Impact of the 2009 American Thyroid Association guidelines on the choice of operation for well-differentiated thyroid microcarcinomas

BackgroundThe 2009 ATA Guidelines state “lobectomy alone may be sufficient treatment for small (<1 cm), low risk, unifocal, intrathyroidal papillary carcinomas in the absence of . . . nodal metastases.” We determined how often these criteria are satisfied, and whether tumor size alone can dictate operative management.MethodsMedical records of 346 patients with well-differentiated thyroid cancer (WDTC) who underwent thyroidectomy from January 1, 2007 to November 10, 2009, were reviewed. There were 130 patients with tumors ≤1 cm and negative lateral nodes. Pathology reports were reviewed to identify adverse features including multifocality, extrathyroidal extension, vascular invasion, and central node metastases.ResultsEighty-four percent underwent total thyroidectomy and 16% central node dissection. All but 2 patients had papillary cancer. Sixty-one percent with cancers 6–10 mm (group 1) had adverse pathologic features compared with 32% with cancers <6 mm (group 2). Multifocality was most common: 55% in group 1 versus 32% in group 2 (P = .004). Positive central nodes were identified in 23% of group 1 versus 4% of group 2 (P = .004). Of patients in group 1, 88% had positive or suspicious fine-needle aspiration biopsy (FNAB) preoperatively.ConclusionWe recommend that total thyroidectomy be considered as the initial operation for thyroid tumors 6–10 mm in size in which the preoperative FNAB is diagnostic or suspicious for WDTC.