Predictive Factors for Initial Cure and Relapse Rate After Pituitary Surgery for Cushing’s Disease

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Abstract
Twenty-seven patients with Cushing’s disease underwent transsphenoidal pituitary surgery. After the operation 16 patients were cured, and 11 remained hypercortisolemic. In the cured patients a significantly lower incidence of paradoxical responsiveness to TRH or to LRH was found preoperatively (1 of 16) than in the failures (6 of 11; P < 0.02, by Fisher’s x2 test). Furthermore, responsiveness of cortisol to CRH administration was significantly lower in the failures [maximum, 0.30 + 0.10 μmol/L (10.8 + 3.6 μmolg/dL) vs. 0.50 + 0.07 μmol/L (18.1 + 2.5 μg/dL) in the cured patients; P < 0.05]. There were no differences in basal plasma cortisol levels, ACTH levels, or suppressibility by dexamethasone between the 2 groups. In the 16 patients who were cured initially, 4 patients relapsed after a mean period of 4 yr. These 4 patients had significantly higher basal cortisol levels postoperatively than those who remainedremained in remission [0.14 + 0.03 μmol/L (5.1 + 0.8 μg/dL) vs. 0.04 + 0.01 μmol/L (1.4 + 0.3 μg/dL); P < 0.01]. cortisol responses to CRH after the operation positively correlated with the basal cortisol levels at that time (P < 0.05, by Spearman’s rank correlation test; r = 0.64), thus, the relapsing patients had higher cortisol responses to CRH than patients who stayed in remission [maximum response, 0.31 + 0.07 (11.2 + 2.5 μg/dL) vs. 0.12 + 0.03 μmol/L (4.3 + 1.1 μg/dL), respectively; P < 0.05]. We conclude that 1) patients responding paradoxically to TRH and/or LRH have a lower chance of being cured after pituitary surgery; and 2) patients with higher cortisol levels (>0.10 μmol/L; 3.6 μg/dL) after being cured initially have a higher chance of recurrence of their disease. (J Clin Endocrinol Metab69: 1122, 1989)