Cortisol Levels After Surgery Predict Recurrence of Cushing’s Disease, Indian Study Finds

Long-term follow-up and analysis of cortisol levels may help predict the recurrence of Cushing’s disease among patients who underwent surgery to remove their pituitary adenomas, a new study from India concludes.

The study, “Duration of post-operative hypocortisolism predicts sustained remission after pituitary surgery for Cushing’s disease,” appeared in the journal Endocrine Connections.

Surgery is the primary treatment approach for Cushing’s disease, but its effectiveness varies greatly among patients, with remission rates ranging from 52 to 96.6 percent. Even in cases where surgery is effective, 15 percent to 66 percent of patients eventually see the disease return — highlighting the need for long-term follow-up to ensure prompt and adequate care.

“Understanding the predictors of sustained remission might help us to better strategize follow-up care of patients,” the researchers wrote.

Studies have suggested that low levels of cortisol — known as hypocortisolism — after surgery, or tumor size and invasiveness, could be predictors for remission following surgery. But the accuracy of these factors as predictors of disease progression is still debatable.

Attempting to identify such predictors, Indian researchers evaluated the post-operative remission and recurrence rates of 230 patients with Cushing’s disease who underwent surgery between 1987 and 2015 in a single treatment center.

Overall, 65.5 percent of patients went into remission following surgery — ut after a mean follow-up of 74 months, 41 percent of them saw the disease come back. The team found that early remission – low levels of cortisol five days after surgery – was significantly associated with small tumors. However, patients with invasive large tumors had poorer remission rates.

“Similar to that reported in most previous studies, in [the] current study, we found that none of the clinical or biochemical parameters had predictive value for remission,” they wrote, adding that their results further support the hypothesis that differences in remission rates may be explained by tumors’ biological behavior, such as size and invasiveness.

Regarding recurrence rates, the study found that patients with delayed remission – low levels of cortisol detected within a few months of follow-up – were more likely to see their tumors return than those in early remission.

The researchers hypothesized that residual tumor cells in circulation may cause the delayed remission. “They are more likely to recover later (over months to years) and account for [the] observed higher recurrence rate,” they wrote, adding that “regular biochemical surveillance may help in identifying recurrence early.”

Overall, low cortisol levels for 13 months or more were found to be a good predictor of sustained remission. In addition, frequent evaluation of cortisol levels significantly improved early detection of disease recurrence.