Impact of Multimorbidity Burden on Mortality Risk among Colon Cancer Survivors

<b>Purpose:</b> Multimorbidity among colon cancer survivors reflected the coexistence of multiple chronic conditions. This study aimed to understand the comorbidity risks for long-term colon cancer survivors using a real-world population database. <b>Methods:</b> Taiwan cancer registry from 2016 to 2021 identified patients diagnosed with colon cancer, selecting those who survived beyond five years. Charlson Comorbidity Index (CCI) was used to assess the level of comorbidities, categorizing patients into no (CCI=0), mild (CCI=1-2), and severe (CCI≥3) comorbidity groups, for estimating the impact on survival. Cox regression model was applied to estimate risk factors associated with comorbidities among long-term colon cancer survivors. <b>Results:</b> In this cohort study of 13,209 colon cancer survivors, most had no comorbidity (82.23%), following as mild (10.03%) and severe (7.74%) comorbidity. Our study revealed the significant association between higher CCI scores and increased mortality risk. Compared with patients without comorbidities, mild comorbidities patients exhibited a significantly higher risk of mortality (HR:4.56; 95% CI:3.93-5.28), and those with severe comorbidities had an increased risk (HR:12.67; 95% CI:11.15-14.40) after adjusting potential confounders. Subgroup of sex, age, clinical stage, and treatment types show that colon cancer survivors with mild/severe comorbidities had significant higher mortality risk than those without comorbidities. <b>Conclusion:</b> This study indicated the critical role of comorbidity management may improve the survival outcomes for colon cancer patients, particularly those with high-risk factors and severe comorbidities.