PMID- 24099966 OWN - NLM STAT- MEDLINE DCOM- 20140928 LR - 20161125 IS - 1873-4022 (Electronic) IS - 1873-4022 (Linking) VI - 39 IP - 1 DP - 2014 Spring TI - Image-guided intensity-modulated radiotherapy for prostate cancer: Dose constraints for the anterior rectal wall to minimize rectal toxicity. PG - 12-7 LID - S0958-3947(13)00096-4 [pii] LID - 10.1016/j.meddos.2013.08.007 [doi] AB - Rectal adverse events (AEs) are a major concern with definitive radiotherapy (RT) treatment for prostate cancer. The anterior rectal wall is at the greatest risk of injury as it lies closest to the target volume and receives the highest dose of RT. This study evaluated the absolute volume of anterior rectal wall receiving a high dose to identify potential ideal dose constraints that can minimize rectal AEs. A total of 111 consecutive patients with Stage T1c to T3a N0 M0 prostate cancer who underwent image-guided intensity-modulated RT at our institution were included. AEs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The volume of anterior rectal wall receiving 5 to 80Gy in 2.5-Gy increments was determined. Multivariable Cox regression models were used to identify cut points in these volumes that led to an increased risk of early and late rectal AEs. Early AEs occurred in most patients (88%); however, relatively few of them (13%) were grade >/=2. At 5 years, the cumulative incidence of late rectal AEs was 37%, with only 5% being grade >/=2. For almost all RT doses, we identified a threshold of irradiated absolute volume of anterior rectal wall above which there was at least a trend toward a significantly higher rate of AEs. Most strikingly, patients with more than 1.29, 0.73, or 0.45cm(3) of anterior rectal wall exposed to radiation doses of 67.5, 70, or 72.5Gy, respectively, had a significantly increased risk of late AEs (relative risks [RR]: 2.18 to 2.72; p /= 2 early AEs (RR: 6.36 to 6.48; p = 0.004). Our study provides evidence that definitive image-guided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer is well tolerated and also identifies dose thresholds for the absolute volume of anterior rectal wall above which patients are at greater risk of early and late complications. CI - Copyright (c) 2014 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved. FAU - Peterson, Jennifer L AU - Peterson JL AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. Electronic address: peterson.jennifer2@mayo.edu. FAU - Buskirk, Steven J AU - Buskirk SJ AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Heckman, Michael G AU - Heckman MG AD - Section of Biostatistics, Mayo Clinic Florida, Jacksonville, FL. FAU - Diehl, Nancy N AU - Diehl NN AD - Section of Biostatistics, Mayo Clinic Florida, Jacksonville, FL. FAU - Bernard, Johnny R Jr AU - Bernard JR Jr AD - Section of Biostatistics, Mayo Clinic Florida, Jacksonville, FL; Department of Radiation Oncology, Southern Ohio Medical Center, Portsmouth, OH. FAU - Tzou, Katherine S AU - Tzou KS AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Casale, Henry E AU - Casale HE AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Bellefontaine, Louis P AU - Bellefontaine LP AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Serago, Christopher AU - Serago C AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Kim, Siyong AU - Kim S AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Vallow, Laura A AU - Vallow LA AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Daugherty, Larry C AU - Daugherty LC AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. FAU - Ko, Stephen J AU - Ko SJ AD - Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL. LA - eng PT - Journal Article DEP - 20131004 PL - United States TA - Med Dosim JT - Medical dosimetry : official journal of the American Association of Medical Dosimetrists JID - 8908862 SB - IM MH - Aged MH - Aged, 80 and over MH - Dose-Response Relationship, Radiation MH - Female MH - Humans MH - Male MH - Middle Aged MH - Organ Sparing Treatments/methods MH - Organs at Risk/radiation effects MH - Prostatic Neoplasms/*diagnostic imaging/*radiotherapy MH - Radiation Injuries/*etiology/prevention & control MH - Radiation Protection/methods MH - Radiography MH - Radiotherapy Dosage MH - Radiotherapy, Conformal/*adverse effects/*methods MH - Rectal Diseases/*etiology/prevention & control MH - Reproducibility of Results MH - Retrospective Studies MH - Risk Assessment MH - Sensitivity and Specificity MH - Treatment Outcome OTO - NOTNLM OT - Prostate OT - Radiotherapy OT - Toxicity EDAT- 2013/10/09 06:00 MHDA- 2014/10/01 06:00 CRDT- 2013/10/09 06:00 PHST- 2013/03/28 00:00 [received] PHST- 2013/08/10 00:00 [revised] PHST- 2013/08/14 00:00 [accepted] PHST- 2013/10/09 06:00 [entrez] PHST- 2013/10/09 06:00 [pubmed] PHST- 2014/10/01 06:00 [medline] AID - S0958-3947(13)00096-4 [pii] AID - 10.1016/j.meddos.2013.08.007 [doi] PST - ppublish SO - Med Dosim. 2014 Spring;39(1):12-7. doi: 10.1016/j.meddos.2013.08.007. Epub 2013 Oct 4.