Fine-needle aspiration biopsy of pancreatic ductal adenocarcinoma: loss of diagnostic accuracy with small tumors.

Eighty-three patients underwent CT-directed fine-needle aspiration biopsies (FNAB) for pancreatic ductal adenocarcinoma. Five factors that might have influenced the diagnostic sensitivity of FNAB were analyzed: clinical history, the number of passes for each FNAB, and three radiologic criteria including tumor size, tumor location, and the presence or absence of suspected tumor necrosis by CT scan. Sixty-three patients had a diagnosis of pancreatic carcinoma confirmed by FNAB (overall sensitivity = 76%). Tumor size was the only factor that correlated with the diagnostic sensitivity of FNAB. [table: see text] Of 12 patients whose FNAB was negative but suspicious for malignancy, 10 had a repeat FNAB and 4 were positive for carcinoma. We conclude that the diagnostic sensitivity of FNAB decreases significantly with decreasing tumor size and that a repeat FNAB for suspicious biopsies should be done to increase the diagnostic yield.