E207: Safe Successful Surgery: Re-visiting survival outcomes defined by margin status in the era of neoadjuvant therapy utilization in pancreatic ductal adenocarcinoma

ePoster Abstract Author(s)

Susan K. Campbell, MD (she/her/hers)

Resident Physician
University of Vermont Medical Center, United States

Submitter(s)

Susan K. Campbell, MD (she/her/hers)

Resident Physician
University of Vermont Medical Center, United States

Author(s)

Susan K. Campbell, MD (she/her/hers)

Resident Physician
University of Vermont Medical Center, United States
SS

Shruthi Santhanakrishnan, n/a

Medical Student
Larner College of Medicine at the University of Vermont, United States
CO

Conor O'Neill, MD MSc, FSSO

Assistant Professor
University of Vermont Medical Center, United States
PC

Peter Callas, B.A., M.S., Ph.D.

Research Associate Professor
University of Vermont, United States

Introduction: Recently, the treatment algorithm for PDAC has shifted from upfront surgery (UFS) toward neoadjuvant therapy (NAT). Margin status is an important predictor of overall survival: Patients with an R1 resection were half as likely to survive at 5 years compared to patients with negative margins (R0), but twice as likely to survive compared to patients who did not receive UFS, suggesting an aggressive surgical approach is warranted if near-negative margins can be achieved. This study focuses on the uptrending utilization of NAT and its effect on the overall survival for patients with R1 resection status.

Methods: The NCDB was utilized to identify patients who underwent treatment for resectable PDAC between 2006 and 2020. Groups were defined as: NAT-R0, NAT-R1, UFS-R0, UFS-R1, and no surgery (NS). Trends in NAT utilization over time were analyzed using a Cochran-Armitage trend test. Overall survival (OS) was analyzed for each group using the Kaplan-Meier method with hazard ratios (HR) obtained from proportional hazard regression. A propensity score match was complete between the NAT-R1 vs NS groups and OS were compared.

Results: 21,170 patients were identified, with 6,464 patients in the NAT-R0 group, 590 in the NAT-R1 group, 11,126 in the UFS-R0 group, 2,990 in the UFS-R1 group, and 408 in the NS group. NAT for all patients has increased year over year with 11% utilization in 2006 to 71% utilization in 2020 (p< 0.001). Median OS in months following UFS-R0: 28.7 (16.0-69.9); UFS-R1 20.3 (12.6-37.3). With NAT: median OS in months NAT-R0: 32.1 (18.0-74.8); NAT-R1: 24.5 (13.9-41.7). HR for death UFS R1 vs UFS R0: 1.15 (1.45-1.58, 95% CI), HR for death NAT R1 vs NAT R0: 1.5 (1.35-1.65, 95% CI), HR for death UFS R1 vs NAT R1: 1.15 (1.04-1.27, 95% Cl, p=0.008), and HR for death UFS-R0 vs NAT R0: 1.11 (1.06-1.15, 95% CI). After propensity score matching NS vs NAT-R1, there were 110 patients per group and a significant difference in OS. Median OS in months for NS: 11.5; for NAT-R1: 24.7. The hazard ratio for death in NS vs NAT-R1 = 3.12 (95% CI, 1.99-4.0, p=0.001).

Conclusions: NAT continues a marked upward trend as we await randomized trial outcomes. NAT provides survival benefit to patients compared to UFS treatment cohorts. Cohorts who have microscopic margin positivity following NAT have median OS of 2 years. After propensity score matching there was a significant increase in overall survival for patients who had an R1 resection compared to no surgical intervention, suggesting that an aggressive surgical approach provides survival benefit.

Learning Objectives:

Upon completion, participants will be able to define the continued role of surgery in the treatment of pancreatic ductal adenocarcinoma.
Upon completion, participants will be able to describe the role of neoadjuvant therapy pertaining to pancreatic ductal adenocarcinoma.
Upon completion, participants will be able to reflect on the increase in utilization of neoadjuvant therapy over the last decade.