Endocrine Abstracts

Recently, we have witnessed an increase in the number of new thyroid cancer (TC) cases and thyroid surgeries. Both the ATA 2015 and 2022 Polish guidelines allow sparing treatment in low-risk TC. Nevertheless, most patients are qualified for total thyroidectomy. The aim of the study was to analyze the possibility of preoperative diagnosis of low-risk TC based on ultrasound examination (US).

Material and method: A retrospective analysis involved 1043 patients diagnosed with TC between 2019 and 2021, among them 962 patients with differentiated TC. All patients underwent fine-needle aspiration biopsy and preoperative neck ultrasound, which assessed tumor diameter, margins, vascularization, signs of extrathyroidal invasion and evaluated neck lymph nodes. Total thyroidectomy was carried out in 967 (92.7%) patients. Postoperatively, low-risk, intermediate-risk, and high-risk TC was diagnosed in 527 (50.5%), 367 (35.2%), and 149 (14.3%) patients.

Results: Nodule diameter ≥17 mm is significantly correlated with the risk of angioinvasion, extrathyroidal extension, neck lymph node metastases and the number of metastatic lymph nodes. The presence of extrathyroidal invasion in the US significantly increased the risk of extrathyroidal extension in histopathological examination (HP) (OR 2.32 [95% CI 1.38-3.82]. Increased vascularisation in the nodule was related to a significantly higher risk of angioinvasion in HP (OR 2.83 [95%CI 1.53-5.17]. The presence of suspected lymph nodes (LN) in the US significantly increases the risk of LN metastases in HP (OR 12.98 [95%CI 8.05-21,42]. In univariate analyses, the presence of ill-defined nodule margins, thyroid capsule invasion, microcalcifications, and suspected LN in the US significantly increases the risk of recurrence. Suspected lymph nodes and thyroid capsule invasion were the only factors significantly increasing the risk of recurrence in multivariate analysis. Considering these results, 468 patients (44.9%) could be qualified based on the preoperative US for thyroid lobectomy as a sufficient surgical procedure.

Conclusions: Some features observed in preoperative neck ultrasound may be helpful in preoperative thyroid cancer risk stratification and planning the adequate extent of primary surgery.