The causes of prostate cancer are not fully understood, but age, family history, and race are the strongest known risk factors
Prostate cancer develops when cells in the prostate gland begin to grow abnormally. Doctors do not yet know exactly why this happens in some men and not others. What researchers have found is that certain factors make the disease more likely — but having a risk factor does not mean a man will definitely get prostate cancer, and some men without any known risk factors develop it anyway.
The most reliable predictors are things you cannot change: how old you are, your family's medical history, and your race or ethnicity. Lifestyle factors like diet and weight may play a role, but the evidence is less clear. Understanding what is known — and what remains uncertain — can help you talk with your doctor about your own risk.
Key Takeaways
- Age is the strongest risk factor; prostate cancer is rare before age 40 and becomes more common after 65.
- Men with a father or brother who had prostate cancer face roughly double the risk, and the risk is higher if relatives were diagnosed young.
- Black men have higher rates of prostate cancer and are more likely to be diagnosed at a younger age and with more advanced disease.
- Obesity, a diet high in red meat and dairy, and lack of physical activity may increase risk, though the evidence is not conclusive.
- Some inherited genetic mutations, including BRCA1 and BRCA2, raise prostate cancer risk, but these account for only a small percentage of cases.
Age as the primary risk factor
Prostate cancer is largely a disease of older men. It is rare before age 40, and the risk rises steadily after age 50. By age 70, autopsy studies suggest that many men have some prostate cancer cells in their gland, though most never develop symptoms or die from the disease.
This age pattern is one reason screening decisions are different for younger and older men. A man in his 40s with no symptoms and no family history faces a very low chance of having prostate cancer. A man in his 70s faces a higher chance, but doctors must weigh that against the risks of testing and treatment.
Family history and inherited risk
If your father or brother had prostate cancer, your risk is roughly two to three times higher than a man with no family history. The risk climbs further if multiple relatives were affected, or if they were diagnosed before age 65.
A small number of prostate cancers run in families because of inherited gene mutations. The most studied are mutations in the BRCA1 and BRCA2 genes, which also raise breast and ovarian cancer risk in women. Men carrying these mutations have a higher lifetime risk of prostate cancer. Other inherited mutations — in genes like HOXB13, PALB2, and CHEK2 — have also been linked to prostate cancer, but they are uncommon and account for only a fraction of familial cases.
Genetic testing for these mutations is available but not routine. It is most useful if you have a strong family history of prostate cancer, breast cancer, or ovarian cancer. A genetic counselor or your doctor can help you decide whether testing makes sense for you.
Race and ethnicity
Black men have the highest prostate cancer incidence and mortality rates in the United States. They are diagnosed at younger ages, with more advanced disease, and have worse outcomes overall compared to white men. Asian and Hispanic men have lower rates than white men.
The reasons for these differences are not fully clear. Some of the gap may reflect biological differences in how aggressive the cancer is in Black men. Some reflects differences in screening rates and access to care. Socioeconomic factors, environmental exposures, and healthcare disparities all likely play a role. Researchers are still working to untangle these causes.
Because of these patterns, some medical organizations recommend that Black men and men with a family history of prostate cancer discuss screening earlier and more frequently with their doctor — starting at age 40 rather than 50.
Lifestyle factors and diet
Several lifestyle factors have been studied as possible prostate cancer risk factors, though the evidence is mixed and often weaker than for age or family history.
Obesity has been linked to higher prostate cancer risk in some studies, particularly for more aggressive forms. Diet may matter: some research suggests that men who eat large amounts of red meat and high-fat dairy products have higher risk, while diets rich in vegetables, fruits, and fish may be protective. Physical activity has been associated with lower risk in some studies. However, these associations are not as strong or consistent as the link between age and prostate cancer, and it is difficult to prove that changing diet or exercise actually prevents the disease.
Other factors once suspected — such as vasectomy, sexually transmitted infections, and sexual activity — have not been confirmed as causes in large studies. Smoking does not appear to increase prostate cancer risk directly, though it does raise the risk of dying from it.
Hormones and inflammation
Testosterone and other male hormones called androgens are necessary for the prostate to function, and they may also fuel prostate cancer growth. Men with higher testosterone levels have been studied to see if they face higher cancer risk, but the relationship is complicated and not fully understood. Some men with high testosterone never develop cancer, while some with lower levels do.
Chronic inflammation in the prostate has also been investigated as a possible risk factor. Some research suggests that long-term inflammation may increase cancer risk, but this remains an area of active study rather than an established cause.
What is not proven to cause prostate cancer
Several factors once suspected have been largely ruled out by research. Vasectomy — a surgical procedure for male sterilization — was studied extensively and does not appear to increase prostate cancer risk. Benign prostate hyperplasia (BPH), an enlargement of the prostate common in older men, is not a cause of cancer, though the two conditions can occur together.
Sexually transmitted infections, including human papillomavirus (HPV), have been studied but are not established as causes. Prostatitis, an inflammation or infection of the prostate, is also not proven to lead to cancer, though some research continues in this area.
Frequently Asked Questions
Can prostate cancer be prevented?
There is no proven way to prevent prostate cancer entirely. Maintaining a healthy weight, staying physically active, and eating a diet rich in vegetables and fruits may lower risk, but these steps do not may provide prevention. Men at high risk because of age, family history, or race should discuss screening options with their doctor.
Does having a risk factor mean I will get prostate cancer?
No. Risk factors increase the likelihood, but many men with one or more risk factors never develop the disease. Conversely, some men without known risk factors do develop prostate cancer. Your doctor can help you understand your individual risk and what screening or monitoring might be right for you.
Should I get genetic testing if prostate cancer runs in my family?
Genetic testing may be worth discussing with your doctor if multiple family members had prostate cancer, especially if they were diagnosed before age 65, or if your family also has a history of breast or ovarian cancer. A genetic counselor can help you understand whether testing is appropriate and what the results would mean for you.
Does diet really affect prostate cancer risk?
Some studies suggest that diet may play a role — with red meat and high-fat dairy possibly increasing risk and vegetables and fish possibly lowering it — but the evidence is not as strong as for age or family history. Eating a healthy diet is worthwhile for many reasons, but it should not be relied on as cancer prevention on its own.
Is prostate cancer hereditary?
Most prostate cancers are not hereditary. However, some families carry inherited gene mutations that raise the risk. If you have multiple relatives with prostate cancer or a family history of breast or ovarian cancer, your doctor may recommend genetic counseling to assess whether hereditary risk applies to you.