Micromedullary thyroid cancer: how micro is truly micro?
Academic Article
Overview
abstract
BACKGROUND: The aggressive nature of medullary thyroid cancer (MTC) is evidenced by its propensity to present early with lymph node (LN) metastases. The clinical significance of sporadic MTC < or =1 cm (micro-MTC) is not clearly defined. METHODS: We performed a retrospective review of the clinical, laboratory, and pathologic data for all patients treated or followed at our institution for sporadic micro-MTC from 1987 through 2008. RESULTS: A total of 18 patients met the criteria for inclusion in our study. All tumors were unifocal and C-cell hyperplasia distant from the tumors was uniformly absent. Fourteen (78%) patients underwent total thyroidectomy, and the remaining four (22%) patients with tumors < or =0.5 cm had lobectomy with isthmusectomy alone. Four (22%) patients were found to have LN metastases. However, none of the nine patients with tumors <0.5 cm had clinical evidence of LN metastases. Patients were followed for a median of 3.3 (mean, 4.5) years, and there were no deaths. Postoperative calcitonin levels were available for all patients, of whom 14 had normal levels (range, 0-3.9 pg/ml). The four patients with elevated postoperative calcitonin levels (range, 6.3-644 pg/ml) had tumors ranging from 0.7-0.9 cm in size. CONCLUSIONS: Tumors <0.5 cm were associated with a complete absence of clinically detectable nodal disease or elevated postoperative calcitonin levels. The complete absence of multifocal or bilateral disease argues against the need for completion thyroidectomy for sporadic micro-MTC.
