Clinical implications of a prostate-specific antigen bounce after radiation therapy for prostate cancer

• Published in: International journal of clinical oncology Vol. 20; no. 3; pp. 598 - 604
• Main Authors: Naghavi, Arash O., Strom, Tobin J., Nethers, Kevin, Cruz, Alex A., Figura, Nicholas B., Shrinath, Kushagra, Yue, Binglin, Kim, Jongphil, Biagioli, Matthew C., Fernandez, Daniel C., Heysek, Randy V., Wilder, Richard B.
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.06.2015; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Antigens; Cancer Research; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Oncology; Original Article; Prostate cancer; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - drug therapy; Prostatic Neoplasms - radiotherapy; Radiation therapy; Surgical Oncology; Radiotherapy; Prostate-specific antigen; Prostatic neoplasms
• ISSN: 1341-9625; 1437-7772
• DOI: 10.1007/s10147-014-0745-8

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.