitaxel and carboplatin after standard-dose chemoradiation therapy, using image guided intensity modulated radiation therapy techniques. METHODS AND MATERIALS: Eligible patients were given weekly doses of paclitaxel (45 mg/m2) and carboplatin (area under the curve 1.5) for 5 weeks with concurrent radiation therapy (50 Gy), immediately followed by an HFRT boost to the GTV with the same chemotherapy regimen. The boost doses were escalated in increments of 7.2 Gy delivered in 6 twice-daily fractions of 1.2 Gy using a modified Fibonacci design. Once the MTD was established, additional patients were treated at that dose to determine the safety. RESULTS: Thirty-one patients fulfilled the inclusion criteria. The incidence of dose-limiting toxicity was 0 of 3, 0 of 3, 0 of 3, 1 of 6 (grade 4 esophagitis), 0 of 3, and 2 of 3 (1 case each of grade 5 esophageal fistula and grade 3 pneumotitis) at 7.2, 14.4, 21.6, 28.8, 36, and 43.2 Gy, respectively, indicating an MTD of 36 Gy. Ten patients treated with this MTD showed no dose-limiting toxicities. The most common acute grade 3 or greater toxicities were esophagitis (26%) and neutropenia (19%). Late toxicity of grade 2 esophageal stricture occurred in 4 patients. The overall response rate was 84% (95% confidence interval, 42%-93%) in the entire cohort. The 1-year local control rate was 100% among those receiving a cumulative dose of the MTD or greater. CONCLUSIONS: The MTD of the HFRT boost after standard chemoradiation therapy in the setting of concurrent chemotherapy was 36 Gy, resulting in the cumulative tumor dose of 86 Gy in patients primarily with advanced intrathoracic/cervical esophageal squamous cell carcinomas and not adenocarcinomas of the gastroesophageal junction. A phase 2 study to further evaluate this regimen is underway.


Assuntos
Quimiorradioterapia/efeitos adversos , Neoplasias Esofágicas/terapia , Carcinoma de Células Escamosas do Esôfago/terapia , Dose Máxima Tolerável , Radioterapia de Intensidade Modulada/efeitos adversos , Reirradiação/efeitos adversos , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Área Sob a Curva , Carboplatina/administração & dosagem , Quimiorradioterapia/métodos , Fracionamento da Dose de Radiação , Fístula Esofágica/etiologia , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/patologia , Esofagite/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neutropenia/etiologia , Paclitaxel/administração & dosagem , Pneumonite por Radiação/etiologia , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Reirradiação/métodos , Carga Tumoral
10.
Br J Radiol ; 93(1107): 20190669, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31799859

RESUMO

OBJECTIVE: This study is part of ongoing efforts aiming to transit from measurement-based to combined patient-specific quality assurance (PSQA) in intensity-modulated proton therapy (IMPT). A Monte Carlo (MC) dose-calculation algorithm is used to improve the independent dose calculation and to reveal the beam modeling deficiency of the analytical pencil beam (PB) algorithm. METHODS: A set of representative clinical IMPT plans with suboptimal PSQA results were reviewed. Verification plans were recalculated using an MC algorithm developed in-house. Agreements of PB and MC calculations with measurements that quantified by the γ passing rate were compared. RESULTS: The percentage of dose planes that met the clinical criteria for PSQA (>90% γ passing rate using 3%/3 mm criteria) increased from 71.40% in the original PB calculation to 95.14% in the MC recalculation. For fields without beam modifiers, nearly 100% of the dose planes exceeded the 95% γ passing rate threshold using the MC algorithm. The model deficiencies of the PB algorithm were found in the proximal and distal regions of the SOBP, where MC recalculation improved the γ passing rate by 11.27% (p < 0.001) and 16.80% (p < 0.001), respectively. CONCLUSIONS: The MC algorithm substantially improved the γ passing rate for IMPT PSQA. Improved modeling of beam modifiers would enable the use of the MC algorithm for independent dose calculation, completely replacing additional depth measurements in IMPT PSQA program. For current users of the PB algorithm, further improving the long-tail modeling or using MC simulation to generate the dose correction factor is necessary. ADVANCES IN KNOWLEDGE: We justified a change in clinical practice to achieve efficient combined PSQA in IMPT by using the MC algorithm that was experimentally validated in almost all the clinical scenarios in our center. Deficiencies in beam modeling of the current PB algorithm were identified and solutions to improve its dose-calculation accuracy were provided.


