Our endocrine glands produce hormones, which are like the body’s messengers—they move through the bloodstream until they reach their target organ, and then they deliver instructions telling that organ exactly how to behave. These “messages” trigger important processes, like metabolism, growth, reproduction and even mood.

Occasionally, in one of the endocrine glands, a change in the DNA (known as a mutation) causes abnormal cells to grow, and a tumor forms. Most endocrine tumors are benign (not cancerous), but a few will become cancerous. Collectively, endocrine cancers are much less common than other kinds of cancer. “However, thyroid cancer, which is an endocrine cancer, is the fifth most common cancer among women in the United States,” notes Yale Medicine endocrinologist Elizabeth Holt, MD, who is also the co-director of the endocrine neoplasia disease team and an associate professor of medicine (endocrinology) at Yale School of Medicine. She is part of Yale Cancer Center’s Endocrine Cancers Program.

Because hormones play such a key role in keeping the body balanced, both benign and cancerous endocrine tumors have the potential to cause serious problems. For this reason, they may require some form of treatment such as surgery or radiation therapy.  Almost all endocrine tumors require at least some evaluation and monitoring, she says.

“At the Endocrine Cancers Program,” says Dr. Holt, “patients with endocrine cancers are cared for by a multidisciplinary team of doctors and nurses, including those in endocrinology, endocrine surgery, radiology, nuclear medicine, pathology, genetics and medical oncology.” This team of experts meets weekly to discuss patient care and to share new research. 

Tumors can occur in any of the major endocrine glands, including the thyroid, parathyroid, pituitary and adrenal glands, and the pancreas. The most common sites are as follows:

• Thyroid gland: Most endocrine cancers develop in the thyroid gland (a butterfly-shaped organ in the lower neck). Thyroid cancer is far more common in women than men. Statistics show that the annual rate of thyroid cancer is on the rise, both in the United States and worldwide. The good news is, most tumors (referred to as nodules) of the thyroid are not cancerous.
• Pituitary gland: A pea-sized organ attached to the brain, the pituitary gland produces hormones that influence growth and fertility. Pituitary tumors are almost always benign but can result in too much or too little of one or more hormones, which in turn can upset the balance of other glands.
• Adrenal gland: The two adrenal glands, which reside just above the kidneys, produce hormones that regulate metabolism (cortisol), the stress response (adrenaline), blood pressure (aldosterone) and certain sexual characteristics (androgens).
• Pancreas: Though the pancreas plays an active role in the digestive system, it’s also the source of important hormones, including insulin. Rare tumors can produce too much insulin or other related hormones, which can impact blood sugar levels.

Though some cases are inherited, the cause of most endocrine cancer is usually unclear.

Some patients with thyroid tumors notice a lump on their neck. Others don’t—and for other endocrine tumors, no general rules apply. Some tumors cause severe hormonal shifts or discomfort, whereas other tumors cause no symptoms at all.

So, when is a tumor likely to have symptoms? Basically, it has symptoms if it’s functional (it makes excess hormones), rather than nonfunctional (it doesn’t make them). For example, an adrenal tumor that produces excess testosterone might cause a female patient to develop certain male traits, such as facial hair.

Symptoms can also occur as a tumor grows larger. A large tumor destroys a portion of the gland, leading to a shortage of hormones. It can also affect nearby structures. For example, a large pituitary tumor might press on the nerve running between the eyes and the brain, causing vision changes.

When endocrine tumors do not have symptoms, doctors may notice them incidentally, while evaluating a patient for another reason.

Doctors can perform a number of tests to check for a suspected endocrine tumor:

• A medical history and physical exam to assess for physical or behavioral changes related to hormone function.
• Lab tests to check for abnormal hormone levels in the blood or urine.
• Imaging studies (CT scan, MRI or ultrasound) to look for evidence of abnormal tissue in the gland.
• A biopsy to obtain a sample of abnormal tissue and analyze it for cancer cells.

For any endocrine tumor, treatment might involve surgery to remove it. For those that are cancerous, another approach sometimes used is radiation therapy. Patients sometimes receive hormonal therapy to balance out the hormone levels in the body. Depending on the type of tumor, your doctor may suggest other targeted regimens to meet your individual needs.

“At the Endocrine Cancers Program, we are able to address all aspects of patient care in one center,” says Dr. Holt. “Often, our satellite facilities make it possible to receive the same expert testing and treatment closer to home.” We use electronic medical records, which allows our caregivers to communicate effectively and facilitates patient communication with the team. Patients can also be scheduled to see multiple caregivers on the same day.