Comparison of adequacy rate between different cytology sampling models for thyroid nodules using internationally standardized super⁃fine needle aspiration
Objective:To evaluate the effects of the two different models on diagnostic rates using different combinations of smear and liquid-based cytology during thyroid fine needle aspiration(FNA). Methods:We recruited 613 thyroid nodules from 591 patients with thyroid nodules. All thyroid nodules underwent four passes of FNA in two modes. Mode 1,304 nodules were aspirated with the first two passes for traditional smear,while the latter two passes using SurePath with liquid - based cytology. Mode 2,the other 309 nodules were aspirated in the opposite sequence with the first two passes for liquid - based cytology,while the later two passes for traditional smear cytology. The cytopathologists read each slide blindly and separately. The diagnostic rates of each model were compared. Results:We found that the diagnostic rate of the mode 2 with the first two passes for liquid-based cytology using SurePath and the latter two passes for conventional smear was 82.2%,which was significantly higher than 74.7%(P=0.023)in the group of mode 1 using the first two passes for conventional smear and the following two passes for liquid-based cytology using SurePath. For nodules larger or equal to 10 mm,the diagnostic rate of the mode 2 was 83.2%,which was also significantly higher than the diagnostic rate of 75.4%(P=0.048)in the mode 1 group. The diagnostic rate of the first two passes using liquid-based cytology alone was 78.0%,which was significantly higher than 63.8%(P < 0.001)in the conventional smear group also using the first two passes. For nodules larger or equal to 10 mm,the diagnostic rate of liquid - based cytology in the first two passes alone was 78.3%,which was also significantly higher than 62.6%(P < 0.001)in the conventional smear group similarly using the first two passes. Conclusion:As for diagnostic rate,cytology sampling model using liquid - based preparation as the first two passes followed by later two passes using smear is superior to the model using the combination with opposite sequence. If only one sampling method is applied,liquid - based cytology method would yield higher diagnostic rate.