Assuntos
Algoritmos , Método de Monte Carlo , Terapia com Prótons/normas , Garantia da Qualidade dos Cuidados de Saúde , Radioterapia de Intensidade Modulada/normas , Análise de Dados , Humanos , Terapia com Prótons/instrumentação , Terapia com Prótons/métodos , Controle de Qualidade , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/normas , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia de Intensidade Modulada/instrumentação , Radioterapia de Intensidade Modulada/métodos , Reprodutibilidade dos Testes , Síncrotrons
11.
Br J Radiol ; 93(1107): 20190879, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31804145

RESUMO

OBJECTIVE: Locally recurrent disease is of increasing concern in (non-)small cell lung cancer [(N)SCLC] patients. Local reirradiation with photons or particles may be of benefit to these patients. In this multicentre in silico trial performed within the Radiation Oncology Collaborative Comparison (ROCOCO) consortium, the doses to the target volumes and organs at risk (OARs) were compared when using several photon and proton techniques in patients with recurrent localised lung cancer scheduled to undergo reirradiation. METHODS: 24 consecutive patients with a second primary (N)SCLC or recurrent disease after curative-intent, standard fractionated radio(chemo)therapy were included in this study. The target volumes and OARs were centrally contoured and distributed to the participating ROCOCO sites. Remaining doses to the OARs were calculated on an individual patient's basis. Treatment planning was performed by the participating site using the clinical treatment planning system and associated beam characteristics. RESULTS: Treatment plans for all modalities (five photon and two proton plans per patient) were available for 22 patients (N = 154 plans). 3D-conformal photon therapy and double-scattered proton therapy delivered significantly lower doses to the target volumes. The highly conformal techniques, i.e., intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), CyberKnife, TomoTherapy and intensity-modulated proton therapy (IMPT), reached the highest doses in the target volumes. Of these, IMPT was able to statistically significantly decrease the radiation doses to the OARs. CONCLUSION: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. They, however, significantly differ in the dose deposited in the OARs. The therapeutic options, i.e., reirradiation or systemic therapy, need to be carefully weighed and discussed with the patients. ADVANCES IN KNOWLEDGE: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. In light of the abilities of the various highly conformal techniques to spare specific OARs, the therapeutic options need to be carefully weighed and patients included in the decision-making process.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Recidiva Local de Neoplasia/radioterapia , Órgãos em Risco/efeitos da radiação , Fótons/uso terapêutico , Terapia com Prótons/métodos , Reirradiação/métodos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Conjuntos de Dados como Assunto , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Órgãos em Risco/diagnóstico por imagem , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Resultado do Tratamento
12.
Br J Radiol ; 93(1107): 20190573, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31778315

RESUMO

OBJECTIVE: Classical robust optimization (cRO) in intensity-modulated proton therapy (IMPT) considers isocenter position and particle range uncertainties; anatomical robust optimization (aRO) aims to consider additional non-rigid positioning variations. This work compares the influence of different uncertainty sources on the robustness of cRO and aRO IMPT plans for head and neck squamous cell carcinoma (HNSCC). METHODS: Two IMPT plans were optimized for 20 HNSCC patients who received weekly control CTs (cCT): cRO, using solely the planning CT, and aRO, including 2 additional cCTs. The robustness of the plans in terms of clinical target volume (CTV) coverage and organ at risk (OAR) sparing was analyzed considering stepwise the influence of (1) non-rigid anatomical variations given by the weekly cCT, (2) with fraction-wise added rigid random setup errors and (3) additional systematic proton range uncertainties. RESULTS: cRO plans presented significantly higher nominal CTV coverage but are outperformed by aRO plans when considering non-rigid anatomical variations only, as cRO and aRO plans presented a median target coverage (D98%) decrease for the low-risk/high-risk CTV of 1.8/1.1 percentage points (pp) and -0.2 pp/-0.3 pp, respectively. Setup and range uncertainties had larger influence on cRO CTV coverage, but led to similar OAR dose changes in both plans. Considering all error sources, 10/2 cRO/aRO patients missed the CTV coverage and a limited number exceeded some OAR constraints in both plans. CONCLUSION: Non-rigid anatomical variations are mainly responsible for critical target coverage loss of cRO plans, whereas the aRO approach was robust against such variations. Both plans provide similar robustness of OAR parameters. ADVANCES IN KNOWLEDGE: The influence of different uncertainty sources was quantified for robust IMPT HNSCC plans.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Carcinoma de Células Escamosas de Cabeça e Pescoço/radioterapia , Incerteza , Humanos , Órgãos em Risco/efeitos da radiação , Posicionamento do Paciente , Lesões por Radiação/prevenção & controle , Erros de Configuração em Radioterapia , Radioterapia de Intensidade Modulada/normas , Estudos Retrospectivos
13.
Br J Radiol ; 93(1107): 20190601, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31529979

