LOS ANGELES (Reuters Health) - Statin therapy is associated with improved relapse-free survival after radiotherapy for prostate cancer, particularly among patients with more aggressive cancers, researchers reported here at the annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO).

Dr. Michael J. Zelefsky of Memorial Sloan-Kettering Cancer Center in New York and colleagues there and at Concord Hospital in New Hampshire conducted a retrospective study of 871 men with T1-T3 prostate adenocarcinomas treated between January 1995 and July 2000.

The investigators compared outcomes of 168 men who were on statin therapy during radiation therapy with that of 703 men not on statins but receiving similar radiation therapy. The median radiation dose was 81 Gy, with a range of 75.6-86.4 Gy. Median follow-up was 85 months post-radiation therapy.

Dr. Zelefsky announced that the PSA-relapse-free survival rate at 5 years was 91% for patients on a statin and at 10 years it was 76%. That compares with corresponding rates of 81% and 66% for those not on statin therapy.

There was also a trend toward a lower incidence of distant metastases for men on statin therapy that did not quite reach statistical significance, the researcher added.

"Statins may interfere with the metastatic mechanism, but that hasn't been proven," Dr. Zelefsky told Reuters Health.

Statin use appeared to have the greatest benefit in those with the most aggressive disease, he added.

"We can't say on the basis of this trial that all patients with prostate cancer need to be on these medications," Dr. Zelefsky said. "Randomized controlled trials are needed."

The researcher cautioned that this is a very preliminary study. "We don't know which statins work best, the duration or the best timing of therapy ... or if there is a causative effect," he stressed.