Carcinoma of the Ampulla of Vater morphological and immunophenotypical classification predicts overall survival

OBJECTIVES: The objective of the study was to verify if histopathological differentiation of ampullary carcinoma after surgical resection may be related to survival. METHODS: The prognostic role of an accurate histological and immunohistochemical classification has been investigated in a multicentric series of carcinoma of the ampulla of Vater. Immunohistochemical expression of cytokeratin 7 (CK7) and CK20 were analyzed in the different morphological histotypes of ampullary cancers, and results were compared with overall survival. RESULTS: Of 72 ampullary cancers, 48.6% were classified as pancreaticobiliary-type carcinomas, 43.1% were classified as intestinal-type carcinomas, and 8.3% were classified as "unusual"-type carcinomas. Cytokeratin 20 was expressed in 28 (90.3%) of the 31 intestinal-type carcinomas, whereas it was always negative in the pancreaticobiliary histotype; CK7 was expressed in 32 (91.4%) of the 35 pancreaticobiliary-type carcinomas and in 18 (58.1%) of the 31 intestinal-type carcinomas. By univariate analysis, overall survival was influenced significantly by pathological T factor, lymph node involvement, and histological/immunohistochemical subtyping. Furthermore, using a multivariate Cox regression model, lymph node metastasis and CK20 were identified as significant independent factors related to prognosis. CONCLUSION: Our results prove the clinical use of ampullary cancer subclassification based on different histotypes and indicate the useful role of the CK7/CK20 expression profile for consistent histopathological classification and prognostic relevance.