RESUMO

Proton beam therapy is a highly conformal form of radiation therapy, which currently represents an important therapeutic component in multidisciplinary management in paediatric oncology. The precise adjustability of protons results in a reduction of radiation-related long-term side-effects and secondary malignancy induction, which is of particular importance for the quality of life. Proton irradiation has been shown to offer significant advantages over conventional photon-based radiotherapy, although the biological effectiveness of both irradiation modalities is comparable. This review evaluates current data from clinical and dosimetric studies on the treatment of tumours of the central nervous system, soft tissue and bone sarcomas of the head and neck region, paraspinal or pelvic region, and retinoblastoma. To date, the clinical results of irradiating childhood tumours with high-precision proton therapy are promising both with regard to tumour cure and the reduction of adverse events. Modern proton therapy techniques such as pencil beam scanning and intensity modulation are increasingly established modern facilities. However, further investigations with larger patient cohorts and longer follow-up periods are required, in order to be able to have clear evidence on clinical benefits.


Assuntos
Neoplasias/radioterapia , Terapia com Prótons/métodos , Neoplasias Ósseas/radioterapia , Neoplasias do Sistema Nervoso Central/radioterapia , Criança , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Neoplasias da Retina/radioterapia , Retinoblastoma/radioterapia , Sarcoma/radioterapia , Neoplasias de Tecidos Moles/radioterapia , Neoplasias da Coluna Vertebral/radioterapia
14.
Int J Radiat Oncol Biol Phys ; 106(2): 329-339, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31629837

RESUMO

PURPOSE: Our purpose was to describe the patterns and predictors of treatment failure in patients receiving definitive chemoradiation therapy (CRT) for anal squamous cell carcinoma (ASCC), delivered using intensity modulated radiation therapy (IMRT). METHODS AND MATERIALS: Our study was a retrospective cohort analysis of consecutive patients treated with curative intent for ASCC using CRT delivered with a standardized IMRT technique in 5 UK cancer centers. Patients were included from the start of UK IMRT guidance from February 2013 to October 31, 2017. Collected data included baseline demographics, treatment details, tumor control, sites of relapse, and overall survival. Statistical analysis to calculate outcomes and predictive factors for outcome measures were performed using SPSS and R. RESULTS: The medical records of 385 consecutive patients were analyzed. Median follow-up was 24.0 months. Within 6 months of completing CRT, 86.7% of patients achieved a complete response. Three-year disease-free survival and overall survival were 75.6% and 85.6%, respectively. Of all relapses, 83.4% occurred at the site of primary disease. There were 2 isolated relapses in regional nodes not involved at outset. Predictive factors for cancer recurrence included male sex, high N-stage, and failure to complete radiation therapy as planned. CONCLUSIONS: The treatment results compare favorably to published outcomes from similar cohorts using 3-dimensional conformal CRT. The observed patterns of failure support the current UK IMRT voluming guidelines and dose levels, highlighting our prophylactic nodal dose as sufficient to prevent isolated regional relapse in uninvolved nodes. Further investigation of strategies to optimize CR should remain a priority in ASCC because the site of primary disease remains the overwhelming site of relapse.


