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The role of prophylactic cranial irradiation (PCI) and thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer remains controversial. The authors examined the National Cancer Database and identified patients with extensive-stage small cell lung cancer with no brain metastasis. Patients were excluded if they died 30 days from diagnosis, did not receive polychemotherapy, had other palliative radiation or had missing information. A propensity score-matched analysis was also performed. A total of 21,019 patients were identified. The majority of patients did not receive radiation (69%), whereas 10% received PCI and 21% received TRT. The addition of PCI and TRT improved median survival and survival at 1 and 2 years (p ≤ 0.05). The propensity score-matched analysis confirmed the same overall survival benefit with both PCI and TRT. This registry-based analysis of >1500 accredited cancer programs shows that PCI and TRT are not commonly utilized for extensive-stage small cell lung cancer patients who are treated with multiagent chemotherapy. The addition of PCI and TRT significantly improves overall survival in this otherwise poor prognostic group. Further research is needed to confirm the role of PCI and TRT, especially in the era of improved systemic therapy.
Lay abstract The role of radiation therapy in patients with metastatic small cell lung cancer remains controversial. The authors examined the National Cancer Database and identified patients with metastatic small cell lung cancer without brain metastasis. Patients were excluded if they died 30 days from diagnosis, did not receive multiagent chemotherapy, had other palliative radiation or had missing information regarding treatment. A total of 21,019 patients were identified. The majority of patients did not receive radiation (69%), whereas 10% received radiation to the brain and 21% received radiation to their lungs. The addition of brain and lung radiation therapy improved median survival and survival at 1 and 2 years. The addition of prophylactic cranial irradiation and thoracic radiation therapy improves survival in extensive-stage small cell lung cancer. Future research is needed to evaluate the role of radiation in the era of chemoimmunotherapy.
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Neoplasias Encefálicas/prevención & control , Quimioradioterapia/estadística & datos numéricos , Irradiación Craneana/estadística & datos numéricos , Neoplasias Pulmonares/terapia , Carcinoma Pulmonar de Células Pequeñas/prevención & control , Adulto , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/secundario , Quimioradioterapia/métodos , Bases de Datos Factuales/estadística & datos numéricos , Femenino , Estudios de Seguimiento , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pautas de la Práctica en Medicina/estadística & datos numéricos , Pronóstico , Sistema de Registros/estadística & datos numéricos , Estudios Retrospectivos , Carcinoma Pulmonar de Células Pequeñas/diagnóstico , Carcinoma Pulmonar de Células Pequeñas/mortalidad , Carcinoma Pulmonar de Células Pequeñas/secundario , Análisis de Supervivencia , Estados Unidos/epidemiología , Adulto JovenRESUMEN
Major categories of radiotherapy (RT) for prostate cancer (CaP) treatment are: (1) external beam RT (EBRT), and (2) brachytherapy (BT). EBRT are performed using different techniques like three-dimensional conformal RT (3D-CRT), intensity modulated RT (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic body radiation therapy (SBRT), stereotactic radiosurgery (SRS) and intensity modulated proton therapy (IMPT), etc., using a variety of radiation delivery machines, such as a linear accelerator (Linac), Cyberknife robotic system, Gamma knife, Tomotherapy and proton beam machine. The primary advantage of proton beam therapy is sparing of normal tissues and organ at risks (OARs) with comparable coverage of the tumor volume. MR-Linac is the latest addition in the image-guided RT. Robot-assisted brachytherapy is one of the latest technological innovations in the field. With the advancement of technology, radiation therapy for prostate cancer can be improved using high quality multimodal imaging, robot-assistance for brachytherapy as well as EBRT. This chapter presents the advances in radiation therapy for the treatment of prostate cancer.
