Thyroid function is essential to life, and though thyroid hormone can be replaced with medication, it’s not the same as having your own gland. Unless there is a good reason to remove it or part of it, the best place for your thyroid to be is in your neck doing its job.
Thyroid surgery is undertaken for three main reasons: nodules with thyroid cancer or concern for cancer, benign enlargement causing compression of nearby structures, or if the gland is producing too much hormone.
Thyroid nodules are extremely common, and are found in about 50% of people. About 90% of these nodules are benign, and the best place for a benign nodule is in your neck. Nodules are assessed through ultrasound, and certain characteristics increase or decrease the likelihood of a thyroid nodule requiring further workup. If the nodule meets the criteria, a fine needle aspiration biopsy will be recommended to sample the cells inside the nodule to see if there is concern for cancer. If there is thyroid cancer or concern for thyroid cancer, surgery will be recommended. Nodules that are very large (>4 cm) require surgical excision because the risk of a false negative fine needle aspiration biopsy (benign biopsy, when in fact cancer is present) is about 15%.
A thyroid goiter is a benign enlargement of the thyroid gland. It has many nodules, which can grow and compress the nearby structures in your neck such as your trachea (windpipe) or esophagus. Large thyroid nodules or goiters cause symptoms such as difficulty swallowing or a sensation of choking when you are laying down. There is no exact size at which a nodule can become symptomatic, but it is generally about 3 cm in size. It really depends on each individual’s unique anatomy. Occasionally, a thyroid goiter will grow down into the chest. These goiters are called substernal goiters, because of their location beneath the sternum (breastbone). These goiters are nearly always symptomatic in some form, and they should be removed with surgery. 99% of these goiters can be removed from an incision in the neck, but occasionally the sternum (breastbone) must be split to remove a diseased thyroid in its entirety.
Hyperthyroidism, or an overactive thyroid, occurs when a nodule or the entire gland produces more hormone than necessary. Symptoms of hyperthyroidism include sweating, palpitations, tremors, weight loss, and insomnia. Overactive nodules are called toxic nodules. If the entire thyroid is overactive, the problem is an autoimmune disease known as Graves’ disease. In this disease, the body produces an antibody which inappropriately stimulates the thyroid gland. For both of these conditions, the treatment can either be anti-thyroid medications such as methimazole or propylthiouracil (rarely used), radioactive iodine (a pill which uses radioactivity to destroy the overactive portions of the thyroid gland, or surgery to remove the overactive portion of the gland.