Thyroid cancer

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 15, 2016
StartDiseasesThyroid cancer

Thyroid cancer occurs when abnormal cells of the thyroid begin to develop into a malignant tumor. Thyroid cancer of any variety is very rare, only affecting 13.5 people per 100,000 according to the National Cancer Institute. Women are three times more likely to develop this disease than men.

Contents

Definition & Facts

The thyroid is a gland located at the base of the neck. It is small and butterfly-shaped, and as long as it is healthy, it is not normally visible externally. This gland is responsible for taking in iodine and converting it into thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine) which control a person’s metabolism, temperature, and heart rate. The pituitary gland in the brain signals the thyroid via TSH (thyroid-stimulating hormone) how much T3 and T4 it should produce.

As with nearly any body part, cancer can develop in the thyroid. There are many different types of thyroid cancer, but the most common one is called papillary carcinoma. This type accounts for about 80% of thyroid cancers according to the American Cancer Society.

Symptoms & Complaints

Typical complaints may include swelling or a lump in the neck (referred to as a nodule until confirmed cancerous), difficulty swallowing or difficulty breathing, neck pain, throat pain and/or ear pain, a frequent cough apart from a common cold, and wheezing.

Sometimes a tumor will push against the vocal cords, causing hoarseness. Depending on the progression of the tumor, it may become large enough to be visible as a lump on the neck.

A nodule is the most common symptom, but without pain or other troubles, this is not always noticed by the patient. Instead, it may be discovered at a routine physical when the doctor is feeling the neck. Certain symptoms of thyroid cancer can seem minor, but should be brought to a physician’s attention rather than ignored.

Causes

The cause of thyroid cancer is not fully understood. A history of radiation in childhood, particularly around the neck or head, can increase a person’s chances of developing the disease. This may be from radiation treatment for cancer, or from growing up in an area of the United States where nuclear testing was performed during the 1940s-1960s.

Family history of thyroid cancer and a personal history of goiters also indicate an increased risk. There is a correlation between a diet insufficient in iodine and one rare type of the disease, follicular thyroid cancer. Another uncommon type, medullary thyroid carcinoma, results from an inherited abnormal gene. Other risk factors include being female, being between 25 and 65, and being of Asian descent.

Diagnosis & Tests

There are several tests that may be ordered if thyroid cancer is suspected. Blood tests may be ordered to check for unusual level of TSH, which wouldn’t necessarily indicate cancer but would show that something is amiss. Most commonly, abnormal TSH levels indicate hypothyroidism or hyperthyroidism, which are an under-active and overactive thyroid, respectively. These are easily treated with medication.

An ultrasound is frequently done to produce an image of the nodule in order to show the size, location, and whether it is solid or fluid-filled. Only one in 20 thyroid nodules are actually cancerous, according to the American Cancer Institute. Due to this, less invasive procedures are often favored first. Should the nodule appear suspicious, a fine-needle aspiration (or biopsy) can be done, often guided by ultrasound. This will draw out cells from the nodule with a syringe, which can then be microscopically examined by a pathologist.

In most cases, this can conclusively show whether or not the nodule is malignant. This procedure can be uncomfortable, but is brief and does not require sedation in adults or an overnight stay. Occasionally, the results are unclear and a partial thyroidectomy may need to be performed. Each case is different and usually a primary physician, surgeon and endocrinologist are all involved in the patient’s care decisions.

Treatment & Therapy

Once the diagnosis is made, thyroid cancer is usually highly treatable, as long as it hasn’t yet spread to other parts of the body. The most common treatment is to surgically remove part or all of the thyroid, depending on how far the malignancy has spread. Even if the entire thyroid is removed, a person can be prescribed hormones to replace the role of the thyroid.

Radiation therapy may be used in addition to surgery, to ensure that all the cancerous cells were wiped out. Chemotherapy may also be done to treat the tumor. Patients may also consider taking part in clinical trials, particularly if their options are limited by the type or stage of their cancer.

In general, treatments for thyroid cancer are very successful. According to the National Cancer Institute, the five-year survival rate for a person diagnosed with thyroid cancer is 97.9%. This is an excellent prognosis compared to other types of cancer.

Prevention & Prophylaxis

There is not much that can be done proactively to prevent thyroid cancer, apart from avoiding unnecessary radiation. However, being aware of the symptoms can help a person to catch it in its earliest stages. Regular physicals can sometimes catch the disease, as well as being important to screen for other diseases.

Also, one can periodically do a thyroid self-check, much like women are encouraged to do a regular breast self-exam. The thyroid is located directly under the Adam’s apple, with a left and right lobe and a thin connecting tissue in the middle. Normally, it will just feel like fleshy tissue. However, if one found any nodules it would be important to bring it to a doctor’s attention.

For thyroid cancer survivors, regular monitoring as recommended by a doctor is important. As with any cancer, recurrence is possible. Overall, however, there is little that can be done for prevention. However, prognosis of the disease almost always entails a full recovery.