Perineural infiltration as a prognostic factor in surgically treated gallbladder cancer: a single center experience and literature review

INTRODUCTION: Gallbladder cancer (GBC) is the most incident cancer of the biliary tract with only 5-13% of the sufferers surviving for five years. The aim of this study was to evaluate the prognostic role of perineural invasion (PNI) and its association with several clinicopathological variables in a cohort of surgically treated patients, and through a comprehensive review of the scientific literature. MATERIALS AND METHODS: Twenty-five consecutive patients submitted to curative surgery for GBC from 2008 through 2016 were enrolled. Demographic, clinical and pathological data were retrieved from medical files, and specimens were re-examined by two experienced pathologists. The Pubmed database was searched for articles reporting on perineural infiltration on gallbladder cancer. RESULTS: Perineural invasion was observed in 14 (56%) cases, and it was more frequent in higher pathological stages. A statistically significant association was found with high preoperative serum Ca 19-9 levels. Fourteen (56%) patients died during the follow-up; survival was lower in patients with perineural invasion in comparison to those without, but not statistically significant. Twelve English-language articles reporting on PNI were retrieved and discussed. CONCLUSIONS: Perineural invasion is associated with higher stage and poorer survival in surgically treated GBC patients. In patients with locally advanced GBC resection of the extrahepatic biliary duct and frozen section examination of the distal stump must be taken into consideration, especially in cases of tumor arising from the hepatic side of the gallbladder. In cases without residual disease but with pathological evidence of PNI, a careful follow-up is suggested to early detect recurrences.