Measurement of Free PSA ratio in patients after definitive radical treatment for prostate cancer, and assessment of whether post-treatment free PSA ratio can function as a biomarker for advanced disease in prostate cancer patients.
Prostatic specific antigen (PSA) circulates mostly in complex with protease inhibitors, but 10-30% circulates as inactive free-PSA (FPSA). In patients with prostate cancer (PCa), pretreatment FPSA is lower and used to risk-stratify patients for biopsy. However, posttreatment FPSA ratio (FPSAR) is rarely quantified, with an unexplored clinical value. Methods The institutional database was queried to identify patients following radical prostatectomy (RP cohort) or radiotherapy (RT cohort) between 2000 and 2017. For validation, the investigators identified an independent prospective cohort with biochemical recurrence (BCR) after RP, using biobank samples (biobank cohort). All patients had at least one posttreatment FPSAR test. Kaplan-Meier (KM) method was used to compare the metastasis-free (MFS), castration-resistant PCa (CRPC)-free, and cancer-specific-survival (CSS) rates. Multivariable Cox models determined the association between posttreatment FPSAR, metastases, and CRPC.
Study Type
OBSERVATIONAL
Enrollment
822
Free PSA ratio blood test done on biobank samples of patients after radical prostatectomy who developed biochemical recurrence.
Princess Margaret Cancer Center
Toronto, Ontario, Canada
Metastasis free survival
Rate of Metastasis correlated to the first post-treatment free PSA ratio
Time frame: From date of diagnosis to date of Metastasis development, assessed up to 200 months
Castrate resistant prostate cancer (CRPC) free survival
Rate of CRPC correlated to the first post-treatment free PSA ratio
Time frame: From date of Diagnosis to date of CRPC development, assessed up to 200 months
Cancer specific survival
Rate of Cancer specific survival correlated to the first post-treatment free PSA ratio
Time frame: From date of diagnosis to date of cancer specific death, assessed up to 200 months
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