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Neoplasias de la Próstata/radioterapia , Radiocirugia , Radioterapia de Intensidad Modulada , Humanos , Masculino , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por ComputadorRESUMEN
PURPOSE: The addition of a braided bio-absorbable vicryl coating to the surface of radioactive seeds used for low dose rate (LDR) prostate brachytherapy is intended to reduce the incidence of seed movement and migration. Here, we present a single-institution study of the frequency and severity of seed slippage (initial seed movement) of coated seeds in comparison with uncoated seeds. METHODS: Forty-seven patients received permanent prostate brachytherapy, with either coated (n = 26) or uncoated (n = 21) seeds. AgX100 125 I seeds, coated or uncoated, and uncoated Model 200 103 Pd seeds were used. During the ultrasound-guided implantation procedure, each implanted seed was categorized as having remained in the implanted position after being placed, having moved slightly, or having left the ultrasound field of view. RESULTS: 3.1% of the coated seeds (AgX100 seeds, n = 70) and 6.9% of the uncoated seeds (AgX100 and Model 200 seeds, n = 128) were observed to have moved at least 2 mm from their initial implant positions, respectively. The difference in incidence of this movement was 54.4% (P = 0.0026). Coated AgX100 seeds demonstrated a 66.7% lower rate of movement of at least 2 mm than that for uncoated AgX100 seeds (P = 0.038), and a 49.0% lower rate than that for Model 200 seeds (P = 0.021). While no significant differences were noted in prescription dose coverage of the prostate or the studied dosimetric parameters for the organs at risk between the coated and uncoated seeds (P > 0.05) in the CT-based Day-0 postoperative plans, the limited sample size and differences in energies between the 125 I and 103 Pd seeds make further analysis of postoperative dosimetric coverage difficult without additional data directly comparing the coated and uncoated 125 I seeds. CONCLUSION: When the vicryl coating is used, seeds have a significantly lower propensity to slip from their initial implant locations. This may help maintain dosimetric integrity, warranting further study of postoperative dosimetry.
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Braquiterapia/instrumentación , Radioisótopos de Yodo/uso terapéutico , Movimiento (Física) , Siembra Neoplásica , Polímeros/química , Neoplasias de la Próstata/radioterapia , Prótesis e Implantes , Anciano , Estudios de Seguimiento , Migración de Cuerpo Extraño/diagnóstico por imagen , Humanos , Masculino , Pronóstico , Estudios Retrospectivos , Ultrasonografía/métodosRESUMEN
PURPOSE: We conducted this dosimetric analysis to evaluate the feasibility of a multi-center stereotactic body radiation therapy (SBRT) trial for renal cell carcinoma (RCC) using different SBRT platforms. MATERIALS/METHODS: The computed tomography (CT) simulation images of 10 patients with unilateral RCC previously treated on a Phase 1 trial at Institution 1 were anonymized and shared with Institution 2 after IRB approval. Treatment planning was generated through five different platforms aiming a total dose of 48 Gy in three fractions. These platforms included: Cyberknife and volumetric modulated arc therapy (VMAT) at institution 1, and Cyberknife, VMAT, and pencil beam scanning (PBS) Proton Therapy at institution 2. Dose constraints were based on the Phase 1 approved trial. RESULTS: Compared to Cyberknife, VMAT and PBS plans provided overall an equivalent or superior coverage to the target volume, while limiting dose to the remaining kidney, contralateral kidney, liver, spinal cord, and bowel. CONCLUSION: This dosimetric study supports the feasibility of a multi-center trial for renal SBRT using PBS, VMAT and Cyberknife.
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AIM: This systematic review summarizes the clinical data on focal therapy (FT) when used alone as definitive therapy for primary prostate cancer (PCa). METHODS: The protocol is detailed in the online PROSPERO database, registration No. CRD42014014765. Articles evaluating any form of FT alone as a definitive treatment for PCa in adult male patients were included. RESULTS: Of 10,419 identified articles, 10,401 were excluded, and thus leaving 18 for analysis. In total, 2288 patients were treated using seven modalities. The outcomes of FT in PCa seem to be similar to those observed with whole gland therapy and with fewer side effects. CONCLUSION: Further research, including prospective randomized trials, is warranted to elucidate the potential advantages of focal radiation techniques for treating PCa. Prospero Registration Number: CRD42014014765.
