M. Bosley1, C. Cox1, M. Jones1, D. Carneiro-Pla1 1MUSC,Oncologic And Endocrine Surgery/Department Of Surgery,Charleston, SC, USA
Introduction: Thyroid cancer is the most common endocrine cancer in the United States and accounts for 3.8% of all new cancer diagnosis. The rate for new thyroid cancer diagnosis has been rising on average 5% each year over the last 10 years. It has been suggested that over diagnosis of micropapillary carcinomas (<1 cm) is the main contributor to the increase in thyroid cancer incidence. These tumors are believed to rarely result in symptoms or death, only occasionally growing or spreading beyond the thyroid gland, so much that specialists have been urged not to work up or treat these “indolent” small tumors. Ultrasonography is limited in diagnosing central neck node metastasis which is the most sensitive method of evaluation available for these patients who now more often are recommended active surveillance rather than surgery. The goal of this study is to report the incidence of metastatic disease from micropapillary thyroid cancers.
Methods: Medical records of 213 consecutive patients with thyroid cancers measuring on final pathology 1 cm or less were retrospectively reviewed. All patients were evaluated with preoperative US and operated on by a single endocrine surgeon between January 2007 and December 2015. Pathology reports were reviewed for tumor size, presence or absence of metastases in the central and lateral node basins and multifocality.
Results: Of the 213 patients, 188(88%) were females, 164(77%) caucasian, average age 56(19-89) years old. Thirty-one of 213 (14%) were found to have node metastases. Four out the 31 patients also had positive lateral neck node metastases. Thus, approximately 13% of patients with node metastasis also required selective lateral neck dissections. Furthermore, 34% of these patients had multifocal disease at the time of the diagnosis.
Conclusion: Although recent studies have shown that only 1.5% of the patients with micropapillary thyroid cancer will develop metastatic disease during surveillance, this report demonstrates that 14% of these small cancers are metastatic at the time of the diagnosis, not only to the central neck but also to lateral neck node basins.