Papillary thyroid microcarcinoma: extrathyroidal extension, lymph node metastases, and risk factors for recurrence in a high prevalence of goiter area

BACKGROUND: Although papillary thyroid microcarcinoma (PTMC) is diagnosed with increasing frequency, the best therapeutic option and follow-up protocol have not been established yet, especially in the case of incidental diagnosis. We reviewed our series of patients with PTMC to determine risk factors for recurrence in an area where there is a high prevalence of goiter. METHODS: The medical records of all patients who underwent thyroidectomy with a final pathology report of PTMC between October 2002 and June 2007 were reviewed. PTMC was defined as a papillary thyroid carcinoma 10 mm or less in diameter. Follow-up evaluation was obtained by outpatient consultation and/or telephone interview. RESULTS: In a series of 2,220 patients who underwent thyroidectomy for a thyroid carcinoma, 933 had a PTMC. Diagnosis was incidental in 704 patients (75.5%). Upon multivariate analysis, tumor size, nonincidental diagnosis, and neck node metastases at diagnosis were independent risk factors for extracapsular spread (ECS), while ECS, multifocal disease, and number of removed lymph nodes were independent risk factors for lymph node metastases at diagnosis. Follow-up evaluation was completed in 287 patients, 9 (3.1%) of whom experienced recurrence. The number of removed and metastasized nodes at first operation and the length of the follow-up were independent risk factors for recurrent disease. CONCLUSIONS: Incidental diagnosis of PTMC is frequent in a high prevalence of goiter area. PTMC shows a variable degree of aggressiveness. Management protocols should be based on patient- and tumor-related prognostic factors, as for larger tumors.