Transsphenoidal surgery for acromegaly in Wales: Results based on stringent criteria of remission

We retrospectively analyzed 90 patients who underwent transsphenoidal surgery (performed by three surgeons) in our center as initial therapy for acromegaly. We used a combination of modern, evidence-based remission criteria including mean day curve GH less than 2.5 µg/liter (5 mU/liter), a nadir GH less than 1.0 µg/liter (2 mU/liter) after an oral glucose tolerance test, and normal age-related IGF-I levels (where available). Fifty-seven of 90 (63%) patients remained in remission after surgery. Seventy-nine percent of patients with microadenomas but only 56% of patients with macroadenomas achieved remission (P < 0.001). Eighty-six percent of patients with preoperative GH levels below 10 µg/liter (day profile or after oral glucose tolerance test) went into remission, compared with 51% of patients with GH levels above 25 µg/liter at diagnosis (P < 0.002). The remission rate was also related to the period of surgery that was significantly higher in 1998–2001 (76%; P < 0.05) compared with 1990–1997 (54%) and 1980–1989 (63%). There were no recurrences or perioperative deaths. Meningitis occurred in 3% of patients, cerebrospinal fluid rhinorrhea in 7%, and permanent diabetes insipidus in 15%. The proportion of patients who developed new anterior pituitary hormone deficiencies and panhypopituitarism was significantly less in the period 1998–2001 (P < 0.001) when compared with the periods from 1990–1997 and 1980–1989. Transsphenoidal surgery is a safe and effective treatment for acromegaly, and our results compare favorably with those from published series. The presence of an intrasellar lesion and low preoperative GH levels is a good predictor of remission in the long term, but historically in our center this can only be achieved in a significant proportion of patients at the expense of some degree of hypopituitarism. However, surgical outcome in our center, including a reduced frequency of hypopituitarism, has improved significantly over time, coincident with the arrival of a dedicated pituitary neurosurgeon and the use of selective adenomectomy as the preferred surgical approach wherever possible. Abbreviations: CSF, Cerebrospinal fluid; DI, diabetes insipidus; ES, extrasellar; IS, intrasellar; ITT, insulin tolerance test; OGTT, oral glucose tolerance test; PRL, prolactin; SST, short synacthen test.