Assuntos
Neoplasias do Ânus/terapia , Carcinoma de Células Escamosas/terapia , Quimiorradioterapia/métodos , Recidiva Local de Neoplasia , Radioterapia de Intensidade Modulada/métodos , Reirradiação , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Ânus/mortalidade , Neoplasias do Ânus/radioterapia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/radioterapia , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , Fatores de Risco , Terapia de Salvação/estatística & dados numéricos , Fatores Sexuais , Falha de Tratamento , Reino Unido
15.
Int J Radiat Oncol Biol Phys ; 106(3): 621-629, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31759074

RESUMO

PURPOSE: Preclinical research into ultrahigh dose rate (eg, ≥40 Gy/s) "FLASH"-radiation therapy suggests a decrease in side effects compared with conventional irradiation while maintaining tumor control. When FLASH is delivered using a scanning proton beam, tissue becomes subject to a spatially dependent range of dose rates. This study systematically investigates dose rate distributions and delivery times for proton FLASH plans using stereotactic lung irradiation as the paradigm. METHODS AND MATERIALS: Stereotactic lung radiation therapy FLASH-plans, using 244 MeV scanning proton transmission beams, with the Bragg peak behind the body, were made for 7 patients. Evaluated parameters were dose rate distribution within a beam, overall irradiation time, number of times tissue is irradiated, and quality of the FLASH-plans compared with the clinical volumetric-modulated arc therapy (VMAT) plans. RESULTS: Sparing of lungs, thoracic wall, and heart in the FLASH-plans was equal to or better than that in the VMAT-plans. For a spot peak dose rate (SPDR, the dose rate in the middle of the spot) of 100 Gy/s, ∼40% of dose is delivered at FLASH dose rates, and for SPDR = 360 Gy/s this increased to ∼75%. One-hundred percent FLASH dose rate cannot be achieved owing to small contributions from distant spots with lower dose rates. The total irradiation time varied between 300 to 730 ms, and around 85% of the dose-receiving body volume was irradiated by either 1 or 2 beams. CONCLUSIONS: Clinical implementation of FLASH using scanning proton beams requires multiple treatment planning considerations: dosimetric, temporal, and spatial parameters all seem important. The FLASH efficiency of a scanning proton beam increases with SPDR. The methodology proposed in this proof-of-principle study provides a framework for evaluating the FLASH characteristics of scanning proton beam plans and can be adapted as FLASH parameters are better defined. It currently seems logical to optimize plans for the shortest delivery time, maximum amount of high dose rate coverage, and maximum amount of single beam and continuous irradiation.


Assuntos
Neoplasias Pulmonares/radioterapia , Terapia com Prótons/métodos , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Coração , Humanos , Pulmão , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco , Estudo de Prova de Conceito , Terapia com Prótons/efeitos adversos , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Medula Espinal , Parede Torácica , Fatores de Tempo
16.
Int J Radiat Oncol Biol Phys ; 106(3): 630-638, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31759076

RESUMO

PURPOSE: Intensity modulated proton therapy (IMPT) of locally advanced prostate cancer can spare the bowel considerably compared with modern photon therapy, but simultaneous treatment of the prostate (p), seminal vesicles (sv), and lymph nodes is challenging owing to day-to-day organ motion and range uncertainties. Our purpose was, therefore, to generate a plan library for use in adaptive IMPT to mitigate these uncertainties. METHODS AND MATERIALS: We retrospectively included 27 patients with a series of computed tomography scans throughout their treatment representing day-to-day variation. In 18 of the patients, target motion was analyzed using rigid shifts of prostate gold markers relative to bony anatomy. A plan library with different p and sv planning target volume (p/sv-PTV) positions was defined from the distribution and direction of these shifts. Delivery of IMPT using plan selection from the library was simulated for image guidance on bony anatomy, in the remaining patients and compared with nonadaptive IMPT. RESULTS: The plan library consisted of 3 small margin p/sv-PTVs: (1) p/sv-PTV shifted 1.5 systematic error (Σ) of the population mean in the anterior and cranial directions, (2) p/sv-PTV shifted 1.5Σ in the posterior and caudal directions, and (3) p/sv-PTV in the planning position. The conventional p/sv-PTV was also available for backup. Plan selection compared with nonadaptive IMPT resulted in a reduction of the rectum volume receiving 60 Gy relative biological effect (RBE) (V60GyRBE) from on average 12 mL to 9 mL. For the bladder the average V45GyRBE was reduced from 36% to 30%. Large and small bowel doses were also reduced, whereas target coverage was comparable or improved compared with nonadaptive IMPT. CONCLUSIONS: Plan selection based on a population model of rigid target motion was feasible for all patients. Compared with conventional IMPT, plan selection resulted in significant dosimetric sparing of rectum and bladder without compromising target coverage.


