Thyroid cancer occurs when abnormal cells begin to form in your thyroid, a gland located at the center of your throat just below your Adam’s apple. This butterfly-shaped gland is a critical part of your endocrine system. It’s in charge of regulating your body’s metabolism, including your energy levels, temperature control, heart rate, digestion, how fast sugar is made and used in your body, bone loss, and other important bodily functions. It does this by making thyroid hormone.
About 53,000 people are diagnosed with thyroid cancer in the US each year, the majority of them women, according to the American Cancer Society.
Differentiated or Nondifferentiated Tumors
Your tumor will be classified as differentiated or nondifferentiated.
Differentiated tumors start in the follicular cells that make your thyroid’s metabolism-controlling hormones. Under a microscope, they still look like normal thyroid cells. They usually respond to treatment better than nondifferentiated cancers. Differentiated thyroid cancers include papillary thyroid cancer and follicular or
Hurthle cell thyroid cancers.
Poorly Differentiated Tumors
Poorly differentiated tumors start in the cells that control calcium, the immune cells that fight infections within your thyroid, or in the follicular cells. These poorly differentiated thyroid cancers include medullary thyroid cancer, thyroid lymphoma, and anaplastic thyroid cancer.
Most thyroid cancer is caused by factors that are out of your control. Being diagnosed with thyroid cancer is not your fault.
Risk factors include:
Women get thyroid cancer about three times more often than men do. We don’t know why.
Thyroid cancer is most commonly diagnosed in women who are in their 40s and 50s, and in men in their 60s and 70s.
Most people who have thyroid cancer have no genetic mutations or family history. However, certain cancers are more likely than others to be an inherited type of cancer. For example, about 20% of medullary thyroid cancers start from an inherited gene. These cancers are called familial medullary thyroid carcinoma. They can start in childhood or early adulthood and spread early. Some people who have thyroid cancer have an inherited syndrome called Cowden disease.
Some thyroid cancers happen in families. They usually start when you’re younger. If you have a family history of thyroid cancer, talk to your doctor about genetic counseling to find out if you have an inherited gene mutation. But if your parent, brother, sister, or child has had thyroid cancer even without a known gene mutation, you may be at higher risk for thyroid cancer.
Radiation exposure can cause thyroid cancer. Exposure can include radiation fallout from nuclear power plants or nuclear weapons and having head and neck radiation treatments when you were a child.
The risk of thyroid cancer increases with higher body mass index.
Most people in the US get enough iodine through table salt and other foods. But too little iodine can lead to follicular thyroid cancer, and too much can lead to papillary thyroid cancer.
Signs of Thyroid Cancer
Please get in touch with your doctor if you have any of the following symptoms:
- A lump in your neck, called a nodule
- Swollen lymph nodes in your neck
- Changes in your voice, including hoarseness
- Trouble swallowing or breathing
- Throat or neck pain that can extend to your ears
- Coughing that’s not related to an upper respiratory infection
- Coughing that is not related to a cold
You might feel a thyroid nodule—a lump on your thyroid—when you swallow or when you touch your neck. These lumps are common, and most are not cancer even if they cause symptoms. It’s important to get any lump checked by your doctor.
Symptoms of Anaplastic Thyroid Cancer and Thyroid Lymphoma
These types of thyroid cancers tend to grow faster. They usually form larger, firmer lumps so they interfere with swallowing and breathing and result in more voice changes.
Diagnosis and Staging
In most cases, a lump (nodule) in your neck is the first sign of thyroid cancer. Because not all nodules are cancer, your doctor will evaluate it to determine the next steps.
You’ll have a physical exam, including giving your doctor your medical history. Then, you’ll have blood tests and usually an ultrasound of the neck. Finally, you may have a biopsy—a small outpatient procedure in which a small needle is used to remove a few cells—to find out the risk of cancer in that nodule.
Thyroid Blood Tests
Your doctor will talk to you about signs and symptoms of hyperthyroidism and hypothyroidism. These symptoms include changes in your energy levels, weight changes, and feeling too hot or too cold.
You’ll likely have a full thyroid blood panel to look at your thyroid hormone levels: TSH, t#, and T4. Most people with thyroid cancer have normal levels.
If you have high levels of calcitonin and/or CEA in your blood, you might have medullary thyroid cancer. If your doctors think you may have a genetically inherited disease, they may send you to a genetic counselor to see if you should have further testing.
Thyroid Imaging Tests
You might have a thyroid ultrasound, which uses sound waves to create a picture of your thyroid and surrounding tissues. Certain results suggest a higher risk of cancer. If you have a suspicious nodule, you will have a biopsy to further check for thyroid cancer.
We use a small, thin needle to extract a small cell sample from your nodule. This is called a fine needle aspiration. A pathologist will examine the cells under a microscope for abnormalities. At our clinic, a pathologist will be in the room to look at your biopsy results to make sure we get enough cells to make a diagnosis and lower the chance that you’ll need another biopsy. At the Columbia Thyroid Center, the chance of needing another biopsy is less than 1%. At other centers, more than 10% of people need to come back for repeat biopsy because they did not get enough cells the first time.
Tests After Diagnosis
If you have thyroid cancer, you may have a body scan to find out if the disease has spread to other parts of your body.
Ultrasound (Lymph Node Mapping)
Ultrasound (lymph node mapping) is an ultrasound of the neck that determines if there are any suspicious looking lymph nodes in the neck. If there are lymph nodes that look suspicious, then we will arrange for a fine needle biopsy. If there are cancerous lymph nodes, we will remove them at the time of your thyroid surgery.
CT (Computed Tomography) Scan
A CT (computed tomography) scan takes data from several X-ray images of your chest, abdomen, or pelvis and converts them into pictures on a monitor. It can show tissues and blood vessels in addition to bones. CT scans are often used if you have a large thyroid nodule or anaplastic thyroid cancer.
PET (Positron Emission Tomography) Scan
A PET (positron emission tomography) scan uses a small amount of radioactive glucose injected into your vein to show where glucose is being used in your body. A scanner rotates around your body to create an overall picture. Cancer cells use more glucose than normal cells do. PET scans are often used if you have thyroid lymphoma.
Thyroid Cancer Stages
Staging your cancer helps determine what treatment you will have and your likely outcome. Staging groups thyroid cancer based on size, spread, and lymph node involvement.
Cancer is assigned a stage of I, II, III, or IV. Stage I cancer is usually confined to the original site—in this case, your thyroid gland. Stage IV cancer has spread to distant sites in your body. All anaplastic thyroid cancers are considered Stage IV.
Thyroid cancer is staged using the TNM system:
- T stands for the size of the tumor and if it is contained to your thyroid
- N describes lymph node spread
- M describes metastasis, or spread to other organs
Each category has a subset, and the subset combinations determine the stage of your cancer.