Feasibility assessment of Halcyon 3.0 dual-isocenter IMRT plan in postoperative radiotherapy of radical mastectomy for left side of breast cancer / 中国医学装备

Objective:To assess the feasibility of the designed dual-isocenter IMRT plans based on Halcyon 3.0 linear accelerator in postoperative radiotherapy of radical mastectomy for left side of breast cancer.Methods:A total of sixteen patients received the postoperative radiotherapy of radical mastectomy for left side of breast cancer at Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from December 2022 to June 2023 were retrospectively selected.The dual-isocenter plans based respectively on Halcyon 3.0 linear accelerator and Truebeam linear accelerator were designed,and the dosimetric parameters included conformity index(CI)values of target region,homogeneity index(HI)values and doses to organs at risk(OAR)of the two plans were calculated as statistic method.And then,the dosimetric performance of Halcyon 3.0 dual-isocenter plan was compared and analyzed.Utilizing two dose verification tools,ArcCHECK and Portal Dosimetry,to assess the precision of beam delivery of Halcyon 3.0 dual-isocenter plan.Results:The Halcyon dual-isocenter plan and the Truebeam single-isocenter plan had similar plan quality.There were not statistically significant differences(P>0.05)in dosimetric parameters such as CI,HI,exposure dose to 2%of the target volume(D2%)and exposure dose to 98%of the target volume(D98%).Compared to the average monitor unit(MU)of Truebeam single-isocenter plan,the MU values of Halcyon 3.0 dual-isocenter plan increased by 366 MU,while the difference was not statistically significant(P>0.05).The Halcyon 3.0 dual-isocenter plan provided comprehensive protection for OAR,which was better than that of the Truebeam single-isocenter plan.The values of the left side of lung volume(V20)that were covered by 20 Gy dose of the Halcyon 3.0 dual-isocenter plan and the Truebeam single-isocenter plan were respectively 20.41%±1.56%and 24.88%±2.95%,and the difference was statistically significant(t=6.413,P<0.05).There were not significant differences in other OAR dosimetric parameters between the two kinds of plans(P>0.05).The verification pass rates of the Halcyon 3.0 dual-isocenter plans on the ArcCHECK and Portal Dosimetry platforms were respectively 97.6%-98.9%and 98.1%-100%when the ratio of dose tolerance(DT)to distance to agreement(DTA)was set at 2%/2 mm.The verification pass rates of the Halcyon 3.0 dual-isocenter plans on the ArcCHECK and Portal Dosimetry platforms were respectively 99.1%-100%and 99.7%-100%when DT/DTA was set at 3%/3 mm.The beam delivery precision of the Halcyon 3.0 dual-isocenter plan could meet verification standards of clinical treatments.Conclusion:The Halcyon 3.0 dual-isocenter IMRT plan demonstrates a higher feasibility in the postoperative radiotherapy of radical mastectomy for left side of breast cancer.The precision of dose delivery of plan is high,and the dose of target area is sufficient,uniform and favorable conformability.It can effectively limit the OAR exposure dose at the same time.

Acceptance testing and clinical assessment of the in-vivo dose measurement EPIgray system / 中国医学装备

Objective:To assess the accuracy of dose reconstruction of the in-vivo dose verification EPIgray system in intensity-modulated radiation therapy(IMRT)and volumetric-modulated arc therapy(VMAT)through acceptance testing,and to explore the preliminarily clinical application of that.Methods:A total of 37 patients with cancer at various parts were selected for clinical testing.Referring to the suggestions of the acceptance manual of manufacturer and the American Association of Physicists in Medicine(AAPM)TG-119 report,the square field,strip field and intensity-modulated plan were adopted to test the precision of dose reconstruction of EPIgray system on phantom.The recognition ability of the system for error was researched through changed the thickness of homogeneous phantom and the skin distance of exposure source.A total of 37 patients with cancer at different parts who underwent VMAT were selected to conduct clinical test,and then,the consistence between the dose reconstruction of EPIgray system and the counted dose of treatment plan system were further analyzed.Results:In the tests of square field,EPIgray dose reconstruction demonstrated excellent linearity and higher accuracy.On the phantoms with different thicknesses of fields with different sizes,the highest precision of dose reconstruction of central axis of field was(0.10±0.39)%.The all precisions of dose reconstruction were within 3.0%besides the built region of dose and field edges.In the tests of IMRT and VMAT plan,the deviation of dose reconstruction was<5.0%.With the increasing of the complexity of plan and the heterogeneity of phantom,there was a slight decrease in the reconstruction precision,but all deviations of dose reconstruction were within the range of allowable deviations.In clinical testing of 37 patients,the average reconstruction deviation of the prescription dose point was(-0.6±4.8)%,and the average deviation of sampling points within the range of target area was(-2.1±2.7)%.The reconstruction deviations outside of field and that with large dose gradient were larger.Conclusion:The dose reconstructions of in-vivo dose verification system EPIgray has better consistency with treatment planning system in calculating dose,and the precision of dose reconstruction can meet the requirement of clinical application.

