Hospital Diagnosed Chronic Diseases and Risk of Colorectal Cancer Recurrence in Stage I-III Patients

Background: Chronic disease prevalence at colorectal cancer (CRC) diagnosis has increased with population ageing. We evaluated the association between chronic diseases prevalent at CRC resection and recurrence. Methods: This nationwide Danish registry-based cohort study included patients who underwent curative-intent resection for stage I–III CRC from January 2002 through June 2020. Chronic diseases before resection were ascertained from hospital diagnoses using a modified Charlson Comorbidity Index that omitted malignancies and added five psychiatric disorders (20 diseases). Diseases were grouped into five clinical categories: cardiopulmonary, neurological, mental health, metabolic, and gastrointestinal. Recurrence was identified using a validated registry-based algorithm. We estimated 1-, 3-, and 5-year cumulative incidences and Cox hazard ratios (HRs) with 95% confidence intervals (CIs), adjusting for age, sex, calendar year, smoking, alcohol, and body mass index. Results: Among 39,239 patients, 7,326 (19%) developed recurrence within 5 years. Cumulative incidences for patients with versus without chronic disease were 5.0% versus 5.5% at 1 year, 14.7% versus 15.5% at 3 years, and 18.5% versus 19.6% at 5 years; adjusted HRs were 1.01 (95% CI, 0.96–1.07), 1.03 (0.98–1.08), and 1.03 (0.98–1.08). The 5-year adjusted HR was 1.11 (1.02–1.21) for mental health and 0.79 (0.58–1.07) for neurological diseases. Conclusions: Prevalent chronic diseases overall were not associated with increased CRC recurrence risk, although risk was higher with mental health diseases and lower with neurological diseases. Impact: Poorer survival in patients with CRC and chronic disease is unlikely to reflect more frequent recurrence. Future studies should clarify whether treatment tolerance contributes to these survival disparities.