A new study has found that patients with a mild form of Cushing syndrome, a metabolic disorder caused by adrenal tumors, show considerable clinical improvement after adrenalectomy.
The study, conducted by researchers at UT Southwestern Medical Center, is the largest series of surgical outcomes reported in patients with subclinical Cushing syndrome to date.
"We don't have enough data to come out with a definitive statement that everyone with an adrenal tumor and mild cortisol excess should have the adrenal tumor removed," said Dr. Richard Auchus, associate professor of internal medicine at UT Southwestern and co-author of the study.
"We can say, however, that there are many people with large adrenal tumors who, while not meeting classical criteria for Cushing syndrome, nonetheless suffer from the hormonal disorder and will benefit from surgery," he added.
Cushing syndrome occurs when the body's tissues are exposed to excessive levels of cortisol, a hormone which helps regulate glucose and fat metabolism.
Though the more overt Cushing's affects about 1 in every 5,000 to 10,000 people, milder, or subclinical, Cushing syndrome may affect as many as 1 in every 1,000 people in the population, Dr. Auchus said.
In the current study, Dr. Auchus' research group examined the records of 24 patients who underwent adrenalectomy at UT Southwestern between 2003 and 2006 because of unusually high cortisol production. Of the 24 patients, nine met the researchers' definition of subclinical Cushing syndrome.
Dr. Auchus said the results were significant. Diabetes and hypertension improved considerably in most affected patients after adrenalectomy. In addition, all eight patients who reported easy bruising before surgery noted resolution of the problem, and seven of the nine patients lost weight.
Fat accumulation around the neck disappeared and muscle weakness improved, often markedly, the researchers found.
"We cannot promise everybody the same results. But we found that adrenalectomy can dramatically help some patients," he said.
Dr. Auchus, however, added that there are many caveats to their findings, chief among them that the study was not random.
"It was a very select group.Because they had certain clinical symptoms, we offered them surgery. We now have a handful of additional people who have biochemical indications of subclinical Cushing syndrome, but we haven't recommended surgery because they don't have hypertension, obesity or easy bruising. We're continuing to repeat their blood and urine tests for cortisol function over time," he said.
Dr. Fiemu Nwariaku, associate professor of GI/endocrine surgery and vice chairman of surgery, said the message to physicians is to maintain a high level of suspicion for hypercortisolism in patients whose biochemical tests are not completely normal and repeat biochemical studies periodically.
"Unless a patient's test results are clearly negative, they should probably get more complete testing," said Dr. Nwariaku, senior author of the study.
The study will be published in the December issue of the journal Surgery.