Background: The factors that affect the number of needle passes needed to diagnose pancreatic malignancies using endoscopic ultrasound (EUS) -guided fine-needle aspiration are unknown.
Methods: Patient and endosonographic data were prospectively recorded on 121 consecutive patients with pancreatic malignancy. Of these, 110 underwent EUS-guided fine-needle aspiration. A cytopathologist was in attendance for all aspiration procedures.
Results: Initial EUS detected a pancreatic mass in 96% of cases; 23% of these were not seen by computed tomography. EUS-guided fine-needle aspiration was performed in 109 of 110 (99%) patients, including 95 masses, 7 lymph nodes, and 7 hepatic metastases. EUS-guided fine-needle aspiration provided a cytologic diagnosis of malignancy in 104 of 110 (95%). Only tumor differentiation and the site of aspiration affected the number of passes.
Conclusions: With the participation of a cytopathologist, EUS-guided fine-needle aspiration can diagnose pancreatic malignancies with a high degree of accuracy. Only the aspiration site (mass versus node/liver metastasis) can be used to direct the number of passes if a cytopathologist is not present. Without a cytopathologist in attendance, 5 to 6 passes should be made for pancreatic masses and 2 to 3 for liver metastases or lymph nodes; however, this approach will be associated with a 10% to 15% reduction in definitive cytologic diagnoses, extra procedure time, increased risk and additional needles.