Prostrate cancer risk factors, basically there are five risk factors for prostrate cancer. Age, prostrate cancer occurs mainly in older men about six cases in ten are diagnosed in men aged 65 or older, and it is rare before the age of 40. The average age at the time of diagnosis is about 66 years of age. Ethnicity, prostate cancer occurs more often in African-American men and less often in Asian men. Family history, having a father or brother with prostate cancer more than doubles a man's risk for developing this disease. There are some genes that are associated with prostate cancer, including HoxB13, BRCA1,2, MSH2, and MLH1. And finally, it appears that a diet high in red meat and low in vegetables leads to increased risk of prostate cancer. Let's look at some of these in more detail. Age, prostate cancer occurs mainly in older men. About six cases in ten are diagnosed in men aged 65 years or older. It is rare before age 40. The average age at the time of diagnosis is about 66 to 70 years of age. If you look at the numbers, 1 in 10,000 men under age 40 will be diagnosed. 1 in 38 men, ages 40 to 59, and 1 in 14 men, age 60 to 69, are diagnosed. Overall, 1 in 7 men will be diagnosed with prostate cancer in their lifetime. Many men never know that they have prostate cancer. Autopsy studies of men who died of other causes have found prostate cancer in 30% in their 50s and in 80% of men in their 70s. This is often termed histologi or indolen prostrate cancer. We will talk more about this types of prostrate cancer when we talk about localized treatment in Lecture 3. Family history, a man with a father or brother who developed prostrate cancer, is twice as likely to develop the disease. This risk is further increased if the cancer was diagnosed in family members at a younger age (less than 55 years of age) or if it affected three or more family members. There are a few genes that may be involved in the development of prostate cancer. Inherited mutations in particular genes, such as BRCA1, BRCA2, and HOXB13 account for some cases of hereditary prostate cancer. Men with mutations, in these genes, have a high risk of developing prostate cancer, and in some cases other cancers during their lifetimes. It has been difficult to determine the exact percent risk associated with these genes. Recently, it is been demonstrated that men who develop metastatic prostate cancer have a higher chance of having a mutation in BRCA1, BRCA2 or other genes that help with DNA repair. Approximately 10% of these men have a germline mutation, meaning in the DNA they were born with. And approximately another 10% develop somatic mutations, meaning they have mutations that develop during the lifetime of the cancer cells. What about race? African American men are more likely to develop prostate cancer compared with Caucasian men and are nearly 2.5 times as likely to die from the disease. It remains unclear why this is true. Conversely Asian men who live in Asia have the lowest risk. When these men move to the United States, the risk goes up. Let's take a closer look at why this may be true. It appears where you live may affect your chances of getting prostate cancer. Men who live in cities north of 40 degrees latitude, for example, north of Philadelphia, Pennsylvania, have a higher risk of dying from prostate cancer than men who live below or south of 40 degrees of latitude. This effect may be due to inadequate sunlight during three months of the year which reduces Vitamin D levels. However, this is not been proven. Perhaps more interesting for men in the US, the risk of developing prostate cancer overall is about 17%, or one in seven. For men who live in rural China, it's about 2%. This has been shown not to be due to differences in prostrate cancer screening. When Chinese men move to the western culture, their risk increases substantially. It is now known that the diet high in fat and low in vegetables appears to increase risk of developing cancer overall, as well as developing prostate cancer. Asian men as they move to the United States, tend to eat a diet that is higher in fat and lower in vegetables than they did in China, for example. What the graph on the right shows you is that men in the United States and Canada and Western Europe eat much more animal fat than men in Japan. There are many myths associated with prostate cancer risk. Now I just wanted to go through this list of things that are not associated with prostate cancer risk. Again, benign prosthetic hyperplasia, or BPH, is benign growth of the prostate, and is not associated with prostate cancer risk. Prostatitis, infection of the prostate, not associated with prostate cancer risk. Sexual activity, not associated. Vasectomy, no clear association. Bike riding, no association. Alcohol consumptions, no association. There are some potential risk factors associated with aggressive versus slow growing prostate cancer. For example, it has been suggested that smoking leads to a higher risk of developing a more aggressive form of prostate cancer. Lack of vegetables in the diet, especially broccoli family vegetables, has been linked to a higher risk of aggressive prostate cancer. Obesity and lack of exercise have been associated with developing more aggressive form of prostate cancer. Agent orange exposure, especially important for Vietnam veterans, has been associated with developing more aggressive forms of prostate cancer. None of these studies suggested direct cause, but simple in association with a tendency to see higher grade prostate cancers in men who have these associated characteristics, for example, obesity or smoking. These types of risk factors, have led many people to ask, is there any way to prevent prostate cancer? Unfortunately, there are no known proven strategies. Possibilities include, eating a diet high in fiber, and low in fat. Staying physically active and maintaining normal weight. The good news is that these prevention strategies are important for maintaining good health across a lifetime, and if they are associated with decreased cancer risk and increased heart health, that's only good.