Thyroid cancer

Thyroid cancer

General
Cancer is a group of malignant cells that can form a growth, also called a carcinoma. These cells invade the surrounding healthy tissue and/or break away and spread throughout the body, sometimes causing new growths (metastases) elsewhere in the body. In the Netherlands, about 670 people are diagnosed with thyroid cancer every year. The disease is more than twice as common in women as in men. The exact cause of thyroid cancer is usually not known. Hereditary predisposition plays a role in some types. Previous radiation therapy in the neck also increases the risk of thyroid cancer. Radioactivity released during accidents can also cause thyroid cancer.

Symptoms
Thyroid cancer can cause the following symptoms (although you may experience no symptoms at all):

• the feeling that something is stuck in your throat;
• difficulty swallowing; the feeling that there is food stuck in your throat, for instance;
• shortness of breath or noisy breathing;
• hoarseness;
• pain in your neck;
• swelling in the neck.

The amount of thyroid hormone produced is almost always normal in people with thyroid cancer. The symptoms will therefore not usually include an excess or deficiency of thyroid hormone.

Tests
The tests to assess and diagnose thyroid cancer are basically the same as for a thyroid nodule and will almost always consist of a blood test, an ultrasonography, and a puncture. Sometimes a special thyroid scan may also be performed. 

Blood tests
The thyroid gland produces a number of thyroid hormones that can be measured in the blood. If there is a nodule in the thyroid, the level of these hormones may be elevated, depressed, or normal. The next steps will be worked out depending on the results of the blood test.

Ultrasound
An ultrasound is performed at the radiology department. During the examination you will be asked to lie down on the ultrasound table. A transparent gel will be applied to your neck. The radiologist will then move an ultrasound probe over your neck. The ultrasound device emits sound waves. These sound waves are bounced back through the body and the echoes are picked up by the probe. The thyroid gland is displayed on the monitor. The ultrasound is used to find out what the goiter looks like. The nodule is also measured. In addition to the thyroid nodule, the lymph nodes in the neck are also assessed. This procedure is not painful. You do not need to fast before this procedure.

Puncture biopsy
The nodule must be punctured to determine whether it is benign or malignant. This is called a puncture biopsy. The radiologist will use an ultrasound probe to locate the nodule and then puncture the nodule with a thin needle. This is similar to drawing blood from a vein. No anesthetic will be given for this procedure as it would mean puncturing the skin with two needles. Cells are collected from the nodule through a needle. Sometimes it is not possible to collect enough cells in one go and a second puncture will be necessary. If the lymph nodes look abnormal, a biopsy will also be taken of these to determine if there are any metastases.

There is a small chance that the puncture may cause bleeding in the neck. If the swelling in the neck increases after the puncture, you should contact the hospital. If you are on blood thinning medication, it is important that you inform the physician of this prior to the puncture. Not all nodules will require a puncture.

Diagnosis
There are four types of thyroid cancer:

Papillary carcinoma: This is the most common type of carcinoma. It is a slow-growing tumor and metastases rarely occur outside the thyroid. However, the tumors can occur in several places inside the thyroid gland.

Follicular carcinoma: Follicular thyroid carcinoma is less common than papillary thyroid carcinoma. Follicular thyroid carcinoma, as the name implies, originates in the follicular cells of the thyroid gland. A follicle is a sac. Normal thyroid tissue is made up of sacs. A carcinoma can develop in these. This type of tumor also grows slowly.

Anaplastic carcinoma: This is a rare type of thyroid cancer. It is an aggressive type and the carcinoma grows rapidly. It rapidly invades surrounding tissue and spreads easily.

Medullary carcinoma: This is also a rare type of thyroid cancer. The carcinoma is not formed in the thyroid cells that produce the thyroid hormone, but in the cells that produce calcitonin. Calcitonin regulates the level of calcium in the bones. Medullary carcinoma can be hereditary, in which case it is part of the “MEN 2 syndrome”. There is also an increased risk of tumors in the parathyroid and adrenal glands if you have this hereditary type of medullary carcinoma.

In addition to these four types, there are also a small number of very rare types of thyroid cancer.

There are are various treatment options, which will depend on your diagnosis. 

Treatment 
Treating thyroid cancer often involves surgery to remove the tumor. If the tumor is small, the removal of half of the thyroid gland is enough. However, tumors are often too large and the entire thyroid gland has to be removed. Several weeks after the removal of an entire thyroid gland, the surgery is often followed by radioactive iodine treatment.

Depending on the type of thyroid cancer and how advanced it is, you may be referred to Erasmus MC for treatment. The joint multidisciplinary team meetings make it possible to determine what the best treatment is for which patients and at which hospital. Any referrals to Erasmus MC can be arranged quickly through these meetings.

Click here for the Thyroid Network’s patient leaflet about thyroid cancer (Dutch).
Click here for the Thyroid Network’s patient leaflet about thyroid surgery (Dutch).