A popular diabetes drug, metformin, appears to help patients with several types of cancer, including cancer of the prostate, liver and pancreas, researchers are revealing or are about to reveal at the American Association For Cancer Research Meeting, 2012, Chicago, USA. Two separate studies showed that metformin, also known by its brand name Glucophage, prolongs life expectancy for patients with early-stage pancreatic cancer, slows down prostate cancer growth, and appears also to help prevent primary liver cancer.

Other research has shown that metformin may also have benefits for those with oral cancer and possibly some types of melanoma.

The presenters stressed that although these anti-cancer properties related to metformin show great promise, further studies are required before seeking approval from regulatory authorities.

Dr. Michael Pollak, professor of oncology and of medicine at McGill University in Montreal, and co-author in the prostate cancer trial, says further studies need to determine metformin’s safety and efficacy, as well as finding out what the ideal dosages might be. Experts are not sure whether a metformin derivative might be better than the drug itself for cancer treatment.

Dr. Pollak explained that the diabetes medication may also have benefits for patients with breast or colon cancers.

Pollack and team gave 22 adult males, all of them with prostate cancer, 500 milligrams of metformin three times daily. They had all been set to have a prostatectomy (removal of the prostate gland). Metformin was given to them beforehand. They received the diabetes medication for an average of 41 days.

After their prostates were removed, samples were analyzed in the lab, and results compared with previous biopsies. The researchers found that the rate of growth of the tumors among those on metformin had slowed down. Another benefit was a reduction in BMI (body mass index), blood glucose levels, and insulin growth factor (results from metformin’s anti-diabetes qualities).

Lead author, Dr. Anthony Joshua, of Princess Margaret Hospital, Toronto, explained that none of the men in the prostate cancer trial had diabetes. Who might benefit the most from metformin treatment is not yet known – they could be prostate cancer patients with diabetes.

The scientists could not explain why metformin helps in prostate cancer treatment. They suggest that the reduction in circulating insulin in the blood may be a cause.

Scientists from the University of Maryland Marlene and Stewart Greenebaum Cancer Center reported in Cancer Prevention Research that metformin may help prevent primary liver cancer (hepatocellular carcinoma), a typically deadly form of the disease. Primary liver cancer is becoming more common worldwide, especially among American males.

Primary liver cancer is much more common among patients with diabetes type two; about two to three times more common compared to diabetes-free individuals. Primary liver cancer risk is also higher among those who have hepatitis, are obese, or have NAFLD (non-alcoholic fatty liver disease).

Senior author, Geoffrey D. Girnun, Ph.D., said:

“Our research demonstrated that metformin prevents primary liver cancer in animal models. Mice treated with metformin had significantly smaller and fewer tumors than those who did not receive the medication. Based on these findings, we believe metformin should be evaluated as a preventive agent in people who are at high risk. Many patients with diabetes already are taking this medication, with few side effects.

There have been several retrospective epidemiological studies linking metformin with reduced risk of liver cancer, but our study is the first to formally test whether metformin can protect against carcinogenesis – not just tumor growth and development, but actual tumor formation in the liver. ”

Girnun says he and his team are applying for federal funding for a clinical trial to determine what anti-cancer properties and benefits metformin might have on individuals with diabetes type 2.

E. Albert Reece, M.D., Ph.D., M.B.A., vice president of medical affairs at the University of Maryland, and also dean of the University of Maryland School of Medicine, explained:

“Hepatocellular carcinoma represents a serious public health threat worldwide. With the alarming increases in obesity, Type II diabetes and hepatitis B and C, an even greater number of people will be at risk of developing this cancer in the future.

Not only do we need to find more effective treatments, we must also find ways to prevent it. This study conducted by Dr. Girnun and his colleagues is an excellent first step that may ultimately help us to prevent liver cancer in targeted populations.”

Kevin J. Cullen, M.D., director of the University of Maryland Greenebaum Cancer Center, and also professor of medicine at the University of Maryland School of Medicine, said:

“This study increases our knowledge of cancer cell metabolism and offers new insights into a possible mechanism for preventing a difficult-to-treat cancer. Translational research is an important focus of our cancer center, and we plan to continue this important area of research as part of a clinical study to determine if there is a possible benefit to patients.”

Lipogenesis is the process of converting glucose into fatty acids – this occurs in the liver. Lipogenesis occurs at higher rates in patients with fatty liver disease, diabetes, cancer and hepatitis. Metformin lowers sugar levels and undermines this fatty acid synthesis.

Dr. Girnun said:

“When you block this process, you prevent the cells from making more building blocks to make more cells. There is also no energy to put the building blocks together, and the cells are not able to proliferate, thereby preventing tumors from developing.”

In animal studies carried out on mice, there were 57% fewer liver tumors among those given metformin, compared to the mice which did not receive the medication. Tumor size was also approximately 37% smaller.

Written by Christian Nordqvist