Thyroid Cancer: Early Diagnosis Is Key to Successful Treatment

Many people with early-stage thyroid cancer don’t have obvious symptoms. As a result, most don’t think they have cancer until they go for an annual physical exam, and the doctor suspects a problem after palpating the neck and feeling a lump or swelling they hadn’t noticed.

In most cases, a lump or swelling will turn out to be an infection, a harmless growth, or some other noncancerous condition. There’s more concern if the lump or swelling occurs below or near the larynx (Adam’s apple), where the thyroid gland resides.

If further tests do lead to a diagnosis of early thyroid cancer, it’s good to know that this condition often can be successfully treated long before symptoms such as fatigue, hoarse voice, or difficulty swallowing develop. While most cancers are evaluated for five-year survival rates, thyroid cancer is so slow-growing that a 10-year scale is used. And the average 10-year survival can be well over 90%.

But thyroid cancer is still serious. “Like any cancer, if it’s not diagnosed early and successfully treated, it can spread to other organs, cause complications, and possibly even be fatal,” says Courtney Gibson, MD, a Yale Medicine endocrine surgeon.

Although thyroid cancer isn’t one of the more common cancers, the American Cancer Society estimates that about 44,020 people in the United States—12,670 men and 31,350 women—will be diagnosed with the disease in 2025.

Below, Dr. Gibson talks more about thyroid cancer and offers advice on how to get an early diagnosis and effective treatment.

The thyroid—a small, butterfly-shaped gland that’s at the base of the neck—makes the hormones that regulate the body’s metabolism (the transformation of food into energy), blood pressure, body temperature, and heart rate.

When cancer develops in the thyroid, the exact cause is unknown. Thyroid cancer is not associated with conditions such as hypothyroidism (an underactive thyroid) or hyperthyroidism (an overactive thyroid), Dr. Gibson says. Nor is alcohol consumption or cigarette smoking considered to be a risk factor, she adds. “When people are diagnosed with cancer, they often wonder if they should change their diet or lifestyle in some way. But this cancer has nothing to do with lifestyle or what they ate or drank.”

Studies have shown that about 5% of cases of thyroid cancer may be related to a family history of thyroid cancer. In these cases, the cancer is thought to have a genetic basis or be related to a tumor syndrome such as multiple endocrine neoplasia, a rare inherited disorder that causes tumors in endocrine glands, including the thyroid.

There is no standard or routine screening for thyroid cancer, and usually no noticeable symptoms in the initial stages of the disease. In time, swelling or a lump may develop in the front of the neck, in the area where the thyroid gland resides. When the cancer advances, hoarseness, trouble swallowing, or a constant cough often develop.

Thyroid cancer may be detected when a health-care provider palpates a patient’s neck and finds abnormal swelling. An ultrasound can then show whether the swelling is due to a thyroid nodule. In most people, a thyroid nodule will not turn out to be cancerous.

If a suspicious nodule is identified, a fine-needle aspiration biopsy, which involves the insertion of a needle into the nodule with ultrasound guidance, may be performed to remove a small piece of tissue to determine whether cancer is present. A growing awareness of thyroid cancer has likely prompted doctors to order more thyroid imaging, perhaps leading to recent spikes in thyroid cancer diagnoses, Dr. Gibson says.

There are three main types of thyroid cancer. In roughly 80% to 85% of patients diagnosed with the disease, it will be papillary thyroid cancer. This slow-growing cancer, which is easily treated, occurs most often before the age of 45.

Other types of thyroid cancer are rarer and more aggressive. For example, medullary thyroid cancer is more likely to have spread to other organs, such as the lungs and liver, before a thyroid nodule is discovered. Anaplastic thyroid cancer is the rarest and most aggressive type. It tends to cause large thyroid masses that are more likely than other types of thyroid cancer to spread quickly to other parts of the body.

The size of the thyroid nodule matters. If it measures less than a centimeter, the American Thyroid Association and the American College of Radiology recommend against a biopsy. “It would not be beneficial to biopsy every single nodule that we come across,” Dr. Gibson says. She notes that in nodules that small, the accuracy of a fine-needle aspiration biopsy is low.

Instead, treatment decisions may be based on the Thyroid Imaging Reporting & Data System (TI-RADS), a risk-stratification system used to determine the likelihood of cancer in a thyroid nodule on the basis of its imaging features, including irregular borders, small microcalcifications (tiny white specks within the nodule), or whether it has a large number of blood vessels. When TI-RADS results suggest that a nodule could be harboring cancer, the patient is referred for a fine-needle aspiration biopsy of those lesions.

Sometimes a nodule will have both normal and abnormal—or indeterminate—characteristics. In these cases, further information can be gleaned from molecular tests that analyze tissue for markers or mutations to help determine whether or not cancer is likely. These tests, also performed with ultrasound and a fine needle aspiration, “can provide more information so that a patient can feel feel more comfortable with the decision they are making,” Dr. Gibson says.

