Poorly differentiated resectable pancreatic cancer: Is upfront resection worthwhile?

Background: Poorly differentiated, resectable pancreatic ductal adenocarcinoma is associated with early recurrence and may benefit from neoadjuvant treatment. The aim of this study was to evaluate clinicopathologic characteristics and survival of patients with resectable pancreatic ductal adenocarcinoma according to histologic grading. Methods: A total of 502 patients who underwent resection for pancreatic ductal adenocarcinoma between 1990 and 2008 were analyzed via the use of different histologic grading. Results: Well-differentiated (G1), moderately differentiated (G2), and poorly differentiated (G3) pancreatic ductal adenocarcinomas were found in 23 (4.5%), 310 (62%), and 169 (33.5%) patients. Adjuvant therapy, N status, grading, and R status were independent predictors of disease-specific survival for the entire cohort, with 1- and 5-year disease-specific survival rates of 81% and 21%, respectively. Only the presence of symptoms was a significant clinical predictor of G3 status (P = .035). G3 neoplasms were characterized by a greater rate of lymph node metastases, microvascular/perineural invasion, and R2 resections. Median disease-specific survival was 77, 26, and 20 months for G1, G2, and G3 neoplasms (P <.0001). Median disease-free survival was 63, 14, and 9 months for G1, G2, and G3 pancreatic ductal adenocarcinoma (P <.0001). Adjuvant therapy improved disease-specific survival in G2 (P <.04) and G3 (P <.0001) pancreatic ductal adenocarcinoma, with a greater survival benefit for G3 neoplasms (hazard ratio: 1.334 vs 2.116). Conclusion: G3 pancreatic ductal adenocarcinoma is associated with a lesser rate of disease-free survival after resection and with the presence of other poor prognostic factors. The benefit of adjuvant therapy is greater in G3 than in G1 and G2 neoplasms. On the basis of these findings, patients with resectable G3 PDAC can be considered as possible targets for neoadjuvant treatment.