Thyroid Cancer

Thyroid cancer develops in your thyroid, a small, butterfly-shaped gland at the base of your neck. This gland makes hormones that regulate how your body uses energy. Thyroid hormones also help control your body temperature, blood pressure and heart rate.

About 44,000 people in the U.S. develop cancer in their thyroid glands each year. Most are treatable and curable.

But your experience depends on lots of things, like the type of thyroid cancer and how advanced it is.

Types of thyroid cancer

Healthcare providers classify thyroid cancer based on the type of cells from which the cancer grows. The most common types of thyroid cancer include:

• Papillary: Up to 90% of thyroid cancers are papillary. This type grows slowly. Although papillary thyroid cancer often spreads to lymph nodes in your neck, the disease responds very well to treatment. Papillary thyroid cancer is highly curable and rarely fatal.
• Follicular: Follicular thyroid cancer accounts for up to 15% of thyroid cancer diagnoses. This cancer is more likely to spread to your bones and organs, like your lungs. Metastatic cancer (cancer that spreads) may be more challenging to treat.
• Oncocytic: Oncocytic thyroid cancer makes up between 3% to 5% of thyroid cancers. It’s more likely to spread than papillary or follicular types. It’s also harder to treat.
• Medullary: Less than 5% of thyroid cancers are medullary. A quarter of people with medullary thyroid cancer have a family history of the disease. A faulty gene may be to blame.
• Anaplastic: This aggressive thyroid cancer is the hardest to treat. It can grow fast and often spreads into surrounding tissue and other parts of your body. This rare cancer type accounts for about 2% of thyroid cancer diagnoses.

Symptoms of thyroid cancer

The first sign of thyroid cancer is usually a painless lump in your neck. It’s called a thyroid nodule. But don’t panic if you feel one. Most nodules aren’t cancer. Only about 1 out of 10 thyroid nodules turns out to be cancerous.

Most thyroid cancers don’t cause any symptoms. Your healthcare provider may find it during an unrelated procedure.

Some symptoms associated with thyroid cancer include:

• Neck swelling or swollen lymph nodes
• Voice hoarseness
• Trouble breathing or swallowing

Thyroid cancer causes

Thyroid cancer forms when DNA in a cell changes (mutates). Most mutations happen over time, but some are passed down from your biological parents.

Risk factors

Females are three times more likely than males to get thyroid cancer. It’s more common in females in their 40s and 50s, and males in their 60s and 70s.

Other risk factors include:

• Family history of thyroid cancer
• Inherited syndromes, including multiple endocrine neoplasia type 2A (MEN2A) or type 2B (MEN2B), Cowden syndrome and familial adenomatous polyposis
• Obesity
• Low iodine intake
• Radiation therapy for head and neck cancer, especially during childhood
• Exposure to radioactive fallout from nuclear weapons or a power plant accident

How doctors diagnose this condition

If you have signs of thyroid cancer, your healthcare provider may order one or more of these tests:

• Thyroid blood test: This test checks whether your thyroid is releasing hormones properly. Usually, the cancer doesn’t impact your hormone function.
• Biopsy: During a fine-needle aspiration biopsy, your provider removes cells from your thyroid to test for cancer.
• Imaging scans: Imaging tests detect thyroid cancer and cancer spread. They include ultrasounds, radioactive iodine scans, CT scans and PET scans.

What are the thyroid cancer stages?

Thyroid cancer stages range from 1 (I) to 4 (IV). The higher the number, the bigger the tumor or the more the cancer has spread. Usually, cancer cells spread to nearby structures and lymph nodes first. After that, they spread to distant lymph nodes, organs and bones.

The specifics of thyroid cancer staging systems differ based on the cancer type. Your age matters, too, for some thyroid cancer types. To learn how cancer staging applies to you, talk to your healthcare provider.

How is thyroid cancer treated?

Surgery is the most common treatment. A surgeon may remove all of your thyroid gland (thyroidectomy). Or they may just remove the diseased parts (lobectomy). They’ll also remove any lymph nodes where cancer cells are.

Other treatments include:

• Radioiodine therapy: You may need this treatment after surgery to kill any remaining cancer cells. You’ll swallow a pill or liquid that contains radioactive iodine. Only thyroid tissue absorbs it. The radiation destroys diseased tissue.
• Radiation therapy: Some cancers can’t absorb the iodine in radioiodine therapy. You may need radiation therapy that uses a machine to deliver the radiation instead.
• Hormone therapy: This treatment stops new thyroid tissue from growing back after surgery. This can keep the cancer from returning.
• Targeted therapy: This treatment targets weaknesses in cancer cells with specific gene mutations. Healthcare providers mostly use it to treat aggressive or advanced cancers.
• Chemotherapy: Chemo uses drugs to kill cancer cells throughout your body. Providers rarely use it during thyroid cancer treatment. But you may need it for aggressive cancer that isn’t responding to treatment.
• Clinical trial: You may need a clinical trial to access new treatments. This is a good option if other treatments aren’t helping enough.

If you have surgery or radiation to your thyroid, you’ll likely need thyroid hormone replacement therapy for life. You may get synthetic thyroid hormones, like levothyroxine (Synthroid®).

When should I see my healthcare provider?

You’ll need regular doctor visits so your provider can see if the cancer has come back after treatment. Thyroid cancer can return, but it’s uncommon. Only 2 out of 10 papillary thyroid cancers (the most common type) recur.

Call your healthcare provider if you notice signs that the cancer has come back after treatment. Usually, blood work detects signs of recurrence. But you may notice new neck swelling or enlarged lymph nodes.

What’s the thyroid cancer survival rate?

Thyroid cancer has a five-year survival rate of over 98%. This means that you’re about just as likely to live for at least five years as someone who doesn’t have thyroid cancer. Usually, the cancer stays in remission. Remission means there are no signs or symptoms of cancer.

These numbers vary, though, depending on the cancer type and cancer stage. For example, the five-year survival rate is excellent even when papillary and follicular cancers have spread. On the other hand, less than half of people with advanced medullary thyroid cancer survive. All forms of the rare anaplastic type involve a shortened life expectancy.

Your healthcare provider can explain how your diagnosis relates to your life expectancy.

Is thyroid cancer curable?

Yes, most thyroid cancers are permanently curable with treatment. This is especially the case if the cancer hasn’t spread to distant parts of your body. Treating thyroid cancer in the early stages reduces the risk of cancer spread.

If treatment doesn’t fully cure thyroid cancer, your healthcare provider can design a treatment plan to manage it.

Can I prevent thyroid cancer?

Not usually. But if you know you’re at risk, you may be able to take steps for early detection. Options include:

• Getting preventive screening: A genetic test can tell if you were born with a gene change that increases your risk of thyroid cancer. If you have it, your provider may recommend annual imaging or surgery for early identification and prevention of cancer.
• Taking potassium iodide: Taking this medicine within 24 hours of radiation exposure during a nuclear disaster can lower your cancer risk. Potassium iodide (Pima^®) blocks your thyroid gland from absorbing too much radiation.

At what age do people get thyroid cancer?

Anyone can get thyroid cancer. But the average age of diagnosis is 51. Females tend to get diagnosed at younger ages than males.

How does thyroid cancer affect pregnancy?

Thyroid cancer is the second most common cancer diagnosed in pregnancy. Breast cancer is the first.

Your healthcare provider may delay treatment until after you deliver your baby. If treatment can’t wait, most people can safely have surgery to remove the cancerous gland. Your provider may wait to use tests or treatments involving radiation until after you’ve finished breastfeeding.