Initial pancreatic ductal adenocarcinoma tumor resectability status is associated with early distant recurrence after neoadjuvant therapy followed by resection

Abstract

Presenter: Da Eun Cha MD | Icahn School of Medicine at Mount Sinai Background: Neoadjuvant therapy (NAT) is increasingly utilized in the treatment of pancreatic ductal adenocarcinoma (PDAC); however, there are limited data on risk factors and patterns of recurrence after NAT followed by resection. The aim of this study was to analyze timing and recurrence patterns of PDAC after NAT followed by curative resection. Methods: Patients treated with NAT for PDAC at a single health system from January 1, 2012 to January 1, 2020 who underwent curative resection were retrospectively reviewed. Patient characteristics, clinicopathologic factors, recurrence, and survival were analyzed. Resectability at diagnosis was determined using AHPBA/SSAT/SSO/NCCN definitions. Early recurrence was defined as recurrence within 12 months of operation. Results: Of the 91 patients included, 75 (82%) patients were alive at last follow up. Median age at time of surgery was 66 years (IQR 58.1-74.4) and median follow up was 20.1 months (IQR 2.3 to 56.2 mo). 35 patients had resectable PDAC at time of diagnosis. Recurrence occurred in 50 (55%) patients with median RFS of 11.9 months (IQR 7.35-17.06 mo). Perineural invasion (PNI) was significantly higher in recurrence group (83.3%) than in no recurrence group (52.6 %) (p=0.001). Of 50 patients with recurrence, 18 (36%) patients had local and 32 (64%) had distant recurrences. Median recurrence free survival and overall survival between local and distant recurrence were not significantly different (10.1 mo vs 12 mo, p=0.39 and 28.7 mo vs 35.1 mo, p=0.75, respectively). 25 (50%) out of 50 patients developed early recurrence within 12 months of resection. PNI was a significant risk factor for early recurrence (OR 11.3, 95% CI: 1.3-98.9). Of the distant recurrence cases, 15 (46.9%) occurred early. Borderline or locally advanced PDAC was a significant risk factor for early distant recurrence (OR 4.88, 95%CI: 1.1-22.4, p=0.04). R1 (margin positive) resection was a significant risk factor for early distant recurrence as well (OR 10.7, 95% CI:1.1-103.2; p=0.02). Conclusion: Of all recurrence cases in PDAC patients who underwent neoadjuvant therapy followed by resection, PNI was significantly higher in the recurrence group. While limited by number, borderline or locally advanced-PDAC, and R1 resection status increased the risk for early distant recurrence.