Dosimetric study on middle ear with three whole-brain radiotherapy techniques / 中国辐射卫生

Objective This study aims to compare the advantages and disadvantages of the three techniques in improving the target volume dose and protecting the auris media cavity and eustachian tube isthmus region by investigating the dosimetric differences of three whole-brain radiotherapy techniques. Methods Thirty patients with whole brain metastases were randomly selected to design fixed field intensity modulated radiotherapy (ff-IMRT) plan, volumetric arc modulated therapy (VMAT) and three-dimensional conformal radiotherapy (3DCRT) plan, and to meet a 95% PTV prescription dose (40 Gy). The dosimetric parameters and monitor units of the target volume and organ at risk (OAR) in the three groups of treatment plans were compared and analyzed. Results The Conformity Index (CI) of the ff-IMRT plan (0.93 ± 0.02) was better than the VMAT plan (0.89 ± 0.01) and the 3DCRT plan (0.73 ± 0.03), respectively, and the difference was statistically significant (P < 0.05). The Homogeneity Index (HI) of the three plans were ff-IMRT (0.05 ± 0.01)、VMAT(0.08 ± 0.1) and 3DCRT (0.08 ± 0.01), respectively, and the difference was not statistically significant (P > 0.05). The Gradient Index (GI) were ff-IMRT (1.77 ± 0.1), VMAT (1.61 ± 0.07), 3DCRT (1.39 ± 0.08), respectively. The difference was statistically significant (P < 0.05). The monitor units (MU) were ff-IMRT (1551.97 ± 85.02), VMAT (303.7 ± 24.28) and 3DCRT (226.2 ± 2.5), respectively, the difference was statistically significant (P < 0.05). The Dmax of the middle ear of the three plans were ff-IMRT (2557.54 ± 477.39) cGy, VMAT (3107.9 ± 362.28) cGy, 3DCRT (4055.37 ± 71.45) cGy, respectively. The Dmax of the eustachian tube isthmus were ff-IMRT (2425 ± 380.4) cGy, VMAT (2902.4 ± 526.3) cGy and 3DCRT (3862.7 ± 135.9) cGy, the difference were statistically significant (P < 0.05). Conclusion In whole-brain radiotherapy, ff-IMRT and VMAT significantly reduced the dose of the bilateral middle ear cavities and eustachian tube isthmus compared with 3DCRT. VMAT is recommended for WBRT for reducing the number of monitor units significantly.

Dosimetric evaluation of 6 MV and 18 MV intensity-modulated radiotherapy plans for treatment of carcinoma of the cervix

Introduction: Cervical cancer (Ca Cx) is the fourth most frequent cancer in women with an estimated 57000 new cases in 2018 representing 6.6% of all female cancers. Approximately 90% of deaths from cervical cancer occurred in low- and middle-income countries. Material and Methods: A retrospective radiotherapy treatment planning comparative study conducted at the Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Bangalore during June 2018- March 2019. Result: All the plans were normalized to 100 % at Target mean to achieve a similar target dose for quantitative comparison of DVHs. The results for target coverage, OAR sparing, integral dose, and monitoring units. Conclusions: The tradeoff of using 6 MV and 18 MV for cervix patients depends on many parameters. Since the same PTV coverage was forced for both energies by having the same optimization constraints, there was little difference in target coverage and conformity index for both energies.

Irradiated dose to unprotected lymph node stations in the VMAT and IMRT treatment of patients with upper thoracic esophageal cancer / 中华放射医学与防护杂志

Objective@#To compare the irradiated dose to unprotected lymph node stations (LNS) between volume-modulated arc therapy (VMAT) and 5-field intensity-modulated radiotherapy (5F-IMRT) in the treatment of patients with upper thoracic esophageal cancer.@*Methods@#A total of 20 patients were selected for re-planning. LNS were not included in the GTV and CTV, instead, LNS were contoured as normal tissues. However, LNS were not constrained in the VMAT and 5F-IMRT inverse optimization for protection. Dosimetric parameters of conformal index (CI), homogeneity index (HI) of targets, V95, V110 of planning target volume (PTV), Dmean, V5, V20, V30 of lung, Dmean, V25 of heart, Dmax of spinal cord, MU, as well as the equivalent uniform dose (EUD) and V40 of LNS were compared between the two plans.@*Results@#5F-IMRT was superior in PTV_V95% (t=-9.4, P<0.05), but worse in terms of CI (t=-5.3, P<0.05) compared with VMAT. 5F-IMRT reduced the V5 of lung by 10.9% (t=-7.8, P<0.05) and the Dmax of spinal cord by 9% (t=-10.2, P<0.05), but increased the MU (t=-6.2, P<0.05) compared with VMAT. The average EUD and V40 of LNS in upper thoracic were significantly increased by 4.7% and 2.4% in 5F-IMRT compared with VMAT, respectively. The irradiated doses to LNS were significantly associated with the volume of PTV (R=0.716-0.933, P<0.05) expect for 106tbL.@*Conclusions@#The irradiated doses to unprotected LNS were less for IMRT plans and were highly associated with PTV volume in patients with upper thoracic esophageal cancer.

