Thyroid Cancer Surgery

How common is thyroid cancer and who does it affect?

Thyroid cancer represents 1% of new cancer diagnoses annually. In the U.S. approximately 35,000 people are diagnosed with thyroid cancer yearly. Thyroid cancer is about 3 times more common in women than men and is usually diagnosed between the age of 25 to 65, peaking in the 3^rd and 4^th decades. With recent advances in the treatment of thyroid cancer, it remains to have an extremely favorable prognosis with an over 90% cure rate in most patients.

What are the different types of thyroid cancer?

Thyroid cancers are divided into four types, namely papillary, follicular, medullary and anaplastic thyroid carcinoma. Rare thyroid cancers include lymphoma, sarcoma and squamous cell carcinoma. Papillary and follicular thyroid carcinomas are referred to as well-differentiated types of thyroid cancer and represent 80-90% of all thyroid cancers with papillary being the most common. Medullary thyroid carcinomas accounts for 5-10% of all thyroid cancers and anaplastic carcinoma accounts for only 1-2%. The other types combined account for less than 1% of all thyroid cancers.

How do patients with thyroid cancer usually present?

Thyroid cancer most commonly presents as a painless, palpable, solitary thyroid nodule which is usually picked up during examination either by the patient or physician or more commonly these days incidentally with the advent of detailed imaging modalities such as CT, MRI, PET or ultrasound. Nodules and cysts are not uncommon findings among the general population as they occur in up to 7% of all adults in the United States. Although the majority of these nodules, over 80%, are benign in nature, all masses within the thyroid gland warrant further attention as 5-10% will turn out to be cancerous.

Which patients are at higher risk for thyroid cancer?

Patients are risk-stratified usually by their thyroid specialist, whether this is a surgeon or endocrinologist. Risk factors include age at presentation. The patient’s age at presentation is important because solitary nodules are more likely to be malignant in patients older than 60 years and in patients younger than 30 years. In addition, thyroid nodules are associated with an increased rate of malignancy in male individuals. Rapid growth of a nodule may suggest malignancy. Sudden onset of pain is more strongly associated with benign disease, such as hemorrhage into a benign cyst or subacute inflammatory thyroiditis, than with malignancy. Hoarseness suggests involvement of the recurrent laryngeal nerve and vocal fold paralysis and may be a sign of malignancy. Difficulty swallowing may be a sign of impingement of the lower throat or esophagus. Other risk factors include whether or not the tumor is limited to the thyroid gland, whether it’s size is less than 4 centimeters, and whether there are distant metastases. Relative risk factors include whether there is a history of radiation exposure or a family history of thyroid cancer.

What is the usual work-up and treatment of a suspicious thyroid nodule?

As such any nodule in the thyroid gland that is greater than 1cm in size or is changing in size or is found in a patient in a high risk group as described above requires further workup. The usual workup of a thyroid nodule or cyst is thyroid function tests (labs) and a thyroid ultrasound followed by ultrasound-guided fine needle aspiration (FNA) of the suspected lesion to determine if it appears benign or is concerning for malignancy. If deemed benign, the lesion may be observed for any changes with serial exams or ultrasounds, however if found to be suspicious then a surgical procedure, namely a diagnostic hemithyroidectomy, is recommended to confirm or deny malignancy. Rarely if the mass is found to be malignant on FNA, then a total thyroidectomy is performed from the start. A hemithyroidectomy is where half of the gland is removed and intraoperatively looked at by pathologists to determine if the nodule is malignant. If the mass is definitively found to be malignant in the operating room, then a total thyroidectomy is performed right then and there. If it cannot be determined during surgery whether the mass is benign or malignant, then the patient is closed up and will follow up in the office one week later for final pathology results. At that time if the mass is found benign, then no further surgery is warranted, however if it is found to be malignant then the patient is brought back to the operating room for a completion thyroidectomy to remove the other half of the thyroid gland and perform a central neck compartment dissection. New studies have confirmed that a staging central neck dissection should be considered in all high-risk patients with confirmed thyroid cancer at the same time a total thyroidectomy is performed. This does not add much more risk to the procedure in that a sampling of lymph nodes draining the thyroid gland in the affected area are removed for pathologic analysis. However if a palpable lymph node is found during the work-up of thyroid cancer then a selective or modified lateral neck compartment dissection is recommended.