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Técnicas de Ablación , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/terapia , Técnicas de Ablación/efectos adversos , Técnicas de Ablación/métodos , Terapia Combinada , Humanos , Masculino , Estadificación de Neoplasias , Neoplasias de la Próstata/mortalidad , Resultado del TratamientoRESUMEN
A novel FDA approved in vivo dosimetry device system using plastic scintillating detectors placed in an endorectal balloon to provide real-time in vivo dosimetry for prostatic rectal interface was tested for use with stereotactic body radiotherapy (SBRT). The system was used for the first time ever to measure dose during linear accelerator based SBRT. A single patient was treated with a total dose of 36.25 Gy given in 5 fractions. Delivered dose was measured for each treatment with the detectors placed against the anterior rectal wall near the prostate rectal interface. Measured doses showed varying degrees of agreement with computed/ planned doses, with average combined dose found to be within 6% of the expected dose. The variance between measurements is most likely due to uncertainty of the detector location, as well as variation in the placement of a new balloon prior to each fraction. Distance to agreement for the detectors was generally found to be within a few millimeters, which also suggested that the differences in measured and calculated doses were due to positional uncertainty of the detectors during the SBRT, which had sharp dose falloff near the penumbra along the rectal wall. Overall, the use of a real time in vivo dosimeter provided a level of safety and improved confidence in treatment delivery. We are evaluating the device further in an IRB-approved prospective partial prostate SBRT trial, and believe further clinical investigations are warranted.
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Tomografía Computarizada de Haz Cónico/métodos , Dosimetría in Vivo/métodos , Neoplasias de la Próstata/cirugía , Radiocirugia/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Recto/efectos de la radiación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana Edad , Dosificación RadioterapéuticaRESUMEN
BACKGROUND: High-dose-rate (HDR) brachytherapy (BT) has been acknowledged as a widely utilized treatment for patients with intermediate- and high-risk prostate cancer, despite its side effects such as edema, incontinence, and impotence. Nevertheless, the treatment is consistently limited by the potential danger of excessive irradiation to organs-at-risk (OARs) like the urethra, bladder, and rectum. PURPOSE: This study aims to introduce curvilinear catheter implantation in the prostate gland for HDR treatment. The objective is to improve the radiation dose distribution by offering access channels conformal to the prostate anatomy. This approach seeks to minimize toxicity to nearby OARs while utilizing a reduced number of needles, potentially leading to improved clinical outcomes. METHODS: Curvilinear catheters were first pre-planned for an anonymized patient using Oncentra treatment planning system (TPS) and hybrid inverse planning optimization (HIPO) algorithm. The trajectories of the catheters were then analyzed using MATLAB to extract their radius of curvature. Tendon-driven active needles were then used to implant curvilinear catheters inside an anthropomorphic phantom. RESULTS: Proposed curvilinear catheter implantation resulted in significant improvement in terms of dosimetric constraints to the OARs and coverage to the prostate. Tendon-driven active needles were shown to be capable of realizing the required pre-planned curvatures inside prostate. It was shown that the active needle can realize a desired radius of curvature and a desired trajectory with an average accuracy of 9.1 ± 8.6 and 1.27 ± 0.50 mm in air and inside a tissue-mimicking phantom, respectively. CONCLUSION: This work demonstrates the feasibility of using tendon-driven active curvilinear catheter implantation in prostate to improve the outcomes of HDR-BT via improved radiation dose distribution to the prostate and reduced toxicity to the OARs.
