Neoadjuvant Chemotherapy Enhances Local Postoperative Histopathological Tumour Stage in Borderline Resectable Pancreatic Cancer - A Matched-Pair Analysis

Background: Neoadjuvant chemotherapy (NAC) is established in the treatment of ductal pancreatic adenocarcinoma for downsizing borderline-resectable pancreatic cancer (BRPC) and may affect nodal positivity and rates of R0 resection. This study aimed to identify the impact of NAC on postoperative histopathological parameters with a prognostic relevance. Patients and Methods: A one-to-three matched-pair analysis, including an overall total of 132 patients (25% treated with NAC and subsequent resection and 75% undergoing upfront surgery) was performed. Influence of NAC on nodal positivity, lymphatic, vascular and perineural invasion, as well as resection stage and grading, was examined. Furthermore, perioperative complications, in-hospital stay, re-admission rates, mortality, as well as preoperative body mass index and American Association of Anesthesiologist classification scores, were evaluated. Results: Patients treated with NAC significantly less frequently had lymphatic tissue invasion (lymph node invasion: 51.5% vs. 72.7%; p=0.032, and lymphatic vessel invasion 9.4% vs. 55.3%; p=0.0004), whereas vascular and perineural invasion, as well as grading and resection state were not significantly different. Carbohydrate antigen 19-9 regression in correlation with nodal positivity also did not differ, and both groups showed comparable perioperative complication rates. Occurrence and severity of postoperative pancreatic fistula (18.2% vs. 24.3%; p=0.034) were significantly lower in patients who had undergone NAC. Conclusion: NAC significantly affects postoperative histopathological tumour stage in BRPC and appears to be a safe treatment option without increased perioperative complications, re-admission, in-hospital stay, or mortality. Further studies are mandatory to underline the suitability of NAC for ductal pancreatic adenocarcinoma subgroups in order to guide clinicians in their daily decision-making comprehensively.