Treatment depends on the specific reason for excess cortisol and may include surgery, radiation, chemotherapy, or the use of cortisol-inhibiting drugs. If the cause is long-term use of glucocorticoid hormones to treat another disorder, the doctor will gradually reduce the dosage to the lowest dose adequate for control of that disorder. Once control is established, the daily dose of glucocorticoid hormones may be doubled and given on alternate days to lessen side effects. In some cases, noncorticosteroid drugs can be prescribed.
Several therapies are available to treat the ACTH-secreting pituitary adenomas of Cushing’s disease. The most widely used treatment is surgical removal of the tumor, known as transsphenoidal adenomectomy. Using a special microscope and fine instruments, the surgeon approaches the pituitary gland through a nostril or an opening made below the upper lip. Because this procedure is extremely delicate, patients are often referred to centers specializing in this type of surgery. The success, or cure, rate of this procedure is more than 80 percent when performed by a surgeon with extensive experience. If surgery fails or only produces a temporary cure, surgery can be repeated, often with good results.
After curative pituitary surgery, the production of ACTH drops two levels below normal. This drop is natural and temporary, and patients are given a synthetic form of cortisol such as hydrocortisone or prednisone to compensate. Most people can stop this replacement therapy in less than 1 or 2 years, but some must be on it for life.
If transsphenoidal surgery fails or a patient is not a suitable candidate for surgery, radiation therapy is another possible treatment. Radiation to the pituitary gland is given over a 6-week period, with improvement occurring in 40 to 50 percent of adults and up to 85 percent of children. Another technique, called stereotactic radiosurgery or gamma knife radiation, can be given in a single high-dose treatment. It may take several months or years before people feel better from radiation treatment alone. Combining radiation with cortisol-inhibiting drugs can help speed recovery.
Drugs used alone or in combination to control the production of excess cortisol are ketoconazole, mitotane, aminoglutethimide, and metyrapone. Each drug has its own side effects that doctors consider when prescribing medical therapy for individual patients.
Ectopic ACTH Syndrome
To cure the overproduction of cortisol caused by ectopic ACTH syndrome, all of the cancerous tissue that is secreting ACTH must be eliminated. The choice of cancer treatment—surgery, radiation, chemotherapy, immunotherapy, or a combination of these treatments—depends on the type of cancer and how far it has spread. Because ACTH-secreting tumors may be small or widespread at the time of diagnosis, making them difficult to locate and treat directly, cortisol-inhibiting drugs are an important part of treatment. In some cases, if other treatments fail, surgical removal of the adrenal glands, called bilateral adrenalectomy, may replace drug therapy.
Surgery is the mainstay of treatment for benign and cancerous tumors of the adrenal glands. Primary pigmented micronodular adrenal disease and the inherited Carney complex—primary tumors of the heart that can lead to endocrine overactivity and Cushing’s syndrome—require surgical removal of the adrenal glands.