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Purpose: Stereotactic body radiation therapy (SBRT) is considered the standard of care for medically inoperable early-stage non-small cell lung cancer. There is mixed evidence on the prognostic significance of tumor metabolic activity assessed by positron emission tomography combined with computed tomography (PET/CT) using F-18 fluorodeoxyglucose (FDG). The objectives of this study were to evaluate the maximum standardized uptake value (SUVmax) pretreatment and at 3 and 6 months after SBRT for prediction of tumor control and survival outcomes. Methods and Materials: Consecutive patients from a single institution with T12N0M0 non-small cell lung cancer receiving primary treatment with SBRT with pretreatment FDG-PET/CT (n = 163) and follow-up FDG-PET/CT at 3 or 6 months (n = 71) were included. Receiver operator characteristic analysis was performed to dichotomize variables for Kaplan-Meier survival analysis. Multivariate analysis was performed with Cox proportional hazards regression. Results: Median follow-up was 19 months. For the whole cohort, 1-year and 2-year local control, progression-free survival (PFS), and overall survival (OS) were 95.0% and 80.3%, 87.1% and 75.4%, and 67.0% and 49.6% respectively. The following pre-SBRT SUVmax cutoffs were significant: SUV > 4.0 for distant failure-free survival (adjusted hazard ratio [aHR], 3.33, P = .006), >12.3 for PFS (aHR, 2.80, P = .011), and >12.6 for OS (aHR, 3.00, P = .003). SUVmax decreases of at least 45% at 3 months (aHR, 0.15, P = .018), and 53% at 6 months (aHR, 0.12, P = .046) were associated with improved local failure-free survival. Conclusions: Pre-SBRT SUVmax cutoffs can predict distant failure, PFS, and OS. At both 3 and 6 months after SBRT, cutoffs for percentage change in SUVmax can potentially stratify risk of local recurrence.
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PURPOSE: A new technique called "curvilinear approach" for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. METHODS: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V(100)). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D(90), V(150), V(200)), urethra (D(30), D(10)) and rectum (D(5), V(100)) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. RESULTS: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D(30) reduced by 10.1% (p < 0.01) and D(10) reduced by 9.9% (p < 0.02). Reduction in rectum dose D(5) was 18.5% (p < 0.03) and V(100) was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V(150) and V(200) coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. CONCLUSIONS: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V(150), V(200)) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the curvilinear implantation approach is dosimetrically superior to conventional rectilinear implantation technique.
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Braquiterapia/instrumentación , Agujas , Neoplasias de la Próstata/radioterapia , Implantación de Prótesis/instrumentación , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Masculino , Dosificación Radioterapéutica , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Purpose: The volume of Venezia applicator with vaginal caps can be relatively large compared to target volumes. This study investigated the dosimetric and radiobiological effects of applicator volume removal for cervical cancer patients treated with Venezia (VZ) and tandem and split-ring (TSR) applicators used in the clinic. Material and methods: A total of 40 patients (101 plans) with stage IIA-IIIC cervical cancer were retrospectively reviewed. Thirty patients were treated with VZ and ten patients were treated with TSR. Applicators were contoured on planning CTs where target contours were involved. Applicator contours were subtracted from the target contours. External beam radiation therapy (EBRT) and brachytherapy doses were calculated in biologically equivalent doses in 2 Gy fractions (EQD2) and combined using full parameter addition for dose-volume histogram (DVH) parameters of composited dose. D90%, D50%, V100%, V150%, V200%, and tumor control probability (TCP) were evaluated and compared for targets after applicator exclusion. Results: The average volume changes in gross tumor volume (GTV), high-risk clinical target volume (HR-CTV), and intermediate-risk clinical target volume (IR-CTV) after VZ applicator exclusion were 1.4 ±1.5 cm3, 15.7 ±6.6 cm3, and 33.8 ±15.1 cm3, respectively. VZ exclusion resulted in significant changes (p < 0.05) in small volume parameters (D50%) and high-dose parameters (V150% and V200%) for HR-CTV and IR-CTV. Dosimetric impact of TSR exclusion on targets was not significant. There was no significant change in TCP after applicator exclusion. Conclusions: Venezia applicator with vaginal caps has significant impact on small volume and high-dose DVH parameters of the target. Applicator contour exclusion is recommended for dosimetric evaluation when Venezia applicator is used.
