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Men fear prostate cancer more than almost any other diagnosis – and with good reason. It’s the most common cancer in men besides skin cancer, and it’s the second leading cause of cancer death in men. About 1 in 9 American men will be diagnosed with prostate cancer in his lifetime (ACS, 2019). PSA screening makes early detection possible, but with numbers like this, many men are interested in doing all they can to try and the development of prostate cancer. So is it preventable? Are there things men can do to at least lower their risk? Well, what we know for sure is that there are risk factors that we can control and others we can’t. Fortunately, some basic behaviors that are good for general health may also decrease an individuals’ risk of developing prostate cancer.
- The three most important risk factors for prostate cancer are family history, age, and African American heritage (Gann, 2002).
- While these risk factors for prostate cancer cannot be modified, several healthy lifestyle behaviors seem to decrease the risk of prostate cancer.
- Finasteride, and dutasteride—two drugs used to treat benign prostatic hyperplasia (BPH)—have been evaluated in clinical trials if they are useful in the prevention of prostate cancer.
- Some research has backed up the theory that ejaculating more frequently may decrease the risk of prostate cancer.
Inherited risk vs. acquired risk
Like with many other diagnoses, prostate cancer has inherited risk factors and acquired risk factors. The three most important risk factors for prostate cancer are family history, age, and African American heritage (Gann, 2002).
People with a first-degree relative diagnosed with prostate cancer have 2–3 times the risk of the general population. Having more than one first-degree relative raises that risk even higher. Family history is an inherited risk factor for prostate cancer that cannot be modified, but, as we’ll see in a moment, everyone can engage in healthy behaviors that may reduce the risk.
Age is technically an acquired risk factor for prostate cancer because we acquire it as we get older. This is due to a buildup of genetic mutations that happens with age, increasing the risk of many cancers, prostate cancer being just one of them. Prostate cancer is rare before 50 (0.2%) and becomes more common as we age (7.9% in those over 70) (ACS, 2019).
African American men have approximately 60% higher risk of prostate cancer than whites and double the risk of dying from prostate cancer. It is not clear why the risk is elevated for African Americans. It may be due to inherited genes, shared environmental factors, or a combination of both. Either way, African American heritage is a non-modifiable inherited risk factor prostate cancer even if environmental factors are at play.
Now that we’ve discussed prostate cancer risk factors that cannot be modified, what can be if anything, to lower the risk of prostate cancer?
Lifestyle plays a role
While the most important risk factors for prostate cancer cannot be modified, several healthy lifestyle behaviors seem to decrease the risk of prostate cancer. As expected, they include maintaining healthy eating and exercise habits, but one or two practices you might not expect may be beneficial as well. Here are some things you can do no matter what your family history or background.
Choose a Healthy Diet
Many nutrients and foods have been studied (Lin, 2015) as potentially being able to lower prostate cancer risk. These include:
- Protein and specific types of protein
- Animal protein
- Dairy protein
- Soy protein
- Fat and specific types of fat
- Saturated fat
- Omega-3 fatty acids
- Omega-6 fatty acids
- Vitamin E
- Vitamin D
- Vitamin K
Unfortunately, nutrition research tends to be very confusing, and nutrition to lower the risk of prostate cancer is no exception. Most of the individual nutrients and foods that have been studied show mixed findings, with some studies showing benefit or harm and others showing no benefit or harm. For example, folate and folic acid (a synthetic form of folate found in fortified foods and supplements) (Rycyna, 2013) have been found in some studies to be associated with increased prostate cancer risk, in others decreased prostate cancer risk, and in others, it seems to have no effect. Currently, scientists think that folate may protect against cancer development, but it may speed tumor growth in those who already have prostate cancer.
Nutrition research is often complicated by the fact that single foods and nutrients are just one aspect of a complex dietary pattern. Even if a given food or nutrient increases (or decreases) the risk of prostate cancer, this can easily be obscured by the rest of the diet or even other lifestyle factors. Fortunately, some patterns do seem to affect prostate cancer risk.
