Objectives: Endonasal endoscopic transsphenoidal surgery (TSS) and resection of pituitary adenomas is considered to be the gold standard treatment for Cushing's Disease (CD). Even with various recent advances in management, disease persistence and recurrences are common in these patients. The remission rate in the global population after surgery has been reported to vary widely from 64 to 93%. This study aims to determine various clinical, biochemical, radiological and histological factors that correlate with persistence and recurrence in patients with CD. This study also aims to understand the clinicopathological significance of EGFR-MAPK, NF-kB and SHH pathway activation and to study the protein expression levels of activation markers of these pathways viz. c-Fos , c-Jun, GLI-1 , pMEK, NR4A1 and p44 in functioning corticotroph pituitary adenomas.
Methods: From January 2009 to September 2022, the clinical data of 167 patients who underwent surgical treatment (n=174 surgeries) for Cushing's disease was ambispectively analysed with a median follow up of 8.1 years (1-13.29 years). The preoperative clinical, biochemical, radiological features, operative findings, postoperative clinical and biochemical data, histopathological and molecular profile, were retrieved from electronic records. The patients were followed up to assess the remission status.
Results: Among the 174 surgeries performed, 140 were primary surgeries, 22 were revision surgeries, 24 surgeries were for paediatric patients and 12 surgeries were performed in patients with Nelson syndrome. In the primary surgery cohort, 74.3% were females and the average age was 28.73 years (SD 10.15). 75% of the patients experienced remission after primary surgery compared to 47.4% in revision surgery. The remission rate in paediatric patients was 55.5%. Post-operative day 1 plasma cortisol (p<0.001; AUC 0.8894 [0.8087-0.9701]) and ACTH (p<0.001; AUC 0.9 [0.7386-1]) levels were seen to be strong independent predictors of remission in the primary surgery cohort. Remission rates after Endoscopic TSS were more than that after microscopic TSS, in patients undergoing primary surgery (81.08% vs 57.14%; p=0.008). Presence of adenoma on histopathological examination (HPE) was also a strong predictor of disease remission (p=0.020). On categorising based on surgical approach and HPE, microscopically operated patients without histopathological evidence of adenoma had significantly higher odds of non-remission (OR 38.1 95% CI 4.2-348.3) compared to endoscopically operated patients with adenoma on HPE. Lower immune reactivity score (IRS) of NR4A1 was found to correlate with higher remission rates (p=0.074). However, none of the molecular markers studied viz. c-Fos , c-Jun, GLI-1, pMEK and p44 showed a significant correlation with the preoperative cortisol values.
Conclusion: Remission rate after primary surgery is higher as compared to that after revision surgery, and that in paediatric patients is lower as compared to adults. Post-operative day 1 plasma cortisol and ACTH levels are strong independent predictors of remission in the primary surgery cohort. Endoscopic approach with histopathological evidence of adenoma is associated with a higher remission rate and thus endoscopy should be the approach of choice in these patients with the goal of identification of an adenoma on histopathological analysis.
Keywords: ACTH; Cushing’s disease; corticotroph adenomas; cortisol; endoscopic endonasal transsphenoidal surgery; molecular markers; pituitary surgery.
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