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570,000 people worldwide are diagnosed with thyroid cancer every year, the vast majority of whom are women. In this article, we discuss the characteristics and symptoms of thyroid cancer, and its diagnosis process. We also look at treatment and chances of survival.
What is thyroid cancer?
Thyroid cancer is due to cancerous cells appearing in the thyroid gland, which can form a tumor. Located at the base of the neck, the thyroid gland secretes specific hormones that contribute to the proper functioning of several organs.
Thyroid cancer causes a disruption in the production of hormones. Treatment often involves removal of the thyroid gland. The prognosis is very good, with a cure rate exceeding 90% and rare recurrences.
There are several types of thyroid cancer. Differentiated thyroid cancers (papillary cancer and follicular cancer) are treated very effectively. Poorly differentiated thyroid cancers (medullary cancer and anaplastic cancer) can be more difficult to treat.
Furthermore, with the evolution of diagnostic techniques, it is estimated that more than half of thyroid cancers identified are micro-cancers with a tumor smaller than 1 centimeter. The majority of these cancers do not evolve into clinical cancers.
What are the symptoms of thyroid cancer?
The most common sign of thyroid cancer is a thyroid nodule, that is a small, firm lump located in the thyroid gland in the neck. This nodule is often discovered by chance, during a routine palpation or during an imaging exam.
Nodules are very common in women after the age of 50. They sometimes come with a ganglion in the neck, a goiter that increases in volume, or an alteration of the voice, which becomes a little more hoarse.
In 95% of cases, thyroid nodules are not cancerous. They are benign and only require monitoring. In rare cases, the nodule may develop into thyroid cancer, requiring surgery. To determine if a nodule is cancerous, several tests are required.
How is thyroid cancer diagnosed?
Following the discovery of a nodule, doctors usually prescribe two tests:
– A blood test to measure the amount of TSH (thyroid-stimulating hormone) in the blood. This hormone controls the production of hormones by the thyroid gland. An abnormality in the functioning of the thyroid gland often leads to excessively low or excessively high levels of TSH. To find out more about thyroid blood tests and how to interpret their results, read our guide.
– A cervical ultrasound to identify the characteristics of the nodule (including its size and location) and determine if it is at risk of cancer. Ultrasound also helps to observe the lymph node chains in the neck.
While these tests are indicated to diagnose thyroid cancer, they can also allow to detect hyperthyroidism, a thyroid disorder that requires specific treatment.
When is a nodule considered suspicious?
A nodule is considered suspicious when it is solid and has a diameter greater than 1 centimeter. In this case, a cytopuncture can be performed. A very fine needle is inserted into the thyroid nodule to extract a few cells. These are then analyzed to confirm the diagnosis. Cytopuncture is not always conclusive and it may be necessary to repeat the examination. Furthermore, in some rare cases, a thyroid scan may be required.
How is thyroid cancer treated?
The main treatment for thyroid cancer is surgery. If the diagnosis is confirmed, an operation called thyroidectomy will be scheduled to remove the thyroid gland. In most cases, a total thyroidectomy is performed, but in some cases only one lobe is removed (lobectomy) in particular when the puncture has not accurately characterized the nature of the tumor. If the lymph nodes are affected, a lymph node dissection may be undertaken at the same time.
The operation takes place under general anesthesia and is often performed by a specialized team. Innovative technologies such as FLUOBEAM® LX help make thyroid surgery safer. This imaging device exclusively dedicated to thyroid surgery allows to identify and preserve the parathyroid glands. There is a risk of involuntary damage to these very small glands located at the back of the thyroid gland during surgery. And damage to these glands or their accidental removal can lead to hypocalcemia, an abnormal drop in the level of calcium in the blood.
Following the operation, in some cases, treatment with radioactive iodine may be prescribed to remove remaining cancer cells. In addition, hormone replacement therapy is required if the thyroid is completely removed (and sometimes partially removed). It consists of taking a daily thyroid hormone tablet.
Thyroid cancer is therefore easy to detect. Following the discovery of a nodule, a blood test and a thyroid ultrasound will be performed, sometimes followed by cytopuncture. If the diagnosis is confirmed, an operation will have to be scheduled. The treatment of thyroid cancer is first and foremost surgical, with the removal of the thyroid gland. This allows patients to maintain a good quality of life. The cure rate is very high compared to other types of cancer.