The impact of colectomy and chemotherapy on risk of type 2 diabetes onset in patients with colorectal cancer: Nationwide cohort study in Denmark

Background

Comorbidity with type 2 diabetes (T2D) results in worsening of cancer-specific and overall prognosis in colorectal cancer (CRC) patients. The treatment of CRCper semay be diabetogenic. We assessed the impact of different types of surgical cancer resections and oncological treatment on risk of T2D development in CRC patients.

Method

We developed a population-based cohort study including all Danish CRC patients, who had undergone CRC surgery between 2001-2018. Using nationwide register data, we identified and followed patients from date of surgery and until new-onset of T2D, death or end of follow-up.

Results

In total, 46,373 CRC patients were included and divided into six groups according to type of surgical resection: 10,566 Right-No-Chemo (23%), 4,645 Right-Chemo (10%), 10,151 Left-No-Chemo (22%), 5,257 Left-Chemo (11%), 9,618 Rectal-No-Chemo (21%) and 6,136 Rectal-Chemo (13%). During 245,466 person-years of follow-up 2,556 patients developed T2D. The incidence rate (IR) of T2D was highest in the Left-Chemo group 11.3 (95%CI: 10.4-12.2) per 1,000 person-years and lowest in the Rectal-No-Chemo group 9.6 (95%CI: 8.8-10.4). Between-group unadjusted hazard ratio (HR) of developing T2D was similar and non-significant. In the adjusted analysis, Rectal-No-Chemo was associated with lower T2D risk (HR 0.86 [95%CI 0.75-0.98]) compared to Right-No-Chemo.

For all six groups, an increased level of BMI resulted in a nearly twofold increased risk of developing T2D

Conclusion

This study suggests postoperative T2D screening should be prioritized in CRC survivors with overweight/obesity regardless of type of colorectal cancer treatment applied.

Funding

The Novo Nordisk Foundation (NNF17SA0031406);TrygFonden (101390; 20045; 125132).