Long-term outcome of CO 2 insufflation in thoracoscopic esophagectomy after neoadjuvant chemotherapy for esophageal squamous cell carcinoma: A retrospective cohort study Short title: Outcome of CO 2 insufflation in esophagectomy

Abstract

Abstract Background Thoracoscopic esophagectomy, with CO2 insufflation as a prerequisite, is increasingly performed for esophageal cancer. However, there is limited evidence on the influence of CO2 insufflation on the long-term postoperative survival. We aimed to estimate long-term outcomes with or without CO2 insufflation during thoracoscopic esophagectomy. Methods We enrolled 182 patients who underwent thoracoscopic esophagectomy for esophageal cancer between January 2003 and October 2013 and categorized them into two groups: with and without CO2 insufflation. The primary endpoint was the 5-year overall survival (5y-OS). Secondary endpoints included other long-term (i.e., 5-year relapse-free survival [5y-RFS] and 5-year cancer-specific survival [5y-CSS]) and short-term (i.e., surgical and non-surgical complications and 30-day reoperation) outcomes. Results Follow-up until death or the 5-year postoperative period was 98.9% complete (median follow-up duration: 6 years, in survivors). After adjusting for age and sex, the analyses showed no significant differences in 5y-OS (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.50–1.40), 5y-RFS (0.79, 0.49–1.31), and 5y-CSS (0.74, 0.43–1.27). For short-term outcomes, significant intergroup differences in the thoracic operative time (p = 0.02), thoracic blood loss (p < 0.001), postoperative length of stay (p < 0.001), and atelectasis (p = 0.004) were observed, and the results of sensitivity analysis were similar to the main results. Conclusions CO2 insufflation in thoracoscopic surgery for esophageal cancer seemingly does not change the long-term prognosis and is possibly safe in other thoracic procedures.