Neoadjuvant chemotherapy for pancreatic cancer and changes in the biliary microbiome

Abstract

Background: The use of neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC) has increased in recent years. Limited data exists on the impact of NAC on biliary microbiome.

Methods: Patients who underwent pancreaticoduodenectomy (PD) for PDAC between 2014 and 2017 were reviewed. Patients were stratified into two groups based on their NAC status for comparison.

Results: Of 168 patients included, 63 (37.5%) received NAC. Patients who received NAC exhibited significantly increased growth of Gram-negative anaerobic bacteria (p = 0.043). Patients in the non-NAC group were more likely to grow pathogens resistant to ampicillin-sulbactam (47% vs 21%, p = 0.007), cefazolin (49% vs 28%, p = 0.040), cefoxitin (42% vs 11%, p = 0.009) and cefuroxime (26% vs 4%, p = 0.019). NAC status did not impact infectious postoperative outcomes, including SSIs.

Conclusion: Patients who did not receive NAC were more likely to grow pathogens resistant to cephalosporins. Perioperative antibiotic prophylaxis should be tailored to cover Gram-negative organisms and enterococci.

Keywords: Antibiotic prophylaxis; Biliary microbiome; Infectious complications; Neoadjuvant chemotherapy; Pancreatic ductal adenocarcinoma.