Risk-adjusted Screening for Prostate Cancer—Defining the Low-risk Group by Data from the PROBASE Trial

Abstract

BACKGROUND: Risk-adjusted screening for prostate cancer (PCa) aims to reduce harms by less frequent retesting, especially in men at a low risk of PCa. Definitions of low risk are based mainly on studies in men starting screening at age 55-60 yr. OBJECTIVE: To identify men at age 45 yr with a low risk of PCa. DESIGN, SETTING, AND PARTICIPANTS: A population-based, risk-adjusted PCa screening trial was conducted in Germany using baseline prostate-specific antigen (PSA) starting in young men (PROBASE). INTERVENTION: PSA measurements starting at the age of 45 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The incidence of PCa within 5 yr was assessed in men with screen-negative baseline PSA <1.5 ng/ml compared with those with PSA 1.5-≤3.0 ng/ml. RESULTS AND LIMITATIONS: Of 23301 men who received a first PSA test at age 45 yr, 0.79% had a screen-positive PSA value of ≥3 ng/ml. Among the 89% of men who had a screen-negative baseline PSA value of <1.5 ng/ml, only 0.45% received a positive PSA test ≥3 ng/ml upon retesting after 5 yr. By contrast, for those with a screen-negative baseline PSA value of 1.5-3 ng/ml, 13% surpassed 3 ng/ml upon biennial testing within the next 4 yr. The incidence of PCa in subsequent screening rounds increased with increasing baseline PSA levels, from 0.13 per 1000 person-years for men with initial PSA level of <1.5 ng/ml to 8.0 per 1000 person-years for those with PSA levels of 1.5-3.0 ng/ml. A limitation is a follow-up time of only 5 yr, so far. CONCLUSIONS: Men with baseline PSA <1.5 ng/ml at age 45 yr are at a very low risk of PCa over the next 5 yr. PATIENT SUMMARY: The PROBASE study showed that men with baseline prostate-specific antigen (PSA) <1.5 ng/ml at age 45 yr have a very low prostate cancer detection rate over 5 yr and do not need PSA retesting during this time.