Survival Impact of Chronic Obstructive Pulmonary Disease or Acute Exacerbation on Patients with Rectal Adenocarcinoma Undergoing Curative Resection: A Propensity Score-Matched, Nationwide, Population-Based Cohort Study

SIMPLE SUMMARY: This study is the first to estimate the impact of smoking-related chronic obstructive pulmonary disease (COPD) in patients with rectal adenocarcinoma undergoing curative resection. In these patients, current smokers with smoking-related COPD had worse survival outcomes than nonsmokers without COPD. Moreover, hospitalization for COPD with acute exacerbation within 1 year before diagnosis was an independent risk factor for OS in these patients, with a higher number of hospitalizations being associated with poorer survival. ABSTRACT: Purpose: The survival effect of current smoking-related chronic obstructive pulmonary disease (COPD) and COPD with acute exacerbation (COPDAE) is unclear for patients with rectal adenocarcinoma undergoing curative resection. Methods: We recruited patients with clinical stage I–IIIC rectal adenocarcinoma from the Taiwan Cancer Registry Database who had received surgery. The Cox proportional hazards model was used to analyze all-cause mortality. We categorized the patients into two groups by using propensity score matching based on COPD status to compare overall survival outcomes: Group 1 (current smokers with COPD) and Group 2 (nonsmokers without COPD). Results: In the multivariate Cox regression analyses, the adjusted hazard ratio (aHR; 95% confidence interval (CI)) of all-cause mortality for Group 1 compared with Group 2 was 1.25 (1.04–1.51). The aHRs (95% cis) of all-cause mortality for frequency of ≥1 hospitalizations for COPDAE or ≥2 hospitalizations within 1 year before diagnosis were 1.17 (1.05–1.51) and 1.48 (1.03–2.41) compared with no COPDAE in patients with rectal adenocarcinoma undergoing curative resection. Conclusion: In patients with rectal adenocarcinoma undergoing curative resection, being a current smoker with COPD (Group 1) was associated with worse survival outcomes than being a nonsmoker without COPD (Group 2). Being hospitalized at least once for COPDAE within 1 year before the diagnosis of rectal adenocarcinoma is an independent risk factor for poor overall survival in these patients, and a higher number of hospitalizations for COPDAE within 1 year before diagnosis was associated with poorer survival.