Endocrine Abstracts

JOINT2711

Introduction: We present a study aimed at exploring the advantages and disadvantages of isthmusectomy (IE), as well as determining the indications and limitations for its application. Considering the relatively favorable prognosis associated with well-differentiated thyroid cancer (WDTC), there is growing interest in minimizing the extent of invasive procedures and the risk of surgical complications. Currently, there are no recommendations regarding the extent of thyroid resection for tumors confined to the isthmus. However, scientific evidence supports IE as a potentially safe and effective method.

Materials and Methods: A retrospective analysis was conducted to evaluate the treatment outcomes of 32 patients who underwent internal excision for tumors confined to the isthmus at the Endocrinology Research Centre (median age: 47years [25;70], 78.13% under 55 years). Demographic data, clinical and pathological characteristics of tumors based on ultrasound findings, results of fine needle aspiration biopsy (FNAB), and morphological examination (ME) of postoperative specimens were recorded. In cases with confirmed malignancy staging was performed according to the American Joint Committee on Cancer (AJCC) system (8th edition) and risk stratification for recurrence.

Results: FNAB results confirmed malignant thyroid tumors in 11 patients (34.4%) (Bethesda VI), in 8 patients (25,0%) a Bethesda V, in 13 patients (40.6%) a Bethesda IV. Histologically, WDTC was confirmed in 22 patients, all staged as I: T1a (50.0%), T1b (40.9%), T2 (9.1%). The mean tumor size was 15 mm [6;32]. ME revealed metastases in adjacent lymph nodes (LN) (N1a) in 2 patients, each measuring less than 1 cm, with fewer than 5 affected LN. 21 patients (95.5%) with confirmed WDTC were at low risk, while 1 patient (4.5%) was classified as high risk for disease recurrence. Papillary thyroid cancer was confirmed in 21 patients, with high-grade differentiated thyroid carcinoma diagnosed in 1 patient who subsequently underwent total thyroidectomy. Regarding early postoperative complications, only one patient experienced transient hypocalcemia. The median follow-up period was 18 months [8;34] with no reported recurrences of the disease. Patient observations are ongoing.

Conclusions: The findings indicate the potential of IE as a surgical treatment for lesions confined to the isthmus, provided that an appropriate assessment of the characteristics of the detected lesion and the overall health status of the patient is conducted at the preoperative stage. The implementation of IE into surgical practice may lead to a reduction in the risks of typical postoperative complications associated with this localization, such as recurrent laryngeal nerve injury, hypoparathyroidism, and hypothyroidism.