Multiprobe FISH on Pancreatic Adenocarcinoma Diagnosed by EUS-FNA of the Pancreas: A Validation Study

Abstract

Introduction: Cautious approach to pancreatic FNA often results in an indeterminate diagnosis on pancreatic endoscopic ultrasound guided (EUS) fine needle aspiration. Utilization of ancillary studies may help confirm a diagnosis of carcinoma of the pancreas. This has a distinct potential to help patients and clinical teams arrive at early informed patient management decisions. Recent recommendations on utilization of ancillary studies in pancreatobiliary tree analysis suggested a possible role for fluorescence in situ hybridization (FISH) studies as an adjunct to cytology for pancreatic masses (Diagn. Cytopathol. 2014; 42:351e362). Our objective for the study was to determine performance characteristics of commercially available multiprobe FISH (CEP3, CEP7, CEP17 and locus specific probe for chromosome 9p21) on EUS-FNA of the pancreas. Materials and Methods:We prospectively collected EUS-FNA samples for UroVysion (Abbott Inc) multiprobe FISH analysis. Residual FNA sample after the diagnosis was forwarded for FISH analysis in preservecyt. Sample preparation and analysis were performed as per the manufactures’ suggested protocol. A statistical analysis using a two tailed student t test was performed. Results: We analyzed 32 samples from 30 patients. The mean age was 67 yrs (range: 42-90 yrs). The tumor size ranged from 1.1 e 7 cms (mean 3.0 cms). Eighteen of the 19 (95%) adenocarcinoma were positive for UroVysion FISH. Of the 2 cases deemed negative by cytology both were considered UroVysion negative. Aneusomy was statistically significantly associated with adenocarcinoma (pZ 0.014). Of the 8 indeterminate cases 4 cases each were considered as either atypical or suspicious for adenocarcinoma. Lack of cellularity precluded adequate analysis by FISH in suspicious (nZ 3) and atypical (nZ3) cases. One of 4 (25%) cases suspicious for carcinoma was positive by FISH. Conclusion: Aneusomy on UroVysion FISH can be used as an ancillary tool to support a diagnosis of pancreatic carcinoma on EUS-FNA samples.