Medullary thyroid cancer symptoms & treatment

Medullary thyroid cancer (MTC), also called medullary thyroid carcinoma, is a rare form of thyroid cancer that makes up less than 2% of all thyroid carcinomas. It occurs mostly in older adults.

What is medullary thyroid cancer?

Medullary thyroid cancer originates within the thyroid gland, the butterfly-shaped gland located at the front of your neck. You can get this form of cancer sporadically or if you have a family history of a condition known as multiple endocrine neoplasia.

Medullary thyroid cancer grows in the parafollicular cells, otherwise known as C cells. These cells produce calcitonin, a hormone that regulates blood calcium levels.

When medullary thyroid cancer develops within these cells, it disrupts this function, often resulting in elevated calcium levels in the bloodstream. Elevated levels of calcium in your blood are a characteristic marker of this form of thyroid cancer.

What is the difference between thyroid cancer and medullary carcinoma?

Thyroid cancer is a broad term encompassing various cancer types originating in the thyroid, including medullary thyroid cancer, papillary thyroid cancer, follicular thyroid cancer and anaplastic thyroid cancer.

Some differentiating traits of medullary cancer include:

• Genetic factors: Medullary thyroid cancer can occur sporadically or can be due to family history, while other thyroid cancer types may involve different genetic factors.
• Hormone production: Medullary carcinoma cells increase the amount of calcitonin the thyroid produces, whereas other thyroid cancer types may not involve abnormal hormone secretion.
• Origins: Thyroid cancer can grow in either follicular cells or parafollicular cells. In all cases of medullary cancer, the tumor grows in the parafollicular cells.

Medullary thyroid cancer symptoms

Symptoms of medullary thyroid cancer can be different for you than for someone else, or you may not experience any symptoms. However, as the cancer progresses, the following symptoms may emerge:

• Bone pain
• Difficulty breathing
• Difficulty swallowing
• Diarrhea or constipation
• Enlargement of the thyroid gland
• Fatigue
• Flushed skin
• Hoarseness or alterations in voice
• Neck pain
• Presence of a painless lump, known as a thyroid nodule, on the front of the neck
• Swollen lymph nodes
• Weight loss

It's important to note that many of these symptoms can also be attributed to other conditions. If any of these symptoms persist or if you notice any unusual changes in your neck, contact your provider for an exam.

Diagnosing medullary thyroid cancer

Medullary thyroid cancer is diagnosed through a combination of medical history review, physical exam, imaging tests and laboratory tests. Medullary thyroid cancer is treatable if found early and if it hasn’t spread to other parts of the body.

To diagnose, your doctor will ask about any family history of thyroid cancer and do a physical exam of your thyroid gland. They’ll check for a lump on your neck or noticeable enlargement of the thyroid gland.

They may order a blood test to check thyroid function and calcitonin. These tests measure your levels of thyroid hormones and check for elevated levels of calcitonin. Abnormal levels may indicate thyroid dysfunction, which could suggest medullary thyroid cancer. High levels of calcitonin may indicate medullary thyroid cancer.

If your doctor suspects cancer after blood tests and a physical exam, they may recommend you have additional tests, including:

• Biopsy: This involves the removal of a small piece of thyroid tissue for examination under a microscope.
• Fine needle aspiration biopsy: A thin needle is inserted into a lump to extract cells for microscopic analysis, aiding in the detection of cancer.
• Core needle biopsy: If your fine needle aspiration biopsy is inconclusive, your doctor may use a bigger needle to get tissue from the thyroid gland.
• Digital imaging tests: An ultrasound, MRI, PET scan or CT scan may be used to obtain detailed images of the thyroid gland.

Once medullary thyroid cancer is diagnosed, further tests may be performed, including surgery to remove the thyroid gland, for both diagnosis and treatment purposes.

Medullary thyroid cancer treatment 

Treatment options for medullary thyroid cancer are diverse and are determined by several factors, including the cancer stage, your overall health and personal treatment preferences.

Treatments for medullary thyroid cancer include:

• Chemotherapy: The use of chemotherapy drugs is typically reserved for cases where the cancer has spread to distant organs or when other treatments have proved ineffective.
• Radioactive iodine therapy: This treatment is employed for medullary cancer that has metastasized to other regions of the body and exhibits excessive calcitonin production. Radioactive iodine is absorbed by thyroid cells, effectively destroying them through radiation.
• Radiation therapy: Utilizing high-energy beams, radiation therapy aims to eliminate cancer cells. It may be employed post-surgery to eradicate any remaining cancer cells or to treat cancer. External beam radiation therapy is commonly applied in cases of medullary thyroid cancer.
• Surgery: The most common approach involves thyroidectomy, the partial or complete removal of the thyroid gland. If the cancer has spread to nearby lymph nodes, your surgeon may also conduct a lymph node dissection to remove them.

Through a collaborative approach to care, your Aurora Health Care multidisciplinary care team will tailor a treatment plan to address your individual needs.