Irradiated dose to unprotected lymph node stations in the VMAT and IMRT treatment of patients with upper thoracic esophageal cancer / 中华放射医学与防护杂志

Objective To compare the irradiated dose to unprotected lymph node stations (LNS) between volume-modulated arc therapy (VMAT) and 5-field intensity-modulated radiotherapy (5F-IMRT) in the treatment of patients with upper thoracic esophageal cancer.Methods A total of 20 patients were selected for re-planning.LNS were not included in the GTV and CTV,instead,LNS were contoured as normal tissues.However,LNS were not constrained in the VMAT and 5F-IMRT inverse optimization for protection.Dosimetric parameters of conformal index (CI),homogeneity index (HI) of targets,V95,V110 of planning target volume (PTV),D V5,V20,V30 of lung,D V25 of heart,Dmax of spinal cord,MU,as well as the equivalent uniform dose (EUD) and V40 of LNS were compared between the two plans.Results 5F-IMRT was superior in PTV_ V95％ (t=-9.4,P＜0.05),but worse in terms of CI (t=-5.3,P＜0.05) compared with VMAT.5F-IMRT reduced the V5 of lung by 10.9％ (t=-7.8,P＜0.05) and the Dmax of spinal cord by 9％ (t=-10.2,P＜0.05),but increased the MU (t=-6.2,P＜0.05) compared with VMAT.The average EUD and V40 of LNS in upper thoracic were significantly increased by 4.7％ and 2.4％ in 5F-IMRT compared with VMAT,respectively.The irradiated doses to LNS were significantly associated with the volume of PTV (R =0.716-0.933,P＜0.05) expect for 106tbL.Conclusions The irradiated doses to unprotected LNS were less for IMRT plans and were highly associated with PTV volume in patients with upper thoracic esophageal cancer.

Dosimetric parameters of heart and left ventricle – comparison of 3D CRT and IMRT in left cancer breast

Background: Conformal Radiotherapy techniques adapting to the ballistics of delineated volumes allowed significant reduction in excess radiation induced mortality however the increasing number of long-term survivors and expanding use of cardiotoxic drug highlight the persistent need for maximal cardiac possible sparing. The low dose volume of left ventricle are better predictor of acute coronary events than mean heart dose. Materials and Methods: 38 post-MRM patients were randomized to treatment by 3Dimensional Conformal Radiotherapy (3D CRT) and Intensity Modulated Radiotherapy (IMRT) technique. Two tangential beams were used in 3D CRT technique while five to seven (mostly tangential beams) were used in inversely planned IMRT technique. The dose volume parameters of planning target volume, heart and left ventricle were compared. Results: The dosimetry of Planning target volume showed significantly better coverage in IMRT technique (D90, D95) however the D50 was comparable in both the techniques. In dosimetry of heart, the high dose volumes (V30, V40) were nearly comparable in both the techniques. The other dose volume parameters (V5, V10, V20, V25, D33, D67, D100) and the mean dose were significantly lesser in 3D CRT technique along with significantly better sparing of left ventricle (Dmean and V5). Conclusion: The dosimetry of target volume was better with IMRT technique, but this was accompanied by a huge increase in dose to whole heart and specifically the left ventricle which has strong potential to translate into an increased cardiotoxicity. A better distribution of the target region may be obtained by multiple segmentation of the two tangential fields in 3D CRT plans with further reduction in dose to heart and left ventricle.

