EUS-FNA Predicts 5-Year Survival in Pancreatic Endocrine Tumors (PETs)

Abstract

Background: PETs differ in clinical behavior and prognosis. Determination of malignant potential by EUS-FNA can help management. Aim: To determine the performance of EUS-FNA for diagnosing and classifying the malignant potential of PETs based on WHO classification. Methods: Single-center retrospective study. A review of medical records from 01/1999 to 08/2008 was performed to identify patients who had been diagnosed with PETs and submitted to EUS-FNA. The diagnosis of PET was established by EUS-FNA and/or histopathologic evaluation obtained by surgical resection. Antibodies against synaptophysin, chromogranin A, p53, Ki-67 were used. The lesions were classified as recommended by the WHO. Results: In overall, 90% (77/86) of patients had the diagnosis obtained by EUS-FNA. The sensitivity did not vary with size, type, location, and presence of hormonal secretion. Of 86 patients, 30 (35%) were submitted to surgery. The kappa index between the classification obtained by EUS-FNA and by surgery was 0.38 (p=0.003). Major discrepancies were found in the group of endocrine tumor of uncertain behavior(UBWDET) obtained by EUS-FNA, since 72% turned out to be well-differentiated endocrine carcinoma(WDEC). Sixteen patients(27%) died during a mean follow-up of 34 ± 27 months. The 5-year survival rates were 100% for endocrine tumors, 68% for WDEC, and 30% for poorly-differentiated endocrine carcinomas(PDEC)(p=0,008). Conclusions: This largest single-center experience demonstrated the accuracy of EUS-FNA in diagnosing and determining the malignant behavior of PETs. EUS-FNA predicts 5-year survival. Notes: BBWET=well differentiated endocrine tumor of benign behaviour