The available dose/volume/outcome data for rectal injury were reviewed. The volume of rectum receiving ≥60Gy is consistently associated with the risk of Grade ≥2 rectal toxicity or rectal bleeding. Parameters for the Lyman-Kutcher-Burman normal tissue complication probability model from four clinical series are remarkably consistent, suggesting that high doses are predominant in determining the risk of toxicity. The best overall estimates (95% confidence interval) of the Lyman-Kutcher-Burman model parameters are n = 0.09 (0.04–0.14); m = 0.13 (0.10–0.17); and TD50 = 76.9 (73.7–80.1) Gy. Most of the models of late radiation toxicity come from three-dimensional conformal radiotherapy dose-escalation studies of early-stage prostate cancer. It is possible that intensity-modulated radiotherapy or proton beam dose distributions require modification of these models because of the inherent differences in low and intermediate dose distributions.
Last. James D. Cox(University of Texas MD Anderson Cancer Center)H-Index: 91
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Purpose To update the incidence of late toxicity of RTOG 9406, a three-dimensional conformal radiation therapy (3DCRT) dose escalation trial for prostate cancer. Methods and Materials A total of 1,084 men were registered to this Phase I/II trial of 3DCRT (eligible patients, 1,055). The dose for level I was 68.4 Gy; 73.8 Gy for level II; 79.2 Gy for level III; 74 Gy for level IV; and 78 Gy for level V. Patients in levels I to III received 1.8 Gy/fraction, and those in levels IV to V received 2.0 ...
Purpose The radiobiology of prostate cancer favors a hypofractionated dose regimen. We report results of a prospective Phase II clinical trial of stereotactic body radiotherapy (SBRT) for localized prostate cancer. Methods and Materials Forty-one low-risk prostate cancer patients with 6 months' minimum follow-up received 36.25 Gy in five fractions of 7.25 Gy with image-guided SBRT alone using the CyberKnife. The early ( 6 months) urinary and rectal toxicities were assessed using validated qualit...
#1Michael J. Zelefsky(MSK: Memorial Sloan Kettering Cancer Center)H-Index: 117
#2Emily J. Levin(MSK: Memorial Sloan Kettering Cancer Center)H-Index: 1
Last. Howard I. Amols(MSK: Memorial Sloan Kettering Cancer Center)H-Index: 30
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Purpose To report the incidence and predictors of treatment-related toxicity at 10 years after three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for localized prostate cancer. Methods and Materials Between 1988 and 2000, 1571 patients with stages T1–T3 prostate cancer were treated with 3D-CRT/IMRT with doses ranging from 66 to 81 Gy. The median follow-up was 10 years. Posttreatment toxicities were all graded according to the National Cancer Institute's...
#1H. J. N. Andreyev(The Royal Marsden NHS Foundation Trust)H-Index: 20
Up to 300 000 patients per year undergo pelvic radiotherapy worldwide. Nine out of 10 will develop a permanent change in their bowel habit as a result. Five out of 10 of all patients will say that this change in their bowel habit affects quality of life and two to three out of 10 will say that this effect on quality of life is moderate or severe. Between one in 10 and one in 20 patients will develop very serious complications within the first 10 years after treatment. This number will increase t...
Purpose: To find predictors for rectal and intestinal acute toxicity in patients with prostate cancer treated with ≥70 Gy conformal radiotherapy. Methods and Materials: Between July 2002 and March 2004, 1,132 patients were entered into a cooperative study (AIROPROS01-02). Toxicity was scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale and by considering the changes (before and after treatment) of the scores of a self-administered qu...
Purpose: Accurate modeling of rectal complications based on dose–volume histogram (DVH) data are necessary to allow safe dose escalation in radiotherapy of prostate cancer. We applied different equivalent uniform dose (EUD)–based and dose–volume–based normal tissue complication probability (NTCP) models to rectal wall DVHs and follow-up data for 319 prostate cancer patients to identify the dosimetric factors most predictive for Grade ≥ 2 rectal bleeding. Methods and Materials: Data for 319 patie...
Last. Joos V. Lebesque(NKI-AVL: Netherlands Cancer Institute)H-Index: 18
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Purpose: Late gastrointestinal (GI) toxicity after radiotherapy can be partly explained by late effects of acute toxicity (consequential late damage). We studied whether there is a direct relationship between acute and late GI toxicity. Patients and Methods: A total of 553 evaluable patients from the Dutch dose escalation trial (68 Gy vs. 78 Gy) were included. We defined three outcomes for acute reactions: 1) maximum Radiation Therapy Oncology Group acute toxicity, 2) maximum acute mucous discha...