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Purpose: This study quantified the dosimetric uncertainty caused by needle-tip detection errors in ultrasound images due to bevel-tip orientation differences, with respect to the location on template grid. Material and methods: Trans-rectal ultrasound (TRUS) system with physical template grid and 18-gauge bevel-tip brachytherapy needles were used. TRUS was set at 6.5 MHz in water phantom, and measurements were taken with 50% and 100% B-mode TRUS gains. Needle-tip localization errors were then retrospectively applied back to 45 prostate seed implant plans to evaluate the important planning parameters for the prostate (D90, V100, V150, and V200), urethra (D10 and D30), and rectum (V100, D2cc, and D0.1cc), following the ABS and AAPM TG-137 guidelines. Results: The needle-tip detection errors for 50% and 100% TRUS gains were 3.7 mm (max) and 5.2 mm (max), respectively. The observed significant decrease in prostate coverage (mean D90 lower by 12.8%, and V100 lower by 3.9% for smaller prostates) after seed placements were corrected by compensating the needle-tip detection errors. Apex of the prostate was hotter, and the base was cooler. Dosimetric difference for urethral and rectal parameters were not statistically significant. Conclusions: This study revealed that the beveled needle-tip orientation could considerably impact the needle tips detection accuracy, based on which the seeds might be delivered. These errors can lead to significant dosimetric uncertainty in prostate seed implantation.
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In this study we present a new approach to plan a high-dose-rate (HDR) prostate brachytherapy (BT) using active needles recently developed by our group. The active needles realize bi-directional bending inside the tissue, and thereby more compliant with the patient's anatomy compared with conventional straight needles. A computational method is presented to first generate a needle arrangement configuration based on the patient's prostate anatomy. The needle arrangement is generated to cover the prostate volume, providing accessible channels for the radiation source during a HDR BT. The needle arrangement configuration avoids healthy organs and prevents needle collision inside the body. Then a treatment plan is proposed to ensure sufficient prescribed dosage to the whole prostate gland. The method is applied to a prostate model reconstructed from an anonymized patient to show the feasibility of this method. Finally, the active needle's capability to generate the required bending is shown. We have shown that our method is able to automatically generate needle arrangement configuration using active needles, and plan for a treatment that meets the dose objectives while using fewer needles (about 20% of conventional straight needles) than the conventional HDR BT performed by straight needles.
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PURPOSE: Stereotactic body radiation therapy (SBRT) has become the standard of care for medically inoperable early-stage non-small cell lung cancer. We investigated 2 modalities of lung SBRT, CyberKnife (CK) and volumetric modulated arc therapy (VMAT), for differences in dosimetric parameters, tumor control, and clinical outcomes. METHODS AND MATERIALS: Patients who underwent SBRT for T1-2N0M0 non-small cell lung cancer from 2012 to 2018 were included. Dosimetric parameters for target volume coverage and organ-at-risk dose distribution were collected. Survival outcomes were evaluated using the Kaplan-Meier method with log-rank test. A multivariate Cox proportional hazards model was analyzed for local, regional, and distant tumor control; overall survival (OS) and progression-free survival; and radiation pneumonitis. RESULTS: Two hundred twenty-seven patients (142 CK, 85 VMAT SBRT) met inclusion criteria. Overall, the local, regional, and distant control rates were 89.3%, 86.3%, and 87.4% at 2 years, and the OS was 67.5% and 32.8% at 2 and 5 years, respectively. VMAT delivered higher maximum doses to the gross tumor volume and planning target volume and had a lower lung and heart V5. Although there was no difference in local or distant failure, progression-free survival, or OS, VMAT was associated with superior freedom from regional failure (adjusted hazard ratio, 0.26; P = .045). With no difference between treatment modalities, 11.9% of patients developed grade 1 to 2 radiation pneumonitis. There were no grade 3+ events of radiation pneumonitis. CONCLUSIONS: This study revealed that VMAT and CK provided comparable local and distant control and survival outcomes; however, VMAT exhibited better regional control. Further study in this regard is imperative.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Neumonitis por Radiación , Radiocirugia , Radioterapia de Intensidad Modulada , Carcinoma Pulmonar de Células Pequeñas , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Humanos , Neoplasias Pulmonares/patología , Aceleradores de Partículas , Neumonitis por Radiación/etiología , Radiocirugia/métodos , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodosRESUMEN
