Cases of aggressive prostate cancer appear to be on the rise, researchers reported Tuesday.
The good news is it's still rare for prostate cancer to spread, NBC News reported. Just 3 percent of cases have already started spreading when men are diagnosed and prostate cancer overall has not become more common, the team found.
However, they found that cases of metastatic prostate cancer — the type that has started to spread in the body — nearly doubled in men aged 55 to 69 since 2004. The reason is not yet clear.
"One hypothesis is the disease has become more aggressive, regardless of the change in screening," said Dr. Edward Schaeffer, chair of urology at Northwestern University Feinberg School of Medicine and Northwestern Medicine, who led the study.