A new study revealed that the number of new cases of metastatic prostate cancers in the United States have soared by 72 percent in the past decade from 2004 to 2013.

The study, published in the journal Prostate Cancer and Prostatic Disease, suggests that the recent increase in new cases of metastatic prostate cancer might be attributed to the decreased number of men being screened. It also means that the disease is becoming much more aggressive.

"One hypothesis is the disease has become more aggressive, regardless of the change in screening," said senior study author Dr. Edward Schaeffer, chair of urology at Northwestern University Feinberg School of Medicine and Northwestern Medicine, in a statement. "The other idea is since screening guidelines have become more lax, when men do get diagnosed, it's at a more advanced stage of disease. Probably both are true. We don't know for sure but this is the focus of our current work."

For the study, researchers analyzed information from the National Cancer Data Base, including 767,550 men from 1,089 facilities nationwide who had been diagnosed with prostate cancer between 2004 and 2013.

The researchers discovered that three percent of the patients included in the study have metastatic prostate cancer. There were 2,890 new cases of metastatic prostate cancer in 2013, which is 72 percent greater than the 1,685 new cases in 2004.

Also, men between 55 and 69 years old have the largest increase with 1,345 new cases, up by 92 percent compared to the 702 new cases in 2004. Furthermore, Men diagnosed with metastatic prostate cancer in 2014 have an average prostate-specific antigen (PSA) of 49, nearly doubled compared to the average PSA of men diagnosed with metastatic prostate cancer in 2003, which is 25.

According to the report from the Centers from Disease Control and Prevention, approximately 176,450 men in the United States were diagnosed with prostate cancer in 2013, including the 27, 681 men who died because of the disease.