PURPOSE: Recently, several robotic systems have been developed to perform accurate and consistent image-guided brachytherapy. Before introducing a new device into clinical operations, it is important to assess the reliability and mean time before failure (MTBF) of the system. In this article, the authors present the preclinical evaluation and analysis of the reliability and MTBF of an autonomous robotic system, which is developed for prostate seed implantation. METHODS: The authors have considered three steps that are important in reliability growth analysis. These steps are: Identification and isolation of failures, classification of failures, and trend analysis. For any one-of-a-kind product, the reliability enhancement is accomplished through test-fix-test. The authors have used failure mode and effect analysis for collection and analysis of reliability data by identifying and categorizing the failure modes. Failures were classified according to severity. Failures that occurred during the operation of this robotic system were considered as nonhomogenous Poisson process. The failure occurrence trend was analyzed using Laplace test. For analyzing and predicting reliability growth, commonly used and widely accepted models, Duane's model and the Army Material Systems Analysis Activity, i.e., Crow's model, were applied. The MTBF was used as an important measure for assessing the system's reliability. RESULTS: During preclinical testing, 3196 seeds (in 53 test cases) were deposited autonomously by the robot and 14 critical failures were encountered. The majority of the failures occurred during the first few cases. The distribution of failures followed Duane's postulation as well as Crow's postulation of reliability growth. The Laplace test index was -3.82 (<0), indicating a significant trend in failure data, and the failure intervals lengthened gradually. The continuous increase in the failure occurrence interval suggested a trend toward improved reliability. The MTBF was 592 seeds, which implied that several prostate seed implantation cases would be possible without encountering any critical failure. The shape parameter for the MTBF was 0.3859 (<1), suggesting a positive reliability growth of this robotic system. At 95% confidence, the reliability for deposition of 65 seeds was more than 90%. CONCLUSIONS: Analyses of failure mode strongly indicated a gradual improvement of reliability of this autonomous robotic system. High MTBF implied that several prostate seed implant cases would be possible without encountering any critical failure.
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Braquiterapia/instrumentación , Neoplasias de la Próstata/radioterapia , Radioterapia Asistida por Computador/instrumentación , Robótica/instrumentación , Humanos , Imagenología Tridimensional , Masculino , Radiometría , Reproducibilidad de los ResultadosRESUMEN
There has been growing interest in utilizing information from cone-beam computed tomography (CBCT) to help guide both treatment delivery and prognosis. In this assessment of locally advanced unresectable stage III non-small cell lung cancer (NSCLC) treated with definitive chemoradiation, we aimed to determine the survival advantage associated with using CBCT to measure tumor regression. Patient, tumor, and treatment characteristics were collected. The serial tumor shrinkage for each patient was determined from tumor volume contours on weekly CBCTs. Survival analysis was performed using the Kaplan-Meier technique and a Cox proportional hazards model. At least two-thirds of patients had a tumor volume reduction of at least 5% after each week of chemoradiation. A weekly reduction in tumor volume of 5% or greater seen on the CBCT images during radiation therapy was significantly associated with improved overall survival, which remained significant when adjusted for age, histology, grade, and T- and N-stages (p = 0.0036). Additionally, the presence of N3 disease was associated with a five-fold increased risk of recurrence (p = 0.0006) and a nearly three-fold increased risk of death (p = 0.053) compared with N0-N2 disease. Tumor volume shrinkage observed in the CBCT images during definitive chemoradiation holds promise as a prognostic indicator of stage III NSCLC, especially given its affordability, availability, and applicability. Further evaluation in a prospective fashion is warranted to validate the tumor volume shrinkage and its clinical utility.