In a study reported in the Journal of Clinical Oncology, Derya Tilki, MD, and colleagues identified a prostate-specific antigen (PSA) level cutpoint, above which initiation of salvage radiation therapy after radical prostatectomy was associated with an increased risk of all-cause mortality in patients with prostate cancer.
The study cohort consisted of 25,551 patients with pT2-4N0 or NXM0 disease consecutively treated between June 1990 and June 2020 at the University Hospital Hamburg-Eppendorf (n = 24,345) or the University of California, San Francisco (n = 1,206). Patients could have at most one high-risk factor—ie, pT3/4 disease or a Gleason score between 8 and 10. Cox regression analysis was used to determine whether a significant increase in all-cause mortality risk was observed when salvage radiation therapy was delivered above a particular PSA level, beginning at 0.10 ng/mL and in 0.05 increments up to 0.50 ng/mL vs at or below that level. The model was adjusted for age at and year of radical prostatectomy, established prostate cancer prognostic factors, institution, and time-dependent use of androgen-deprivation therapy.
Among patients with at most one high-risk factor, initiating salvage radiation therapy above a PSA level of 0.25 ng/mL was associated with increased all-cause mortality risk.— Derya Tilki, MD, and colleagues
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Median follow-up was 6 years.
Patients who received salvage radiation therapy at a PSA level of > 0.25 ng/mL had a significantly higher risk of all-cause mortality (adjusted hazard ratio [aHR] = 1.49; 95% confidence interval [CI] = 1.11–2.00, P =.008) vs those who received salvage radiation therapy at PSA levels of ≤ 0.25 ng/mL.
Patients who received salvage radiation therapy at a PSA level of > 0.25 ng/mL had a numerically elevated risk of prostate cancer–specific mortality (aHR = 1.43, 95% CI = 0.80–2.55) vs those who received salvage radiation therapy at PSA levels of ≤ 0.25 ng/mL.
Elevated risk of all-cause mortality was significant for all PSA cutpoints above 0.25 ng/mL through 0.50 ng/mL. At the 0.50 ng/mL cutpoint, the adjusted hazard ratio was 1.61 (95% CI = 1.21–2.14, P = .001).
Adjusted hazard ratios for PSA cutpoints of 0.20, 0.15, and 0.10 were 1.28, 1.11, and 0.88, respectively, with none being statistically significant.
The investigators concluded: “Among patients with at most one high-risk factor, initiating salvage radiation therapy above a PSA level of 0.25 ng/mL was associated with increased all-cause mortality risk.”
Anthony V. D’Amico, MD, PhD, of the Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the UCSF Goldberg-Benioff Program in Translational Cancer Biology. For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.