How Family History Affects Prostate Cancer Risk

It has long been known that men with a family history of prostate cancer are at higher risk of getting it themselves. Now researchers from Sweden have calculated just how much having a brother or father with prostate cancer – or both – raises the risk. They also figured out how likely it is that a man with a family history will get a mild or aggressive (fast-growing) type of the disease. The authors suggest their findings can be useful in counseling men who have prostate cancer in the family.

Having more information about the risks of getting an aggressive type of prostate cancer can help men make their own personal decision about testing and treatment.

It seems like it would make sense for everyone to get checked to find out if they have cancer. But screening isn’t perfect. Sometimes screening misses cancer, and sometimes it finds something suspicious that turns out to be harmless. Also, there aren’t reliable tests yet to tell the difference between prostate cancer that’s going to grow so slowly it will never cause a man any problems, and dangerous cancer that will grow quickly. Treatments for prostate cancer can have urinary, bowel, and sexual side effects that may seriously affect a man’s quality of life.

The American Cancer Society recommends that men with a family history of prostate cancer should talk to their doctor at age 40 or 45 about the pros and cons of prostate cancer testing. Because African American men are at higher risk for the disease, they should also have this talk – whether they have a family history or not. Everyone else should begin talking to their doctor about testing at age 50.

Brothers and fathers

The researchers looked at medical records of 52,000 men in Sweden with brothers and fathers who had prostate cancer. They found:

  • Men with a brother who had prostate cancer had twice as high a risk of being diagnosed as the general population. They had about a 30% risk of being diagnosed before age 75, compared with about 13% among men with no family history.
  • Men with a brother who had prostate cancer had about a 9% risk of getting an aggressive type of prostate cancer by age 75, compared with about 5% among other men.
  • Men with both a brother and father with prostate cancer had about 3 times the risk of being diagnosed as the general population. They had about a 48% chance of getting any type of prostate cancer, compared with about 13% among other men.
  • Men with both a brother and father with prostate cancer had about a 14% chance of getting an aggressive type of prostate cancer by age 75, compared with about 5% among other men.

The researchers found that while the number of close relatives with prostate cancer affected the risk, the type of prostate cancer in the family did not have a strong effect on risk. For example, the risk of an aggressive prostate cancer was just as high in men whose brothers had the mildest form of prostate cancer as those whose brothers had an aggressive type.

While the results of study might provide men with better estimates of their risk when deciding whether to be tested, one note of caution is that the study looked only at men in Sweden. While the results might be similar in other parts of the world where prostate cancer screening rates are fairly high and where people come from similar genetic backgrounds, such as in other parts of northern Europe and North America, it is not clear how well these results would apply among people with different genetic makeups, such as African Americans.

The study was published online July 10, 2016 in the Journal of the National Cancer Institute.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Family History and Probability of Prostate Cancer, Differentiated by Risk Category: A Nationwide Population-Based Study. Published online July 10, 2016 in the Journal of the National Cancer Institute. First author, Ola Bratt, MD, PhD, Karolinska Institute, Stockholm, Sweden.


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