A growing number of medical studies suggest that diabetes might contribute to the development of certain cancers. The exact mechanism linking the two diseases are yet unknown. During the annual meeting of the European Association for the Study of Diabetes (EASD) in Stockholm, Sweden (Seeptember 22 – 24, 2010), Dr Hsin-Chieh Yeh, Johns Hopkins University, Baltimore, Maryland, USA, discussed the growing evidence base and called for experts across both specialties to ‘wage war’ together.
Such joint efforts would, concluded Yeh, lead to greater reductions in mortality than initiatives directed at either disease alone.
T2DM shares modifiable lifestyle risk factors with several cancer types. Those common factors include obesity, physical inactivity, and unhealthy diet. Many population based studies have found that T2DM may alter the risk of developing a variety of cancers and may increase the risk of cancer death.
“Some recent studies suggested diabetes treatments may influence risk of cancer or cancer prognosis, but the evidence for specific drugs is still inconclusive,” said Yeh.
Pre-existing diabetes is associated with reduced survival after cancer diagnosis and with increased postoperative mortality in cancer surgery patients. Possible explanations for increased mortality include tumor progression due to higher levels of insulin and glucose, less aggressive cancer treatment due to the presence of diabetes-related co-morbid conditions, and sub-optimal diabetes care due to the presence of cancer.
Many ongoing studies to examine this association are epidemiological, association studies using data from cancer registries or clinical populations. Yeh said that such international collaborations are already becoming evident in the area of diabetes and cancer. The ongoing multi-nation clinical trial of metformin in early stage breast cancer is a good example. Also, many population-based cohort studies are multi-national.
“At Johns Hopkins, we are working with oncologists to plan for various types of studies locally, such as molecular epidemiology, analysis of large cancer databases, and possible clinical trials of diabetes management in cancer patients with diabetes.”
“Diabetes may be associated with cancer outcomes across the full spectrum —from cancer development, cancer progression, to death from cancer. We urge a multidisciplinary collaboration between basic scientists, endocrinologists, oncologists, surgeons, primary care physicians, and clinical researchers to elucidate the biological mechanisms and improve clinical outcomes for both conditions,” concluded Yeh
Earlier this year, experts assembled jointly by the American Diabetes Association and the American Cancer Society published a consensus statement reviewing the state of science concerning the association between diabetes and cancer incidence or prognosis, risk factors common to both diabetes and cancer, possible biologic links between diabetes and cancer risk, and- whether diabetes treatments influence risk of cancer or cancer prognosis.