Endoscopic Surgery Should Be Standard for Cushing’s Patients with Large Tumors, Review Study Suggests

Cushing’s disease patients with macroadenomas — pituitary tumors larger than 10 mm — should undergo transsphenoidal pituitary surgery using the endoscopic technique, according to a new systematic review.

The study, “Endoscopic vs. microscopic transsphenoidal surgery for Cushing’s disease: a systematic review and meta-analysis,” was published in the journal Pituitary.

Cushing’s disease develops due to an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma. The first-choice treatment for Cushing’s disease is transsphenoidal pituitary surgery, which is performed through the nose to remove pituitary tumors.

There are two main methods to conduct this kind of surgery: microscopic, which is done using a magnifying tool, and endoscopic surgery, which uses a thin, lighted tube with a tiny camera. The microscopic technique was the established method for transsphenoidal surgery, until physicians started doing endoscopic pituitary surgery in 1992.

Most surgical centers choose to perform either the microscopic or endoscopic technique but do not offer both. As a result, only a few small studies have compared the outcomes of microscopic and endoscopic surgical techniques in Cushing’s disease performed at the same center. These studies showed no clear differences in remission rates or surgical morbidity.

To date, no systematic review comparing the microscopic and the endoscopic surgical techniques in Cushing’s disease has been conducted and, therefore, convincing evidence to support either technique is lacking.

To address this, researchers set out to conduct a systematic review and meta-analysis that compares the endoscopic and microscopic transsphenoidal surgery techniques for Cushing’s disease with regards to surgical outcomes and complication rates.

Researchers searched through nine electronic databases to identify potentially relevant articles. In total, 97 cohort studies with 6,695 patients were included in the study. Among the total patient population, 5,711 received microscopical surgery and 984 were endoscopically operated.

Overall remission was achieved in 80 percent of patients, with no clear differences between the techniques. The recurrence rate was around 10 percent, and short-term mortality was less than 0.5 percent.

Cerebrospinal fluid leak (due to a hole or a tear) occurred more often in patients who underwent endoscopic surgery. On the other hand, transient diabetes insipidus — short-term diabetes — occurred more often in patients who received endoscopic surgery.

When classifying patients by tumor size, however, researchers found that patients with macroadenomas — tumors larger than 10 mm — had higher rates of remission and lower recurrence rates after endoscopic surgery. Patients with microadenomas (tumors smaller than 10 mm) had comparable outcomes with either technique.

“Endoscopic surgery for patients with Cushing’s disease reaches comparable results for microadenomas, and probably better results for macroadenomas than microscopic surgery,” the investigators wrote.

Taking these results into account, the researchers suggest that endoscopic surgery may be considered the current standard of care, though microscopic surgery can be used based on the neurosurgeon’s preference.

They also emphasize that centers that solely perform the microscopic technique should consider at least referring Cushing’s disease patients with macroadenomas to a center that performs the endoscopic technique.