Endocrine System Tumors Health Article

Definition

The group of tumors that are associated with the hormone-secreting (endocrine) glands of the body.

Description

The glands in the body that make and secrete hormones comprise the endocrine system. All endocrine glands secrete hormones directly into the bloodstream, where they travel to a target organ or cell to trigger a specific reaction. These glands are primarily involved in controlling many of the slow and long-term activities in the body, such as growth, sexual development, and regulation of blood levels for many important proteins and essential chemical elements.

Endocrine glands are found in the head and neck region, the abdominal region, and the pelvic area (the region where the reproductive organs are located). The following are the main endocrine glands of the body:

• Pituitary gland. Found at the base of the brain, this small gland is important because it secretes several hormones that control the activity of other endocrine glands.
• Thyroid gland. Situated in the front of the neck, in the region of the Adam's apple, this gland secretes hormones that regulate body temperature, heart rate, and metabolism.
• Parathyroid glands. These four glands, with a pair on either side of the thyroid gland in the neck region, produce parathyroid hormone, which helps control the level of calcium in the blood.
• Pancreas. Found close to the stomach in the abdominal region, the pancreas contains two groups of cells. One group functions as an exocrine gland, secreting digestive enzymes into the intestines through a duct. The other, known as islets of Langerhans (or islet cells), functions as an endocrine gland and secretes hormones that control blood sugar levels and aid digestion.
• Adrenal glands. These two glands, one located above each kidney, secrete hormones that prevent inflammation and help regulate blood pressure, blood sugar levels, and metabolism.
• Ovary. A woman has two small ovaries in the pelvic area. They contain the egg cells and secrete the hormones progesterone and estrogen. These hormones have many functions, including controlling the onset of puberty, the timing of menstruation, and the changes associated with pregnancy.
• Testis (also called testicle). Men typically have two testes located outside the body in the lower pelvic area. They produce sperm and the hormone testosterone, which signals the onset of puberty, maintains the expression of male characteristics, such as facial hair, and stimulates sperm production.

Endocrine system tumors are rare. Although certain types are likely to be diagnosed as malignant (cancerous), endocrine tumors are often noncancerous (benign). Each year endocrine system cancers account for only around 4% of all new cancer cases in the United States. In 2001, it is expected that 53, 460 Americans will develop an endocrine system cancer, resulting in an estimated 16, 600 deaths.

The most common cancers of the endocrine system are ovarian cancer and thyroid cancer. Ovarian cancer represents about 44% of all endocrine system cancers and affects eight out of every 100, 000 American women. New cases of ovarian cancer in 2001 will likely reach over 23, 000, and nearly 13, 000 will die from the disease. Roughly six out of every 100, 000 Americans develop thyroid cancer, which accounts for 36% of all endocrine system cancers. It is estimated that 19, 000 new cases will be diagnosed in 2001 and result in 1, 300 deaths. Other malignant endocrine tumors are much rarer. Testicular cancer affects about two out of every 100, 000 American men, while the remaining cancer types combined affect roughly one out of every 100, 000 Americans.

Endocrine system tumors

Pituitary tumors

Thyroid tumors

Parathyroid tumors

Endocrine pancreatic tumors, including gastrinoma, insulinoma, and glucagonoma

Adrenal tumors, including pheochromocytoma and adrenocortical carcinoma

Ovarian tumors

Testicular tumors

Multiple endocrine gland tumors (tumors on several endocrine glands at once)

Many benign and malignant endocrine tumors are treatable with a combination of surgery and medication, and the survival rates for many endocrine cancers is good. Two exceptions are ovarian cancer and adrenocortical carcinoma, a tumor of the adrenal gland. About 50% of ovarian cancer patients and 40% of those diagnosed with an adrenocortical carcinoma will survive five years or more after the initial diagnosis. These cancers have poor survival rates because they are usually first diagnosed after they have spread or reached an advanced stage. Among the different cancers, thyroid cancer and testicular cancer have some of the better 5-year survival rates; both approach 95%.

Symptoms of many endocrine tumors are associated with the excessive secretion of hormones. Hormone-producing tumors are called functional tumors, while those that do not secrete hormones are called nonfunctional tumors. Both types are potentially malignant.