BACKGROUND: The objectives are to determine predictors of a prostate-specific antigen (PSA) bounce, whether a PSA bounce after radiotherapy for prostate cancer is associated with biochemical disease-free survival (bDFS), and the time course to a PSA bounce versus a biochemical failure post-irradiation.
METHODS: Between July 2000 and December 2012, 691 prostate cancer patients without regional or distant metastases were treated with external beam radiation therapy and/or brachytherapy, and had at least 12 months of follow-up. A PSA bounce was defined as a temporary PSA increase of ≥0.4 ng/mL. bDFS was defined according to the nadir + 2 definition.
RESULTS: The median follow-up was 42 months. The median time to first PSA bounce was 17 months (95 % confidence interval 15-18 months). In contrast, the median time to biochemical failure was 41 months (95 % confidence interval 28-53 months). Two hundred and twenty-six of 691 (33 %) patients had at least one PSA bounce with a median magnitude of 1.0 ng/mL (range 0.4-17.0). A Gleason score of 6 (p < 0.0001) predicted a PSA bounce on multivariate analysis. Patients with a PSA bounce experienced improved bDFS on multivariate analysis (p = 0.002).
CONCLUSIONS: Patients with a Gleason score of 6 were more likely to experience a PSA bounce which was associated with improved bDFS. A PSA bounce occurred sooner after radiotherapy than a biochemical failure. The authors recommend against performing prostate biopsies within 24-30 months of radiotherapy since an elevated PSA may simply represent a benign PSA bounce.
Naghavi AO, Strom TJ, Nethers K, Cruz AA, Figura NB, Shrinath K, Yue B, Kim J, Biagioli MC, Fernandez DC, Heysek RV, Wilder RB. Are you the author?
Department of Radiation Oncology, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL, 33612, USA.
Reference: Int J Clin Oncol. 2014 Sep 6. Epub ahead of print.