Assuntos
Movimentos dos Órgãos , Neoplasias da Próstata/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Pontos de Referência Anatômicos/diagnóstico por imagem , Marcadores Fiduciais , Ouro , Humanos , Bibliotecas Digitais , Linfonodos/diagnóstico por imagem , Irradiação Linfática/métodos , Masculino , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Próstata/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Reto/diagnóstico por imagem , Estudos Retrospectivos , Glândulas Seminais/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Incerteza , Bexiga Urinária/diagnóstico por imagem
17.
Br J Radiol ; 93(1107): 20190378, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31430188

RESUMO

Radiation therapy is an essential component of treatment for locally advanced non-small cell lung cancer (NSCLC) but can be technically challenging because of the proximity of lung tumors to nearby critical organs or structures. The most effective strategy for reducing radiation-induced toxicity is to reduce unnecessary exposure of normal tissues by using advanced technology; examples from photon (X-ray) therapy have included three-dimensional conformal radiation therapy versus its predecessor, two-dimensional radiation therapy, and intensity-modulated photon radiation therapy versus its predecessor, three-dimensional conformal therapy. Using particle-beam therapy rather than photons offers the potential for further advantages because of the unique depth-dose characteristics of the particles, which can be exploited to allow still higher dose escalation to tumors with greater sparing of normal tissues, with the ultimate goal of improving local tumor control and survival while preserving quality of life by reducing treatment-related toxicity. However, the costs associated with particle therapy with protons are considerably higher than the current state of the art in photon technology, and evidence of clinical benefit from protons is increasingly being demanded to justify the higher financial burden on the healthcare system. Some such evidence is available from preclinical studies, from retrospective, single-institution clinical series, from analyses of national databases, and from single-arm prospective studies in addition to several ongoing randomized comparative trials. This review summarizes the rationale for and challenges of using proton therapy to treat thoracic cancers, reviews the current clinical experience, and suggests topics for future research.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Órgãos em Risco/efeitos da radiação , Terapia com Prótons/métodos , Lesões por Radiação/prevenção & controle , Radioterapia de Intensidade Modulada/métodos , Carcinoma Pulmonar de Células não Pequenas/patologia , Previsões , Humanos , Neoplasias Pulmonares/patologia , Tratamentos com Preservação do Órgão/métodos , Estudos Prospectivos , Terapia com Prótons/economia , Terapia com Prótons/tendências , Qualidade de Vida , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/economia , Radioterapia de Intensidade Modulada/tendências , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Resultado do Tratamento
18.
Tumori ; 106(1): 39-46, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31451102

RESUMO

BACKGROUND: We evaluated the prognostic role of gross tumor volumes (GTVs) of primary tumor and positive lymph nodes on overall survival (OS) and progression-free survival (PFS) in locally advanced unresectable sinonasal cancer (SNC) treated with definitive intensity-modulated radiotherapy (IMRT) with or without chemotherapy. METHODS: Primary tumor GTV (GTV-T), pathologic neck nodes GTV (GTV-N), and positive retropharyngeal nodes GTV (GTV-RPN) of 34 patients with epithelial nonglandular SNC receiving IMRT with or without chemotherapy were retrospectively measured. The GTV variables were analyzed in relation with OS and PFS. Survival curves were estimated using the Kaplan-Meier method and compared with the log-rank test. We also estimated the crude cumulative incidence of locoregional relapses only. The optimal volume cutoff value was determined using an outcome-oriented method among the observed values. RESULTS: GTV-T was significantly associated with decreased OS (P=0.003) and PFS (P=0.003). Moreover, patients with disease total volumes (GTV) smaller than 149.44 cm³ had better OS and PFS than patients with higher volumes (P<0.0001 for both). Neck nodal metastasis impacted on OS and PFS (P=0.030 and P=0.033, respectively), but GTV-N did not (P=0.961; P=0.958). Retropharyngeal nodes metastasis was not associated with prognosis (OS: P=0.400; PFS: P=0.104). When GTV-RPN was added to GTV-N (GTV-TN), a relation with PFS (P=0.041) and a trend toward significance for OS (P=0.075) were found. CONCLUSIONS: Our results show that tumor volume is a powerful predictor of outcome in SNC. This could be useful to identify patients with worse prognosis deserving different treatment strategies.


