Patient-reported intestinal toxicity from whole pelvis intensity-modulated radiotherapy: First quantification of bowel dose-volume effects

C. Sini, B. Noris Chiorda, P. Gabriele, G. Sanguineti, S. Morlino, F. Badenchini, D. Cante, V. Carillo, M. Gaetano, T. Giandini, V. Landoni, A. Maggio, L. Perna, E. Petrucci, V. Sacco, R. Valdagni, T. Rancati, C. Fiorino, C. Cozzarini

Research output: Contribution to journalArticlepeer-review


BACKGROUND AND PURPOSE: Intestinal toxicity is commonly experienced during whole-pelvis intensity-modulated radiotherapy (WPRT) for prostate cancer. The aim of the current study was to assess bowel dose-volume relationships for acute patient-reported intestinal symptoms of patients treated with WPRT for prostate cancer. MATERIALS AND METHODS: Complete data of 206 patients were available; the median dose to pelvic nodes was 51.8Gy (range 50.4-54.4, 1.7-2Gy/fr). Intestinal symptoms were assessed as changes in the Inflammatory Bowel Disease Questionnaire scores relative to the Bowel Domain (IBDQ-B) between baseline and radiotherapy mid-point/end. The 25th percentiles of the most severe worsening from baseline (DeltaIBDQ-B) were set as end-points. The impact of bowel loops and sigmoid colon dose-volume/surface parameters as well as selected clinical parameters were investigated using multivariate logistic regression. RESULTS: Analyses were focused on the four questions showing a median DeltaIBDQ-B>0. No dose volume/surface parameters were predictive, other than DeltaIBDQ5>/=3 (loose stools): when grouping patients according to bowel DVHs (high risk: V20>470cc, V30>245cc, V42>110cc; low risk: all the remaining patients), a two-variable model including high-risk DVH-shape (OR: 9.3) and age (protective, OR: 0.94) was assessed. The model showed good calibration (slope: 1.003, R2=0.92) and was found to be robust after bootstrap-based internal validation. CONCLUSIONS: Constraining the bowel loops may reduce the risk of loose stools. The risk is higher for younger patients.
Original languageEnglish
Pages (from-to)296-301
JournalRadiotherapy and Oncology
Issue number2
Publication statusPublished - Aug 1 2017


  • Acute bowel toxicity
  • Diarrhea
  • Intensity-modulated radiotherapy
  • Predictive models
  • Prostate cancer


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