Outcome of Cushing's disease following transsphenoidal surgery in a single center over 20 years. 
Historically, Cushing's disease (CD) was associated with a 5-yr survival of just 50%.  Although advances in CD management have seen mortality rates improve, outcome from transsphenoidal surgery (TSS), the current first-line treatment, varies significantly between centers.  The aim of the study was to define outcome including mortality in a cohort of CD patients treated with TSS over 20 yr.  We conducted a retrospective cohort study of 80 patients who underwent TSS to treat CD between 1988 and 2009.  In 72 cases, data on clinical features and outcomes were collected from medical records.  In eight patients, records were unavailable, but in all cases mortality data were obtained from National Health Service (NHS) registries and recorded as standardized mortality ratio.  The study was conducted in a United Kingdom tertiary referral center.  Adult patients confirmed to have CD participated in the study.  All patients underwent TSS.  Patients were subdivided into groups based on disease response after initial treatment.  Mortality according to subgroup was also assessed.  Median follow-up for clinical data was 4.6 yr.  Three outcome groups were identified: cure, 72% (52 of 72); persistent disease, 17% (12 of 72); and disease recurrence, 11% (eight of 72).  Median time to recurrence after initial remission was 2.1 yr (interquartile range, 1.3-3.1 yr).  Mean follow-up for mortality was 10.9 yr.  Thirteen of 80 patients had died: five of 52 in the cure group, two of eight in the disease recurrence group, two of 12 with persistent disease, and four of eight of those followed up by NHS registry search only.  Overall, the standardized mortality ratio was 3.17 [95% confidence interval (CI), 1.70-5.43], whereas in the cure group it was 2.47 (95% CI, 0.80-5.77), and it was 4.12 (95% CI, 1.12-10.54) for disease recurrence/persistent disease groups.  We report long-term cure rates in excess of 70%.  Mortality is increased in CD and may be higher in patients with persistent/recurrent disease compared to patients cured after initial treatment.