Treatment options range from active surveillance (more on that below) to monitor a small cancerous nodule for changes over time to surgery for a larger cancer.

When surgery is recommended for thyroid cancer, the results are usually excellent, Dr. Gibson says. This is partly because many such cancers are removed before they have spread, but even “when cancer does go beyond the thyroid, there's usually just local invasion, such as some lymph-node involvement in the neck, which we still can largely control surgically," she adds.

Total thyroidectomy, or removal of the entire thyroid, is used to treat thyroid cancers that are larger than 4 centimeters in diameter. (This procedure is called a “partial thyroidectomy” if less than the entire thyroid is removed.) This traditional open or minimally invasive surgery is followed by lifelong therapy with a synthetic hormone to replace the hormone that would be produced by a healthy thyroid gland.

Another type of surgery, lobectomy, involves removal of only one of the two thyroid lobes. This procedure is usually sufficient if lesions are 4 centimeters or smaller in diameter, and there is no evidence that the cancer has spread beyond the thyroid, Dr. Gibson says. In most cases in which a cancerous lesion is less than 4 centimeters and there is no lymph-node involvement, a lobectomy leaves patients with enough residual thyroid function that lifelong hormone treatment isn’t needed, she adds.

While thyroid surgery is generally safe, in rare cases it can lead to complications such as low calcium levels if the parathyroid glands are damaged in a total thyroidectomy, and hoarseness if the laryngeal nerves are irritated, Dr. Gibson says.

Several weeks after surgery, patients who are at higher risk for recurrence than others, depending on such factors as the size and type of the initial cancer, may be given a single treatment of radioactive iodine therapy, a targeted form of radiation in the form of a pill, liquid, or injection. This therapy is far less likely to cause side effects or complications that can happen with more intensive forms of radiation used for some other cancers, because it targets only the thyroid tissue and any cancer cells within it—and not the rest of body, Dr. Gibson says.

Meanwhile, experts are following research into expanding the use of radiofrequency ablation (RFA) for primary thyroid cancers (those that originate in the thyroid). RFA is a minimally invasive technique that involves inserting a needle into the thyroid nodule and sending radio waves that produce heat to destroy the cells within the nodule. So far in the U.S., RFA is used only for benign thyroid conditions and small recurrent cancers. “We don't have enough information yet to say for sure that RFA could be a primary treatment option for thyroid cancer,” Dr. Gibson says.

Active surveillance, also known as “watch and wait,” has become more common as experts have learned more about thyroid cancer. This strategy is recommended for papillary cancer that is small and low-risk. The approach involves forgoing immediate treatment but monitoring the cancer through periodic ultrasounds, bloodwork, and medical visits. Active surveillance also can be used if thyroid cancer has been treated, but the patient needs to be followed because of a high risk of recurrence.

“Studies have shown that many patients who have a known thyroid cancer that's a centimeter or less have been followed for 20-plus years with no significant growth,” Dr. Gibson says.

Recurrences can usually be detected through bloodwork in patients who have been treated for thyroid cancer. These patients can often be treated with another dose of radioactive iodine therapy, Dr. Gibson says. If a recurrence leads to an enlarged lymph node that is visible with magnetic resonance imaging (MRI), a second operation may be necessary, she says.

“Sometimes we know there's probably microscopic residual disease present, but the person has no symptoms and there's nothing physically to treat,” Dr. Gibson says. “Those patients will live with a low-level of thyroid cancer. We explain to them that we're managing it with a long-term strategy, as we would someone who has hypertension or diabetes.”

Whether thyroid cancer is caught early or at a more advanced stage, the average age at diagnosis is 51 years—when most people have busy lives and aren’t necessarily worried that they might get cancer.

"Many people assume that just because they’re (relatively) young, they are healthy,” Dr. Gibson says. “They may have children who are in their teens or younger, and they're thinking, ’I'm right in the midst of raising my family and now I have this diagnosis.’"

Understandably, it’s common to react emotionally to a thyroid cancer diagnosis, she adds. “I have patients who look fine on the outside, but they feel like no one really understands what they're feeling on the inside because of this diagnosis. They’ve been treated and seem to be recovering physically, but emotionally they were hit with a whopper. They’re thinking, ‘How do I trust my body? I had no symptoms and yet I had cancer.’"

To address these feelings, it can help to join a thyroid cancer survivor group if there is one in your area, or at least talk to other people who have been treated for the disease, she says. “Patients really appreciate talking with other thyroid cancer patients who can validate that, ‘Yes, you were a cancer patient, you are a survivor, and this was a significant event in your life,’” she says. The ThyCa: Thyroid Cancer Survivors’ Association provides helpful information on its website, www.thyca.org.