Endocrine Abstracts

There have been few reports of long term remission rates after transsphenoidal surgery for Cushing's disease which incorporate both initial failure rates and later relapse rates. We have studied this in patients diagnosed and treated between 1979 and 2000. An early post-operative 0800h serum cortisol was measured 24h after the last dose of hydrocortisone, in addition to a low dose dexamethasone suppression test. Of the initial 63 patients, 18 did not achieve remission after surgery. In these failures no cases of ectopic ACTH syndrome have emerged after prolonged follow-up. Forty-five patients remained who were considered to be in remission both clinically and biochemically. The mean age of these patients at diagnosis was 40.3y (range 40-70) and mean follow-up 9.6yr. Current clinical status and recent 24h urinary cortisol values were used as a measure of present activity of Cushing's disease. Four of the 45 patients died during follow up but had remained in remission until death. The relapse rate was 24% (10/41) after a mean follow-up period of 9.6y, with a mean time to relapse 5.2y. Two of the 10 patients who had relapsed had completely unmeasurable basal cortisol values in the immediate post-operative period. There was evidence of cyclical cortisol secretion in 5 of the 10 patients, some identified before and some after surgery.

In summary, this detailed ongoing endocrinological evaluation of patients following transsphenoidal surgery showed that after a mean follow-up period of 9.6y, although 71% achieved initial remission, only 49% of the initial cohort of 63 are still in remission after about 10 years of follow-up. These disappointing results are in keeping with other specialist centre results world wide and call into question what has become almost a routine decision that all patients with well established pituitary-dependent Cushing's syndrome should have pituitary surgery as initial therapy.