Microscopic positive surgical margins in thyroid carcinoma: a proposal for thyroid oncology teams.

PURPOSE In the case of well-differentiated thyroid cancer, the importance of microscopic margin status remains controversial. We discuss the relevance of the effect of microscopic positive surgical margins in the early stages of differentiated thyroid cancer. METHODS A comprehensive literature search and review of available evidence in English literature was undertaken. RESULTS A previous meta-analysis did not find an association between microscopic positive surgical margins and local recurrence. Heterogeneity of definitions and differences between microscopic surgical margins and extrathyroid extension are discussed. Impact on clinical decision-making is explored. CONCLUSION The finding of microscopic positive surgical margins in a patient with a thyroid tumor without intraoperative evidence of macroscopic invasion to adjacent structures, with complete resection made by the surgeon and without pathological report of extrathyroid extension, does not have a worse prognostic effect. We present a classification of surgical margins that may help thyroid oncology teams to tailor further management in patients with thyroid cancer.