Influence of the duration of type 2 diabetes mellitus on colorectal cancer outcomes

Type 2 diabetes mellitus (T2DM) is a progressive disease, which affects colorectal cancer (CRC) survival. However, data on the relationship between CRC survival and T2DM duration is scarce and controversial. A retrospective observational study was conducted. Sub-cohorts were created based on the duration of T2DM as follows, ≤ or > 5/10/15/20 years. 204 of the 817 (24.95%) included study participants had T2DM at any point of CRC. 160 of the 204 CRC + T2DM patients had detailed T2DM duration data. At the time of CRC diagnosis, 85, 50, 31, and 11 patients had T2DM for > 5/10/15/20 years, respectively, which increased to 110, 71, 45, and 17 during the course of the study. Despite constant glycated hemoglobin values throughout the study, shorter overall and disease-specific survival times were observed for the > 5/10/15 years cohorts and longitudinal survival modeling techniques confirmed the significant effect of T2DM duration in all cohorts. While in the first 3 years after CRC diagnosis, the best survival was found for the ≤ 5 years cohort, all diabetes cohorts had the same survival thereafter. T2DM duration affected CRC survival significantly, therefore, a closer follow-up of this sub-populations is suggested.