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Tomografía Computarizada de Haz Cónico Espiral , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Carcinoma de Pulmón de Células no Pequeñas/terapia , Tomografía Computarizada de Haz Cónico , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/terapia , Recurrencia Local de Neoplasia , Proyectos Piloto , Pronóstico , Estudios ProspectivosRESUMEN
PURPOSE: The in vivo dosimetric monitoring in HDR brachytherapy is important for improving patient safety. However, there are very limited options available for clinical application. In this study, we present a new in vivo dose measurement system with a plastic scintillating detector (PSD) for GYN HDR brachytherapy. METHODS: An FDA approved PSD system, called OARtrac (AngioDynamics, Latham, NY), was used with various applicators for in vivo dose measurements for GYN patients. An institutional workflow was established for the clinical implementation of the dosimetric system. Action levels were proposed based on the measurement and system uncertainty for measurement deviations. From October 2018 to September 2019, a total of 75 measurements (48 fractions) were acquired from 14 patients who underwent HDR brachytherapy using either a multichannel cylinder, Venezia applicator, or Syed-Neblett template. The PSDs were placed in predetermined catheters/channels. A planning CT was acquired for treatment planning in Oncentra (Elekta, Version-4.5.2) TPS. The PSDs were contoured on the CT images, and the PSD D90% values were used as the expected doses for comparison with the measured doses. RESULTS: The mean difference from patient measurements was -0.22% ± 5.98%, with 26% being the largest deviation from the expected value (Syed case). Large deviations were observed when detectors were placed in the area where dose rates were less than 1 cGy/s. CONCLUSIONS: The establishment of clinical workflow for the in vivo dosimetry for both the intracavitary and interstitial GYN HDR brachytherapy will potentially improve the safety of the patient treatment.
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Braquiterapia , Braquiterapia/métodos , Catéteres , Estudios de Factibilidad , Humanos , Radiometría , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por ComputadorRESUMEN
Multi-modality imaging constitutes a foundation of precision medicine, especially in oncology where reliable and rapid imaging techniques are needed in order to insure adequate diagnosis and treatment. In cervical cancer, precision oncology requires the acquisition of 18F-labeled 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET), magnetic resonance (MR), and computed tomography (CT) images. Thereafter, images are co-registered to derive electron density attributes required for FDG-PET attenuation correction and radiation therapy planning. Nevertheless, this traditional approach is subject to MR-CT registration defects, expands treatment expenses, and increases the patient's radiation exposure. To overcome these disadvantages, we propose a new framework for cross-modality image synthesis which we apply on MR-CT image translation for cervical cancer diagnosis and treatment. The framework is based on a conditional generative adversarial network (cGAN) and illustrates a novel tactic that addresses, simplistically but efficiently, the paradigm of vanishing gradient vs. feature extraction in deep learning. Its contributions are summarized as follows: 1) The approach -termed sU-cGAN-uses, for the first time, a shallow U-Net (sU-Net) with an encoder/decoder depth of 2 as generator; 2) sU-cGAN's input is the same MR sequence that is used for radiological diagnosis, i.e. T2-weighted, Turbo Spin Echo Single Shot (TSE-SSH) MR images; 3) Despite limited training data and a single input channel approach, sU-cGAN outperforms other state of the art deep learning methods and enables accurate synthetic CT (sCT) generation. In conclusion, the suggested framework should be studied further in the clinical settings. Moreover, the sU-Net model is worth exploring in other computer vision tasks.
