Current tests to "grade and stage" prostate cancer could be underestimating the severity of the condition of about half of the men whose disease is labeled "slow growing."
Researchers looked at how cancer was graded in 800 men both before and after they had surgery to remove their prostate, a University of Cambridge news release reported.
The team found that 415 of the men whose cancer had been labeled as "slow growing" and confined to the prostate, but half (209) of these study subjects had cancer that was more aggressive than originally diagnosed. Almost a third (131) of these men's cancer had spread beyond the prostate after surgery.
"Our results show that the severity of up to half of men's prostate cancers may be underestimated when relying on tests before they have surgery," Greg Shaw, a urological surgeon and one of the study authors based at the Cancer Research UK Cambridge Institute said in the news release.
"This highlights the urgent need for better tests to define how aggressive a prostate cancer is from the outset, building on diagnostic tests like MRI scans and new biopsy techniques which help to more accurately define the extent of the prostate cancer. This would then enable us to counsel patients with more certainty whether the prostate cancer identified is suitable for active surveillance or not," he said.
Active surveillance may not be a safe enough option for some men; about a third of all men who rely on this method will require radiation therapy or surgery within a five year period.
Prostate cancer is the most common type of cancer in the U.K., about 41,700 new cases are diagnosed every year.
"Despite the limitations that this study shows, all evidence so far points to active surveillance being safe provided men are carefully selected. But we need better methods of assigning a grade and stage so that no man has to unnecessarily undergo treatment, while at the same time making sure we detect and treat the cancers that really need it," Professor Malcolm Mason, Cancer Research UK's prostate cancer expert , said in the news release.
