Efficacy of platinum chemotherapy agents in the adjuvant setting for adenosquamous carcinoma of the pancreas.

Abstract

e15028 Background: Pancreatic adenosquamous carcinoma (PASC) is a rare morphological subtype of pancreatic adenocarcinoma. PASC accounts for only 1-4% of exocrine pancreatic cancers and carries a particularly poor prognosis. Due to the rarity of PASC, studies of therapies specifically targeting this histopathologic entity are exceedingly limited. Based on efficacy exhibited by platinum agents against squamous carcinoma of other body sites, addition of these agents to adjuvant regimens may benefit patients with PASC. This retrospective study was performed among the largest series of patients with PASC identified to date in order to determine whether addition of platinum agents improves survival. Methods: Records of all patients who underwent pancreatic resection at our institution from 1986-2012 were reviewed to identify those with PASC. Demographic, surgical, pathologic, adjuvant therapy, and survival data were collected. Patients were divided into non-platinum (NPG) and platinum (PG) groups based on whether or not they received a platinum agent as part of adjuvant therapy. Results: In total, 62 patients with PASC were identified among 5,627 cases (1.1%). Fourteen patients received a platinum agent in the adjuvant setting (PG), while 48 did not (NPG). These two groups were comparable in regard to median age (65 vs. 69 yrs, p=0.34), gender (36 vs. 46% female, p=0.50), performance status (78 vs. 79% ECOG 0, p=0.98), histologic grade (86 vs. 77% grade 3, p=0.49), positive resection margins (14 vs. 29%, p=0.26), lymph node involvement (71 vs. 79%, p=0.54), median tumor diameter (4.0 vs. 4.3 cm, p=0.64), and proportion receiving radiotherapy (57 vs. 42%, p=0.31). PG patients received a median of 5.5 cycles (IQR, 3.3-6.0) of platinum chemotherapy, with 10 patients (71%) receiving cisplatin-based regimens and 4 (29%) receiving oxaliplatin-based regimens. PG patients experienced significantly longer median survival (19.1 months, 95% CI 12.8-25.4) compared to NPG patients (9.8 months, 95% CI 7.3-12.4) (p=0.024). Conclusions: Addition of a platinum agent to adjuvant regimens for resected PASC may improve survival among these high risk patients, though collaborative prospective investigation is needed.