What is the next management step for a 3 cm thyroid mass on the lobe with a Bethesda (Bethesda System for Reporting Thyroid Cytopathology) category 4 result: lobectomy or total thyroidectomy?

From the Guidelines

For a thyroid mass measuring 3 cm on the lobe with a Bethesda category 4 classification, the recommended management is lobectomy (option a). According to the NCCN guidelines insights: thyroid carcinoma, version 2.2018 1, indications for total thyroidectomy or lobectomy, if all criteria are present, include no prior radiation exposure, no distant metastases, no cervical lymph node metastases, no extrathyroidal extension, and tumor ≤4 cm in diameter. Given the 3 cm size of the nodule and the Bethesda 4 classification, which indicates a follicular neoplasm or suspicious for follicular neoplasm, lobectomy is the most appropriate initial surgical approach. This procedure allows for definitive histological diagnosis while minimizing surgical risks compared to total thyroidectomy. Some key points to consider in the management of thyroid carcinoma include:

• The use of thyroid and neck ultrasound to assess the status of lymph node chains 1
• The consideration of vocal cord mobility evaluation in patients with abnormal voice, surgical history involving the recurrent laryngeal or vagus nerves, invasive disease, or bulky disease of the central neck 1
• The potential role for lobectomy with or without frozen section if FNA is suspicious but not diagnostic for papillary carcinoma 1
• The recommendation for total thyroidectomy for tumors >4 cm in diameter, or in the presence of extrathyroidal extension, poorly differentiated tumors, or cervical lymph node metastases 1 If final pathology confirms malignancy with high-risk features, a completion thyroidectomy may be considered as a second procedure. Total thyroidectomy would be overly aggressive as the initial approach since many Bethesda 4 nodules prove benign on final pathology, and unnecessary total thyroidectomy would commit the patient to lifelong thyroid hormone replacement therapy. The 2010 ESMO clinical practice guidelines for diagnosis, treatment, and follow-up of thyroid cancer 1 also support the use of less extensive surgical procedures for unifocal DTC diagnosed at final histology after surgery performed for benign thyroid disorders, provided that the tumor is small, intrathyroidal, and of favorable histological type. However, the most recent and highest quality study, the NCCN guidelines insights: thyroid carcinoma, version 2.2018 1, takes precedence in guiding management decisions. In terms of morbidity, mortality, and quality of life, lobectomy is the preferred initial approach for a 3 cm thyroid mass with a Bethesda category 4 classification, as it balances the need for definitive diagnosis with the potential risks and consequences of more extensive surgery.

From the Research

Thyroid Nodule Management

The management of a thyroid nodule with a size of 3 cm and a Bethesda classification of IV is a critical decision.

• The preferred surgical approach for patients with high-risk nodules and indeterminate cytology is diagnostic lobectomy, in the absence of factors suggesting total thyroidectomy 2.
• However, total thyroidectomy may be considered for larger nodules (≥4 cm) due to a higher malignancy rate and increased risk of local/lymphovascular invasion 2.
• The Bethesda classification system has improved the accuracy of fine needle aspiration biopsy (FNAB) reports, reducing the number of lesions reported as 'benign' or 'nondiagnostic' 3.
• Studies have shown that thyroid nodule size at ultrasound is a poor predictor of malignancy, but a relatively good predictor of final pathologic size 4.
• The relationship between nodule size and malignancy risk is complex, with larger nodules having lower malignancy rates, but size alone should not be considered an independent risk factor 4.

Surgical Approach

• Diagnostic lobectomy is the preferred initial surgical approach for Bethesda IV nodules, unless factors suggest total thyroidectomy 2.
• Total thyroidectomy may be necessary for larger nodules or those with suspicious features, but the decision should be individualized based on patient factors and nodule characteristics.
• The choice of surgical approach should be guided by the Bethesda classification, nodule size, and other clinical and radiographic factors 2, 4, 5.