Metformin/Statin Combination Lowers Prostate Cancer Risk

The combination of metformin and statins appears to significantly reduce the risk of prostate cancer in veterans with type 2 diabetes, according to a recent study.1

In the study, published in the journal Diabetes Care, researchers looked at data on 5,042 men with type 2 diabetes treated at the VHA. They selected participants with no history of cancer and who were treated with metformin or sulfonylurea as a hypoglycemic medication between 1999 and 2005.

In five-year follow-ups of the men, 7.5% of the patients had been diagnosed with prostate cancer. There was a significant correlation between use of metformin and lower prostate cancer incidence among patients on statins (hazard ratio [HR], 0.69; 17 cases in 533 metformin users vs. 135 cases in 2,404 sulfonylureas users). At the same time, patients not on statins showed an elevated incidence of the cancer (HR, 2.15; 22 cases in 175 metformin users vs. 186 cases in 1,930 sulfonylureas users). Patients treated with metformin and statins had a prostate cancer hazard ratio of 0.32, compared with patients on neither medication.

The authors concluded, “among men with type 2 diabetes, [prostate cancer] incidence among metformin users varied by their statin use. The potential beneficial influence on [prostate cancer] by combination use of metformin and statin may be due to synergistic effects.”

1. Lehman DM, Lorenzo C, Hernandez J, Wang CP. Statin Use As a Moderator of Metformin Effect on Risk for Prostate Cancer Among Type 2 Diabetic Patients. Diabetes Care. 2012 Mar 28. [Epub ahead of print] PubMed PMID: 22456867.

Prostate Cancer, Heart Disease Could Have Shared Causes

The significant correlation between prostate cancer and coronary artery disease suggests shared causes, according to researchers from the Durham, NC, VA Medical Center and the Duke Cancer Institute.1

Those results, which appeared online in the journal Cancer Epidemiology, Biomarkers & Prevention, could lead to preventive measures to combat prostate cancer, such as weight loss, exercise and a healthy diet, all of which are known to prevent heart disease.

“What’s good for the heart may be good for the prostate,” said Jean-Alfred Thomas II, MD, a postdoctoral fellow at Duke and lead author of the study.

Researchers used data from 6,390 men enrolled in a large study called REDUCE, a four-year, randomized trial to test the prostate-cancer risk-reduction benefits of a drug called dutasteride. All the study participants, who provided a detailed medical history including their weight, incidence of heart disease, alcohol intake, medication use and other factors, had undergone prostate biopsy at the two- and four-year marks, regardless of their PSA levels.

Coronary artery disease was in the medical histories of 547 of the patients, who tended to be older, heavier and less healthy, with higher baseline PSA levels. They also were more likely to suffer from diabetes, hypertension and high cholesterol.

After accounting for baseline differences, those men were 35% more likely to develop prostate cancer than men without heart disease. The relative risk increased over time, starting at 24% within the first two years and rising to 74% four years into the study.

Senior author Stephen Freedland, MD, a surgeon at the Durham VAMC, said the study had some shortcomings, especially in that it relied on a previous trial that didn’t account for factors such as diet, physical activity and severity of heart disease.

“This is giving us a lot of good ideas for what to look at next,” Freedland said.

1. Thomas JA 2nd, Gerber L, Bañez LL, Moreira DM, Rittmaster RS, Andriole GL, Freedland SJ. Prostate Cancer Risk in Men with Baseline History of Coronary Artery Disease: Results from the REDUCE Study. Cancer Epidemiol Biomarkers Prev.

Calcium Intake Shows Promise in Reducing Prostate Cancer Risk

Calcium from food appears to be protective against prostate cancer, especially for African-American men, according to a study that found the mineral was associated with lower risk for high-grade prostate cancer among all men.1

The study, done at the Durham, NC, VA Medical Center, used data from a case-control study conducted among veterans treated at the medical center between 2007 and 2010 to examine the association between calcium intake and prostate-cancer risk.

Researchers looked at 108 biopsy-positive prostate cancer cases, 161 biopsy-negative controls and 237 healthy controls. Associations were examined based on race and the prostate cancer grade, with a Gleason score below 7 deemed low-grade and a Gleason score equal to or greater than 7 considered high-grade.

The Harvard food frequency questionnaire was used to assess diet and estimate calcium intake.

The study found an inverse relationship between intake of calcium from food sources and prostate-cancer risk among all races in a comparison of cases and biopsy-negative controls (P = .05) and cases and healthy controls (P = .02).

Total calcium was associated with lower prostate-cancer risk among black men but not among white men in analyses of healthy controls. Those with the highest calcium intake appeared to have lower risk for high-grade prostate cancer in a comparison of high-grade cases and biopsy-negative controls (OR, 0.37; 95% CI, 0.15-0.90) and high-grade cases and healthy controls (OR, 0.38; 95% CI, 0.17-0.86).

1. Williams CD, Whitley BM, Hoyo C, Grant DJ, Schwartz GG, Presti JC Jr, Iraggi JD, Newman KA, Gerber L, Taylor LA, McKeever MG, Freedland SJ. Dietary calcium and risk for prostate cancer: a case-control study among US veterans. Prev Chronic Dis. 2012 Jan;9:E39. Epub 2012 Jan 12. PubMed PMID: 22239754.

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