A systematic review and meta-analysis of palpation versus ultrasound-guided fine needle aspiration of thyroid nodules

Abstract

Background: Thyroid nodules are a common clinical finding. Fine-needle aspiration (FNA) is the most widely accepted diagnostic tool used to differentiate malignant and benign thyroid nodules. FNA can be carried out by manual palpation of the nodule or with ultrasound guidance. Existing clinical practice guidelines give mixed recommendations regarding the use of ultrasound guidance for thyroid FNA. Given the inconsistencies in the guidelines, we performed a systematic review and meta-analysis to compare the diagnostic accuracy of palpationguided fine needle aspiration (PG-FNA) versus ultrasound-guided fine needle aspiration (USG-FNA). Methods: Studies comparing PG-FNA and USG-FNA were identified through a search of PubMed, the Cochrane Library, and Embase (1990- December 2011). Titles and abstracts were reviewed and studies were selected for a full text review. Meta-analysis of included studies was performed to estimate the average sensitivity, specificity, and rate of inadequate samples for each technique. Results: We screened 1934 citations and selected seven studies meeting our predefined inclusion criteria. The pooled sensitivity of USG-FNA was found to be higher than PG-FNA [0.91 (CI=0.82, 1.0) and 0.79 (CI=0.69, 0.85), respectively]. The pooled specificity of USG-FNA was also found to be slightly higher than PG-FNA [0.77 (CI=0.69, 0.85) and 0.73 (CI=0.64, 0.81), respectively]. The mean rate of inadequate samples was higher for PG-FNA at 14.7% versus 8.4% for US-FNA. Conclusions: Our findings show that USG-FNA has a higher diagnostic accuracy than PG-FNA and a lower rate of inadequate samples. Overall, these findings suggest an advantage to the use of USG-FNA over PG-FNA.