Correlation between dosimetrical data and rectal bleeding in radiotherapy of prostate cancer: A retrospective analysis

C. Bianchi, G. M. Cattaneo, C. Cozzarini, C. Fiorino, C. Mordacchini, A. Piazzolla, M. Reni, V. Vavassori

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Abstract

The purpose of current study is to search for possible correlation between dosimetry-clinical-technical parameters and late grade II/III rectum bleeding through a retrospective analysis of 175 patients (conformal: 115; non-conformal: 60) treated in the two Institutes for prostate carcinoma with curative or adjuvant intent (ICRU dose ranging from 60 to 76 Gy) in the years 1994-1998. The dose-volume-histograms (DVH) and dose statistics were collected together with a number of clinical and technical/dosimetry data. Mean, median and maximum dose and the fraction of rectum receiving more than 50, 55, 60, 65, 70 and 75 Gy were considered (V50,55,60,65,70,75). Rectal toxicity was scored through the RTOG/EORTC scale [1]: minimum follow-up was 15 months. 23/ 175 patients (13.1%) experienced grade II-III bleeding (grade III: 1/175). Posterior wall irradiation (more than 2 cm, 33% vs. 8.5%) and type of technique (conformal or not, 6% vs. 26%) were significantly correlated with the risk of grade II/III bleeding (p <0.001, χ2 test). When considering the ≥ 70 Gy patients (n = 126) a number of constraints resulted to be significant (χ2 test): mean dose (≥ 57 Gy, p = 0.03); median dose (≥ 64 Gy, p = 0.025); V70 (≥ 35%, p = 0.025); V65 (≥ 48%, p = 0.03); V50 (≥ 69%, p = 0.04).

Original languageEnglish
Pages (from-to)112-113
Number of pages2
JournalPhysica Medica
Volume17
Issue numberSUPPL. 2
Publication statusPublished - 2001

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Keywords

  • Conformal radiotherapy
  • Dose-volume histograms
  • Normal tissue complications

ASJC Scopus subject areas

  • Biophysics
  • Physics and Astronomy(all)

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