A new experimental test may be able to help doctors in the near future to better identify which prostate cancer patients need aggressive treatment.

As it stands now, once prostate cancer is diagnosed, there’s really no way to know exactly which cases are life-threatening – and most are not. But, now scientists have created a test that tracks the activity of four genes within prostate tumors.

They say it might help doctors identify dangerous tumors more accurately than is possible now. In a new study, they report boosting accuracy to 91 percent from 84 percent.

Prostate cancer is the most common cancer in U.S. men after skin cancer, the American Cancer Society said on its website. For 2010, it was estimated that more than 215,000 new cases of prostate cancer would be diagnosed with more than 30,000 men dying from the disease.

The results of the study were published online Wednesday by the journal Nature.

The Associated Press contributed to this report.