Positive predictive value (PPV) of prostate specific antigen (> ng/ml) and abnormal digital rectal exam for prostate cancer on the Caribbean island of Tobago

ABSTRACT

OBJECTIVE: To establish and compare the positive predictive values (PPV) for elevated (4 ng/ml) prostate specific antigen (PSA) and abnormal digital rectal exam (DRE) in an Afro-Caribbean population. DESIGN AND METHODS: We screened 728 men aged 40-79 years, recruited from the general population on the Caribbean island of Tobago. Ninety-five percent reported African ancestry. This population had not previously undergone screening for prostate cancer. RESULTS: PSA was elevated (> or = 4 ng/ml) and/or DRE was abnormal in 291 (40 percent) men. Pathological diagnosis of random sextant biopsies was completed in 191 (66 percent) of men. Ninety-two (13 percent) of the screened men were diagnosed with prostate cancer. Among men biopsied for abnormal DRE in the presence of normal PSA, PPV for abnormal DRE was 26 percent (11/43), range 9-50 percent across age groups. Among men with elevated PSA and normal DRE, the PPV for PSA was 46 percent (29/63), range 42-54 percent (no men aged 40-49 years (n=105) fell into this category). When all men with elevated PSA were considered, ignoring DRE status, PPV for PSA was 55 percent (79/144), range 50-60 percent. If both PSA and DRE were abnormal, the PPV was 63 percent. CONCLUSIONS: The PPV of abnormal DRE was similar to that observed in other populations undergoing screening for the first time. We speculate that a lower PSA cut-off point may be appropriate for optima ascertainment of cases in this high-risk population.(Au)