Prognostic Value (Pv) Of Pathologic Response (Pr) To Neoadjuvant Chemotherapy (Nc) Alone In Resected Pancreatic Cancer (Pdac): Initial Analysis

771 Background: As neoadjuvant Rx for resected PDAC often includes chemoradiation, the PV of PR includes its impact. We began analysis of the impact of NC alone in this setting. Methods: Patients (pts) were identified from the Virginia Mason Pancreaticobiliary Cancer Database. Inclusion criteria: 1) Dx 1/2010 - 3/2019; 2) Path dx PDAC stage I-III; 3) NC ( any type) as sole neoadjuvant Rx; 4) complete surg path data; 5) longitudinal OS known. Exclusion criteria: 1) neoadjuvant chemoradiation; 2) unknown NC (outside providers only). Histologic response was scored as follows: ( 0=complete response, 1 ≥95% response, 2=50-95% response, 3<50% response). Results: Results for 134 pts are in Table. Median (med) f/u was 33 months (mo). In univariate analysis, all path features examined were statistically significant re med/5-yr OS. In multivariate analysis, risk increased with tumor size (HR 1.9, 95% CI 1.1-3.2) and tumor differentiation (HR 1.8, 95% CI 1.1-3.1 ) independent of other variables. Conclusions: 1) In univariate analysis, all PR features after NC had PV for med/5-yr OS, especially tumor size and histologic response score. NC type was not significant. 2) In multivariate analysis, risk increased with tumor size and tumor differentiation.3) This data needs extension to a bigger pt base/correlation with other variables (Ca 19.9, postop Rx, recurrence pattern etc.) for greater utility ( now underway). 4) This approach may aid postop Rx decision -making in this setting. [Table: see text]