P-0167 Association of CK20 Expression and Relapse After Curative Surgery for Ampullary Adenocarcinomas

Abstract

ABSTRACT Introduction Ampullary cancer (AC) is a rare malignancy. Curiously, the ampulla is formed by the union of two distinct types of mucosa: intestinal-type and pancreatobiliary-type. There is evidence in the literature that tumors originating from the intestinal-type mucosa has a better prognosis. Among the markers of intestinal origin, cytokeratin 20 (CK20) has a great importance. Methods Between 2007 and 2012 we performed a retrospective analysis of patients with AC that underwent a pancreaticoduodenectomy (PD) with curative intent in our institution. We evaluated the relationship among the immunohistochemical expression of CK20 and disease relapse and recurrence pattern. Results Twenty-four patients underwent PD, (M:F=13:11), median age was 63 (range35-83), 87% had R0 resection, median of resected lymph-nodes was 8.5 (range 2-30), 29% had positive lymph-nodes, 46% had perineural invasion, 21% had vascular invasion, 29% had lymphatic invasion, 50% had tumors >2 cm, 54% had moderately differentiated tumors. AJCC stage pathologic grouping was: I=37.5%, II=29%, III=33%; Median follow-up was 27 months, median progression free survival was 29 months and median overall survival was 101 months. The relapse rate was 23% for stage I, 50% for stage IIa, 100% for stage IIb and 75% for stage III. Only lymph-node status was independent prognostic factor for disease free survival on multivariate analysis (p=0.045, HR: 7.8). Distant metastasis without local relapse was the most common pattern of failure (87%). Among the 24 patients, 17 were evaluated for the expression of CK20. There were 8 positive tumors (47%) and 9 negative tumors (53%). An association among recurrence, stage and expression of CK20 was detected. Positive tumors were associated with early-stage (85.7% vs 14.3% for stage I and III respectively, p=0.024) and lower rate of recurrence (25% vs 75% for positive and negative tumors respectively, p=0.015). Distant metastasis without local relapse was the pattern of recurrence most commonly observed among patients with negative tumors for the expression of CK20 (87%). Conclusion In the literature, pancreatobiliary versus intestinal type of differentiation seems to predict the outcome. CK20 is a marker of intestinal origin. Our study shows an association among expression of CK20, early-stage and lower incidence of relapse in patients with well operated ampullary cancer.