A retrospective study recently published in Cancer Medicine states that use of statins as monotherapy or with metformin is linked with lower mortality among men with high-risk prostate cancer.
“Both metformin and statins have been associated with longer life [among men with] prostate cancer, yet because they are commonly prescribed together, no study we know of has looked at these two medications separately,” Grace Lu-Yao, PhD, associate director of population science at Sidney Kimmel Cancer Center at Jefferson Health, said in a recent press release.
Nearly 15% of men diagnosed with prostate cancer can be categorized as high-risk, meaning they have a significantly higher chance of developing systemic or local recurrence and a higher risk for death due to the disease. Although earlier studies have implied the diabetes drug metformin and cholesterol-lowering statins might delay prostate cancer metastases, the individual and joint effects of their use among men with high-risk disease had not been confirmed.
To quantify the above claims, the research team utilized the SEER-Medicare linked database to retrospectively analyze 12,700 men between the ages of 70-80 diagnosed with high-risk prostate cancer between 2008 and 2011 who survived for at least 6 months. They defined high-risk disease as T category of T2c or greater, PSA of 20 or greater, or Gleason score of 8 or higher.
Among these men, about 4,500 did not take metformin or statins, 435 took metformin alone, nearly 6,000 took statins alone and almost 2,000 took metformin in combination with statins.
Median follow-up was 42 months (range, 26.4-57.6), during which 2,182 men (17.2%) died of any cause and 1,078 (8.5%) died of prostate cancer.
Results showed median survival of 3.1 years with metformin monotherapy, 3.6 years with statin monotherapy and 3.9 years with metformin in combination with metformin. Men who used neither drug had median survival of 3.1 years.
Using Cox proportional hazards models, researchers observed significant associations between the use of metformin plus statins (HR = 0.75; 95% CI, 0.67-0.83), as well as statin monotherapy (HR = 0.89; 95% CI, 0.83-0.96), and lower all-cause mortality.
Additionally, metformin plus statin use appeared associated with a 36% reduction in risk for prostate cancer mortality (HR = 0.64; 95% CI, 0.51-0.81). Statin monotherapy appeared associated with a 20% risk reduction (HR = 0.8; 95% CI, 0.69-0.92).
“This shows that metformin monotherapy demonstrated no significant association with all-cause or prostate cancer mortality,” said Lu-Yao. “But it’s promising to see these results for our future research.”
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