(Ivanhoe Newswire) -- Taking the most commonly-prescribed anti-diabetic
drug, metformin, reduces the risk of developing pancreatic cancer by 62 percent,
according to research from The University of Texas M. D. Anderson Cancer Center.
"This is the first epidemiological study of metformin in the cancer population,
and it offers an exciting direction for future chemoprevention research for a
disease greatly in need of both treatment and prevention strategies," Donghui
Li, Ph.D., lead author and professor in M. D. Anderson's Department of
Gastrointestinal Medical Oncology was quoted as saying.
According to Li, more than 35 million prescriptions for metformin, which is
taken orally, are filled annually. It is most often given to type 2 diabetic
patients who are obese or who have insulin resistance.
"Metformin works by increasing the cellular sensitivity to insulin and
decreasing its level circulating in diabetics. Insulin also seems to have a
growth-promoting effect in cancer," said Li. "Metformin activates the AMP kinase,
which is a cellular energy sensor. Recent publications have described that AMP
kinase also plays an important role in the development of cancer by controlling
cell division and growth."
"Knowing that diabetes is a risk factor for the development of pancreatic cancer
and that 10 percent of such cancers are associated with diabetes, we wanted to
better understand the specific association between different anti-diabetic
therapies and this lethal disease," explained Li.
For the case control study, the researchers enrolled 1,838 participants -- 973
patients with pancreatic cancer treated at M. D. Anderson between 2004 and 2008
-- to compare with 863 cancer-free individuals, all companions of M. D. Anderson
patients. Of all participants, 259 patients and 109 controls were diabetics.
The groups were matched by age, race and sex. Personal interviews were conducted
to collect such information as smoking history, family history of cancer,
alcohol use and body mass index. Diabetics were also asked about their
anti-diabetic medication history.
The researchers found that diabetics who took metformin alone or in any
combination with other diabetic therapies had a 62 percent reduced risk of
developing pancreatic cancer, compared to those who never used the drug.
Li noted the study is not without limitations, including the relatively small
size of the study's diabetic population. She hopes the research will be
replicated using a larger sample size. Still, the findings present the immediate
opportunity to explore metformin as a chemopreventive agent.
Pancreatic cancer is the fourth leading cause of cancer death in this country.
According to the American Cancer Society, more than 42,470 people will be
diagnosed and 35,240 will likely die from the disease in 2009. The median
survival for patients with the disease is less than 10 months and the five-year
survival rate is less than five percent.
"While further validation is needed, our findings show metformin's potential as
a chemopreventive agent," said Li. "Currently, once pancreatic cancer is
diagnosed, we have few successful therapeutic agents to offer our patients, so
obviously, for those at greatest risk, a preventive mechanism such as metformin
would be a welcome option."
In a corresponding editorial, Yu-Xiao Yang, M.D. of the University of
Pennsylvania School of Medicine noted that the American Diabetes Association and
the European Association for the Study of Diabetes have both recommended the
inclusion of metformin for all type 2 diabetes patients without
contraindications and notes that the possible chemopreventive properties of the
drug "may provide an additional incentive for patients and physicians to follow
this recommendation."
SOURCE: Gastroenterology, August 1, 2009
