Relevance 

Nodules of the thyroid gland are a frequent find according to ultrasound data. However, further management tactics are not always clear. What percentage of large nodes is transformed into a malignant neoplasm? What is the frequency of false negative results from a fine needle aspiration biopsy? A meta-analysis will help answer some of these questions.  

Researchers from Chicago (USA) compared the frequency of malignant neoplasms and the frequency of false-negative results according to a fine-needle aspiration biopsy of cytologically benign nodes in patients with small and large thyroid glands .   

Methods

A search was performed for studies published before December 2017 in the PubMed database. 

Researchers identified 342 articles that addressed the evolution of thyroid nodules. As a result, 35 articles were highlighted in which the sizes of the thyroid gland nodes were mentioned. All nodes were stratified by size (3, 4 or 5 cm) and were benign according to cytological diagnosis or post-resection histology

results

• The frequency of malignant neoplasms from all nodes ≥3 cm (13.1%) and from nodes ≥4 cm (20.9%) was lower than from nodes less than <3 cm (19.6%) and <4 cm (19, 9%; odds ratio, 0–72 95% CI, 0.64–0.81 and odds ratio, 0.85, 95% CI 0.77–0.95]).
• The frequency of false-negative results according to the fine-needle aspiration biopsy for nodes ≥3 cm (7.2%) did not differ from that for smaller nodes (5.7%; odds ratio, 1.47 [95% CI 0.80–2 , 69]). 
• The frequency of false negative results for nodes ≥4 cm (6.7%) was slightly higher than for nodes <4 cm (4.5%; odds ratio, 1.38 [95% CI 1.06–1.80] ) 
• It was noted that the most commonly established false negative diagnosis was papillary thyroid carcinoma. 

Conclusion

The frequency of malignant neoplasms and false-negative results according to fine-needle aspiration biopsy varies, but in most studies it is not higher in patients with larger thyroid nodules. 

Patients with large, cytologically benign thyroid nodules do not need immediate surgical resection, since the frequency of false-negative results of a fine-needle aspiration biopsy is low.