The thyroid gland is situated in the lower-front part of the neck. It secretes hormons that regulate body temperature, energy consumption, and the functions of the organs or tissues such as brain, heart and muscle. Nodules are round masses of the thyroid gland, that can be detected with manual examination or ultrasound. Thyroid nodules are seen quite frequently; at 60 years, every one out of two persons have thyroid nodules.
According to their hormonal activity, thyroid nodules are classified as hot, warm and cold nodules. Hot nodules produce more hormons than the normal tissue, warm nodules produce hormons equal to the normal tissue and cold nodules do not produce hormons. Overall, 95% of thyroid nodules are benign and 5%, malignant (cancer). Cold nodules are more likely to be cancer compared to the other types. If the nodule is suspected to be malignant, a fine needle aspiration biopsy (FNAB) must be performed. This biopsy is performed with local anesthesia under ultrasound guidance. A very tiny needle is advanced into the nodule, aspiration is applied with an injector and the needle is moved in various directions. In this way, a large amount of tissue cells are obtained from different parts of the nodule and they are evaluated by the pathology.
If the nodule is diagnosed to be cancer, the thyroid gland can be partly or totally removed with surgery. If the pathology reveals an indeterminate result, the biopsy can be repeated using the core biopsy technique, or the nodule can be surgically removed.
Current treatment options in benign thyroid nodules
If the FNAB reveals benign findings, the treatment decision must be based on the patient complains. These complaints may be just cosmetic (e.g. a visible swelling in the neck) or functional, such as difficulty in swallowing/breathing, voice change and neck pain. If the nodule is hot (hormone secreting), symptoms of hyperthyroidism may develop, such as palpitation, nervousness, anxiety, sweating and hand trembling (tremor). If the nodule does not grow and cause any symptoms, the patient may just be followed up with ultrasound. If the nodule is large, cause symptoms or grows by time, then it is generally treated.
In benign thyroid nodules, the classic treatment is surgical operation. However, since the surgery requires general anesthesia, may have major complications and results in a visible incision scar in the neck, alternative treatments have been developed. These treatments, which have largely replaced surgery, include percutaneous alcohol ablation, laser ablation and radiofrequency ablation. They are all performed with local anesthesia and under ultrasound guidance, by placing special needles percutaneously into the nodule.
Alcohol ablation is the oldest of these treatments. After a tiny needle is placed into the nodule, alcohol is injected and the nodule is chemically ablated. Alcohol ablation is generally preferred for the treatment of cystic (fluid-filled) thyroid nodules. For solid nodules however, it is accepted to be less successful. Despite that, it is still used in the ablation of solid thyroid nodules because it is much cheaper than the other ablation methods.
In solid benign thyroid nodules, today, the preferred nonsurgical methods are laser ablation, radiofrequency ablation and microwave ablation. These methods are more successful than alcohol ablation in such nodules. Besides, safety and efficacy of these techniques have been scientifically proven in many studies. In recent years, laser and radiofrequency ablations have been used more commonly. Despite that, all of these techniques are accepted to be equally successful in the treatment of benign thyroid tumors.