Rectal dose-volume constraints in high-dose radiotherapy of localized prostate cancer.

Abstract

PURPOSE:

To investigate the relationship between rectal bleeding and dosimetric-clinical parameters in patients receiving three-dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer.

METHODS:

In a retrospective national study (AIROPROS01-01, AIRO: Associazione Italiana Radioterapia Oncologica), planning/clinical data for 245 consecutive patients with stage T1-4N0-x prostate carcinoma who underwent 3D-CRT to 70-78 Gy (ICRU point) were pooled from four Italian institutions. The correlation between late rectal bleeding and rectal dose-volume data (the percentage of rectum receiving more than 50, 55, 60, 65, 70, and 75 Gy [V(50-70)]) and other dosimetric and clinical parameters were investigated in univariate (log-rank) and multivariate (Cox regression model) analyses. Median follow-up was 2 years.

RESULTS:

Twenty-three patients were scored as late bleeders according to a modified RTOG definition (Grade 2: 16; Grade 3: 7); the actuarial 2-year rate was 9.2%. Excepting V75, all median and third quartile V(50-70) values were found to be significantly correlated with late bleeding at univariate analysis. The smallest p value was seen for V(50) below/above the third quartile value (66%). The V70 (cut-off value: 30%) was found to be also predictive for late bleeding. In the high-dose subgroup (74-78 Gy), Grade 3 bleeding was highly correlated with this constraint. The predictive value of both V(50) and V(70) was confirmed by multivariate analyses.

CONCLUSIONS:

The present article provides evidence for correlation between rectal DVH parameters and late rectal bleeding in patients treated with curative intent with 3D-CRT. To keep the rate of moderate/severe rectal bleeding below 5-10%, it seems advisable to limit V(50) to 60-65%, V(60) to 45-50%, and V70 to 25-30%.

• Authors: Claudio Fiorino, Giuseppe Sanguineti, Cesare Cozzarini, Gianni Fellin, Franca Foppiano, Loris Menegotti, Anna Piazzolla, Vittorio Vavassori, Riccardo Valdagni
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 57 Issue 4 Pg. 953-62 (Nov 15 2003) ISSN: 0360-3016 [Print] United States
• PMID: 14575825 (Publication Type: Journal Article, Multicenter Study)

Topics

• Aged
• Analysis of Variance
• Follow-Up Studies
• Gastrointestinal Hemorrhage (etiology)
• Humans
• Italy
• Male
• Neoplasm Staging
• Prostatic Neoplasms (radiotherapy)
• Radiation Injuries (complications)
• Radiotherapy Dosage
• Radiotherapy, Conformal (adverse effects)
• Rectal Diseases (etiology)
• Rectum (radiation effects)
• Regression Analysis
• Retrospective Studies