Metformin, Statin Combination Reduces Mortality in High-Risk Prostate Cancer

The use of statins alone, and in combination with metformin, was linked to a reduction in all-cause and prostate cancer mortality in patients with high-risk disease, according to results of a population-based study.

“While there are studies on statins or metformin, data on the combination of statins and metformin in humans are extremely limited,” Dr. Grace Lu-Yao, associate director of population science at Sidney Kimmel Cancer Center at Jefferson and the study’s senior author, said in an interview with CURE®. “We conducted the study to evaluate the outcomes of patients with high-risk prostate cancer in relation to their exposure to statin and metformin.”

To examine the individual and joint effects of statin and metformin use among patients with high-risk prostate cancer, researchers studied 12,700 patients who received diagnoses between 2008 and 2011. During a median follow-up of 42 months, 2,182 patients died from any cause and 1,078 died from prostate cancer.

Researchers also wanted to assess the effects of the therapies in post-diagnostic settings, meaning medications received after prostate cancer diagnosis. They identified that 435 patients received metformin alone, 5,786 received statin alone and 1,911 received both.

Median survival was 3.1 years in those who received metformin, 3.6 years in those who received statins and 3.9 years in those who received both.

Metformin plus statin and statin alone were significantly associated with lower all-cause mortality.

The researchers found a 36% reduction in risk of prostate cancer mortality in those who received metformin plus statins. There was also a 27% reduction in risk of all-cause mortality, and 42% risk reduction of prostate cancer mortality, in those who received statins alone post cancer diagnosis.

Patients who received the combination also experienced a reduction in risk for all-cause mortality (32%) and prostate cancer mortality (54%). However, metformin alone did not have any significant effects on all-cause and prostate cancer mortality.

“Our data support the hypothesis that statins, used in the post-diagnostic setting, have the potential to reduce mortality among patients with high-risk prostate cancer,” Lu-Yao said.

The results, according to Lu-Yao, have the potential to impact various aspects of treatment.

“If the beneficial effect of statin is confirmed in a well-designed clinical trial, the impact on potential lives saved and treatment expenditures will be substantial,” she said. “The median survival gain is about two to five months for patients with metastatic castration-resistant prostate cancer treated with the latest therapies. Moreover, resistance to cancer treatment is common.”

The number of lives saved could exceed 10,000 per year if statins are confirmed to reduce prostate cancer mortality by 30% to 50% among high-risk patients, according to Lu-Yao. Additionally, the use of statins alone or in combination with metformin could reduce the financial burden of treatment significantly.

“In sharp contrast to the staggering cost of novel prostate cancer therapies for advanced prostate cancer — $102,000 to $310,000 per year per life saved — generic statins and metformin are very affordable, with co-pay costs below $200 per year,” Lu-Yao said.