Cancer and cancer treatment can have a significant impact on the body's thyroid gland. When the thyroid is not functioning properly, it can lead to an overproduction or underproduction of the important hormones that this gland produces. Hyperthyroidism, or an overactive thyroid, is one of the most common issues caused by cancer and cancer treatment. In some cases, thyroid cancer may not cause any symptoms at first, but as it grows, it can cause pain and swelling in the neck.
The exact cause of thyroid cancer is unknown, but certain factors can increase a person's risk of developing the condition. Hashimoto's thyroiditis, an autoimmune disease, is the most common cause of hypothyroidism and is linked to an increased risk of thyroid cancer. This disease occurs when the immune system produces antibodies that damage the thyroid and interfere with its ability to release hormones. An abnormally large thyroid gland is sometimes called a goiter.
Diffuse goiters occur when the entire gland is enlarged, while nodular goiters are characterized by an enlarged gland with one or more nodules (bumps). Goiters can be caused by a variety of factors, including an imbalance in certain hormones or a lack of iodine in the diet. Thyroid nodules are lumps or bumps in the thyroid gland. Most nodules are benign, but about 2-3 out of 20 are cancerous.
Nodules that produce too much thyroid hormone are almost always benign and can cause hyperthyroidism. Thyroid nodules are most common in older adults, but fewer than 1 in 10 adults have nodules that can be felt by a doctor. However, when examined with an ultrasound scan, many more people have nodules that are too small to feel. Sometimes benign thyroid nodules can be left untreated and monitored closely as long as they don't grow or cause symptoms. Other times, treatment may be necessary.
If the thyroid gland is removed or damaged due to cancer or other treatments, the body must adapt to taking medication that replaces the hormone that is no longer produced by the thyroid. Anaplastic carcinoma (also called undifferentiated carcinoma) is a rare form of thyroid cancer that accounts for approximately 2% of all cases. This type of cancer occurs when abnormal cells form in the thyroid gland and can destroy normal cells along with cancer cells, which may lead to the need for hormone replacement drugs. If you are at higher risk of recurrence, your doctor may order a complete body scan with RAI tracers to detect any remaining thyroid cells that may indicate a recurrence of cancer. As an alternative to stopping thyroid medication, your doctor might suggest thyrotropin alfa, a recombinant (genetically modified) form of thyroid hormone. Thyroid cancer is a rare type of cancer that affects the butterfly-shaped gland located at the base of the neck just below the Adam's apple. Most cases of this type of cancer differentiate, meaning that when viewed under a microscope, they appear similar to normal cells.
Thyroid cells are unique in that they are the only cells in the body that can absorb iodine, which helps fight against this type of cancer. Although there is no sure way to prevent thyroid cancer in people who are at average risk for developing it, understanding your risk factors and being aware of any changes in your body can help you catch it early and get treatment as soon as possible.