Insulin may be linked to increased cancer risk

NEW YORK Commonly used therapies for the treatment of diabetes may increase a patient's risk of cancer, a review published in the online edition of the International Journal of Clinical Practice suggested.

Cancer expert Michael Pollak, a professor at McGill University in Montreal, Canada, teamed up with diabetes expert David Russell-Jones, a professor from The Royal Surrey County Hospital, Guildford, U.K., to review more than three decades of laboratory and population studies. They believe that their findings will aid clinicians advising diabetic patients who also have been diagnosed with cancer or have a strong family history of cancer.

The review found that diabetes appears to be associated with an intrinsic increase in cancer incidence. A number of meta-analyses have been carried out, showing that:

• Diabetic patients were 30% more likely to develop colorectal cancer (15 studies covering 2.5 million patients)
• Women with diabetes had a 20% greater risk of developing breast cancer, according to 20 studies
• People with diabetes had an 82% higher risk of developing pancreatic cancer (36 studies covering more than 9,000 patients)

"Our review showed that people with diabetes, particularly those with Type 2 diabetes, may face an increased risk of cancer and that their cancer may be modified by treatment choices," Pollak said. "The inter-relationships between cancer and diabetes deserve more attention as both of these diseases are becoming more prevalent globally and it is increasingly more common to see patients with both conditions."