Evaluation of Feasibility and Toxicity of Intensity Modulated Radiotherapy in Post-Operative Cases of Oral Cavity Cancer

Background: The combined modality approach incorporating surgery, radiotherapy(RT) and chemotherapy ( CT) forms the corner-stone of management of locally advanced head and neck squamous cell carcinoma(HNSCC). Intensity modulated radiotherapy (IMRT) is an advanced RT technique where large dose of radiation could be delivered to precisely defined target volumes while reducing dose to surrounding OARs It can be delivered in sequential manner or as simultaneous integrated boost(SIB). Aim – The aim of this study was to evaluate the feasibility and toxicity of of IMRT-SIB in post-operative cases of head and neck squamous cell carcinoma (HNSCC). Methods: This was a retrospective study done on 20 patients of HNSCC who received adjuvant RT with IMRT-SIB. Data was analysed for various dosimetric parameters and toxicity profile of patients. Toxicities were recorded using RTOG acute radiation morbidity scoring criteria. Toxicities were evaluated weekly during RT and monthly up to 3 months after RT completion. Results: The median age was 40.5 years WITH 80% patients having locally advanced disease (stage III and IV). Eleven patients received concurrent cisplatin weekly. Majority (60%) of patients developed Gr 1 mucositis with maximum being grade 3 seen in 1 patient. Maximum skin toxicity that appeared was Grade 2; found in 10% patients. Xerostomia was Grade 2 in 75% patients . Sixty percent of patients experienced Grade 2 dysphagia while 15% grade 3. Seventy five percent patients were treated with dose schedule of 66/60/54 Gy in 33# while remaining with 60/54 in 30#.the dose received by organ at risk(OAR) were within normal limits in all the patients. Conclusions: IMRT with SIB can be safely delivered in post-operative squamous cell carcinoma of oral cavity with acceptable toxicity.

Dosimetric Comparison of IMRT and Rapid ARC for High Grade Gliomas

High grade gliomas are common intracranial tumors and adjuvant radiotherapy after maximal safe surgical resection is the cornerstone of the management. Aim: The aim of the present study was to compare the dose distribution characteristics in patients with high grade gliomas planned with Intensity-modulated radiotherapy (IMRT) and Rapid Arc (RA). Methods: Two plan sets by IMRT and RA were generated for each patient on planning Computed Tomography (CT) data sets and were then compared. Results: Total dose prescribed was 60 Gy given in biphasic manner as per Radiation Therapy Oncology Group (RTOG) guidelines guidelines. Planning Target Volume (PTV) coverage (mean values) for IMRT was found 98% and 96% for RA. Conformity Index (CI) was 1.3 for RA, 1.2 for IMRT. Homogeneity Index (HI) was found to be 1.03 for IMRT, 1.04 for RA. Dose maximum (Dmax) for the PTV was equal for IMRT and RA (106%). Conclusions: The dose to Organ at Risks (OARs) was within the acceptable limits and comparable in both the techniques, however RA augments shorter treatment time.

Assessment Of Set Up Errors And Determination Of Planning Target Volume Margins In Image Guided Radiotherapy For Cervical Cancer Patients Treated In Supine Position

BACKGROUND:Proper positioning of a patient during radiotherapy treatment delivery is crucial for successful implementation of a treatment plan ensuring maximum dose to the target while minimising the dose to the normal tissues. The purpose of this study is to assess the set up errors and to determine the optimal Clinical Target Volume (CTV) to Planning Target Volume (PTV) margins for Cervical Carcinoma patients treated in supine position by Image guided Radiotherapy.METHODS AND MATERIALS: 219 kVCBCTimages were acquired for 10 cervical cancer patients treated with Conformal External Beam Radiotherapy using Image Guidance. Daily set-up errors along the three translational directions were analysed, evaluated for systematic and random errors and optimal CTV-PTVmargin determined.RESULTS:Corresponding CTV-PTVmargins in the X, Yand Z directions were 0.7cm, 1.7cm and 0.4cm respectively.CONCLUSION:IGRTis imperative for ensuring adequate target volume coverage and eliminating geographic miss in IMRTtreatment

Study on dose accumulation in IMRT for left breast cancer patients after radical mastectomy / 中华放射医学与防护杂志

Objective@#To investigate the changes of accumulated dose in target area and organs at risk (OARs) for radiotherapy of left breast cancer by deformable and rigid image registration.@*Methods@#A total of 16 left breast cancer patients treated with 6 MV X-ray IMRT were analyzed retrospectively. All targets included the lymph node drainage area and the chest wall. All patients underwent simulation of the primary positioning and repositioning to obtain CT images. Primary and secondary treatment plans were developed using primary positioning CT (CT1) and repositioning CT (CT2), denoted as Plan1 and Plan2 respectively. The dose distribution of Plan2 was mapped to CT1 with rigid and deformable registration from CT2 to CT1 and then added to the dose distribution of Plan1 to obtain Plan-rigid and Plan-deform, respectively. The dosimetric differences between targets and the OARs of the four plans were compared.@*Results@#The CTV volume on CT2 was reduced by 6.64% from that on CT1. The homogeneity index (HI) increased by 23.05% after deformation-based accumulation. The Dice similarity coefficients (DSCs) of the heart, left lung and right lung were lower than those before deformable registration (0.94±0.01 vs. 0.89±0.05, 0.96±0.01 vs. 0.91±0.03, and 0.96±0.01 vs. 0.92±0.03, respectively), and the differences were statistically significant (Z=-3.208, -3.533, -3.535, P<0.05). There were no significant differences in dose-volume indices of heart and left lung between Plan1 with other plans(P>0.05), while the dose-volume indices in Plan-rigid were higher than that in Plan-deform.@*Conclusions@#Rigid registration is recommended in patients undergoing radical resection of left breast cancer with little change in the volume and dose-volume index of the target area and organs at risk. The dose-volume index of the initial intensity modulation plan can basically reflect the dose-volume statistics of both lungs and heart.

