Study: After radiotherapy, statins protect against prostate cancer relapse

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Adding to a growing body of literature establishing a relationship between statins and cancer, statin use was associated with a significant improvement in prostate-specific antigen relapse-free survival among a group of prostate cancer patients treated with radiotherapy who were at high risk for recurrence, a study published in the March issue of the International Journal of Radiation Oncology*Biology*Physics found.

Several studies have linked the use of cholesterol-lowering statins to enhanced disease control following radiotherapy and chemotherapy treatments of malignant colorectal, hepatobiliary and urothelial cancers. Researchers have offered multiple hypotheses, but the exact mechanism behind this association is not well understood.

The “benefit of statin use on therapeutic outcomes for prostate cancer patients, however, is less well known,” explained Marisa A. Kollmeier, MD, from the department of radiation oncology at Memorial Sloan-Kettering Cancer Center, in Manhattan, N.Y., and colleagues. “We sought to identify a potential outcome benefit these agents may have in a retrospective review of prostate cancer patients treated with definitive high-dose external-beam radiotherapy.”

A total of 1,681 patients treated with radiotherapy for clinically localized stage T1 to T3 prostatic adenocarcinoma participated in the study, which took place between 1995 and 2007. The median administered dose was 81 Gy.

Of the 1,681 patients, 382 were taking statins (3-Hydroxy-3-methylglutaryl coenzyme A reductase). Patients were followed for a median of 5.9 years and observed for prostate-specific antigen (PSA) relapse, following the nadir +2 definition. Nine hundred forty-seven patients also received neoadjuvant androgendeprivation therapy (ADT).

Five- and eight-year PSA relapse-free survival rates were 89 percent and 80 percent for patients taking statins, compared with 83 percent and 74 percent among those patients not on statins. This difference did not reach significance.

Among the 489 patients classified as high-risk by National Comprehensive Cancer Network criteria, the 77 patients on statins experienced a significantly improved PSA relapse-free survival rate compared with the 412 patients not on statins. The statins group showed five- and eight-year PSA relapse-free survival rates of 81 percent and 75 percent, compared with the non-statin group’s 68 percent and 58 percent PSA relapse-free survival rates.

“In our retrospective study, we have demonstrated that statin use during radiotherapy is associated with improved biochemical tumor control among high-risk patients,” Kollmeier and colleagues wrote. “To our knowledge, our series is the first to report a significant biochemical outcome benefit with the use of statin therapy in high-risk prostate cancer patients.”

The authors acknowledged that their retrospective study with a relatively small cohort of statin-taking patients limited their findings. “The specific mechanism for this interaction [between cancer following radiotherapy and statins] is currently unknown,” they continued.

Kollmeier and co-authors said their “data suggest that statins have anticancer activity and possibly provide radiosensitization when used in conjunction with RT [radiotherapy] in the treatment of prostate cancer.” They concluded, though, that “ultimately a prospective randomized trial will be necessary to firmly establish a role of statin therapy and its effect on therapeutic outcomes.”