Family History and Probability of Prostate Cancer, Differentiated by Risk Category: A Nationwide Population-Based Study

Background: Familial prostate cancer risk estimates are inflated by clinically insignificant low-risk cancer, diagnosed after prostate-specific antigen testing. We provide age-specific probabilities of non-low-and high-risk prostate cancer. Methods: Fifty-one thousand, eight hundred ninety-seven brothers of 32 807 men with prostate cancer were identified in Prostate Cancer data Base Sweden (PCBaSe). Nelson-Aalen estimates with 95% confidence intervals (CIs) were calculated for cumulative, family history-stratified probabilities of any, non-low-(any of Gleason score >= 7, prostate-specific antigen [PSA] >= 10 ng/mL, T3-4, N1, and/or M1) and high-risk prostate cancer (Gleason score >= 8 and/or T3-4 and/or PSA >= 20 ng/mL and/or N1 and/or M1). Results: The population probability of any prostate cancer was 4.8% (95% CI = 4.8% to 4.9%) at age 65 years and 12.9% (95% CI = 12.8% to 12.9%) at age 75 years, of non-low-risk prostate cancer 2.8% (95% CI = 2.7% to 2.8%) at age 65 years and 8.9% (95% CI = 8.8% to 8.9%) at age 75 years, and of high-risk prostate cancer 1.4% (95% CI = 1.3% to 1.4%) at age 65 years and 5.2% (95% CI = 5.1% to 5.2%) at age 75 years. For men with one affected brother, probabilities of any prostate cancer were 14.9% (95% CI = 14.1% to 15.8%) at age 65 years and 30.3% (95% CI = 29.3% to 31.3%) at age 75 years, of non-low-risk prostate cancer 7.3% (95% CI = 6.7% to 7.9%) at age 65 years and 18.8% (95% CI = 17.9% to 19.6%) at age 75 years, and of high-risk prostate cancer 3.0% (95% CI = 2.6% to 3.4%) at age 65 years and 8.9% (95% CI = 8.2% to 9.5%) at age 75 years. Probabilities were higher for men with a stronger family history. For example, men with two affected brothers had a 13.6% (95% CI = 9.9% to 17.6 %) probability of high-risk cancer at age 75 years. Conclusions: The age-specific probabilities of non-low-and high-risk cancer presented here are more informative than relative risks of any prostate cancer and more suitable to use for counseling men with a family history of prostate cancer.