Assuntos
Neoplasias dos Seios Paranasais/mortalidade , Neoplasias dos Seios Paranasais/patologia , Neoplasias Faríngeas/mortalidade , Neoplasias Faríngeas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Combinada , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias dos Seios Paranasais/terapia , Neoplasias Faríngeas/terapia , Prognóstico , Modelos de Riscos Proporcionais , Radiometria , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento , Carga Tumoral
19.
Br J Radiol ; 93(1107): 20190359, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31692372

RESUMO

Proton radiation therapy has been used clinically since 1952, and major advancements in the last 10 years have helped establish protons as a major clinical modality in the cancer-fighting arsenal. Technologies will always evolve, but enough major breakthroughs have been accomplished over the past 10 years to allow for a major revolution in proton therapy. This paper summarizes the major technology advancements with respect to beam delivery that are now ready for mass implementation in the proton therapy space and encourages vendors to bring these to market to benefit the cancer population worldwide. We state why these technologies are essential and ready for implementation, and we discuss how future systems should be designed to accommodate their required features.


Assuntos
Previsões , Marketing de Serviços de Saúde , Neoplasias/radioterapia , Posicionamento do Paciente , Terapia com Prótons/métodos , Terapia com Prótons/tendências , Radioterapia de Intensidade Modulada/métodos , Absorção de Radiação , Calibragem , Humanos , Neoplasias/diagnóstico por imagem , Movimentos dos Órgãos , Radioterapia Guiada por Imagem/métodos , Respiração , Fatores de Tempo , Incerteza
20.
Br J Radiol ; 93(1107): 20190638, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31845816

RESUMO

OBJECTIVE: To evaluate dosimetric consequences of inter-fraction setup variation and anatomical changes in patients receiving multifield optimised (MFO) intensity modulated proton therapy for post-operative oropharyngeal (OPC) and oral cavity (OCC) cancers. METHODS: Six patients receiving MFO for post-operative OPC and OCC were evaluated. Plans were robustly optimised to clinical target volumes (CTVs) using 3 mm setup and 3.5% range uncertainty. Weekly online cone beam CT (CBCT) were performed. Planning CT was deformed to the CBCT to create virtual CTs (vCTs) on which the planned dose was recalculated. vCT plan robustness was evaluated using a setup uncertainty of 1.5 mm and range uncertainty of 3.5%. Target coverage, D95%, and hotspots, D0.03cc, were evaluated for each uncertainty along with the vCT-calculated nominal plan. Mean dose to organs at risk (OARs) for the vCT-calculated nominal plan and relative % change in weight from baseline were evaluated. RESULTS: Robustly optimised plans in post-operative OPC and OCC patients are robust against inter-fraction setup variations and range uncertainty. D0.03cc in the vCT-calculated nominal plans were clinically acceptable across all plans. Across all patients D95% in the vCT-calculated nominal treatment plan was at least 100% of the prescribed dose. No patients lost ≥10% weight from baseline. Mean dose to the OARs and max dose to the spinal cord remained within tolerance. CONCLUSION: MFO plans in post-operative OPC and OCC patients are robust to inter-fraction uncertainties in setup and range when evaluated over multiple CT scans without compromising OAR mean dose. ADVANCES IN KNOWLEDGE: This is the first paper to evaluate inter-fraction MFO plan robustness in post-operative head and neck treatment.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Neoplasias Bucais/radioterapia , Neoplasias Orofaríngeas/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Idoso , Carcinoma de Células Escamosas/diagnóstico por imagem , Fracionamento da Dose de Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Neoplasias Orofaríngeas/diagnóstico por imagem , Projetos Piloto , Cuidados Pós-Operatórios , Estudos Retrospectivos , Medula Espinal/efeitos da radiação , Incerteza
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