OBJECTIVE: To investigate the effect of the percentage of free prostate-specific antigen (%fPSA) on future prostate cancer risk.
MATERIALS AND METHODS: We examined serum total PSA (tPSA) and %fPSA annually in a prostate cancer-screening cohort between July 2001 and June 2011. Men with tPSA >4.0 ng/mL or tPSA of 2.0-4.0 ng/mL with %fPSA ≤ 12% were screened as positive and were recommended to undergo a biopsy. The study population consisted of 6368 men, aged 40-79 years, who had tPSA ≤ 4.0 ng/mL at initial screening and who subsequently underwent 1 or more screenings. We calculated the cumulative risk and hazard ratio of prostate cancer stratified by the initial %fPSA groups as quartiles of prostate cancer patients.
RESULTS: During a median follow-up of 36 months, 119 men were diagnosed with prostate cancer. The lowest quartile of %fPSA (< 13.3%) was associated with a 21.2-fold higher risk of having prostate cancer compared with the highest quartile (>22.2%). For the subset with an initial tPSA ≤ 1.0 ng/mL, all men diagnosed with cancer had an initial %fPSA ≤ 33.3% (median). For the subset with tPSA >1.0 ng/mL, men with %fPSA ≤ 23.0% (median) had significantly higher risk for cancer than those with %fPSA >23.0% (P < .0001). Of the 114 men with prostate cancer in whom pathologic findings were available, 79 (69.3%) had a Gleason score ≥3 + 4 = 7.
CONCLUSION: A low %fPSA is a strong predictor of a subsequent diagnosis of prostate cancer among men with tPSA levels ≤ 4.0 ng/mL. Measurement of %fPSA might enhance the detection of high-grade cancer that warrants aggressive treatment.
Sasaki M, Ishidoya S, Ito A, Saito H, Yamada S, Mitsuzuka K, Kaiho Y, Shibuya D, Yamaguchi T, Arai Y. Are you the author?
Department of Urology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Urology, Sendai City Hospital, Sendai, Japan; Miyagi Cancer Society, Sendai, Japan; Division of Biostatistics, Tohoku University Graduate School of Medicine, Sendai, Japan.
Reference: Urology. 2014 Nov;84(5):1163-7.