Patients with diabetes who are diagnosed with cancer are more likely to die early than those without diabetes, according to Danish researchers.
They concluded that patients with both diabetes and cancer constitute a particularly vulnerable group, and efforts are needed to reduce cancer-related mortality among these patients.
The observational study, published in the journal Diabetologia, included all 426,129 cancer patients diagnosed in Denmark during 1995-2009, of which 42,205 also had diabetes.
Patients were classified into four groups at the time of cancer diagnosis – no diabetes, diabetes without medication, diabetes with only oral hypoglycaemic agents or diabetes with insulin treatment.
Overall, cancer patients with diabetes had higher mortality rates than non-diabetic cancer patients, with the highest rates among those receiving either insulin or drug treatment.
Among men, the researchers estimated a 20% two-year survival probability for insulin-treated patients. For OHA-treated patients and patients without history of diabetic therapy, the two-year survival was about 60%. For cancer patients without diabetes, it was almost 70%.
Survival was generally higher among women, but followed the same pattern. Two-year survival probability was around 30% for insulin-treated patients, 70% for OHA- and non-treated patients and 80% for non-diabetic patients.
Lead author Kristina Ranc, from the University of Copenhagen, said: “The results suggest that mortality of cancer patients with pre-existing diabetes is higher relative to non-diabetic patients for all cancers combined and for most individual cancer sites.
“In general, the highest mortality was found for insulin-treated patients, suggesting that cancer patients with more intensive diabetes treatment have a larger degree of comorbidity at the time of cancer diagnosis, and hence poorer survival.
“Diabetes duration at cancer diagnosis did not influence the prognosis,” Dr Ranc added.
She said: “It is crucial that cancer patients with diabetes receive optimal diabetes treatment as well as any cancer-specific therapy; a therapeutic challenge requiring close collaboration.”
- Read the full study paper in Diabetologia