Influence of Tumor Laterality and Focality on Clinical Implications and Tumor Advancement in Well-Differentiated Thyroid Cancer.

[BACKGROUND] The accurate preoperative diagnosis of TC plays a very important role in the selection of an appropriate treatment strategy. In addition to the hypoechogenicity of thyroid lesions on ultrasound and the presence of microcalcifications or high cell atypia on FNAB, highlighting the features of laterality and focality and ascertaining their influence (alone or combined) on TC staging and appropriate treatment are crucial.

[MATERIALS AND METHODS] A retrospective analysis of the clinical data of 697 patients admitted to the study center between 2008 and 2023 was conducted. Preoperative data (age, sex, type of surgery, ultrasound, and FNAB data) and postoperative histopathological data indicating TC advancement (pTNM, extrathyroidal extension, vascular invasion) were collected and analyzed. Patients presenting well-differentiated TCs (papillary TC and follicular TC) were isolated for better clinical evaluation. Finally, patients were divided into four groups according to their laterality and focality features, and the influences of combinations of these features on TC advancement were analyzed.

[RESULTS] The largest group included patients with unilateral and solitary TC ( = 461). This group had the lowest rate of negative prognostic features: extrathyroidal extension, lymph node invasion, distant metastases, and vascular invasion (25.81%, 19.96%, 3.69%, and 26.46%, respectively). In contrast, the group with bilateral and multifocal TC ( = 40) presented the highest percentages of the mentioned features (82.50%, 82.50%, 7.50%, and 77.50%, respectively). All the results were statistically significant ( < 0.0001).

[CONCLUSIONS] Laterality and focality features may be important parameters in the management of TC and should be accurately determined. These features should be combined and a more aggressive treatment method should be selected to reduce the reoperation rate.