Predictors of Survival in Elderly Patients with Metastatic Colon Cancer: A Population-Based Cohort Study

Oncological strategies in the elderly population are debated. The objective of this study was to determine the predictive factors of survival in patients aged 80 years and older with metastatic colon cancer. Data from four digestive tumour registry databases were used in this analysis. This population-based retrospective study included 1115 patients aged 80 years and older with stage IV colon adenocarcinoma diagnosed between 2007 and 2016. Cox regression was used to assess the impact of different prognostic factors. Age was significantly correlated with the surgical treatment (p < 0.001) but not with overall survival. Patients with a low comorbidity burden had better survival than patients with higher comorbidities scores (9.4 (0−123) versus 7.9 (0−115) months) (p = 0.03). Surgery was more common for proximal colon cancer (p < 0.001), but the location of the primary lesion was not correlated with improved survival (p = 0.07). Patients with lung metastases had a better prognosis than those with liver metastases (HR 0.56 95% CI 0.40, 0.77 p < 0.001); multiple organ involvement had the worst survival (HR 1.32 95% CI 1.15, 1.51 p < 0.001). Chemotherapy was associated with improved survival for both operated (HR 0.45 95% CI 0.35, 0.58 p < 0.001) and non-operated patients (HR 0.41 95% CI 0.34, 0.50 p < 0.001). The majority of patients receiving adjuvant treatment had a low comorbidity burden. In our study, the location of metastases but not the primary tumor location had an impact on overall survival. Low comorbidity burden, curative surgery, and chemotherapy had a significant advantage for elderly patients with metastatic colon cancer.