Good prognosis following a PSA bounce after high dose rate brachytherapy and external radiotherapy in prostate cancer

Background: PSA kinetics after curative radiotherapy for prostate cancer is an important part of the posttreatment evaluation. We analysed PSA bounce occurrence after combined high dose rate brachytherapy (HDR-BT) and external radiotherapy (ERT). Material & methods: We analysed 623 patients treated from 1995 to 2008. The median age was 66 years (47–79). The median initial PSA was 12 ng/ml (0.1–224). Neoadjuvant endocrine therapy was given to 429 patients. ERT was given with 2 Gy fractions to 50 Gy and HDR-BT in two 10 Gy fractions. The median follow-up was 11 years (range 2–266 months). PSA bounce was defined as a temporary rise in PSA >0.2 ng/ml. PSA failure was defined according to the Phoenix definition. Results: PSA bounce occurred in 159 patients (26%), where 56 patients had a bounce amplitude >2 ng/ml and 31 patients had multiple bounces. Median time to bounce peak was 15 (3–103) months with a median bounce value of 1.5 (0.3–12) ng/ml. Younger age and lower Gleason scores were associated with PSA bounce. In a Cox regression analysis with PSA bounce as a time-dependent covariate and adjusted for other prognostic factors, PSA bounce was associated with a lower risk for PSA failure (HR = 0.42; 95% confidence interval 0.26–0.70). Conclusion: PSA bounce after HDR-BT combined with ERT is common and associated with a good prognosis. As the relapse risk after an early bounce is very low, the findings should alert clinicians not to initiate salvage treatment too early. Research in prospective identification of PSA bounce is clinically relevant.