Influence of hormonal therapy on late rectal function after permanent prostate brachytherapy with or without supplemental external beam radiotherapy.

Abstract

Recent clinical studies have reported a relationship between the use of hormonal therapy and degradation in rectal function after external beam radiotherapy. Using a patient-administered quality-of-life instrument, we evaluated the effect of hormonal therapy on late rectal function after permanent prostate brachytherapy with or without supplemental external beam radiotherapy. A total of 189 patients were mailed the Rectal Function Assessment Score (R-FAS), which consists of nine questions (score range 0-27, with higher scores indicative of poorer bowel function). Of the 189 surveys sent out, 187 (98.4%) were returned. Of the 187 patients, 149 (79.7%) were hormone naive, and 38 (20.3%) had received hormonal manipulation (median duration 4 months, range 3-36). The median follow-up for the entire group was 66.3 months. The effect of hormonal therapy on bowel function was evaluated by comparing the R-FAS scores across time, by each of the individual nine questions, and by means of a summary question evaluating the patient's perception of overall bowel function. The two groups were also evaluated in terms of clinical, treatment, and dosimetric parameters, including follow-up, age, Gleason score, clinical stage, pretreatment prostate-specific antigen level, number of pretreatment bowel movements/d, prostate volume, and rectal dosimetry. The two groups were well matched in all clinical, treatment, and dosimetric parameters, except the patients receiving hormonal therapy had a statistically shorter follow-up (63.9 vs. 69.4 months, p <0.001) and higher pretreatment prostate-specific antigen level (12.0 vs. 9.8 ng/mL, p = 0.024). The R-FAS scores for the hormone-naive and hormonally manipulated patients were comparable (3.76 vs. 4.55, p = 0.083). In terms of the nine individual R-FAS questions, no statistically significant difference was reported for any question when stratified by hormonal status, including rectal bleeding (p = 0.735). Only 12% and 13% of hormone-naive and hormonally manipulated patients, respectively, reported bowel function to be worse after implantation. With time, a trend for improvement in the R-FAS was noted in both cohorts. After permanent prostate brachytherapy, no statistically significant difference in bowel habits was discerned when stratified by hormonal status. In addition, only 12% of brachytherapy patients reported deterioration in bowel function after implantation.