NEW YORK (Reuters Health) - A "watchful waiting" approach is often recommended for men with high-grade prostate cancer because it's difficult to treat successfully. Now, however, New York-based researchers report that decisive treatment can lead to a significant improvement in survival compared to the conservative approach.

Patients with the most aggressive prostate cancers that haven't yet spread to other sites in the body, if treated by surgical prostate removal or radiation, "can expect to live more than 14 years," lead investigator Dr. Ashutosh Tewari told Reuters Health. "Those treated conservatively will live, on average, less than 7 years."

Tewari and associates at New York Presbyterian Hospital conducted a look-back study involving 453 men with high-grade prostate cancer, and report their findings in the Journal of Urology. Of this group, 197 were treated conservatively, 137 men received radiation therapy and 119 underwent radical prostatectomy (complete surgical removal of the prostate).

The average length of overall survival in the three groups was 5.2, 6.7 and 9.7 years, respectively.

When deaths due specifically to prostate cancer were considered, average survival was 7.8 years for conservative therapy and more than 14 years for radiation therapy and radical prostatectomy.

"The risk of cancer-specific death following radical prostatectomy was 68 percent lower than for conservative treatment and 49 percent lower than for radiation therapy," Tewari's group found.

The researchers conclude that "even high-grade cancers are potentially curable."