Background: Neoadjuvant therapy (NT) for resectable pancreatic adenocarcinoma (PAC) continues to be debated. We sought to establish the relationship between pancreatic tumor size, neoadjuvant chemotherapy (NCT), neoadjuvant chemoradiation (NCRT), and definitive surgery (DS) on survival. Methods: Utilizing the National Cancer Database we identified patients with PAC who underwent NT and DS. Patient characteristics and survival were compared with Mann-Whitney U, Pearson's Chi-square, and the Kaplan-Meier method. Multivariable analysis (MVA) was developed to identify predictors of survival. All tests were two-sided and a <0.05 was significant. Results: We identified 11,707 patients: 9,722 patients with tumors >2 cm and 1,985 with tumors =2 cm. There were 523 patients treated with NCT, 559 treated with NCRT, and 10,625 DS. Patients with tumors >2 cm were more likely to have higher T-stage, P<0.001, positive lymph nodes, P<0.001, poor histologic grade, P<0.001, and R1 resections, P<0.001. The median survival for patients with tumors =2 cm was 30.6 months compared to 20.5 months for those whose tumors were >2 cm, P<0.001. In the >2 cm groups the median survival for NCT, NCRT, and DS was 22.9, 25.8 and 21.3 months, P=0.01. MVA revealed that age, Charlson/Deyo score, N-stage, grade, tumor size >2 cm, R0 resection, and NT were predictors of survival. Ninety-day mortality was worse in both the NCT and NCRT compared to DS, P<0.001. Conclusions: The size of pancreatic cancer correlates to pathologic stage and overall survival. Tumors >2 and <2 cm benefited from a NT. However, the 90-operative mortality was significantly worse in those patients receiving NT.
