Clinical presentation and prognosis of adenosquamous carcinoma of the pancreas – Matched-pair analysis with pancreatic ductal adenocarcinoma

Adenosquamous carcinoma of the pancreas (ASCP) is a rare subtype of pancreatic adenocarcinoma. The aim of this study was to investigate the characteristics and outcomes of ASCP in comparison to pancreatic ductal adenocarcinoma (PDAC).All patients with ASCP treated between December 2001 and December 2017 were identified from a prospective database. Clinicopathological and follow-up data were analyzed. A nested case-control-study with matched-pair analysis was performed to compare overall survival of ASCP and PDAC.Of 4009 patients undergoing surgery for pancreatic adenocarcinoma 91 patients had ASCP. Compared to PDAC ASCP were larger (4.0 vs. 3.2 cm; p 0.0001), more frequently involved lymph nodes (88% vs. 78%; p = 0.0216), more frequently showed poor differentiation (G3: 79% vs. 36%; p 0.0001) and more frequently were located in the pancreatic tail (19% vs. 10%; p = 0.0179). Overall median post-resection-survival was shorter in ASCP (10.8 vs. 20.5 months in PDAC; p = 0.0085), but 5-year survival rates were comparable (18.2% vs. 17.5%). After matching for the unevenly distributed prognostic factors survival after resection of ASCP and PDAC was comparable (p = 0.8301). Localization in the head or several parts of the pancreas, high CA 19-9 levels, and M1 disease were independent predictors of survival in patients with ASCP.ASCP is more aggressive with poorer differentiation and higher rates of lymph node metastases compared to PDAC. In spite of a shorter median survival, 5-year survival rates after surgical resection of about 18% can be expected in ASCP and support resection as part of a multimodal therapy as the treatment of choice in this rare cancer.