Last. Joos V. Lebesque(NKI-AVL: Netherlands Cancer Institute)H-Index: 18
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Purpose: To analyze whether inclusion of predisposing clinical features in the Lyman-Kutcher-Burman (LKB) normal tissue complication probability (NTCP) model improves the estimation of late gastrointestinal toxicity. Methods and Materials: This study includes 468 prostate cancer patients participating in a randomized trial comparing 68 with 78 Gy. We fitted the probability of developing late toxicity within 3 years (rectal bleeding, high stool frequency, and fecal incontinence) with the original...
#2Joos V. Lebesque(NKI-AVL: Netherlands Cancer Institute)H-Index: 18
Last. Peter C.M. Koper(EUR: Erasmus University Rotterdam)H-Index: 29
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Purpose: To identify dosimetric parameters derived from anorectal, rectal, and anal wall dose distributions that correlate with different late gastrointestinal (GI) complications after three-dimensional conformal radiotherapy for prostate cancer. Methods and Materials: In this analysis, 641 patients from a randomized trial (68 Gy vs. 78 Gy) were included. Toxicity was scored with adapted Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer (RTOG/EORTC) ...
Purpose null Late radiation toxicity is a major dose-limiting factor in curative cancer radiotherapy. Previous studies identified several risk factors for late radiation toxicity, including both dose-volume factors and genetic predisposition. Herein, we investigated the contribution of genetic predisposition, particularly compared to dose-volume factors, to the risk of late radiation toxicity in patients treated with highly conformal radiotherapy. null Methods and materials null We included 179 ...
Background: Although there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)’s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT. Methods: While the size of a fu...
Last. Shresth Gupta(International Institute of Information Technology)
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Abstract null null For a Fluence map optimization problem, we present a unique iterative reweighting algorithm-based method to achieve optimality. The purpose of planning is to determine a dose distribution in such a manner that it should cover the maximum part of the target without affecting the functionality of organ at risk. We suggest a unique methodology to solve dose-volume bounds while maintaining their non-convexity, as compared to earlier approaches that dedicated to convex estimation. ...
Last. Tom Depuydt(Katholieke Universiteit Leuven)H-Index: 22
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PURPOSE The integration of auto-segmentation and automated treatment planning methods on a fast-rotating O-ring linac may improve the time efficiency of online adaptive radiotherapy workflows. This study investigates whether automated treatment planning of prostate SBRT with focal boosting on the O-ring linac could generate plans that are of similar quality as those obtained through manual planning on clinical C-arm linacs. METHODS For 20 men with prostate cancer, reference treatment plans were ...
#2Lukas Nierer(LMU: Ludwig Maximilian University of Munich)H-Index: 1
Last. Claus Belka(LMU: Ludwig Maximilian University of Munich)H-Index: 73
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The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were es...
Radiotherapy (RT) is the backbone of multimodality treatment of more than half of cancer cases. Despite new modern RT techniques, late complications may occur such as radiation proctitis (RP). The natural history of RP is unpredictable. Minor symptoms may resolve spontaneously or require conservative treatment. On the other hand, for similar and uncomplicated clinical contexts, symptoms may persist and can even be refractory to the progressive increase in treatment measures. Over the last decade...
Last. Ann Henry(Leeds Teaching Hospitals NHS Trust)H-Index: 32
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Prostate cancer (PCa) may recur after primary treatment but no standard of care exists for patients with pelvic nodal relapse. Based on obervational data, Extended Nodal Irradiation (ENI) might be associated with fewer treatment failures than Stereotactic Ablative Radiotherapy (SABR) to the involved node(s) alone. Ultra hypofractionated ENI is yet to be evaluated in this setting, but it could provide a therapeutic advantage if PCa has a low α/β ratio in addition to patient convenience/resource b...
#1Martin A. Ebert(SCGH: Sir Charles Gairdner Hospital)H-Index: 26
#2Sarah L. Gulliford(UCLH: University College London Hospitals NHS Foundation Trust)H-Index: 23
Last. Claudio Fiorino(UniSR: Vita-Salute San Raffaele University)H-Index: 54
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For decades, dose-volume information for segmented anatomy has provided the essential data for correlating radiotherapy dosimetry with treatment-induced complications. Dose-volume information has formed the basis for modelling those associations via normal tissue complication (NTCP) models and for driving treatment planning. Limitations to this approach have been identified. Many studies have emerged demonstrating that the incorporation of information describing the spatial nature of the dose di...