Very Early Recurrence After Curative Resection for Pancreatic Ductal Adenocarcinoma: Proof of Concept for a "Biological R2 Definition".

Abstract

Very early recurrence after radical surgery for pancreatic ductal adenocarcinoma (PDAC) has been poorly investigated. This study was designed to evaluate this group of patients who developed recurrence, within 12 weeks after surgery, defined as "biological R2 resections (bR2)." Data from patients who underwent surgical resection as upfront procedure or after neoadjuvant treatment for PDAC between 2015 and 2019 were analyzed. Disease-free, disease-specific survival, and independent predictors of early recurrence were examined. The same analysis was performed separately for upfront and neoadjuvant treated patients. Of the 573 patients included in the study, 63 (11%) were classified as bR2. The rate of neoadjuvant treatment was similar in bR2 and in the remaining patients (44 vs. 42%, p = 0.78). After a median follow-up of 27 months, median DFS and DSS for the entire cohort were 17 and 43 months, respectively. Median DSS of bR2 group was 13 months. The only preoperative identifiable independent predictor of very early recurrence was body-tail site lesion, whereas all other were pathological: higher pT (8th classification), G3 differentiation, and high lymph node ratio. These predictors were confirmed for patients undergoing upfront surgery, whereas in the neoadjuvant group the only independent predictor was pT. One of ten patients with "radical" resected PDAC relapses very early after surgery (bR2); hence, imaging must be routinely repeated within 12 weeks. Despite higher biological aggressiveness and worse pathology, this bR2 cluster eludes our preoperative examinations.