Follicular/Hurthle Cell Cancer

Follicular and Hurthle cell cancers are two different types of cancer, but they are often considered in the same category. Together, these cancers are the second most common thyroid cancer, after papillary cancer. They can occur at any age, but are more likely in older people. 

Follicular thyroid cancer does not tend to spread to lymph nodes, but rather spreads through blood vessels to other organs, such as the lungs and bones. Hurthle cell cancers, on the other hand, will sometimes spread to lymph nodes in the neck region but less commonly than papillary thyroid cancer.

Risk Factors

A risk factor is anything that increases a person's chance of getting a disease. Different diseases have different risk factors. Some risk factors can be controlled with lifestyle changes. Other risk factors cannot be changed.

For most patients, the specific reason why they develop thyroid cancer is not known. It is important to note that some patients with multiple risk factors never develop thyroid cancer. In fact, most people who have thyroid cancer have no obvious known risk factor. 

Known risk factors for follicular and Hurthle cell thyroid cancer include:

Radiation exposure: Follicular and Hurthle Cell thyroid cancers are more common in people who have a history of exposure to significant ionizing radiation. Radiation-induced thyroid cancer can happen at any time between a few years after exposure to as long as 30 to 50 years later. Radiation exposure is broken down into three major categories: 
  • Childhood exposure: X-ray treatments were widely used in the 1940s and 1950s. This radiation was used to treat acne, enlarged tonsils, lymphomas, ringworm, enlarged thymus glands, and other ailments. X-rays were also used to measure foot sizes in shoe stores, and many people fondly remember seeing their "glowing green feet" and playing in those shoe fluoroscopes for hours while siblings were fitted for shoes. Children, younger than 15 years old, are most sensitive to radioactive damage to their thyroids.
  • Medical Therapy: Radiation therapy to the head, neck, and upper chest are an increasingly common cause of radiation-induced thyroid cancer. Lymphoma, head and neck cancers, lung cancer, and breast cancer are some of the more common cancers that are associated with radiation exposure to the thyroid.
  • Environmental exposure: Thyroid cancer can be caused by radioactivity released from nuclear incidents such as the 1986 nuclear accident at the Chernobyl power plant in Russia. Many of the children in areas of Russia and the Eastern Bloc countries were inadvertently exposed to radiation and went on to develop thyroid cancer. Some people may also be exposed to radiation at work. However, routine X-ray exposure (for example dental X-rays, chest X-rays, mammograms) have NOT been shown to cause thyroid cancer.
Iodine deficiency: Severe and prolonged iodine deficiency tends to increase the risk of developing follicular cancer. Iodine deficiency is not common in the United States or most of Europe. 

Having one or more of the above risk factors does not mean that you will develop follicular or Hurthle cell cancer. Understanding your risk factors will help you determine, what, if any, precautions and whether there is any special screening you should consider.

Symptoms

Most patients with thyroid cancer do not have any symptoms. Typically, patients have a thyroid nodule that, on further evaluation, is found to be cancer. 

Symptoms may include: 
  • Swelling in the neck 
  • Difficulty with swallowing 
  • Shortness of breath
  • Difficulty with breathing or changes in the voice 
If the nodule is large, it may cause symptoms: 
  • Difficulty swallowing 
  • Choking sensations 
  • A large mass in the neck
Rarely, the cancer can grow into the nerves (i.e. the recurrent laryngeal nerves) that control the voice box and cause hoarseness. 

If you have one or more of the above symptoms, it does not mean that you have follicular and Hurthle cell cancers. If you think you have one of these cancers, please call your doctor.

Treatment

The best treatment for follicular and Hurthle cell cancers is total thyroidectomy (removal of the entire thyroid). However, most of these patients will be initially diagnosed with a follicular or Hurthle cell neoplasm. Therefore, most patients are initially treated with a thyroid lobectomy to remove the nodule and make a diagnosis. If there is no evidence of invasion outside of the nodule, then it is a benign adenoma, and no further surgery is necessary. However, if the cells grow outside of the surrounding capsule (capsular invasion), into blood vessels (vascular invasion), or into the lymphatics (lymphatic invasion), then the patient has cancer and usually needs to have the rest of the thyroid removed in an operation called a completion thyroidectomy. This can be done at any point after the first operation, but most surgeons prefer to do it either within a week or after six weeks of the first operation to reduce scarring and risk for complications.

If the cancer is very small and found only one side of your thyroid, or there is only a small amount of capsular invasion, without any evidence of vascular or lymphatic invasion, it may not be necessary to remove the rest of the thyroid. This decision will be made with your surgeon and medical doctors and depends on certain factors such as age, gender, size of the thyroid cancer, location of the cancer, and existence of enlarged or suspicious lymph nodes in the neck. 

After a total thyroidectomy, patients need to take thyroid hormone replacement pills for the rest of their lives. Patients with thyroid cancer, who do undergo a lobectomy, and have only half of their thyroid removed, may still need to take thyroid hormone after surgery. 

Some Hurthle cell thyroid cancers will spread to lymph nodes in the neck. Removal of these lymph nodes is needed if the thyroid cancer is proven to have spread to them. This is called a lymph node dissection.