The impact of squamous cell carcinoma histology on outcomes in nonmetastatic pancreatic cancer.

Background: The prognosis for nonmetastatic, primary pancreatic squamous cell carcinoma (SCC) is thought to be poor compared with adenocarcinoma (AC); however, this is based on limited data. Additionally, the optimal definitive treatment strategy for nonmetastatic pancreatic SCC is unknown.
Methods: We analyzed patients with nonmetastatic pancreatic cancer using the National Cancer Database for patients diagnosed from 2006 to 2014. Patients were analyzed according to histology-only AC, adenosquamous carcinoma (A-SCC), and SCC were included. The primary endpoint was overall survival (OS) from the time of diagnosis.
Results: A total of 94 928 cases were included; 94 016 AC, 757 A-SCC, and 155 SCC. Median OS was lower for SCC (8.67 months), compared to AC (13.93 months) and A-SCC (12.71 months, P < .001). SCC was resected less often (25.5% vs 46.7% and 74.5%). On subgroup analysis of patients with pancreatic SCC, factors on multivariate analysis associated with improved survival included surgery (HR 0.19, P < .001), and chemotherapy (HR 0.22, P = .01). In 38 patients with SCC undergoing surgical resection, median OS improved (MS = 6.8 months without surgery vs 21.3 months with surgery, P < .001).
Conclusions: Nonmetastatic pancreatic SCC presents with more advanced disease, which is less often surgically resected or treated with any definitive local therapy. In contrast, AC and A-SCC behave more similarly and have higher surgical resection rates and improved survival. In patients with nonmetastatic SCC of the pancreas, surgical resection provides the most significant survival benefit, with systemic chemotherapy providing a less significant benefit, and localized radiation providing no statistical benefit for any subgroup.
(© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)