Thyroid cancer is a rare type of cancer that occurs when malignant (cancer) cells form in the tissues of the thyroid gland. This butterfly-shaped gland is located at the base of the throat near the windpipe. Using iodine found in the diet, it produces hormones responsible for controlling the heart rate, body temperature, metabolism, and amount of calcium in the blood.
According to the Centers for Disease Control and Prevention, about 12,000 men and 33,000 women are diagnosed with thyroid cancer yearly, and about 950 men and 1,100 women die yearly from the disease. In the 2020 publication of the American Thyroid Association, diagnoses have steadily increased in the last decades.
The cause of the uncontrolled growth of cells in the thyroid gland is still unclear, but experts have identified factors that may increase one’s susceptibility. These include a family history of thyroid cancer, radiation exposure in childhood, acromegaly or a condition when the body produces excess growth hormones and other goiter conditions like inflamed thyroid or goiter.
In most cases, thyroid cancer is treatable and can be cured completely but may also recur. The type of treatment that the doctor will recommend normally depends on the type and stage of the cancer, patient’s overall health condition, and preference. For small papillary thyroid cancer, treatment might not be necessary right away because this thyroid cancer subtype has slow growth and does not spread to other parts of the body (metastasis). Instead of opting for removal or surgery, active surveillance that requires frequent monitoring—annual or biannual blood tests and neck ultrasound—of the cancer is the best option. On the other hand, aggressive subtypes of thyroid cancer require standard treatments to avoid metastasis and growth.
Standard treatments for thyroid cancer
Most types of thyroid cancer require one or a combination of treatments, and the timing of when treatments are administered is part of the treatment plan.
Surgery, the most common treatment for thyroid cancer, is the removal of the tumor and some surrounding healthy tissue. Depending on the nodule size, surgical options may include:
Thyroidectomy involves the removal of nearly all of or entire thyroid gland. This is done by making a few inches of incision across the frontal neck, which may leave a little scar after the surgery. To monitor for possible recurrence of the cancer, the doctor will perform radioiodine scans and thyroglobulin blood tests.
Thyroid lobectomy is an operation that removes the thyroid lobe with the cancerous nodule. The surgery is usually performed along the isthmus, the small part of the gland that connects the left and right lobes. Instead of thyroidectomy, lobectomy is used for treating papillary or follicular thyroid cancers, which have small nodules and show no signs of metastasis. Another application of this procedure is for diagnosis when a biopsy result is unclear.
Lymph node dissection applies when cancer has spread until the nearby lymph nodes in the neck. In this procedure, only one or two enlarged cancerous lymph nodes are removed, and small deposits of cancer cells may be left and treated with radioactive iodine.
Patients who have undergone any of the surgical procedures above are often ready for discharge at the hospital the following day after the operation. Although less likely to happen, potential complications like infection, damage to the parathyroid glands, and hoarseness or loss of voice may arise from surgical mistakes.
Thyroid hormone therapy
Along with the surgery, patients may also be required to take hormone treatment to replace the hormone needed by the body and to slow down the growth of any remaining non-aggressive thyroid cancer subtype.
This kind of therapy often comes as a pill containing levothyroxine. Prescribed by an endocrinologist, it is taken daily for continuous hormone supply. If the patient takes other medications and dietary supplements, they should be consulted with the physician to avoid contraindications.
During the first month of treatment, some patients may lose some hair or develop a rash as a side effect of the thyroid hormone pill.
Radioactive iodine treatment
Also called radioiodine therapy, this type of treatment is used to locate and destroy cancerous thyroid cells not removed during surgery as well as those that have spread to lymph nodes and distant sites.
Although the thyroid absorbs almost all iodine inside the body, an endocrinologist or nuclear medicine specialist usually gives a small dose of Iodine-131 first to ensure that it is absorbed by the tumor cells before administering a full treatment.
Iodine-131 often comes as a pill or in liquid form. After taking this medication, a patient may be hospitalized for two to three days. Nausea and vomiting may be experienced during the first day, and other side effects like pain and swelling as well as xerostomia or dry mouth due to the swelling of salivary glands. In the worst case, large doses of iodine may cause infertility or second cancer, so it is important to discuss this treatment properly with the physician.
This type of treatment is used to target specific genes or proteins responsible for the growth and changes of the cancer cells. It works by blocking the growth and metastasis of the cancer cells while at the same time limiting damage to the normal cells. Learn more about this treatment through Understanding Targeted Therapy for Cancer.
A targeted therapy treatment may vary across individuals. Experts find the most effective treatment by running tests that identify the genes and proteins causing the tumor. The U.S. Food and Drug Administration has approved several targeted therapies for each type of thyroid cancer and studies are still ongoing to discover other molecular targets. The use of targeted therapy is often part of a clinical trial.
Depending on the type of drug used, some common side effects of this treatment are diarrhea, fatigue, high blood pressure, mouth sores, and liver problems, but there are medicines available to prevent or treat them. Normally, they go away on their own after the completion of the treatment.
Whichever type of treatment the patient is considering receiving, it is always best to talk with the doctor to learn more about the treatment, its specific purpose, potential side effects, and possible interactions with other medications to achieve the most effective treatment.