Abstract A009: Association between unstable diabetes mellitus and risk of pancreatic cancer

Abstract

Abstract Worsening of hyperglycemia in people with pre-existing diabetes mellitus may be an indicator of undiagnosed pancreatic cancer. However, there is limited evidence from longitudinal studies regarding the association between deterioration of diabetes and pancreatic cancer in people with previously stable diabetes. The size of the association between deterioration of diabetes and pancreatic cancer, and how the association changes over time, needs further investigation. A population-based matched cohort study was conducted within Australian women with stable diabetes mellitus. Unstable diabetes, the exposure of interest, was defined as change in the type of antidiabetic medication or addition of another antidiabetic medication after at least 24 months of stable antidiabetic medication use. The date of exposure was defined as the index date. Each woman with unstable diabetes was matched to 4 women with stable diabetes by birth year (±1 year) at the index date. Flexible parametric survival models were used to estimate hazard ratios (HR) (overall and at different times) and 95% confidence intervals (CI), and absolute risk in both groups at different time points. We identified 134,954 women with unstable diabetes; these were matched to women who had not developed unstable diabetes at the index date. The mean age of the cohort was 68 years. Over a median follow-up period of 2.8 years, 1,315 pancreatic cancer cases were diagnosed. Overall, women who experienced deterioration in glycemic control had a 2.5-fold increased risk of developing pancreatic cancer (HR 2.55; 95% CI 2.29 – 2.85). The risk was very high during the initial few months [HRs at 3 months (5.76; 95% CI 4.72 – 7.04), 6 months (4.56; 95% CI 3.81 – 5.46), and 12 months (3.33; 95% CI 2.86 – 3.89)]. The risk then progressively declined with time. Worsening of glycemic control in those with previously stable diabetes may be an early clinical manifestation of pancreatic cancer. Further research is warranted to differentiate this pancreatic cancer-associated deterioration of glycemic control from other causes. The longer-term (3-7 years) weaker association between pancreatic cancer and deterioration of glycemic control suggests that poorly controlled hyperglycemia is a predisposing factor for pancreatic cancer. Citation Format: Sitwat Ali, Michael Coory, Peter Donovan, Renhua Na, Nirmala Pandeya, Sallie-Anne Pearson, Katrina Spilsbury, Louise Stewart, Bridie Thompson, Karen Tuesley, Mary Waterhouse, Penelope Webb, Susan Jordan, Rachel Neale. Association between unstable diabetes mellitus and risk of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A009.