Thyroid cancer starts in the thyroid gland, located in the front part of the neck. According to the American Cancer Society’s estimated 2017 statistics, nearly 57,000 people will be diagnosed with thyroid cancer and nearly 75% of them will be women. Thyroid cancer has a much lower death rate than most cancers (only about 2,000 of those 57,000 diagnosed) and is normally found at a much younger age than most adult cancers. The diagnosis of thyroid cancer has tripled in the past three decades, but the low death rate has remained steady, due to early detection procedures.
Causes of Thyroid Cancer
The cause of thyroid cancer has not yet been determined. However, several risk factors have been identified. Some of these risk factors can be changed, such as the following:
- Low Iodine diet
- Radiation exposure
- Gender (higher for females)
- Family history
- Hereditary conditions
Symptoms of Thyroid Cancer
- Lump in the neck (these are often benign but should always be checked)
- Pain or swelling in the neck
- Persistent hoarseness or voice changes
- Difficulty in breathing or swallowing
Diagnosis of Thyroid Cancer
Thyroid cancer can sometimes be found during a routine exam by your doctor. Other possible steps include the following:
- Medical history and physical exam
- Blood tests
- Imaging tests like thyroid Ultrasound
- Laryngoscopy (vocal cord exam)
- Thyroid Biopsy
Staging of Thyroid Cancer
The diagnostic tests not only help in making the diagnosis but also in determining the stage of cancer (how far the cancer has spread). Age is a big factor in the staging of thyroid cancer and depends on the type, as listed below:
Differentiated Thyroid Cancer
All patients under age 55 have an excellent chance of survival with this type, so they are always Stage 1 (or 2 if the cancer has distant spread).
For those over age 55:
Stage 1: The cancer is no larger than 4 cm and has not spread to nearby lymph nodes or distant sites.
Stage 2: The cancer is up to 4 cm and has spread to nearby lymph nodes but not distant sites.
OR The cancer is larger than 4 cm but confined to the thyroid or it has grown into the strap muscles around the thyroid. It may or may not have spread to nearby lymph nodes, but not to distant sites.
Stage 3: The cancer is any size and has grown into nearby tissues of the neck (larynx, trachea, esophagus, or the nerve to the larynx). It may or may not be in nearby lymph nodes but has not spread to distant sites.
Stage 4: The cancer is any size and has spread extensively beyond the thyroid (distant lymph nodes, organs, bones).
Undifferentiated Thyroid Cancer is always considered Stage 4.
Medullary Thyroid Cancer
Stage I: Cancer is 2 cm or smaller and has not spread beyond the thyroid.
Stage II: Cancer is 2-4 cm and has not spread to nearby lymph nodes or distant sites. OR
Cancer is bigger than 4 cm and confined to thyroid, or is any size and growing outside the thyroid but not involving nearby structures, nor has it spread to nearby lymph nodes or distant sites.
Stage III: Cancer is any size and might be growing outside the thyroid but has not involved nearby structures. It has spread to lymph nodes in the neck but not to other lymph nodes or to distant sites.
Stage IV: Cancer is any size and has spread into other tissues of the neck (larynx, trachea, esophagus, or nerve to larynx). It may or may not have spread to nearby lymph nodes or distant sites (liver, lungs, bone, or brain).
Treatment of Thyroid Cancer
Treatments options include the following:
- Radioactive iodine treatment
- Thyroid hormone therapy
- External beam radiation therapy
- Targeted therapy
Most of time, thyroid cancer can be cured with one or more of the above treatments.
Prevention of Thyroid Cancer
There is no sure way to prevent thyroid cancer.