Coexisting diabetes ups risk of secondary malignancy, death in cancer patients

In cancer patients, the presence of diabetes appears to aggravate the likelihood of developing a secondary malignancy or death, reports a recent Japan study.

The study included 131,701 cancer patients, of whom 4.7 percent (n=6,135) had coexisting diabetes as determined from prescription records of antidiabetic drugs. Outcomes included overall survival and the risk of developing secondary primary cancers, assessed according to the presence of diabetes.

In cancer patients without coexisting diabetes, the 5-year survival rate was calculated to be 72.7 percent (95 percent confidence interval [CI], 72.4–73.0). In comparison, the 5-year survival rate in patients with coexisting diabetes was only 56.2 percent (95 percent CI, 54.8–57.6).

Moreover, Cox proportional hazards analysis also found that coexisting diabetes was a significant risk factor for developing a secondary primary cancer, increasing such likelihood by over 20 percent (subdistribution hazard ratio [HR], 1.23, 95 percent IC, 1.08–1.41).

In particular, comorbid diabetes aggravated the risk of multiple myeloma (subdistribution HR, 6.04, 95 percent CI, 2.25–16.21), uterus (subdistribution HR, 2.66, 95 percent CI, 1.06–6.70), pancreas (subdistribution HR, 1.89, 95 percent CI, 1.09–3.25), and liver (subdistribution HR, 1.60, 95 percent CI, 1.05–2.44) cancers.

“The efficacy of diabetes prevention and treatment for improving the prognosis of patients with cancer remains a subject for future studies,” the researchers said.