BACKGROUND:
Pancreatic endocrine tumors (PETs) differ in clinical behavior and prognosis. Determination of
malignant potential through specimens obtained by EUS-FNA can help in the management of these patients. OBJECTIVE: To determine the value of EUS-FNA for diagnosing PETs and for classifying their underlying
malignant potential based on the World Health Organization (WHO) classification. DESIGN: Single-center, retrospective,
cohort study. SETTING: Tertiary referral hospital. PATIENTS: This study involved 86 consecutive patients (44 men,
mean age 58 +/- 14 years) who had been diagnosed with PETs and submitted to EUS-FNA from January 1999 to August 2008. INTERVENTION: EUS-FNA of a pancreatic mass and/or a
metastasis site.
Immunohistochemistry on microbiopsies or on
monolayer cytology was routinely used. The
lesions were classified as recommended by the WHO. MAIN OUTCOME MEASUREMENTS: EUS-FNA sensitivity and 5-year survival rate. RESULTS: Overall, in 90% (77 of 86) of patients in this study, PET was diagnosed with EUS-FNA. The sensitivity did not vary with
tumor size, type, location, or the presence of
hormonal secretion. Of 86 patients, 30 (35%) were submitted to
surgical resection. The kappa
correlation index between the WHO classification obtained by EUS-FNA and by
surgery was 0.38 (P = .003). Major discrepancies were found in the group of patients diagnosed with
endocrine tumor of uncertain behavior by EUS-FNA, because 72% turned out to have well-differentiated
endocrine carcinoma. Sixteen patients (27%) died during a
mean follow-up period of 34 +/- 27 months. The 5-year survival rates were 100% for
endocrine tumors, 68% for well-differentiated
endocrine carcinomas, and 30% for poorly differentiated
endocrine carcinomas (P = .008,
log-rank test). LIMITATIONS: Retrospective design,
selection bias, and small
sample size. CONCLUSIONS: This largest single-center experience to date demonstrated the
accuracy of EUS-FNA in diagnosing and determining the
malignant behavior of PETs. EUS-FNA findings predict 5-year survival in patients with PETs.
