A new genetic pattern could identify which prostate cancer patients need to have surgery, Sky News reported.
Men with high levels of certain genes are three times more likely to have a fatal form of the disease than those with the lowest levels, according to the research.
Scientists at the charity Cancer Research U.K. now hope to develop a gene screening test.
Men with aggressive cancers could then choose to run the risk of side effects from the operation, which include impotence and incontinence.
Those with slow-growing cancers could safely forgo surgery.
"Our findings have great potential. It's really encouraging that this could be applied to prostate cancer, where we desperately need a way to predict how aggressive the disease will be," said Professor Jack Cuzick from Queen Mary University of London.
The study, reported in the medical journal Lancet Oncology, looked at 703 men with prostate cancer.