MALIGNANCY RISK OF FOLLICULAR NEOPLASM WITH VARIABLE CUT-OFFS OF TUMOR SIZE

A SYSTEMIC REVIEW AND META-ANALYSIS

Abstract

INTRODUCTION
The decision on diagnostic lobectomy for follicular neoplasm has challenged clinicians. This meta-analysis investigates whether an appropriate size cut-off exists to recommend thyroid surgery for thyroid nodules diagnosed as follicular neoplasm by fine-needle aspiration.

METHODOLOGY
Ovid-Medline, EMBASE, Cochrane, and KoreaMed databases were used to search studies reporting the malignancy rate of follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) according to tumor size through July 2022. The search terms ‘fine needle aspiration,’ ‘follicular neoplasm,’ ‘lobectomy,’ ‘surgery,’ and ‘thyroidectomy’ were used.

RESULTS
Fourteen observational studies with 2016 cases of FN/SFN nodules with postsurgical pathologic reports were included, and two studies reported malignancy rates with various tumor sizes. The pooled malignancy risk of FN/SFN nodules according to size as below: the odds ratio (OR) 2.29 (95% CI: 1.68–3.11) with cut-off of 4 cm (nine studies), OR 2.39 (95% CI: 1.45–3.95) with cut-off of 3 cm (three studies), and OR 1.81 (95% CI: 0.94–3.50) with cut-off of 2 cm (five studies). However, tumors ≥2 cm also showed a higher risk (OR 2.43, 95% CI: 1.54–3.82) based on the leave-one-out meta-analysis after removing one influence study.

CONCLUSION
Tumor size alone is not sufficient for determining diagnostic lobectomy for FN/SFN nodules; however, clinicians are warranted to monitor carefully FN/SFN nodules, especially in tumors larger than 2 cm, and discuss appropriate timing of surgery for FN/SFN nodules with patients.