One observation that suggests that lifestyle plays a role is the different rates of prostate cancer in different regions of the world and how migration changes these risks. For example, Japan has much lower rates of prostate cancer than the United States, but Japanese Americans have a risk that is more similar to other Americans. This suggests that higher rates of prostate cancer in the US may be related to certain local lifestyle factors. One of these factors is dietary patterns in different parts of the world.
Western diets (Ambrosini, 2008) that are high in red meat, processed meat, hamburgers, fried fish, chips, saturated fat, and dairy products seem to increase prostate cancer risk. The Mediterranean diet, which is high in fruits, vegetables, whole grains, olive oil, and fisk, and lower in red meat may lower the risk of prostate cancer (Kapiszewska, 2006). Diets high in soy, green tea, and omega-3 fatty acids may also help reduce the risk of prostate cancer. The best advice is to follow a heart-healthy diet high in fruits and vegetables, and low in red meat and high-fat dairy. This pattern will be good for your heart, but it may also decrease your risk of prostate cancer.
Drugs for prostate cancer prevention
The possibility for drug treatment to decrease the risk of developing prostate cancer is very attractive. In particular, finasteride, and dutasteride—two drugs used to treat benign prostatic hyperplasia (BPH)—have been evaluated in clinical trials if they are useful in the prevention of prostate cancer. These drugs, known as 5-alpha reductase inhibitors (5 AR-Is), work by blocking the conversion of testosterone to dihydrotestosterone (DHT). DHT signals the prostate to grow, and, when it is suppressed with these drugs, the prostate shrinks over time. Since DHT is a potent androgen (male sex hormone) and androgens play a role in prostate cancer, these drugs have been studied to see if they can lower prostate cancer risk.
The Prostate Cancer Prevention Trial (Thompson, 2003) was designed to see whether taking finasteride 5 mg daily would lower prostate cancer risk. After seven years, there was a 24.8% lower risk of prostate cancer in the finasteride group than in the placebo group. However, this difference was accounted for solely by low-grade tumors (Gleason score of less than 7). High-grade tumors (Gleason score of 7 or more) were actually slightly more common in the finasteride group.
The Reduction by Dutasteride of Prostate Cancer Events (REDUCE) (Andriole, 2010) trial examined whether dutasteride 0.5 mg taken for four years would reduce the rate of prostate cancer. The results showed a 23% decrease in prostate cancer diagnoses in the dutasteride group compared to the placebo group. However, unlike the Prostate Cancer Prevention Trial, there was no increased risk of high-grade, aggressive prostate cancers (Gleason score of 7 or more) in the dutasteride group.
More recently, an extensive observational study (Wallerstedt, 2018) performed in Sweden showed a decreased risk of prostate cancer with 5 AR-Is, with longer use showing more substantial decreases in prostate cancer diagnosis. The reduced risk was for cancers with a Gleason score of 6 and 7, and the was no high-grade prostate cancer increases.
5 AR-I use is considered controversial for prostate cancer prevention. It is unknown why studies show mixed results. If you do decide to use 5 AR-Is for prostate cancer prevention, there are a couple of things you should know. These drugs don’t have many side effects, but the most common side effects are sexual in nature, including decreased libido and erectile dysfunction. These drugs also lower prostate-specific antigen (PSA) levels, which can make it more challenging to interpret the test. Your doctor may recommend a PSA test before starting a 5 AR-I, and it’s possible to have prostate cancer even with “normal” PSA levels if you are taking a 5 AR-I.
Can ejaculating more prevent prostate cancer?
The prostate stagnation hypothesis theorizes that one mechanism for the development of prostate cancer is the buildup of carcinogenic (cancer-causing) secretions in the prostate gland over time. This led to the theory that ejaculating more frequently may decrease the risk of prostate cancer by eliminating these secretions from the prostate (and body) regularly. A large study (Rider, 2016) of over 31,000 men with 18 years of follow-up and found that men who ejaculated 21 or more times per month in their 20s and 40s had an approximate 20% decreased the risk of prostate cancer compared to those who ejaculated 4–7 times per month. We cannot say whether the reduced risk was due to more frequent ejaculation, but ejaculating more frequently may be an enjoyable way to decrease the risk of prostate cancer.