PSA bounce phenomenon after transperineal interstitial permanent prostate brachytherapy for localized prostate cancer

Abstract

We described the temporarily increase phenomenon in prostate-specific antigen level (PSA bounce) after transperineal interstitial permanent prostate brachytherapy (TIPPB) for localized prostate cancer. From December 1998 to May 2003, 500 consecutive patients with localized prostate cancer were treated with TIPPB using iodine-125 or palladium-103. We examined 200 patients who have more than 2-year PSA follow-up. Median follow-up length was 1,069 days (range, 712-1,411 days). No patient received neoadjuvant or adjuvant hormone therapy. PSA determinations were performed every 3 months for the first 2 years after procedure, and every 6 months hereafter. PSA bounce was defined as an increase of 0.1 ng/ml or greater above the preceding PSA level after implant followed by a subsequent decrease below that level. The American Society for Therapeutic Radiology and Oncology (ASTRO) consensus panel criteria 1996 were used to define biochemical failure. PSA bounce was observed in 40% (80/200) of the cases receiving TIPPB. The median time to PSA bounce was 13 months from the day of implant. The median magnitude of the PSA bounce was 0.3 ng/ml from the pre-bounce level. Twelve cases demonstrated biochemical failure according to the ASTRO consensus guidelines of three consecutive rises in PSA. Ten of these subsequently showed a drop in PSA, consistent with biologic control of their disease. Two cases remain classified as apparent biochemical failures. A transient rise in the PSA following TIPPB, the so-called "bounce" is a common occurrence. The apparent PSA control of ten of twelve cases failing by the ASTRO criteria raises some concern. Further observation will be necessary to determine ways to discriminate these from true disease progression.