Prostate cancer develops when cells in the prostate gland begin to grow abnormally, but doctors do not yet know exactly why this happens in some men and not others.
The prostate is a small gland that makes fluid for semen. Cancer starts when the DNA inside prostate cells mutates—changes in a way that tells the cells to divide faster than normal and not die when they should. Over time, these abnormal cells pile up and form a tumor. Most prostate cancers grow slowly, and many men with the disease never have symptoms or problems from it.
No single cause has been found. Instead, prostate cancer appears to result from a combination of age, genetics, hormones, and possibly environmental factors. Understanding these risk factors can help you talk with your doctor about screening and what to watch for, but having a risk factor does not mean you will develop cancer.
Key Takeaways
- Prostate cancer happens when cells in the prostate gland mutate and grow abnormally, but the exact trigger is not known.
- Age is the strongest risk factor—most cases occur in men over 65, though it can happen at any age.
- Family history and race matter: Black men have higher rates, and men with a father or brother who had prostate cancer face increased risk.
- Hormones, obesity, and possibly some infections may play a role, but the evidence is still being studied.
- Many prostate cancers grow so slowly that men never notice symptoms, and some are found only by screening tests.
Age as the Primary Risk Factor
Age is the strongest known risk factor for prostate cancer. The disease is rare in men under 40 and becomes more common as men get older. Most cases are diagnosed in men 65 and older, though younger men can develop it.
This pattern suggests that prostate cancer requires time to develop—multiple mutations need to accumulate in cells before a tumor forms. A man's risk rises steadily with each decade of life. If you are over 50, your doctor may discuss screening options with you, depending on your other risk factors and personal preferences.
Family History and Genetic Risk
Men whose father, brother, or son had prostate cancer face a higher risk than men with no family history. The risk is even higher if the relative was diagnosed before age 65 or if multiple family members were affected.
Inherited genetic mutations account for a small percentage of prostate cancers. Some men carry mutations in genes like BRCA1, BRCA2, or Lynch syndrome genes that increase their cancer risk across multiple organs. Genetic testing is available if you have a strong family history, and your doctor can refer you to a genetic counselor to discuss whether testing makes sense for you.
Race and Ethnicity
Black men have higher rates of prostate cancer than white men and are more likely to be diagnosed at a younger age and with more advanced disease. The reasons are not fully understood and likely involve a mix of genetic, hormonal, and social factors—including differences in access to screening and care.
Men of African descent, Caribbean descent, or with family roots in sub-Saharan Africa may want to discuss prostate cancer screening with their doctor starting at age 40 or 45, earlier than the standard recommendation for other men. Your doctor can help you weigh the benefits and risks of screening based on your individual situation.
Hormones and Testosterone
Testosterone and other male hormones appear to fuel prostate cancer growth, though having normal testosterone levels does not cause cancer. Men who have been treated with hormone therapy for other conditions, or who have taken testosterone supplements, may have different cancer risks—the evidence is mixed and still being studied.
Prostate cancer cells need testosterone to survive and grow. This is why some prostate cancer treatments work by lowering testosterone or blocking its effects. However, the relationship between hormone levels and cancer development is complex, and researchers are still working to understand it fully.
Obesity and Diet
Some studies suggest that obesity may increase the risk of prostate cancer, particularly more aggressive forms. Diet has also been studied—some research points to high-fat diets or processed meats as possible risk factors, while other studies have not found clear links.
The evidence is not strong enough to say that any single food or diet pattern causes prostate cancer. Maintaining a healthy weight and eating a balanced diet are good for overall health, but they are not proven to prevent prostate cancer specifically. If you are concerned about your diet and cancer risk, your doctor or a nutritionist can discuss what the current evidence suggests.
Infections and Environmental Factors
Researchers have investigated whether sexually transmitted infections, particularly human papillomavirus (HPV), might increase prostate cancer risk. Some studies suggest a possible link, but the evidence remains unclear and is still being researched.
Environmental exposures—such as pesticides, occupational chemicals, or pollutants—have been studied as possible risk factors, but no clear causal link has been established. Most men who develop prostate cancer have no known environmental exposure that explains it. If you work with chemicals or have concerns about specific exposures, talk with your doctor about your individual risk.
What Does Not Cause Prostate Cancer
Prostate cancer is not caused by sexual activity, masturbation, or vasectomy. It is not contagious and cannot be passed from one person to another. Benign prostate enlargement (BPH), which is common in older men, does not cause cancer, though the two conditions can occur together.
Having symptoms like difficulty urinating or frequent urination does not mean you have cancer—these are common with BPH and other non-cancerous conditions. If you have urinary symptoms, your doctor can evaluate them and determine what is causing them.
Frequently Asked Questions
Can prostate cancer run in families?
Yes. Men with a father, brother, or son who had prostate cancer have a higher risk, especially if the relative was diagnosed before age 65 or if multiple family members were affected. If you have a strong family history, tell your doctor—they may recommend earlier screening or genetic counseling.
Does having a high PSA level mean I have cancer?
No. PSA (prostate-specific antigen) is a protein made by the prostate, and levels can be elevated for many reasons, including infection, benign enlargement, or age. A high PSA may prompt further testing, but it does not diagnose cancer. Your doctor will discuss what your PSA result means for you.
Is prostate cancer preventable?
There is no proven way to prevent prostate cancer. Maintaining a healthy weight, eating well, and staying active are good for overall health, but they are not known to prevent this cancer specifically. Some research suggests certain medications may lower risk, but this is still being studied.
Why do some men get prostate cancer and others do not?
Prostate cancer appears to result from a combination of factors—age, genetics, hormones, and possibly environment—but the exact mix differs from person to person. Even men with multiple risk factors may never develop cancer, while some without known risk factors do. This is why doctors focus on individual risk assessment rather than prediction.
Should I get screened for prostate cancer?
That depends on your age, race, family history, and personal preferences. Most organizations recommend discussing screening with your doctor starting at age 50 (or 40–45 if you are Black or have a family history). Your doctor can help you understand the benefits and risks of screening tests like PSA and digital rectal exam.