Factors affecting the probability of recurrence of the Cushing’s disease within 3 years after effective neurosurgical treatment

Background. Cushing’s disease (СD) is а severe neuroendocrine disease that can rapidly progress with the development of severe complications of hypercorticism requiring immediate treatment. The main method of treatment is a neurosurgical operation, the effectiveness of which at the present time can reach 80% or more, however, about a quarter of patients after successful neurosurgical treatment experience reccurence. Aim. The analysis of prognostic factors potentially affecting the occurrence of recurrence of CD after successful primary transnasal adenomectomy. Material and methods. A retrospective monocenter comparative study of treatment outcomes in 219 patients (32 men, 187 women) with confirmed diagnosis of Cushing's disease who underwent endoscopic transsphenoidal adenomectomy between 2007 and 2014 was performed. The inclusion criteria were: the absence of previous pathogenetic treatment for this disease and the development of remission of the disease in the early postoperative period. The duration of follow-up period was three years and more. We used methods of statistical comparison of groups, including survival analysis and ROC-analysis. Results. Within 3 years the remission was preserved in 172 patients, the recurrence of Cushing's disease developed in 47 patients (21.5% [16%; 28%]). The probability of CD recurrence was associated with morning levels of ACTH and cortisol and evening ACTH in the early postoperative period. As a result of the ROC-analysis for morning ACTH and cortisol, the optimal cutting points were 7 pg/ml and 123 nmol/l respectively. In patients with ACTH level less than 7 pg/ml, three years recurrence appeared to be 7%, 95% CI [3%, 14%], while at the level of ≥7 pg/ml recurrence was observed in 31% [23%, 40%] cases, RR 0.22 [0.09; 0.51], ОR – 0.16 [0.06; 0.43]. In patients with cortisol level below 123 nmol/l the recurrence developed in 13% [9%, 20%] of cases, while in patients with cortisol level ≥123 nmol/l, recurrence was equal to 45% [32%, 59%], RR 0.29 [0.18; 0.50], ОR – 0.19 [0.09; 0.39]. Conclusion. The development of adrenal insufficiency (a decrease in ACTH level less than 7 pg/ml and cortisol level less than 123 nmol/l) statistically significantly reduces the probability of the recurrence of CD within three years after surgery.