Can endosonographers evaluate on-site cytologic adequacy? A comparison with cytotechnologists

Background On-site determination of cytologic adequacy increases the accuracy of EUS-guided FNA (EUS-FNA); however, on-site cytotechnologists are not available to all endosonographers. We hypothesize that experienced endosonographers can accurately assess whether an on-site FNA specimen is adequate. Objective To determine the accuracy of on-site cytopathology interpretation of EUS-FNA specimens by comparing endosonographers with a cytotechnologist. Design Prospective double-blind controlled trial. Setting Academic medical center with a high-volume EUS practice. Patients Consecutive patients undergoing EUS-FNA of lymph nodes or pancreas tumors. Main Outcome Measurements Accuracy, sensitivity, and specificity of 3 endosonographers and 1 cytotechnologist for interpretation of cytologic specimen adequacy and diagnosis compared with a criterion standard of a board-certified cytopathologist. Results There were 59 lymph node, 49 pancreas, and 9 liver specimens (117 total). For determination of adequacy, none of the endosonographers were statistically equivalent to the cytotechnologist ( P = .004). For determination of suspicious/malignant versus benign specimens, all 3 endosonographers were inferior ( P < .001) to the cytotechnologist. Limitations This study represents a small group of trained endosonographers in a high-volume practice and may not be applicable to other settings. The sample size does not allow an accurate evaluation of different biopsy sites (eg, pancreas vs lymph node). Conclusions Even trained endosonographers have variable and, in some cases, inferior abilities to interpret on-site cytologic adequacy compared with cytotechnologists.