Genetics of Prostate Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Introduction
Table 1. Relative Risk (RR) Related to Family History of Prostate Cancera
|Risk Group||RR for Prostate Cancer (95% CI)|
|CI = confidence interval; FDR = first-degree relative.|
|a Adapted from Zeegers et al.|
|Brother with prostate cancer diagnosed at any age||3.4 (3.0–3.8)|
|Father with prostate cancer diagnosed at any age||2.2 (1.9–2.5)|
|One affected FDR diagnosed at any age||2.6 (2.3–2.8)|
|One affected second-degree relative diagnosed at any age||1.7 (1.1–2.6)|
|Affected FDRs diagnosed age <65 y||3.3 (2.6–4.2)|
|Affected FDRs diagnosed age >65 y||2.4 (1.7–3.6)|
|Two or more affected FDRs diagnosed at any age||5.1 (3.3–7.8)|
Using data from the Nationwide Swedish Family-Cancer Database, age-specific HRs for prostate cancer diagnosis and mortality were computed. The analysis was stratified by whether the father and/or brother(s) of affected men also had prostate cancer and by their age at diagnosis. The HRs increased with decreasing age at diagnosis for both fathers and male siblings. As expected, the HR for prostate cancer diagnosis was high in men with a father and two brothers with prostate cancer (HR, 10.86; 95% CI, 7.08–16.66) or with three brothers with prostate cancer (HR, 24.35; 95% CI, 16.18–36.64).
The risk of prostate cancer may also increase in men who have a family history of breast cancer. Approximately 9.6% of the Iowa cohort had a family history of breast and/or ovarian cancer in a mother or sister at baseline, and this was positively associated with prostate cancer risk (age-adjusted RR, 1.7; 95% CI, 1.0–3.0; multivariate RR, 1.7; 95% CI, 0.9–3.2). Men with a family history of both prostate and breast/ovarian cancer were also at increased risk of prostate cancer (RR, 5.8; 95% CI, 2.4–14.0). Other studies, however, did not find an association between family history of female breast cancer and risk of prostate cancer.[38,44] A family history of prostate cancer also increases the risk of breast cancer among female relatives. The association between prostate cancer and breast cancer in the same family may be explained, in part, by the increased risk of prostate cancer among men with BRCA1/BRCA2mutations in the setting of hereditary breast/ovarian cancer or early-onset prostate cancer.[46,47,48,49] (Refer to the BRCA1 and BRCA2 section of this summary for more information.)
Family history has been shown to be a risk factor for men of different races and ethnicities. In a population-based case-control study of prostate cancer among African Americans, whites, and Asian Americans in the United States (Los Angeles, San Francisco, and Hawaii) and Canada (Vancouver and Toronto), 5% of controls and 13% of all cases reported a father, brother, or son with prostate cancer. These prevalence estimates were somewhat lower among Asian Americans than among African Americans or whites. A positive family history was associated with a twofold to threefold increase in RR in each of the three ethnic groups. The overall odds ratio associated with a family history of prostate cancer was 2.5 (95% CI, 1.9–3.3) with adjustment for age and ethnicity.