What is thyroid cancer?
Thyroid cancer is an abnormal growth of cells in the thyroid gland that produces a tumor.
There are basically four types:
- Papillary thyroid cancer: this is the most frequent type of thyroid cancer and in which the mildest tumor develops, let’s say with the best prognosis that exists in all oncology. The cancerous cells, which differ very little from the normal ones, advance very slowly and therefore have a good prognosis in the disease itself.
- Follicular thyroid cancer: like papillary thyroid cancer, this type of cancer originates from follicular cells and generally grows slowly. It is a differentiated thyroid cancer, but is much less frequent than papillary thyroid cancer.
- Medullary thyroid cancer: the origin of this type of cancer is in cells that secrete not thyroid hormone but calcitonin and occurs in a percentage of 30 – 40% of cases with a family origin. This syndrome is also characterized by other types of tumors.
- Anaplastic thyroid cancer: this is a very aggressive cancer caused by a massive differentiation of these follicular cells, i.e. the basic cells of the thyroid. It is mainly suffered by the elderly.
Prognosis of thyroid cancer
Depending on the type of thyroid cancer, the prognosis varies:
- Both papillary thyroid cancer and follicular thyroid cancer originate from follicular cells and generally grow slowly. This slow progression of the cancer means a good prognosis for the patient.
- Patients with medullary thyroid carcinoma live at least 5 years after diagnosis, depending on the stage of the cancer. Women have a better prognosis than men and the 10-year survival rate is 75%.
- Because of the aggressiveness of anaplastic thyroid cancer, it is a cancer that actually has a poor prognosis, but fortunately there are few cases.
Symptoms of thyroid cancer
In the early stages of the disease thyroid cancer usually does not present any signs or symptoms, but as it progresses it can cause:
- Swelling or lump in the neck
- Hoarseness and coughing
- Voice changes
- Difficulty swallowing
- Swollen lymph nodes in the neck
Medical tests for thyroid cancer
A medical examination can diagnose whether the gland is enlarged, and whether there is one or more cancerous nodules. For the identification of cancer a variety of tests are usually performed, such as:
- Physical examination
- Blood tests
- Biopsies through puncture of the nodules.
- Thyroid ultrasound
- Imaging tests
- Genetic testing
What causes thyroid cancer?
Thyroid cancer occurs when thyroid cells undergo genetic changes (mutations). The causes of thyroid cancer are not clear, although in the case of medullary thyroid cancer a certain percentage of its origin is due to genetic syndromes that increase the risk; however, this genetic link is rare.
Can it be prevented?
Since the cause of thyroid cancer is not known with certainty, it is not possible to prevent it. Patients who are at high risk are advised to undergo thyroid surgery to prevent cancer.
Treatments for thyroid cancer
Treatment will depend on the extent of the tumor in each patient. In most cases surgical removal of the nodules is chosen, but there are other treatments including high dose thyroid hormones, radioiodine or external beam radiation therapy.
Depending on the size of the thyroid nodule, the most common surgical options are:
- Lobectomy: the lobe with the cancerous nodule of the thyroid gland is removed.
- Near total thyroidectomy: all but a small part of the thyroid gland is removed.
- Total thyroidectomy: the entire thyroid gland is removed.
There are different surgical techniques that can be used for thyroidectomy: standard thyroidectomy, endoscopic thyroidectomy and robotic thyroidectomy.
If the patient has had a total removal of the thyroid gland (total thyroidectomy), the body will no longer produce the thyroid hormone it needs, so thyroid hormone pills (levothyroxine) must be taken to replace the natural hormone and help maintain normal metabolism, and possibly reduce the risk of the cancer returning.
Radioactive iodine (radioiodine) therapy is also used after thyroidectomy. The goal of this treatment is to destroy all healthy thyroid tissue and any microscopic areas of thyroid cancer that were not removed during surgery. It may also be used to keep thyroid cancer from coming back after treatment or spreading to other places in the body.
External beam radiation therapy for thyroid cancer is another alternative after surgery to remove the thyroid gland. It is applied to patients with advanced stage cancer that has spread to critical areas of the neck, such as the trachea, voice box or esophagus. Treatment is focused on a specific area, affecting only the cancer cells at that site. Radiation therapy is generally not used to manage thyroid cancer in young patients.
What specialist treats it?
Thyroid cancer can be treated by different specialists, either a specialist in General Surgery or a specialist in Medical Oncology. Certainly an endocrinologist will help in the diagnostic process and subsequent postoperative follow-up.