Ferraz, Carolina1; Simões, Vivian1; Faro, Fernanda1; Cabral, Cristal1; Scalissi, Nilza1; Cury, Adriano1; Marone Marilia2; Padovani Rosalia1,2
1 Endocrinology Unit, Internal Medicine Department of Santa Casa de Sao Paulo, School of Medicine Sciences, Sao Paulo, Brazil
2 Nuclear Medicine Service of Santa Casa de Sao Paulo, School of Medicine Sciences, Sao Paulo, Brazil
Background: Thyroid microcarcinoma (TMC) is a differentiated thyroid carcinoma (DTC) classified as low-risk of recurrence and the treatment proposed is lobectomy or even active surveillance1,2. However, some patients show a higher risk of disease recurrence1. Some factors are described as possible indicators for a worse outcome.
Objective: identify possible risk factors associated with TMC incomplete response3,4.
Methods: A retrospective study of 1840 patients were stratified according to persistence/recurrence risk and response to initial therapy. Age, gender, size of the tumor, histological variants, multifocality, vascular invasion, extrathyroidal extension, lymph node and distant metastasis were evaluated.
Results: From 1840 patients, 89.8% were women, mean age 46.8±12.1years. 96% were papillary carcinomas. 25.3% had multifocal disease, 4.7% vascular invasion, 18.5% extrathyroidal extension, 10.4% lymph node metastasis and 0.1% had distant metastasis. Regarding risk of recurrence, 79.7% were low risk and 2.3% high risk. After reclassifying patients, 63.5% had an excellent, 15.1% an indeterminate, 8.5% biochemical incomplete, and 12.6% showed structural incomplete response. Multivariate analysis demonstrated that multifocality (OR:1.53) and lymph node metastasis at diagnosis (OR:2.11) were independently associated with incomplete response. Radioiodine therapy did not influence the type of response in patients with multicentricity.
Discussion/Conclusion: Although patients with TMC are considered low risk and generally evolve well1,2, a special group of patients, showing multifocality and lymph node metastasis at diagnosis, can evolve with disease recurrence and thereby could benefit from a surgical treatment, however without benefit with additional radioiodine treatment.
- Ito Y, Miyauchi A, Kihara M, Higashiyama T, Kobayashi K, Miya A 2014 Patient age is significantly related to the progression of papillary microcarcinoma of the thyroid under observation. Thyroid 24:27–34.
- Haugen BR, et al. The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid, 2016. Volume 26, Number 1.
- Ito Y, Fukushima M, Kihara M, et al. Investigation of the prognosis of patients with papillary thyroid carcinoma by tumor size. Endocr J 2012; 457-464
- Allo MD, Christianson W, KoivunenD . Not all ‘‘occult’’ papillary carcinomas are ‘‘minimal’’. Surgery.1998; 971-97