Cancer incidence gap widens for people with type 2 diabetes, led by obesity-linked tumours

A Danish analysis found that the excess incidence of obesity-related cancers among people with type 2 diabetes increased in the past decade, while lung cancer patterns shifted sharply among women.

A report published by Pharmacy Times, drawing on a European Association for the Study of Diabetes news release, says the gap in cancer incidence between people with type 2 diabetes and those without it has widened over time, with the sharpest increases seen in cancers linked to excess body weight. The underlying Danish analysis compared two periods, from 1996 to 2009 and from 2010 to 2022, and found that obesity-related cancers were increasingly common among people with type 2 diabetes in both men and women. According to the report, incidence was 45% higher in men and 30% higher in women with type 2 diabetes in the later period, up from 34% and 23% in the earlier years. Pharmacy Times said colorectal cancer was also more common in people with type 2 diabetes, while postmenopausal breast cancer was modestly higher in women with the condition.

The picture was less uniform for cancers not normally classed as obesity-related. Pharmacy Times reported that lung cancer incidence in the later period was 23% higher in men and 25% higher in women with type 2 diabetes. Among women, the pattern changed markedly: lung cancer incidence moved from 12% lower in 1996 to 2009 to 25% higher in 2010 to 2022. By contrast, prostate cancer incidence was 19% lower in men with type 2 diabetes. The article quotes lead researcher Tine Laurberg as saying the reason for the shift in women is still unclear and that the study did not have individual smoking data, meaning it could not test whether changing tobacco patterns helped explain the result.

The broader interpretation remains cautious. Pharmacy Times says the investigators stressed that the work was designed to describe differences in incidence, not to prove that type 2 diabetes directly causes cancer. That distinction matters because several overlapping factors can influence risk, including body weight, smoking, alcohol use and physical inactivity. The National Cancer Institute says obesity can raise cancer risk through several biological pathways, including higher oestrogen production, elevated insulin and insulin-like growth factor-1 levels, and chronic inflammation. The Centres for Disease Control and Prevention similarly lists 13 cancers linked to excess weight, including colorectal and postmenopausal breast cancer.

Those links help explain why the findings may be clinically important even though they do not identify a single cause. The American Cancer Society notes that type 2 diabetes is associated with a higher risk of several cancers, including colorectal, liver, gallbladder, breast, pancreatic and endometrial cancers, while also pointing to shared risk factors such as obesity, inactivity and smoking. Research published in BMC Medicine and other reviews has likewise pointed to higher cancer incidence in people with both obesity and type 2 diabetes, reinforcing the view that metabolic health and cancer risk often travel together.

For clinicians, the practical message is less about panic than about prevention. Pharmacy Times says the authors urged greater participation in routine screening programmes for cancers such as colorectal and breast cancer, particularly among people with type 2 diabetes. The American Diabetes Association’s 2026 Standards of Care advise that adults with diabetes be encouraged to keep up with age- and sex-appropriate cancer screening and to address modifiable risks, including obesity, smoking, alcohol use and inactivity. The same guidance says glucagon-like peptide-1 receptor agonists have not been shown in humans to increase the incidence of thyroid, pancreatic or any other cancer, and that evidence for metformin or sulfonylureas as anticancer agents remains insufficient for recommendations.