Endoscopic ultrasonography - Guided fine-needle aspiration biopsy of suspected pancreatic cancer

Background: In many institutions, computed tomography (CT) guided percutane ous fine-needle aspiration (FNA) has become the procedure of choice for bio psies of pancreatic mass lesions. This method of biopsy and others, such as endoscopic retrograde cholangiopancreatography (ERCP) cytology, are proble matic because of a substantial false-negative rate. Objective: To investigate the yield of endoscopic ultrasonography-guided FN A biopsies in patients who had negative results on CT-guided biopsy or nega tive cytologic findings on ERCP sampling. Design: Prospective cohort study. Setting: Tertiary care university medical center. Patients: 102 patients (median age, 65 years; 58 men and 44 women) with sus pected pancreatic cancer who fulfilled the above criteria were prospectivel y identified and underwent endoscopic ultrasonography-guided FNA biopsy. Measurements: The operating characteristics of endoscopic ultra; sonography -guided FNA for diagnosing pancreatic masses were determined. Surgical path ology or long-term follow-up (median, 24 months) was used to identify false -positive or false-negative results. Results: Median mass size was 3.5 cm x 2.7 cm. A median of 3.4 passes were performed. Cytologic results on endoscopic ultrasonography-guided FNA biops y were positive in 57 patients, negative in 37, and inconclusive or nondiag nostic in 8. No false-positive results were observed. A diagnosis of pancre atic cancer was subsequently confirmed in 3 patients who had tested negativ e (false-negative results) and 1 of the 8 patients with nondiagnostic resul ts. Of these 4 patients, 3 had cytologic evidence of chronic pancreatitis o n endoscopic ultrasonography-guided FNA biopsy. The 95% CI for the likeliho od ratio for a positive test result contained all values greater than or eq ual to 9.7. The likelihood ratio for a negative test result was 0.05 (CI, 0 .02 to 0.15). The posterior probability of pancreatic cancer after a defini tely positive result was at least 93.5% by a conservative lower 95% confide nce limit; after a definitely negative test result, it was 6.9%. The preval ence of pancreatic cancer was 59.8% (61 of 102 patients). Self-limited comp lications occurred in 3 of the 102 patients (2.9% [CI, 0.6% to 8.4%]). Conclusion: Endoscopic ultrasonography-guided FNA biopsy may play a valuabl e role in the evaluation of a pancreatic mass when results on other biopsy methods are negative but pancreatic cancer is suspected.