Objectives. Adjuvant radiotherapy to the prostatic bed at moderate doses of 45 to 54 Gy achieves results comparable to higher doses. We studied the effect of moderate doses of postoperative radiation therapy on urinary continence and sexual potency in prostate cancer patients who had undergone nerve-sparing prostatectomy.

Methods. Between November 1983 and December 1992, 255 prostate cancer patients were selected to undergo nerve-sparing prostatectomy. A total of 94 (37%) patients had received adjuvant postoperative radiotherapy, 45 to 54 Gy to the prostatic bed, based on microscopic positive margins, seminal vesicle involvement, and/or Gleason score. Subjective patient reports regarding the potency and urinary continence status were recorded during a semistructured telephone interview at 3 or more years after treatment. The findings in irradiated and nonirradiated patients were compared and correlated to those obtained from the same patients preoperatively and 1 year postoperatively.

Results. At 3 or more years of follow-up no significant difference among irradiated and nonirradiated patients was detected. Most patients described optimal urinary continence and approximately one third had maintained potency after bilateral nerve-sparing prostatectomy. None of the patients who had undergone unilateral nerve-sparing surgery remained potent. Using a multivariable analysis, the significant predictors for maintaining potency were the status at 1 year postoperatively and bilateral versus unilateral nerve-sparing procedure.

Conclusions. Doses of adjuvant radiation therapy in the range used (45 to 54 Gy) did not affect the long-term pattern of maintenance of either function.