Discussion on the treatment model and prognostic analysis of esophageal squamous cell carcinoma treated with induction chemotherapy combined with intensity-modulated radiation therapy / 中华放射医学与防护杂志

Objective@#To analyze the therapeutic effect and prognostic factors of induction chemotherapy plus intensity-modulated radiotherapy (IMRT) with or without consolidation chemotherapy for esophageal squamous cell carcinoma (ESCC).@*Methods@#One hundred and eight patients with ESCC treated between January 2010 to August 2014 were analyzed retrospectively. All patients received IMRT and platinum-based chemotherapy. The overall survival (OS) and local control (LC) rates were calculated using the Kaplan-Meier method and the univariate prognostic analyses were tested by the Log-rank test. The Cox proportional hazard model was used for multivariate prognostic analysis.@*Results@#The follow-up rate was 97.2%. The 1-, 3- and 5-year survival rates were 76.9%, 50.9% and 32.3% respectively, and the LC rates were 73.6%, 58.5% and 54.9% respectively. The median OS with and without consolidation chemotherapy were 51 and 15 months (χ2=5.076, P=0.024), respectively. Multivariate analysis showed that clinical N staging, recent curative effect and consolidation chemotherapy were important prognostic factors for OS, and recent curative effect was associated with LC. The rates of acute grade 3 radiation-induced esophagitis, gastrointestinal side effects, myelosuppression and radiation-induced pulmonary injury were 7.4%, 6.5%, 12% and 0.9%, respectively, and no grade 4 occurred. The late toxicity was mainly radiation-induced pulmonary fibrosis.@*Conclusions@#Induction chemotherapy plus IMRT with or without consolidation chemotherapy is safe and effective in the treatment of ESCC. The addition of consolidation chemotherapy may help prolong the survival of some patients and further research is necessary. Individualized treatment should be selected for patients who cannot tolerate or refuse concurrent chemoradiotherapy.

Study on dose accumulation in IMRT for left breast cancer patients after radical mastectomy / 中华放射医学与防护杂志

Objective To investigate the changes of accumulated dose in target area and organs at risk (OARs) for radiotherapy of left breast cancer by deformable and rigid image registration.Methods A total of 16 left breast cancer patients treated with 6 MV X-ray IMRT were analyzed retrospectively.All targets included the lymph node drainage area and the chest wall.All patients underwent simulation of the primary positioning and repositioning to obtain CT images.Primary and secondary treatment plans were developed using primary positioning CT (CT1) and repositioning CT (CT2),denoted as Plan1 and Plan2 respectively.The dose distribution of Plan2 was mapped to CT1 with rigid and deformable registration from CT2 to CT1 and then added to the dose distribution of Planl to obtain Plan-rigid and Plan-deform,respectively.The dosimetric differences between targets and the OARs of the four plans were compared.Results The CTV volume on CT2 was reduced by 6.64％ from that on CT1.The homogeneity index (HI)increased by 23.05％ after deformation-based accumulation.The Dice similarity coefficients (DSCs) of the heart,left lung and right lung were lower than those before deformable registration (0.94±0.01 vs.0.89± 0.05,0.96±0.01 vs.0.91±0.03,and 0.96±0.01 vs.0.92±0.03,respectively),and the differences were statistically significant (Z =-3.208,-3.533,-3.535,P ＜ 0.05).There were no significant differences in dose-volume indices of heart and left lung between Plan1 with other plans (P＞0.05),while the dose-volume indices in Plan-rigid were higher than that in Plan-deform.Conclusions Rigid registration is recommended in patients undergoing radical resection of left breast cancer with little change in the volume and dose-volume index of the target area and organs at risk.The dose-volume index of the initial intensity modulation plan can basically reflect the dose-volume statistics of both lungs and heart.