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PURPOSE: This study identified and evaluated the factors that are responsible for delay in the clinical workflow of radiation therapy, starting from the CT simulation (CT-Sim) to the first fraction of treatment delivery using the Failure Mode and Effects Analysis (FMEA) methodology. MATERIALS AND METHODS: A total of 1106 patient cases were retrospectively analyzed using FMEA methodology. For each failure mode (FM), the following factors were rated and discussed by the group: occurrence (O), severity (S), detectability (D), and methods of improvement or mitigation. In addition, two new factors, namely social effect (SE) and economic effect (EE), were introduced to evaluate the impact of FM on the department or hospital. Risk priority number (RPN) and the product of RPN, SE, and EE (i.e. RPNSE-EE) were calculated for each FM. RESULTS: Average delay caused by identified FM was 8â¯days while 76% of the FMs resulted in delay of less than 5â¯days. The RPN of all the FMs ranged from 4 to 60 with an average value of 18. "Tumor volume, prescription and objective" had the highest average RPN of 23. The majority of FMs with high RPN were identified in "CT-Sim" (RPN: 21.5⯱â¯11.1; RPNSE-EE: 97.0⯱â¯46.4) and "treatment planning" (RPN: 20.1⯱â¯8.1, RPNSE-EE: 152.9⯱â¯76.5) stages. CONCLUSION: The FMEA enabled identification of the factors that caused delay in the pre-treatment process of radiation therapy. "CT-Sim" and "treatment planning" stages had more FMs with high RPN values which have higher priority for future improvement. Two new factors, SE and EE, were introduced and appeared to be valuable in evaluating the impact of FMs on radiation oncology department or hospital in general.
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Neoplasias/diagnóstico por imagen , Neoplasias/radioterapia , Tiempo de Tratamiento , Simulación por Computador , Análisis de Modo y Efecto de Fallas en la Atención de la Salud , Humanos , Planificación de la Radioterapia Asistida por Computador/métodos , Estudios Retrospectivos , Medición de Riesgo , Tomografía Computarizada por Rayos X , Flujo de TrabajoRESUMEN
PURPOSE: This study assessed the appropriateness of full parameter addition (FPA) methods with respect to the 3-dimensional deformable dose composite method for evaluating combined external beam radiation therapy (EBRT) and intracavitary brachytherapy (ICBT). METHODS AND MATERIALS: A total of 22 patients who received EBRT and high-dose-rate ICBT were retrospectively evaluated. Split-ring and tandem applicators were used for all patients. Additional interstitial needles were used for 5 patients to supplement the implant. Deformable image registrations were performed to deform the secondary EBRT and ICBT planning computed tomography (CT) images onto the reference CT from the third fraction of ICBT. The Dice similarity coefficient was used to evaluate the quality of deformable registration. Doses were transferred to the reference CT, scaled to the equivalent dose in 2-Gy fractions and combined to create the dose composite. Eight dose-accumulation methods were evaluated and compared. D2cc and D0.1cc for organs at risk were investigated. RESULTS: The differences in D2cc for rectum, bladder, sigmoid, and bowel between the FPA method for whole-pelvis EBRT and ICBT, calculated using an old American Brachytherapy Society worksheet (FPA_Eh + I_old) and deformable composite for EBRT with boosts and ICBT (Def_E + B + I) were -2.19 ± 1.37 Gyα/ß = 3, -0.64 ± 1.13 Gyα/ß = 3, -2.06 ± 2.71 Gyα/ß = 3, and -1.59 ± 0.89 Gyα/ß = 3, respectively. The differences in D2cc for rectum, bladder, sigmoid, and bowel between the new ABS worksheet (FPA_Eh + B + I_abs) and the Def_E + B + I method were 1.21 ± 1.22 Gy α/ß = 3, 1.93 ± 1.38 Gyα/ß = 3, 0.72 ± 1.12 Gyα/ß = 3, and 1.19 ± 1.46 Gyα/ß = 3, respectively. Differences in dose-volume histogram parameter values among Def_E + B + I and other FPA methods were not statistically significant (P > .05). CONCLUSIONS: Compared with the FPA-based method, deformable registration-based dose composites demonstrated lower OAR D2cc and D0.1cc values; however, the differences were not statistically significant. The current ABS-recommended FPA-based sheet can serve as an acceptable plan evaluation tool for clinical purposes.