Abstract
BACKGROUND: Prostate-specific antigen (PSA) measurement in midlife predicts long-term prostate cancer (PCa) mortality among white men. OBJECTIVE: To determine whether baseline PSA level during midlife predicts risk of aggressive PCa in black men. DESIGN, SETTING, AND PARTICIPANTS: Nested case-control study among black men in the Southern Community Cohort Study recruited between 2002 and 2009. A prospective cohort in the southeastern USA with recruitment from community health centers. A total of 197 incident PCa patients aged 40-64 yr at study entry and 569 controls matched on age, date of blood draw, and site of enrollment. Total PSA was measured in blood collected and stored at enrollment. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Total and aggressive PCa (91 aggressive: Gleason ≥7, American Joint Committee on Cancer stage III/IV, or PCa-specific death). Exact conditional logistic regression estimated odds ratios (ORs) with 95% confidence intervals (CIs) for PCa by category of baseline PSA. RESULTS AND LIMITATIONS: Median PSA among controls was 0.72, 0.80, 0.94, and 1.03ng/ml for age groups 40-49, 50-54, 55-59, and 60-64 yr, respectively; 90th percentile levels were 1.68, 1.85, 2.73, and 3.33ng/ml. Furthermore, 95% of total and 97% of aggressive cases had baseline PSA above the age-specific median. Median follow-up was 9 yr. The OR for total PCa comparing PSA >90th percentile versus ≤median was 83.6 (95% CI, 21.2-539) for 40-54 yr and 71.7 (95% CI, 23.3-288) for 55-64 yr. For aggressive cancer, ORs were 174 (95% CI, 32.3-infinity) for 40-54 yr and 51.8 (95% CI, 11.0-519) for 55-64 yr. A composite endpoint of aggressive PCa based on stage, grade, and mortality was used and is a limitation. CONCLUSIONS: PSA levels in midlife strongly predicted total and aggressive PCa among black men. PSA levels among controls were similar to those among white controls in prior studies. PATIENT SUMMARY: Prostate-specific antigen (PSA) level during midlife strongly predicted future development of aggressive prostate cancer among black men. Targeted screening based on a midlife PSA might identify men at high risk while minimizing screening in those men at low risk.