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Thyroid Cancer

What is thyroid cancer?

Thyroid cancer is the most common endocrine system cancer. Thyroid cancer occurs when thyroid nodules become cancerous. Thyroid nodules that are cancerous need to be removed to protect thyroid function and prevent thyroid cancer from spreading in the body. The estimated incidence rate of thyroid cancer in various parts of the world ranges from 0.5 to 10 cases per 100,000 persons per year. It is the fastest-growing cancer in the United States in both men and women, with over 62,000 new cases diagnosed every year.

The thyroid gland is butterfly-shaped in the lower part of your neck, in front of your windpipe. It has two lobes: the right lobe and the left lobe. A narrow isthmus joins the right and left lobes.

The thyroid gland is mainly composed of two types of cells: thyroid follicle cells and C cells. The thyroid follicular cells produce thyroid hormones secreted into the blood circulation and regulate the function of every cell and tissue. Your thyroid produces thyroxine (T4) and triiodothyronine (T3), necessary for good health and control of your metabolism and energy levels. C cells produce calcitonin, which helps to regulate calcium metabolism.

The hypothalamus and pituitary gland in your brain regulate T4 and T3 production. When T4 and T3 levels are low, the hypothalamus produces thyrotropin-releasing hormone (TRH) to signal the pituitary gland to produce thyroid-stimulating hormone (TSH). The TSH travels in the bloodstream and signals the thyroid gland to produce more T4 and T3. When T4 and T3 levels are high, the pituitary gland stops producing TSH.

There are four types of thyroid cancer

  1. Papillary carcinoma – Most thyroid cancers are papillary carcinomas. They occur most frequently in women of childbearing age. Papillary carcinoma originates in the thyroid follicle cells. It is generally a very slow-growing cancer that may gradually spread to other parts of the body. Papillary carcinoma tends to spread to the lymph nodes in the neck; most of the time, this is very treatable. Papillary cancer is the least likely type of thyroid cancer to cause death.
  1. Follicular carcinoma – Follicular carcinoma is the second most common type of thyroid cancer. It is more common in countries where people do not eat enough iodine in their diets. This is not a common situation in the United States, where people ingest iodine in table salt and food on a regular basis. Follicular carcinoma usually remains in the thyroid gland, but it may spread to the lungs and bone. It tends to return. Cancer that comes back after treatment is termed recurrent.
  1. Medullary carcinoma of the thyroid (MCT) – Medullary carcinoma of the thyroid gland (MCT) develops in the C cells of the thyroid gland and can quickly spread to the lymph nodes, liver, and lungs. Most cases of MCT are sporadic. However, isolated familial medullary thyroid carcinoma (FMTC) is a type of thyroid cancer that is inherited and can occur in each generation of a family. MCT does not respond to radioactive iodine treatments and tends to have a poor prognosis.
  1. Anaplastic carcinoma – Anaplastic carcinoma is called Cundiff. It is an untreated thyroid, giant cell, and spindle cell carcinoma. It is rare. It can spread very quickly to nearby throat and neck structures. Anaplastic carcinoma does not respond to radioactive iodine treatments.

Most people who develop thyroid cancer have no apparent risk factors. People with all the following risk factors may never develop the condition. However, the chance of developing thyroid cancer increases with the more risk factors you have.

Potential risk factors for thyroid cancer:

  1. Age: Most cases of thyroid cancer occur in people between the ages of 20 and 6.
  2. Sex: Thyroid cancer is three times more common in women than in men.
  3. Follicular thyroid cancer is more common in people with a low-iodine diet
  4. Adults who have had head and neck radiation treatments in childhood have an increased risk of developing papillary thyroid cancer.
  5. Children who receive low-dose radiation treatments for non-Hodgkin’s lymphoma have an increased risk of developing thyroid cancer.
  6. People who have been exposed to radioactive fallout from nuclear reactive material, nuclear weapons testing, or power plant accidents have an increased risk of developing thyroid cancer.
  7. An inherited abnormal gene causes some medullary thyroid cancers. If familial medullary thyroid carcinoma (FMTC) runs in your family, ask your doctor for a test.
  8. Familial syndromes – Gardner syndrome, familial polyposis, and Cowden disease are inherited genetic conditions that are associated with higher rates of thyroid cancer.

Certain families appear to have an excess number of papillary thyroid cancers.

Most thyroid cancers do not cause symptoms in the early stage of the disease. The most common symptom is a fullness or lump in the neck. Larger thyroid gland cancers can cause difficulty swallowing or breathing, pain or discomfort over the neck, and hoarseness of voice. Sometimes, you can have persistent swollen lymph nodes in the neck without infection.

You may feel a lump in the neck, a family member, or your physician. However, most of the time, a thyroid nodule is identified when you go for a radiological exam (e.g., X-ray or CT scan of the neck) not related to the thyroid gland. The experience of thyroid cancer and cancer treatments can be an emotional process for people with cancer and their loved ones.

Dr Reena Thomas will help navigate the treatment of thyroid cancer. She will help diagnose thyroid cancer by doing a comprehensive medical evaluation and physical examination of your neck. She will order blood tests to screen for thyroid function abnormalities.

She will perform an ultrasound of the neck in her office to get an exact picture of the thyroid gland and to characterize the nodule, which may be solid or cystic (fluid-filled). She will also be able to observe if there are any abnormal lymph nodes in the neck.

Depending on the size and characteristics of the nodules, she may refer you for a CT scan of the neck without contrast to find out if there is compression of the windpipe or important structures of the neck.

Fine needle aspiration biopsy (FNA) of thyroid nodule

Dr Reena Thomas will do a fine needle aspiration biopsy after performing a comprehensive ultrasound examination of your neck in her office.

Fine needle aspiration biopsy (FNA) of the thyroid nodule is a procedure in which cells or tissues are collected from the body for further anal sis. A pathologist will examine the sample to determine whether it contains cancerous cells.

FNA of the thyroid nodule is done using ultrasound guidance from Dr. Thomas on the ice. A small tissue sample is removed from the thyroid nodule using a small, thin, fine-gauge needle that is smaller in diameter than the needle used in most blood draws. Medications (1% lidocaine and ethyl chloride spray) are used to numb the area before the biopsy. The sample is sent to the pathology lab for analysis following the FNA. Once the results are available, Dr. Thomas will communicate them to you personally and discuss further management.


If the FNA of the thyroid nodule confirms cancer, she will refer you to an experienced endocrine surgeon for thyroid surgery. Surgery is used to remove all the tumor and all or part of the thyroid gland and any abnormal lymph nodes in the neck. Following surgery, she will review the pathology findings with you and coordinate further management if needed.

Thyroid hormone replacement therapy

If your thyroid gland is partially or completely removed, you must take daily thyroid hormone replacement pills. Thyroid hormone therapy is also used to lower blood TSH levels to help prevent thyroid cancer recurrence.

Radio iodine therapy

Following surgery, if you require radioiodine therapy, Dr. Thomas will refer you for radioiodine therapy to a nuclear medicine specialist.


In advanced or aggressive thyroid cancer, you will be referred to an oncologist for further management.

Lifelong surveillance for the recurrence of thyroid cancer is mandatory. Dr Thomas will see you at regular intervals and do a comprehensive evaluation, including physical examinations and appropriate blood tests to monitor your thyroid hormone replacement therapy and tumor markers. She will also do an ultrasound of the neck at regular intervals to monitor for any recurrence of thyroid cancer.

At a Glance

Dr. Reena Thomas, MD

  • Dual American board-certified endocrinologist
  • Author of numerous academic and clinic research
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