Malignancy Risk of Follicular Neoplasm (Bethesda IV) With Variable Cutoffs of Tumor Size: A Systemic Review and Meta-Analysis

• Published in: The journal of clinical endocrinology and metabolism Vol. 109; no. 5; pp. 1383 - 1392
• Main Authors: Cho, Yoon Young, Ahn, Soo Hyun, Lee, Eun Kyung, Park, Young Joo, Choi, Dughyun, Kim, Bo-Yeon, Jung, Chan-Hee, Mok, Ji Oh, Kim, Chul-Hee, Kim, Sun Wook
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.05.2024
• Subjects: Biopsy; Biopsy, Needle; Cancer; Care and treatment; Decision making; Diagnosis; Malignancy; Meta-analysis; Neoplasia; Nodules; Oncology, Experimental; Reference values (Medicine); Risk factors; Surgery; Thoracic surgery; Thyroid; Thyroid cancer; Thyroid gland; Thyroidectomy; Tumors; South Korea; follicular neoplasm; malignancy risk; diagnostic lobectomy; tumor size cutoff
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/clinem/dgad684

Abstract Context The decision on diagnostic lobectomy for follicular neoplasms (FN) is challenging. Objective This meta-analysis investigates whether an appropriate size cutoff exists for recommending surgery for thyroid nodules diagnosed as FN by fine needle aspiration. Methods The Ovid-Medline, EMBASE, Cochrane, and KoreaMed databases were searched for studies reporting the malignancy rate of FN/suspicious for FN (FN/SFN) according to tumor size, using search terms “fine needle aspiration,” “follicular neoplasm,” “lobectomy,” “surgery,” and “thyroidectomy.” Results Fourteen observational studies comprising 2016 FN/SFN nodules with postsurgical pathologic reports were included, and 2 studies included malignancy rates with various tumor sizes. The pooled malignancy risk of FN/SFN nodules according to size was: odds ratio (OR) 2.29 (95% CI, 1.68-3.11) with cutoff of 4 cm (9 studies), OR 2.39 (95% CI, 1.45-3.95) with cutoff of 3 cm (3 studies), and OR 1.81 (95% CI, 0.94-3.50) with cutoff of 2 cm (5 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 removal of 1 influence study. When each cutoff size was evaluated by summary receiver operating characteristic (sROC) curves, the cutoff of 4 cm showed the highest summary area under the curve (sAUC, 0.645) compared to other cutoffs (sAUC, 0.58 with 2 cm, and 0.62 with 3 cm), although there was no significant difference. Conclusion Although the risk of malignancy increases with increasing tumor size, the risk remains significant at all tumor sizes and no cutoff limit can be recommended as a decision-making parameter for diagnostic surgery in Bethesda IV thyroid nodules.