Organ/space surgical site infection and long-term outcomes of rectal cancer surgery: retrospective population-based cohort study

BACKGROUND: Anastomotic leak and subsequent organ/space surgical site infection (O/S-SSI) after colorectal cancer surgery are associated with poor short-term outcomes; however, the evidence regarding long-term outcomes is inconclusive. This population-based retrospective cohort study aimed to evaluate the association between O/S-SSI and both tumour recurrence and long-term survival after curative rectal cancer surgery. METHODS: Data was obtained for all adults who underwent curative oncological resection of the rectum in the periods 2011-2012 and 2015-2016 (n = 2208) in Spain. Multivariable analysis (Cox proportional hazards model) was used to evaluate the effects of clinical and pathological characteristics, as well as the occurrence of O/S-SSI, on recurrence and survival. RESULTS: In all, 2208 adults underwent curative rectal cancer resection, 1464 of whom were male (66.3%); the median patient age was 69.1 years. O/S-SSI occurred in 291 patients (13%). Independent predictors of recurrence included tumour stage III (hazard ratio (HR) 1.95, 95% confidence interval (c.i.) 1.06 to 3.58; P = 0.032), a positive resection margin (HR 4.03, 95% c.i. 2.58 to 6.29; P < 0.001), and poor quality mesorectal excision (HR 1.81, 95% c.i. 1.11 to 2.95; P = 0.018), but not O/S-SSI (HR 1.02, 95% c.i. 0.78 to 1.34; P = 0.888). However, O/S-SSI was independently associated with reduced overall survival at 1 year (HR 2.20, 95% c.i. 1.39 to 3.48; P < 0.001), 2 years (HR 1.75, 95% c.i. 1.25 to 2.43; P < 0.001), and 5 years (HR 1.33, 95% c.i. 1.05 to 1.68; P = 0.017). CONCLUSION: In this study, O/S-SSI had a negative impact on the long-term survival of patients who underwent rectal cancer surgery, but was not associated with increased tumour recurrence.