Effect of comorbidity on postoperative survival outcomes in patients with solid cancers: A 6-year multicenter study in Taiwan

Purpose: Patients with comorbidities are more likely to experience treatment-related toxicities and death. Our aim was to examine the effect of comorbidity on postoperative survival outcomes in patients with solid cancers. Methods: In total, 37,288 patients who underwent potentially curative operations for solid cancers at four affiliated hospitals of the Chang Gung Memorial Hospital, between 2007 and 2012, were stratified according to the Charlson Comorbidity Index (CCI) for postoperative survival analysis. Multivariate Cox regression was used to adjust hazard ratios of survival outcomes among different CCI subgroups. Results: A significantly greater proportion of patients with comorbidities presented with poorer clinicopathological characteristics compared to those without. After cancer surgery, 26% of patients died after a median follow-up duration of 38.9 months. Overall mortality rates of patients with CCI scores of 0, 1, 2, 3, 4, and 5-8 were 22.9%, 29.5%, 38.2%, 43.2%, 50.2%, and 56.4%, respectively. After adjusting for other clinicopathological factors, patients with increasing CCI scores were associated with significantly reduced overall and noncancer-specific survival rates, while only patients with CCI scores of > 2 were associated with higher cancer-specific mortality rates. Conclusions: Patients with increasing numbers of comorbidities were associated with reduced postoperative survival outcomes. Patients with multiple comorbidities were most vulnerable to both cancer- and noncancer-specific deaths in the first 6 months after cancer surgery. Our results suggest that for both the patient and clinician, it should be taken into consideration about cancer surgery when dealing with multiple comorbidities.