Resected pancreatic adenosquamous carcinoma: clinicopathologic review and evaluation of adjuvant chemotherapy and radiation in 38 patients

Pancreatic adenosquamous carcinoma is a rare morphological variant of pancreatic adenocarcinoma with an especially poor prognosis. The purpose of this study is to identify clinicopathologic features associated with prognosis, assess whether the percentage of squamous differentiation in pancreatic adenosquamous carcinoma is associated with an inferior prognosis, and examine the impact of adjuvant chemoradiation therapy on overall survival. Forty-five (1.2%) of 3651 patients who underwent pancreatic resection at the Johns Hopkins Hospital, Baltimore, MD, between 1986 and 2007 were identified with adenocarcinoma of the pancreas with any squamous differentiation. All pathologic specimens were re-reviewed. Statistical analyses were performed on the 38 patients amenable to adjuvant chemoradiation therapy for whom clinical outcome data could be obtained. Median age was 68 years (61% male). Sixty-one percent underwent pancreaticoduodenectomy. Median tumor size was 5.0 cm. Seventy-six percent of carcinomas were node positive, 37% were margin-positive resections, and 68% had 30% or more squamous differentiation. Median overall survival of the pancreatic adenosquamous carcinoma cohort was 10.9 months (range, 2.1-140.6 months; 95% confidence interval, 8.2-12.5 months). Adjuvant chemoradiation therapy was associated with superior overall survival in patients with pancreatic adenosquamous carcinoma (P = .005). Adjuvant chemoradiation therapy was associated with improved survival in patients with tumors 3 cm or larger and vascular or perineural invasion (P = .02, .03, .02, respectively). The proportion of squamous differentiation was not associated with median overall survival (<30% versus ≥30%, P = .82). Survival after pancreatic resection of pancreatic adenosquamous carcinoma is poor. Treatment with adjuvant chemoradiation therapy is associated with improved survival. The proportion of squamous differentiation in resected pancreatic adenosquamous carcinoma specimens does not appear to impact overall survival.