Novel Approaches for Treating Autonomously Functioning Thyroid Nodules

Benign thyroid nodules are exceedingly common in the adult population. Only a small percentage of nodules are toxic or autonomously functioning thyroid nodules (AFTNs). The options clinicians have for treating the symptoms of hyperthyroidism include anti-thyroidal medications, radioactive iodine, or surgery. Depending on the patient population treated, these options may not be suitable or have inherent risks that are undesirable to the patient. On the other hand, untreated hyperthyroidism can lead to osteoporosis, atrial fibrillation, emotional lability, and neurological consequences. Thus, we present a review of two novel safe and effective approaches for treating AFTN; one surgical (transoral endoscopic thyroid surgery) and one non-surgical (radiofrequency ablation), as a means for expanding our treatment armamentarium. Radiofrequency ablation (RFA) is a novel minimally invasive approach that is a potential alternative to surgery for treating symptomatic benign nodules (43) as well as AFTN (44). This approach eliminates the need for a general anesthetic, an incision, radioactive iodine, or prolonged ATD treatment, making it an attractive non-surgical option. With the use of local anesthesia, the RFA probe is introduced into the midline of the anterior neck at the level of the isthmus, and the nodule is approached using the moving shot technique under ultrasound guidance (45). This causes tissue necrosis and fibrosis by introducing a high frequency alternating current, which raises tissue temperatures to 60 to 100 C (46). Over time, there is progressive shrinkage of the ablated nodule. In benign nodules, the volume of the nodule is thought to decrease between 50 and 80% for most patients, although this is operator and tumor dependent (47, 48). RFA has been offered to patients internationally since 2000 and has been used to treat primary and metastatic tumors of the liver, lung, bone, and kidney and to ablate aberrant conduction pathways in the heart (49–53). More recently, RFA has been applied to the head and neck, particularly for thyroid nodules. While the early results have been promising internationally, there is little North American data (47, 48, 54–61). The current international recommendations for treating benign thyroid nodules include patients who are symptomatic or those who have a disfiguring goiter or a nodule that exceeds 2 cm, or if an AFTN is present (43, 44, 57). Prior to RFA treatment of AFTN, confirmation that the nodule is benign on at least one US-guided FNA or core biopsy is recommended, unless there are concerning features on ultrasound in which case two biopsies should be obtained (43, 44). Nodules that are benign on FNA but that have suspicious US features (EU-TIRADS 5), the latest European Thyroid Association Guidelines strongly recommend (moderate quality evidence) against thyroid ablation to avoid potential delay in treatment of a malignant lesion (62).