To assess whether free PSA ratio (FPSAR) at biochemical recurrence (BCR) can predict metastasis, castrate-resistant PCa (CRPC), and cancer-specific survival (CSS), following therapy for localized disease.
A single-center retrospective cohort study (NCT03927287) including a discovery cohort composed of patients with an FPSAR after radical prostatectomy (RP) or radiotherapy (RT) between 2000-2017. For validation, an independent biobank cohort of patients with biochemical recurrence (BCR) after RP was tested. Using a defined FPSAR cutoff, the metastasis-free-survival (MFS), CRPC-free survival, and CSS were compared. Multivariable Cox models determined the association between posttreatment FPSAR, metastases, and CRPC.
Overall, 822 patients (305 RP- and 363 RT-treated patients and 154 biobank patients) were analyzed. In the RP cohort, a total of 272/305 (89.1%) and 33/305 (10.9%) had an FPSAR test incidentally and reflexively, respectively. In the RT cohort, 155/363 (42.7%) and 208/263 (57.3%) had an FPSAR test incidentally and reflexively, respectively. However, in the prospective biobank RP cohort, FPSAR testing was done on all samples of patients diagnosed with BCR. An FPSAR cutoff of 0.10 was determined using receiver-operating characteristic-analyses in both RP and RT cohorts. FPSAR<0.10 resulted in longer median MFS (14.8 vs. 9.3 years, and 14.8 vs. 13 years, respectively), and longer median CRPC-free survival (median not reached vs. 9.9 years, and 20.7 vs. 13.8 years, respectively). Multivariable analyses showed that FPSAR>=0.10 was associated with increased metastasis in the RP cohort (HR 1.915 [95% CI 1.241-2.955], and RT cohort (HR 1.754 [95% CI 1.112-2.769]), and increased CRPC in the RP cohort (HR 2.470 [95% CI 1.493-4.088]). Findings were validated in the biobank cohort.
Posttreatment FPSAR>=0.10 is associated with more aggressive disease, suggesting a potentially novel role for this biomarker.
BJU international. 2020 Sep 14 [Epub ahead of print]
H Goldberg, R Glicksman, D Woon, A Hoffman, H Shaikh, T Chandrasekar, Z Klaassen, C J D Wallis, A E Ahmad, N Salgado, M Qu, F Y Moraes, E P Diamandis, A Berlin, N E Fleshner
Division of Urology, Department of Surgical Oncology, Princess Margaret Cancer Centre, University Health Network and the University of Toronto, Toronto, Ontario, Canada., Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network and Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada., Department of Urology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA., Division of Urology, Department of Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA., Department of Pathology and Laboratory Medicine, Sinai Health System, University of Toronto, Toronto, Ontario, Canada.