The long-term effect on PSA values of incidental prostatic irradiation in patients with pelvic malignancies other than prostate cancer

Purpose: To determine the effect of external beam radiation therapy on seru m prostate-specific antigen (PSA) production by the benign prostate. Methods and Materials: We studied a cohort of 24 men receiving treatment fo r cancer of the bladder or rectum, The radiation fields in all cases encomp assed the prostate gland, and none of the patients were known to have prost ate cancer. All patients had 2 or more PSA estimations obtained in the year s following their radiation treatment. A second group of 46 patients who ha d undergone radical external beam radiation therapy for prostate cancer and who were clinically disease free 8-22 years later were also observed, with a median of 5.8 years of PSA observations. Results: Only 3 of the 24 patients in the first group showed a significant rise of > 0.2 ng/ml in their serum PSA levels, with a median of 3.3 years f ollow-up from the first PSA test. Seven of 24 showed progressive declines, and 14 of 24 showed steady levels. The median PSA for this group was less t han or equal to 0.5 ng/ml, Only 6 of the 46 in the second group showed a PS A rise of > 0.2 ng/ml, Thirty-four had stable values, and 6 had further dec lines. Again, the median PSA for the entire group was I 0.5 ng/ml, Conclusion: Recovery of prostatic secretory function is an uncommon event a fter external beam radiation. The concern that this might significantly con found new definitions of biochemical failure after radical radiation for pr ostate cancer that are based on progressively rising PSA values thus appear s to be unfounded, (C) 1999 Elsevier Science Inc.