What Prostate Cancer Has To Do With Breast Cancer
A common cause of inherited breast cancer is a change (mutation) in the BRCA genes. Mutations in these genes increase the risk of developing breast cancer. BRCA mutations also increase the risk of other cancers, including prostate cancer. They also increase the risk of more severe forms of prostate cancer.1,2
Because of these increased risks, experts recommend prostate cancer screening in men with BRCA mutations. They also recommend screening for BRCA mutations in some men with prostate cancer. This can help inform doctors on the best possible treatments. Talk to your doctor about your risk for BRCA mutations or prostate cancer.3
What are BRCA genes?
BRCA is the symbol for 2 genes linked to breast cancer. BRCA1 and BRCA2 are genes that cells use to make BRCA1 and BRCA2 proteins. These proteins help repair damaged DNA. When BRCA genes have harmful mutations, these proteins may not work. This can cause cells to grow out of control, leading to cancer.4
You inherit 2 copies of each BRCA gene – 1 from each parent. Inheriting a mutated BRCA gene increases your risk of several cancers. It also increases the risk of developing cancer younger. The most notable risks are for breast and ovarian cancer.4
Most people with BRCA mutations only inherit 1 mutated copy. The other copy is usually a normal BRCA gene. But that normal copy can undergo changes during your life. So you may end up with both copies of a BRCA gene having harmful mutations.4
How do BRCA mutations affect the risk for prostate cancer?
Harmful mutations in BRCA genes increase the risk of prostate cancer. Men with BRCA2 mutations may be twice to 8 times more likely to develop prostate cancer. BRCA2 mutations are also linked to earlier-onset and more severe prostate cancer.5-8
One study screened almost 3,000 men. The men were split into groups based on whether they had a BRCA mutation and – if so – in which gene. The study confirmed the link between BRCA2 mutations and early-onset, severe prostate cancer. Investigators tested participants every year for prostate cancer. After 4 years of screening, the study diagnosed prostate cancer in:5
- 5.2 percent of men with BRCA2 mutations but only 3.0 percent of men without BRCA2 mutations
- 3.4 percent of men with BRCA1 mutations but only 2.7 percent of men without BRCA1 mutations
Another study assessed the overall lifetime risk of prostate cancer. It found a lifetime risk of prostate cancer of:9
- 29 percent for men with BRCA1 mutations
- 60 percent for men with BRCA2 mutations
How do BRCA mutations affect prostate cancer screening?
If you or a family member has a BRCA mutation, talk to your doctor about prostate cancer screening. In 2021, experts from the National Comprehensive Cancer Network (NCCN) expanded their guidelines for screening in men with BRCA mutations. These guidelines also recommend screening for breast, skin, and other cancers in men.3
The expanded guidelines recommend that men with BRCA mutations have:3
- Prostate cancer screening starting at age 40
- Annual breast exams
- Training in breast self-examination to do regularly starting at age 35
- Annual full-body skin exams
What are the guidelines for screening for BRCA mutations?
If you are concerned about having a harmful BRCA mutation, talk to your doctor. They may refer you to a genetic counselor to discuss risk factors. Experts recommend testing only for people with a higher risk of BRCA mutations. About 10 percent of men with metastatic prostate cancer have BRCA mutations.10,11
Genetic testing can help doctors know your risk for prostate cancer and possible severity. It can also help them decide on possible treatments. The 2021 NCCN guidelines recommend genetic testing for BRCA mutations in:3
- People with family members who have BRCA mutations
- People with metastatic prostate cancer
- Other people with prostate cancer in certain high-risk groups
- Certain people with pancreatic, ovarian, or breast cancer
- People with a family history of cancer
The guidelines note that testing may not be useful for men with localized, low-grade prostate cancer and no family history of cancer. Talk to your doctor about whether testing is useful for you. Ask them what possible test results may mean.3
How do BRCA mutations affect prostate cancer treatment?
Treatment for prostate cancer involves some combination of surgery, radiation, and chemotherapy. Men with BRCA-positive prostate cancer may benefit from specific chemotherapies. These are called “targeted therapies.” They work by targeting the DNA repair problem caused by BRCA mutations.10,12
The US Food and Drug Administration (FDA) has approved 2 drugs for men with BRCA-positive prostate cancer:10,12
Both work by blocking a protein called “poly-ADP ribose polymerase” (PARP). PARP is another protein involved in DNA repair. When PARP is blocked, cancer cells have no way to fix problems in their DNA. This causes cancer cells to die.10,12
Ask your doctor if these treatments are right for you. Talk to your doctor about possible risks, including side effects and developing resistance. Ask them whether benefits outweigh these risks.
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