Perioperative versus adjuvant therapy in resectable pancreas cancer.

Abstract

703 Background: Pancreatic ductal adenocarcinoma (PDAC) is the third-leading cause of cancer death in the United States with a 5-year survival rate of 13%. Recurrence rates are high following resection and optimization of neoadjuvant and adjuvant therapy remains under investigation, with the hypothesis that neoadjuvant/perioperative therapy may convert borderline resectable tumors to resectable and prevent progression of micro-metastases in the postoperative setting. Our study evaluates patient outcomes and models predictive and prognostic markers to assist with clinical decision-making in consideration of neoadjuvant therapy for resectable and borderline resectable pancreatic cancers. Methods: We performed a single-institution retrospective analysis of patients who underwent pancreatic resection between January 1, 2016 and December 31, 2020 (n=532). We excluded patients with unresectable disease or a non-PDAC diagnosis. Analysis of the remaining patients (n=175) was performed using automated and manual chart review, basic statistical comparisons with T-tests or Chi-squared tests, Kaplan-Meier Survival analyses, and Cox Proportional Hazard Testing using intention to treat analysis. Results: There were no significant differences (p>0.05) the presenting demographics between the adjuvant (AJ, n=97) and neoadjuvant/perioperative (NP, n=76) groups. Patients were more likely to have a history of pancreatitis, a risk factor for PDAC development, in the NP group (p=0.0153). Patients in the AJ group included patients who ultimately did not receive the recommended adjuvant therapy for various reasons (n=25) and had overall worse performance status (p=0.004) and received less chemotherapy overall compared to the NP cohort (p=0.0003). Adjuvant therapy was more likely to be gemcitabine with capecitabine (n=37, p=0.0007) in the AJ group and gemcitabine with nab-paclitaxel (n=11, p=0.0018) in the NP group. In the neoadjuvant setting, 62% of patients received FOLFIRINOX and 28% received gemcitabine with nab-paclitaxel. Patients in the NP group were more likely to receive radiation (p=0016), including 6 patients who received neoadjuvant radiation. Median overall survival (33.9 [28.8-43.8] versus 38.2 [28.2-47.8] months) and progression free survival (21.1 [18.1-34.2] versus 16.6 [11.7-23.6] months) were not significantly different between the AJ and NP groups, respectively. Conclusions: These results demonstrate similar presenting characteristics between patients with resectable PDAC treated in a period when general practice shifted from adjuvant therapy to a neoadjuvant/perioperative approach. Although patients treated neoadjuvantly received more chemotherapy overall and the chemotherapy regimens differed between the groups, patients had similar outcomes in the two groups.