Prostate specific antigen bounce after radioactive seed implantation followed by external beam radiation for prostate cancer

Purpose: Prostate specific antigen (PSA) may temporarily increase following radiotherapy for prostate cancer without signaling cancer recurrence. We d escribe this phenomenon which is called PSA bounce. Materials and Methods: From 1984 to 1995, 779 stage T1T2N0 cancer cases wer e treated with simultaneous radiotherapy with a (125)iodine prostate implan t followed by external beam radiation. Median pretreatment PSA was 7.7 ng./ ml. (range 0.3 to 188). PSA bounce was defined as an increase of 0.1 ng./ml . or greater above the preceding PSA level after simultaneous radiation fol lowed by a subsequent decrease below that level. Disease-free status was de fined as the ability to achieve and maintain posttreatment PSA 0.2 ng./ml. or less. Results: PSA bounce was observed in 35% of men (273 of 779). Median time to PSA bounce was 18 months from the time of implant and 92% of bounces were observed within 36 months. Median pre-bounce PSA was 0.7 ng./ml. (range 0.1 to 8.9) and median bounce height (increase above the pre-bounce level) was 0.4 ng./ml. (range 0.1 to 15.8). No distinguishing characteristics were ob served between men with PSA bounce and those with cancer recurrence, and bo unce had no prognostic significance relative to recurrence. Conclusions: PSA bounce is common following seed implantation for prostate cancer. It produces anxiety in men previously treated for prostate cancer a nd confounds the diagnosis of recurrence.