Discussion on the treatment model and prognostic analysis of esophageal squamous cell carcinoma treated with induction chemotherapy combined with intensity-modulated radiation therapy / 中华放射医学与防护杂志

Objective To analyze the therapeutic effect and prognostic factors of induction chemotherapy plus intensity-modulated radiotherapy (IMRT) with or without consolidation chemotherapy for esophageal squamous cell carcinoma (ESCC).Methods One hundred and eight patients with ESCC treated between January 2010 to August 2014 were analyzed retrospectively.All patients received IMRT and platinum-based chemotherapy.The overall survival (OS) and local control (LC) rates were calculated using the Kaplan-Meier method and the univariate prognostic analyses were tested by the Log-rank test.The Cox proportional hazard model was used for multivariate prognostic analysis.Results The follow-up rate was 97.2％.The 1-,3-and 5-year survival rates were 76.9％,50.9％ and 32.3％ respectively,and the LC rates were 73.6％,58.5％ and 54.9％ respectively.The median OS with and without consolidation chemotherapy were 51 and 15 months (x2 =5.076,P=0.024),respectively.Multivariate analysis showed that clinical N staging,recent curative effect and consolidation chemotherapy were important prognostic factors for OS,and recent curative effect was associated with LC.The rates of acute grade 3 radiation-induced esophagitis,gastrointestinal side effects,myelosuppression and radiation-induced pulmonary injury were 7.4％,6.5％,12％ and 0.9％,respectively,and no grade 4 occurred.The late toxicity was mainly radiation-induced pulmonary fibrosis.Conclusions Induction chemotherapy plus IMRT with or without consolidation chemotherapy is safe and effective in the treatment of ESCC.The addition of consolidation chemotherapy may help prolong the survival of some patients and further research is necessary.Individualized treatment should be selected for patients who cannot tolerate or refuse concurrent chemoradiotherapy.

Comparación Clínica de radioterapia de intensidad modulada vs. radioterapia 3D en tratamiento neoadyuvante del cáncer de recto localmente avanzado / Clinical comparison of intensity modulated radiotherapy vs. 3D radiotherapy in neoadjuvant treatment of locally advanced rectal cancer

El objetivo de este trabajo fue comparar ventajas potenciales de la radioterapia de intensidad modulada (IMRT) vs. la radioterapia 3D (3DRT) en el control loco-regional y la toxicidad aguda en pacientes con cáncer de recto localmente avanzado (CRLA). Se analizaron retrospectivamente 235 pacientes con adenocarcinoma de recto T2/T4 y N0/N1 sometidos a radioquimioterapia neoadyuvante entre febrero de 2010 y agosto de 2015. La modalidad radiante se correlacionó con los resultados clínicos (control local y a distancia) y las tasas de toxicidades agudas urinarias, hematológicas, gastrointestinales (GI) y dérmicas. Ciento cuarenta (59.6%) recibieron IMRT y 95 (40.4%) 3DRT. La mediana de seguimiento fue de 36 meses. Las tasas de recidiva local y metástasis a distancia fueron similares entre IMRT y 3DRT. No se encontraron diferencias estadísticamente significativas en control local (CL) ni en supervivencia global (SG) entre IMRT y 3DRT (p=0.56 y p=0.24, respectivamente), ni en colostomía libre para tumores rectales bajos (p=0.44). IMRT implicó menor toxicidad cutánea (p<0.001), hematológica (p<0.0001), urinaria (p=0.0017), y gastrointestinal (p=0.0006). La incidencia de diarrea grado ≥ 3 fue del 16% entre los pacientes del grupo 3DRT frente al 5% de del grupo IMRT. En el análisis univariado, el estadio clínico T, edad, KPS, y quimioterapia adyuvante se asociaron con mejor SG (todos p<0.05) y la dosis total de radiación se asoció con mejor período libre de enfermedad (p=0.0065) Postulamos que IMRT permitiría un aumento de dosis en forma segura con el potencial de aumentar la tasa de respuestas patológicas completas (RPC), en particular en tumores rectales bajos (AU)

The aim was to compare the advantages of IMRT vs. 3D in loco regional control and acute toxicity in patients with locally advanced rectum cancer. We analyzed retrospectively 235 patients with rectal adenocarcinoma T2/T4 and N0/N1 undergoing chemo radiation between February 2010 and August 2015. The radiant modality was correlated with clinical outcomes (local and systemic control) and rates of acute urinary, hematological, gastrointestinal and dermal toxicities. One hundred and forty patients (59.6%) received IMRT and 95 (40.4%) received 3D. The median follow-up time was 36 months. The rates of local recurrence and distant metastases were similar between IMRT vs. 3D. No statistically significant differences were found in local control or survival between IMRT and 3D (p=0.56 and p =0.24, respectively), nor in free colostomy for low rectal tumors (p= 0.44). IMRT resulted in lower dermal (p<0.001), hematological (p<0.0001), urinary (p=0.0017), and gastrointestinal toxicity (p=0.0006). The incidence of diarrhea grade ≥ 3 was 16% among 3D patients vs. 5% in IMRT. In the univariate analysis, clinical stage T, age, KPS, and adjuvant chemotherapy were associated with better overall survival (all p<0.05) and the total dose of radiation was associated with better disease-free period (p=0.0065). We postulate that IMRT would allow us to increase dose in a safe manner with the potential to increase rate of complete pathological responses, particularly in low rectal tumors (AU)

