Surgical Strategy for Papillary Thyroid Microcarcinoma / 대한갑상선학회지

ABSTRACT

It is generally agreed that papillary thyroid microcarcinoma (PTMC) demonstrates indolent biological behavior. But PTMCs include at least two biologically distinct subpopulations: indolent tumors with minimal or no potential for progression, and tumors with the propensity for aggressive behavior and dissemination. The ability to stratify those relatively few patients with aggressive PTMC from the vast majority who are low-risk is crucial to offer most appropriate clinical management. Risk factors such as tumor size, age, sex, tumor multifocality, vascular or capsular invasion, extrathyroidal extension, lymph node metastases, histological variants of papillary thyroid cancer (PTC), the presence of mutational markers, and incidentalness need to be considered for a risk-adapted algorithmic approach that would hope to achieve minimal morbidity while still anticipating optimal outcomes at less cost to the patient and to society. But risk factors for recurrence have not been confirmed because of such low recurrence rates, rare mortality rate, and several selection (or therapeutic) biases present in any retrospective series. Larger scale cohort studies showed that recurrence rates did not differ statistically between patients treated with unilateral lobectomy and those treated with bilateral resection, so long as complete tumor resection was achieved. Similarly, more aggressive nodal dissection failed to yield the anticipated reduction in recurrence rates. In conclusion, selection of the minority of PTMC who deserves more aggressive surgery is important, reserving less aggressive treatments for the other, the large majority cases. The ability to stratify those relatively few patients with aggressive PTMC from the vast majority who are low-risk is crucial to offer most appropriate surgical strategy.