Objective: To study the effect of improved preoperative tumour localisation on the outcome of transsphenoidal surgery for Cushing's disease.
Design: Retrospective.
Setting: University Hospital Rotterdam, the Netherlands.
Methods: The case records were studied of 61 patients, operated on for Cushing's disease due to a corticotrophin-secreting microadenoma (diameter < 10 mm), in the period January 1985-September 1995. From 1985, preoperative tumour localisation was performed with computed tomography (CT), from 1989 with Magnetic Resonance Imaging (MRI) and Bilateral Simultaneous Inferior Petrosal Sinus Sampling (BSIPSS). The definition of a successful operation was: morning serum cortisol < 500 nmol/l, and of cure: morning serum cortisol < 140 nmol/l or 24-hr cortisoluria < 250 nmol.
Results: In 1985-1988, a microadenoma was localised preoperatively in 8/22 patients (36%), the operation was successful in 12 (55%), of which 4 (18%) were cured. In 1989-1991, a microadenoma was localised in 12/15 patients (80%), the operation was successful in 11 (73%), of which 4 (27%) were cured. In 1992-1995 a microadenoma was localised preoperatively in 23/24 patients (96%), the operation was successful in 19 (79%), of which 17 (71%) were cured. In the cured group, there was a low incidence (< 10%) of postoperative hypopituitarism in all three periods. There were 1, 0 and 1 recurrences of Cushing's disease respectively after initial cure.
Conclusion: In our institution, improved preoperative localisation of corticotrophin-secreting hypophyseal microadenomas was associated with an important increase of success and cure rate of transsphenoidal surgery, while there was no increase in postoperative hypopituitarism or recurrences of Cushing's disease.