Treatment of Cushing's disease by transsphenoidal, pituitary microsurgery: Prognosis factors and long-term follow-up

Transsphenoidal pituitary microsurgery is considered as the best treatment of Cushing's disease. However, some recent studies reported disappointing results, leading their authors to suggest the possibility of returning to a first line adrenalectomy treatment. The aim of this study was to evaluate long-term results of transsphenoidal surgery in Cushing's disease, with special interest in factors that could affect the surgical outcome on the one hand and particular attention to surgical endocrine effects on the other. Fifty consecutive patients (34 females, 16 males, mean age 29.64 ± 1.52 yr) were studied. The median post-operative follow-up was 71.5 months (range 25-219). Clinical, biological, surgical and pathological data between the success and failure groups were compared. Criteria of cure were: normal urinary free cortisol excretion, circadian cortisol rhythm and low dose dexamethasone test. Recovery of corticotroph and somatotroph functions were followed using the insulin test. Particular attention is given to clinical evolution in evaluating other pituitary functions. T4 or FT4, prolactin, E2 in women, testosterone in men, were measured. TRH and LHRH tests were not systematically performed. Only two parameters differed significantly between the cured and failure groups: the size of the adenomas was smaller and the pathological confirmation of the adenoma more frequent in the cured group. One patient had permanent corticotropic failure while two other had impaired response to hypoglycemia with normal cortisol basal levels. No acquired hypothyroidism nor hypogonadism were observed except in a patient who underwent two operations and radiotherapy. Recovery of GH function was slow. Definitive short stature was observed in all the patients whose disease began before the age of 16. Two patients had permanent diabetes insipidus. In conclusion, the most favorable prognosis in transsphenoidal surgery for Cushing's disease is observed in case of microadenoma confirmed by pathological examination. With this treatment, we obtained satisfactory results in Cushing's disease with minimal complications and no necessity of lifelong endocrine substitutive therapy.