Comparative outcomes of adenosquamous carcinoma of the pancreas: An analysis of the National Cancer Database

Background: A paucity of data exists regarding the natural history and outcome measures of adenosquamous carcinoma of the pancreas (ASCP), a histology distinct from pancreatic adenocarcinoma (PDAC). The aim of this study is to characterize the clinicopathological features of ASCP in a large cohort of patients comparing outcome measures of surgically resected patients to PDAC. Methods: We identified patients diagnosed with ASCP or PDAC from the National Cancer Database from 2004 to 2012. Patient demographics, tumor characteristics, treatment regimens, and overall survival were analyzed between the groups. Results: We identified 207073 patients: 205328 (99%) in the PDAC group and 1745 (1%) in the ASCP group. ASCP tumors were larger, located more frequently in a body/tail location (36% vs 24%, P<0.001), undifferentiated/anaplastic histology (41% vs 17%, P<0.001), and early stage presentation, (39% vs 32%, P<0.001). There was no significant difference in OS when comparing all patients with PDAC and ASCP (6.2 months and 5.7 months, P=0.601). In surgical patients ASCP histology was associated with worse OS (14.8 months vs 20.5 months, P<0.001) but had lower nodal involvement (55% vs 61%, P<0.001). ASCP histology was independently associated with worse OS, after adjusting for tumor characteristics, treatment, and patient demographics. In patients with only resected ASCP histology, negative lymph node status, R0 surgical resection, and receipt of chemotherapy was independently associated with improved overall survival following surgical resection. Conclusion: Although patients with ASCP and PDAC tumors have similar survival when non-surgical and surgical patients are combined, ASCP is associated with worse survival in stage I/II resected patients.