From the Guidelines
Having a brother with prostate cancer increases your risk of developing the disease, with an increased relative risk of 1.8, and you should consider starting prostate cancer screening earlier than the general population, typically around age 45. Family history is a significant risk factor for prostate cancer, with first-degree relatives (father, brother, son) who have had prostate cancer approximately doubling your risk 1. The risk increases further if multiple relatives were affected or if they were diagnosed at a younger age (before 55). This familial risk is due to shared genetic factors and possibly similar environmental exposures.
Key Points to Consider
- The increased relative risk of developing prostate cancer with one first-degree relative diagnosed with PCa is 1.8, which increases to 5.5 if the father and a brother are diagnosed, and 7.7 if two brothers are diagnosed 1.
- Carriers of gene alterations in BRCA2, MSH2, and MSH6 (Lynch syndrome) are at an increased risk, and to a lesser degree, those with BRCA1 1.
- Germline mutations can drive the development of aggressive PCa, and certain men should be considered for germline testing, including those with metastatic PCa, BRCA mutations, or a family history of high-risk germline mutations 1.
- The American Cancer Society recommends that men at higher risk, including those with a family member (father or brother) diagnosed with prostate cancer before age 65 years, should receive information about prostate cancer screening beginning at age 45 years 1.
- Screening involves a prostate-specific antigen (PSA) blood test and possibly a digital rectal examination (DRE), with the interval for further screening based on initial and subsequent PSA levels 1. Given your family history, it's essential to discuss your risk factors with your doctor to develop an appropriate screening plan and consider genetic counseling if multiple family members have had prostate cancer, as certain inherited gene mutations (like BRCA1/2) can increase risk 1.
From the Research
Prostate Cancer Risk
- Having a brother with prostate cancer may increase an individual's risk of developing the disease, as there is a known familial component to prostate cancer risk 2, 3.
- However, the provided studies do not directly address the question of whether having a brother with prostate cancer increases an individual's risk.
5-Alpha-Reductase Inhibitors and Prostate Cancer
- 5-alpha-reductase inhibitors (5-ARIs) have been shown to reduce the risk of prostate cancer, with a relative risk reduction of 25-26% 2, 3, 4, 5.
- Finasteride, a type of 5-ARI, has been specifically shown to reduce the risk of prostate cancer, including high-grade tumors, and improve the performance characteristics of prostate-specific antigen (PSA) testing 2, 3, 4.
- The use of 5-ARIs may also delay the progression of prostate cancer, although the evidence for this is not as strong 6, 5.
Family History and Prostate Cancer Risk
- While the provided studies do not directly address the question of whether having a brother with prostate cancer increases an individual's risk, they do suggest that 5-ARIs may be effective in reducing prostate cancer risk regardless of family history 3, 5.
- However, more research is needed to fully understand the relationship between family history and prostate cancer risk, and how 5-ARIs may impact this risk.