Clinicopathological Significance and Prognosis of Medullary Thyroid Microcarcinoma: A Meta-analysis

• Published in: World journal of surgery 2017-10, Vol.41 (10), p.2551-2558
• Main Authors: Kim, Jin Hwa, Pyo, Jung-Soo, Cho, Won Jin
• Format: Article
• Language: English
• Subjects: Abdominal Surgery; Cardiac Surgery; Cervical Lymph Node Metastasis; Extrathyroidal Extension; General Surgery; Heredity; Lymph nodes; Medical prognosis; Medicine; Medicine & Public Health; Medullary Thyroid; Medullary Thyroid Carcinoma; Meta-analysis; Metastases; Metastasis; Original Scientific Report; Papillary Thyroid Carcinoma; Patients; Prognosis; Surgery; Thoracic Surgery; Thyroid; Thyroid cancer; Vascular Surgery
• ISSN: 0364-2313; 1432-2323
• DOI: 10.1007/s00268-017-4031-6

Background The objective of the present meta-analysis was to evaluate the clinicopathological significance and prognosis of micro-MTC compared to macro-MTC. Methods Relevant articles were obtained by searching the PubMed and MEDLINE databases. A meta-analysis was performed using 15 eligible studies. In addition, subgroup analysis based on heredity was performed in patients diagnosed with micro-MTC. Results The rate of extrathyroidal extension of micro-MTC [0.118 (95% CI 0.073–0.185)] was significantly lower than that of macro-MTC [0.303 (95% CI 0.224–0.395)]. Micro-MTC [0.229 (95% CI 0.161–0.314)] had a significantly lower rate of cervical lymph node (LN) metastasis compared to macro-MTC [0.595 (95% CI 0.486–0.694)]. The rate of multifocality was not significantly different between micro-MTC and macro-MTC [0.394 (95% CI 0.244–0.566) vs. 0.320 (95% CI 0.234–0.421), respectively]. The rate of distant metastasis did not differ significantly between micro-MTC [0.082 (95% CI 0.017–0.314)] and macro-MTC [0.068 (95% CI 0.009–0.376)]. Patients with micro-MTC showed significantly higher disease-free survival rates [hazard ratio [HR] 0.406 (95% CI 0.288–0.575), I 2  = 40.563%] compared to patients with macro-MTC. Conclusion Micro-MTC has aggressive features, such as multifocality and distant metastasis, similar to macro-MTC and a non-negligible rate of extrathyroidal extension and cervical LN metastasis. We suggest that treatment of micro-MTC should be approached with a similar focus as that of macro-MTC. Considering that less extrathyroidal extension and cervical LN metastasis occur in patients with micro-MTC compared to macro-MTC, we propose that treatment of micro-MTC, which has a relatively low disease burden status, should be viewed as an opportunity for improving prognosis.