Endocrine Abstracts

Aim: Well-differentiated thyroid cancer (TC) comprises the most common endocrine malignancy, featuring very good prognosis and 5-year survival rate of nearly 100% after total thyroidectomy. However, the prevalence of incidental thyroid microcarcinoma (mITC) is continuously rising during the last decade. One obvious reason is the high prevalence of total thyroidectomy (TT) as the preferred operation for otherwise benign nodular or diffuse thyroid diseases. The current retrospective study aims to evaluate the prevalence of mITC (max. diam. ≤1 cm) in benign thyroid diseases as a potential parameter for surgical decision regarding the type of thyroidectomy.

Patients-methods: In one Surgical Department, with specialty interest in Neck Endocrine Surgery, a cohort of 793 patients (660 females/133 males; mean age 51,1 years), underwent TT for benign thyroid diseases, during 13 years (1.1.2004-31.12.2016). All patients were referred for surgical treatment from MDs of Internal Medicine or Endocrinology. Patients with positive/suspicious or non-inclusive cytology, or history of TC, were excluded. Pathological report of mITC was recorded and evaluated according to preoperative diagnosis.

Results: The prevalence of mITC was 14.5% (115/793 patients: females/males: 88/27), while 678 patients (85.5%) were free of malignancy. Evaluation regarding the type of thyroid disease revealed that a percentage of 32.3% (40/124 patients) with solitary thyroid nodule-STN and another of 12.8% (68/530 patients) with multinodular goiter-MNG, were harboring an incidentally detected TC. Thyroid diseases with hyperthyroidism, such as Graves’ disease and toxic multinodular goiter featured malignancy in 8.1% (3/37 patients) and 4.6% (4/87 patients) respectively. Interestingly, mITC was diagnosed in 15.4% (2/13 patients) with previous thyroid lobectomy or subtotal thyroidectomy; among them there was a case of mITC with foci of anaplastic TC.

Conclusions: Incidental thyroid microcarcinoma was identified in a significant proportion of patients with otherwise benign thyroid diseases subjected to TT. The vast majority presented in non-toxic disorders, while mITC was detected in nearly 1/6 of patients with nodular recurrence after previous non-total thyroidectomy. These findings can support the choice of TT as the optimal surgical procedure even in benign thyroid diseases with indication for surgery. Moreover, the first choice of TT leads simultaneously to permanent cure of a potential concomitant thyroid carcinoma, excluding the possibility of future neck re-operation and/or complex longtime follow-up.