Clinical Outcomes for Anaplastic Pancreatic Cancer: A Population-Based Study

Abstract

Anaplastic pancreatic cancer (APC) is a rare subtype of pancreatic ductal adenocarcinoma (PDA) that can carry a worse overall survival (OS) when compared with other variants. However, the presence of osteoclast-like giant cells (OCGCs) in APC specimens can predict improved OS. The aim of this study was to evaluate the OS of patients with APC (with and without OCGCs) compared with patients with other subtypes of PDA using a population-based registry. We identified all patients in the Surveillance, Epidemiology and End Results (SEER) database with pathologically confirmed APC and PDA diagnosed between 1988 and 2008. Overall survival was evaluated using Kaplan-Meier and Cox proportional hazard regression. The study cohort included 5,859 (94.3%) patients with PDA and 353 (5.7%) with APC. Overall survival for all patients with APC was significantly worse than for patients with PDA (hazard ratio [HR] = 1.9; 95% CI, 1.7-2.1; p < 0.001); however, in the subgroup of resected patients, APC (n = 81) had similar OS to PDA (n = 3,517) (HR = 0.9; 95% CI, 0.7-1.2; p = 0.37). Patients with APC tumors with OCGCs (n = 11) demonstrated improved OS when compared with all other APC variants without OCGCs (n = 342) (HR = 0.3; 95% CI, 0.1-0.7; p = 0.004), but this survival difference was not observed in the subgroup of resected patients (HR = 0.5; 95% CI, 0.2-1.4; p = 0.18). Anaplastic pancreatic cancer is a rare malignancy with poor OS. The diagnosis of APC with OCGCs is predictive of improved OS compared with other patients with APC. This survival benefit, however, is not observed in patients with resected disease.