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

Abstract

Summary 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.

Efficacy of Platinum Chemotherapy Agents in the Adjuvant Setting for Adenosquamous Carcinoma of the Pancreas

“…Our group previously reported that adjuvant chemoradiation was associated with improved survival (13.6 months) compared to surgery alone (8.6 months) (10). We reported that adjuvant chemoradiation was associated with improved survival in select subgroups, specifically patients with tumors ≥3 cm in diameter, poor differentiation, lymphovascular or perineural invasion, and squamous component of ≥30%.…”

“…One large series of PASC patients failed to demonstrate a significant association between the use of adjuvant radiation or chemotherapy and improved survival; however, this study was unable to account for performance status at the time of treatment (12). On the other hand, our group previously demonstrated a survival benefit with the use of chemoradiation therapy following resection in patients with PASC (10). Additional investigations of the efficacy of adjuvant chemoradiation are limited to anecdotal studies (6)(7)(8)14,(18)(19)(20).…”

“…Despite smaller, conflicting reports suggesting that resection does not prolong survival, it is general practice at most major institutions to attempt resection when feasible. Interestingly, the proportion of squamous cell differentiation (<30% vs. ≥30%) also does not appear to be predictive of overall survival (10). Clinicopathologic factors such as tumor size, histologic grade, and resection margin status, which are historically found to be prognostic for patients with resected pure pancreatic adenocarcinoma, had not been previously associated with outcomes in patients with PASC (11,13) perhaps due to the overall aggressive nature of this morphological subtype or the small sample sizes in the previous investigations.…”

“…Strict classification of PASC is dependent on the presence of ≥30% malignant keratinized squamous cell elements mixed with ductal adenocarcinoma (9), though a lower percentage of squamous component (<30%) in PASC does not appear to be associated with improved clinical prognosis (10). Median overall survival for PASC patients undergoing curativeintent resection has been previously reported to be only 11 months compared to 18 months for resected pure ductal adenocarcinoma at the same institution (11).…”

“…Additional data were obtained in regard to potential prognostic factors identified in previously published reports (4)(5)(6)(7)(8)(10)(11)(12)(13)(14)(15)(18)(19)(20). Patient-specific variables included age, sex, and ECOG performance status.…”