In patients with a diagnosis of Cushing disease in whom magnetic resonance imaging (MRI) shows either no abnormalities or nonspecific abnormalities, surgery is preferable to medical treatment, according to study results published in The Journal of Clinical Endocrinology & Metabolism.
There is a consensus that the first line of treatment for Cushing disease is transsphenoidal surgery to remove the pituitary adenoma causing the disease, with an 80% remission rate following the intervention. However, in the absence of clear evidence of a pituitary adenoma on imaging, there is some controversy regarding the best treatment.
The goal of this retrospective single-center study was to assess the outcomes of surgery in patients with Cushing disease with clear evidence of a pituitary adenoma on MRI compared with outcomes in patients with inconclusive or normal MRI.
The cohort included 195 patients treated with transsphenoidal surgery between 1992 and 2018 (156 women; mean age at surgery, 41 years) classified into 4 MRI groups: 89 patients were found to have microadenoma, 18 had macroadenoma, 44 had nonspecific/inconclusive abnormalities on MRI results, and 44 had normal imaging results.
The researchers reported that MRI performance in their neuroradiology department improved with time; the proportion of inconclusive or normal MRI results decreased from 60% in 1992 to 1996 to 27% in 2012 to 2018 (P =.037).
In analyzing the influence of MRI findings on remission rates, the researchers found no significant difference among the 4 groups: remission rate was 85% for microadenomas, 94% for macroadenomas, 73% for inconclusive MRI, and 75% for negative MRI (P =.11). This finding indicates the overall percentage of patients in remission after transsphenoidal surgery is only slightly lower in those with normal or inconclusive MRI results compared with patients with clear evidence of microadenoma or macroadenoma.
There was no difference in remission rate after a microscopic vs endoscopic surgical approach (P =.16). The researchers found that endoscopic-assisted surgery allowed a higher visualization rate than microscopic-assisted surgery. Although the neurosurgeon had a better visualization rate than MRI (100% vs 72%, respectively), there were some false-positive findings; thus, positive predictive value was similar (84% vs 78%, respectively).
The study had several limitations including the retrospective design. In addition, in light of the long study duration, the researchers noted that changes in MRI technology and surgical procedures occurred over time.
The researchers proposed that after exclusion of nonneoplastic hypercortisolism, patients with Cushing disease, an inconclusive or normal MRI, and a pituitary adrenocorticotropic hormone gradient at bilateral inferior petrosal sampling be directed to an expert neurosurgeon for transsphenoidal surgery rather than treated medically.
Cristante J, Lefournier V, Sturm N, et al. Why we should still treat by neurosurgery patients with Cushing’s disease and a normal or inconclusive pituitary MRI [published online May 14, 2019]. J Clin Endocrinol Metab. doi:10.1210/jc.2019-00333