What is the standard treatment of thyroid cancer?

Thyroid cancer treatment usually requires a collaborative treatment between your endocrinologist and thyroid surgeon for best results. Surgery remains to this day to be the most critical aspect in the treatment of thyroid cancer and as such making sure that your surgeon has extensive experience in the treatment of thyroid cancer and performs over 50 thyroid operations per year is of utmost importance. This surgery is rather delicate as the entire thyroid gland needs to be removed (aka total thyroidectomy) while preserving critical structures like the recurrent laryngeal nerves and parathyroid glands on each side. The traditional approach for this surgery is an 8-10 cm (4-5 inch) incision in the lower central neck with removal of the entire thyroid gland. However, Dr. Alen Cohen at C/V ENT Surgical Group, which serves the Los Angeles and Thousand Oaks areas, is one of a select few surgeons in the country that advocates a minimally invasive approach utilizing a 1.5-2.5 inch incision. This same incision can be used to perform a central neck compartment neck dissection, if indicated. As we all know surgery always carries risks such as pain, bleeding, infection, scarring, and injury to surrounding structures, however this risk can be minimized by carefully selecting your surgeon and making sure they have extensive experience performing this surgery as well as making sure your surgeon utilizes recurrent laryngeal nerve monitoring intraoperatively. In expert hands the risk of permanent vocal cord injury and hoarseness can be minimized to less than 1%. The same goes for the risk of permanent hypoparathyroidism or hypocalcemia.

What happens after surgical treatment of thyroid cancer?

Once surgery is complete and the entire thyroid gland is removed with or without a central neck compartment dissection, then the patient is usually observed overnight in the hospital to make sure their calcium levels are stable before discharge and also to make sure there are no bleeding or breathing issues. The patient is then allowed to heal at home on a low iodine diet and thyroid hormone replacement pills (Synthroid or Cytomel) until 4-6 weeks after surgery when their endocrinologist schedules him/her for radioiodine scanning to detect any microscopic residual cells as well as to evaluate for regional or distant metastases. If this scan is positive, then the patient will have radioactive iodine (RAI) ablation of any microscopic residual thyroid cancer cells. RAI involves the patient being admitted to the hospital and given a radioactive dose of Iodine-131 to ablate these residual cancer cells. This is done in a hospital setting as the patient may be radioactive to family members for days and as such unsafe to be around. This is all that is required for cure in over 90% of patients with well-differentiated thyroid cancer (papillary or follicular thyroid carcinoma). Medullary thyroid carcinoma is a more aggressive type of thyroid cancer and requires a total thyroidectomy and central neck dissection. With this aggressive tumor many thyroid surgeons will advocate an en-bloc resection with sacrifice of the recurrent laryngeal nerve and a lateral neck dissection on the side of the tumor to provide the best chance for cure. Anaplastic thyroid carcinoma is an extremely aggressive type of thyroid cancer with an extremely poor prognosis and treatment is usually aimed at debulking disease and prolonging comfort in patients. External beam radiation is considered in a minority of patients with thyroid cancer who have locally recurrent disease, gross residual disease after surgery, extensive lymph node metastasis or cases of medullary and anaplastic thyroid carcinoma with residual disease after surgery. The role of chemotherapy has never been found to be beneficial in the treatment of thyroid carcinoma except in the treatment of thyroid lymphoma.

How are patients with a history of thyroid cancer followed for recurrence?

Patients with a history of well-differentiated thyroid cancer are usually followed by their thyroid surgeon or endocrinologist annually or semi-annually with laboratory testing to check their thyroglobulin and thyroglobulin antibody levels, radioactive iodine scanning to check for abnormal uptake in the body and more recently high resolution ultrasound of the neck to check for abnormalities. Patients with medullary thyroid cancer are followed by checking their calcitonin levels regularly. More recently PET scanning has become rather important in the follow-up of certain groups of patients with high-risk types of thyroid cancer.