Cáncer anal: resultados clínicos, toxicidades y supervivencia libre de colostomía comparando técnicas de radioterapia conformada tridimensional versus radioterapia de intensidad modulada / Anal cancer: clinical results, toxicities and colostomy-free survival comparing three-dimensional conformal radiotherapy techniques versus intensity modulated radiotherapy

Las técnicas definitivas de quimio-radioterapia para el cáncer anal, radioterapia tridimensional conformada (3DCRT) o radioterapia de intensidad modulada (IMRT) dan excelentes resultados a largo plazo. Evaluamos resultados en centros de radiación basados en la comunidad. Se evaluaron retrospectivamente 281 pacientes tratados con quimio-radioterapia definitiva para carcinoma anal loco-regional, entre 2006 y 2014. El 95% realizó quimioterapia. Se evaluaron datos de toxicidades, progresión de la enfermedad y necesidad de colostomía durante el período de seguimiento. La supervivencia global, supervivencia libre de progresión y colostomía libre se calcularon con métodos de Kaplan-Meier. La edad media fue 63.7 años con seguimiento medio de 60 meses. Ciento sesenta y nueve pacientes recibieron IMRT y 112 recibieron 3DCRT. La dosis total media tumoral fue 54 Gy. El 80% experimentó complicaciones agudas, y el 56% requirió interrupción de tratamiento. No hubo diferencias significativas en supervivencia global, supervivencia libre de progresión, supervivencia libre de colostomía ni control local a dos años entre ambos grupos. La IMRT tuvo menos suspensión del tratamiento (48% vs. 65%) (p=0.0261). El grupo IMRT tuvo una reducción significativa de todas las toxicidades agudas ≥3 y gastrointestinales (GI) tardías, en comparación con los tratados con 3DCRT. Esta serie representa una de las mayores comparaciones 3DCRT vs. IMRT para el tratamiento definitivo de cáncer anal. Los resultados a largo plazo no difieren significativamente en función de la técnica de radioterapia (RT). La IMRT reduce todas las toxicidades ≥ grado 3 y la necesidad de interrupción en comparación con 3DCRT (AU)

The definitive techniques of chemo-radiotherapy for anal cancer, 3DCRT or IMRT, give excellent long-term results. We evaluated results in community-based radiation centers. We retrospectively evaluated 281 patients treated with definitive chemo-radiotherapy for locoregional anal carcinoma, between 2006 and 2014. The 95% performed chemotherapy. Toxicity data, progression of the disease, need of colostomy during the follow-up period were evaluated. Global survival (GS), progression free survival (PFS), and free colostomy survival (CFS) were calculated with Kaplan-Meier methods. Mean age was 63.7 years with a mean follow-up of 60 months. One hundred and sixty nine patients received IMRT and 112 received 3DCRT. The total mean tumor dose was 54 Gy. The 80% experienced acute complications, and 56% required treatment interruption. There was no significant difference in GS, PFS, CFS or local control at two years between both groups. The IMRT had less treatment discontinuation (48% vs. 65%) (p = 0.0261). The IMRT group had a significant reduction in all acute toxicities ≥3 and late gastrointestinal, compared with those treated with 3DCRT. This series represents one of the largest 3DCRT vs. IMRT comparisons for the definitive treatment of anal cancer. The long-term results do not differ significantly depending on the RT technique. The IMRT reduces all toxicities ≥ grade 3 and the need for interruption compared to 3DCRT (AU)

Dosimetric study on radiotherapy for brain metastasis / 实用医学杂志

Objective To investigate the feasibility of sequential intensity-modulated radiotherapy (sIMRT)and simultaneously integrated boost intensity-modulated radiotherapy(SIB-IMRT)in the radiotherapy of brain metastasis,the dosimetric difference of target volumes and organs at risk(OARs). Methods Twenty pa-tients diagnosed as brain metastasis were randomly selected,with SIB-IMRT and sIMRT programs developed for each patient. Dosimetric differences between target areas and OARs were compared between the two radiotherapy protocols. Results Compared with sIMRT,SIB-IMRT had no significant difference in the average irradiation dose of the brainstem[(42.69 ± 2.18)Gy vs.(41.98 ± 0.96)Gy]and homogeneity index(HI)(1.46 ± 0.04 vs.1.42 ± 0.13)of P-CTV(P > 0.05). However,SIB-IMRT plan achieved higher than sIMRT in the conformation index (CI)(0.68 ± 0.05 vs. 0.44 ± 0.04)and HI(1.03 ± 0.01 vs. 1.06 ± 0.01)of P-GTV. Meanwhile,both maximum exposure dose of OARs and CI of P-CTV(0.68 ± 0.05 vs.0.44 ± 0.04)of SIB-IMRT were significant in comparison with sIMRT(P<0.05).Conclusions Both radiotherapies can meet target coverage and dose requirements.Com-pared to sIMRT technique,SIB-IMRT technique can decrease effectively the exposure dose of surrounding organs, and can give the tumor target more uniform physical dose conformation.

