Surgical Site Infection Is Associated with Tumor Recurrence in Patients with Extrahepatic Biliary Malignancies

Background Surgical site infections (SSI) are one of the most common complications after hepato-pancreato-biliary surgery. Infectious complications may lead to an associated immune-modulatory effect that inhibits the body's response to cancer surveillance. We sought to define the impact of SSI on long-term prognosis of patients undergoing surgical resection of extrahepatic biliary malignancies (EHBM). Methods Patients undergoing surgery for EHBM between 2000 and 2014 were identified using a large, multi-center, national cohort dataset. Recurrence free survival (RFS) was calculated and a multivariable Cox proportional hazards model was utilized to identify potential risk factors for RFS including SSI. Results Seven hundred twenty-eight patients included in the analytic cohort; 236 (32.4%) patients had perihilar cholangiocarcinoma, 241 (33.1%) gallbladder cancer, and 251 (34.5%) distal cholangiocarcinoma. A major resection, liver resection, was performed in 205 (28.3%) patients, while 110 (15.2%) patients had a pancreaticoduodenectomy. The overall incidence of morbidity was 55.8%; among the 397 patients who experienced a complication, 161 patients specifically had an SSI. The SSI occurred as an infection of the surgical site (n = 70, 9.6%) or formation of an abscess in the operative bed (n = 91, 12.5%). SSI was associated with long-term survival as patients who experienced an SSI had a median RFS of 19.5 months compared with 30.5 months for those patients who did not have an SSI (HR 1.40, 95% CI 1.08-1.80; p = 0.01). Among 279 patients who had EHBM that had no associated lymph node metastases, well-to-moderate tumor differentiation, as well as an R0 resection margin, SSI remained associated with worse RFS (HR 1.84, 95% CI 1.03-3.29; p = 0.038), as well as overall survival (HR 1.87, 95% CI 1.18-2.97; p = 0.008). Conclusion SSI was a relatively common occurrence following surgery for EHBM as 1 in 10 patients experienced an SSI. In addition to standard tumor-specific factors, the occurrence of postoperative SSI was adversely associated with long-term survival.