Prostate cancer is common. It's also deadly. About 220,000 men in the United States will learn that they have prostate cancer this year. Despite tests to detect it early and several effective treatments, the disease kills about 27,000 men in the United States each year.
On the other hand, many men with prostate cancer have tiny tumors that pose no significant threat to their health. For these men, early detection and treatment provides no benefit. So, it's a big challenge to learn how to detect the dangerous tumors while leaving the others alone. That's not easy.
To make matters worse, non-cancerous enlargement of the prostate, a nearly universal part of aging for men, may mimic prostate cancer . For example, the prostate-specific antigen (PSA) blood test may be high. This can raise concern about prostate cancer even when no cancer is present.
Clearly, we need better ways to identify men who have early prostate cancer requiring treatment. That's why the results of a new research study from Iceland are notable. The study links a gene mutation to an increased risk of aggressive prostate cancer. Interestingly, the mutation is located on a gene – called BRCA2 – known to increase the risk of cancers of the breast and ovary among women.
In this new research, scientists reviewed cases of prostate cancer in Iceland from the last 50 years. They selected study subjects with prostate cancer who also had female relatives with breast cancer. Researchers discovered that men who carried a particular BRCA2 gene mutation tended to have the worst forms of prostate cancer.
For example, men with the BRCA2 mutation had:
· Onset of prostate cancer at a younger age
· More advanced prostate cancer
· Shorter survival
The effect on survival was particularly striking. On average, those with the mutation lived just 2 years from the time of diagnosis. Non-carriers of the mutation survived more than 12 years.
It's hard to know whether these results will have a big impact on prostate cancer detection or treatment. The mutation was found in less than 6% of study subjects with prostate cancer. The rate might have been lower if these men did not have relatives with breast cancer. This mutation might be even rarer outside Iceland.
Still, the findings suggest that looking for mutations in genes with known links to cancer could provide valuable information. It's easy to imagine that genetic testing could someday be a routine part of screening for prostate cancer (and other cancers). Perhaps the results could be used to predict the need for aggressive treatment.
by Harvard Publications