Set-up errors in head and neck cancer treated with IMRT technique assessed by cone-beam computed tomography: a feasible protocol

PURPOSE: To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). METHODS: We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3–5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (∑) and random (σ) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula (2.5∑ + 0.7r). RESULTS: The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0–9 mm in ML direction, 0–5 mm in SI direction and 0–10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. CONCLUSION: Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3–5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.

Trends in intensity-modulated radiation therapy use for rectal cancer in the neoadjuvant setting: a National Cancer Database analysis

PURPOSE: Traditionally, three-dimensional conformal radiation therapy (3D-CRT) is used for neoadjuvant chemoradiation in locally advanced rectal cancer. Intensity-modulated radiation therapy (IMRT) was later developed for more conformal dose distribution, with the potential for reduced toxicity across many disease sites. We sought to use the National Cancer Database (NCDB) to examine trends and predictors for IMRT use in rectal cancer. MATERIALS AND METHODS: We queried the NCDB from 2004 to 2015 for patients with rectal adenocarcinoma treated with neoadjuvant concurrent chemoradiation to standard doses followed by surgical resection. Odds ratios were used to determine predictors of IMRT use. Univariable and multivariable Cox regressions were used to determine potential predictors of overall survival (OS). Propensity matching was used to account for any indication bias. RESULTS: Among 21,490 eligible patients, 3,131 were treated with IMRT. IMRT use increased from 1% in 2004 to 22% in 2014. Predictors for IMRT use included increased N stage, higher comorbidity score, more recent year, treatment at an academic facility, increased income, and higher educational level. On propensity-adjusted, multivariable analysis, male gender, increased distance to facility, higher comorbidity score, IMRT technique, government insurance, African-American race, and non-metro location were predictive of worse OS. Of note, the complete response rate at time of surgery was 28% with non-IMRT and 21% with IMRT. CONCLUSION: IMRT use has steadily increased in the treatment of rectal cancer, but still remains only a fraction of overall treatment technique, more often reserved for higher disease burden.

Comparison of simultaneous integrated boost and late course boost intensity-modulated radiation therapy in the treatment of esophageal carcinoma / 中华放射医学与防护杂志

Objective To analyze and compare the outcomes of esophageal carcinoma treated with simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) and late course boost intensity-modulated radiation therapy (LCB-IMRT).Methods We retrospectively analyzed 128 patients with esophageal squamous cell carcinoma who were treated with SIB-IMRT or LCB-IMRT at the fifth department of radiation oncology in our hospital,from January 2009 to August 2015.Propensity score matching analysis was used to balance the variables differences in the two groups.Survival,failure patterns and toxicities were observed and compared between the two groups.Results one hundred and eleven patients were finally included after propensity scores matching.The 1-,3-and 5-year local control rates and survival rates were 83.6％ vs.81.7％,70.8％ vs.46.3％ and 66.0％ vs.38.2％ in the whole group,respectively.The 1-,3-and 5-year local control rates of SIB-IMRT and LCB-IMRT group were 81.6％ vs.88.0％,72.3％ vs.67.6％ and68.5％ vs.60.8％,respectively (P＞0.05).The 1-,3-and 5-year survival rates of SIB-IMRT and LCB-IMRT group were 81.3％ vs.82.4％,51.7％ vs.36.7％ and 45.8％ vs.26.7％,respectively (P ＞ 0.05).There was no statistical difference between the two group in ≥ grade 3 toxicities (P ＞ 0.05).There were 40 (36.0％) patients result in treatment failure in all.The treatment failure rates in SIB-IMRT and LCB-IMRT group were 33.8％ (26/77) vs.41.2％ (14/34),respectively (P ＞ 0.05).The local failure accounted for 65.0％ (26/40) of all treatment-related failures.Conclusions The toxicities of esophageal squamous cell carcinoma treated with SIB-IMRT and LCB-IMRT have no significant differences and were well tolerated.There were no significant differences in local control rates and survival rates between the two groups.However,SIB-IMRT had better trend than LCB-IMRT.Given SIB-IMRT's convenient manipulation,it could be a better choice in the treatment of advanced esophageal carcinoma.