Introduction: Silent corticotroph staining pituitary adenoma (SCA), represents an uncommon more locally aggressive subset of Non-Functioning adenomas (NFAs). In this multicenter study, we investigate the safety and effectiveness of Stereotactic Radiosurgery (SRS) in patients with SCA compared with other non-SCA NFA’s.
Methods: Eight centers participating in the International Gamma-Knife Research Foundation (IGKRF) contributed to this study. Outcomes of 50 patients with confirmed SCA’s and 307 patients with confirmed non-SCA NFA’s treated with SRS were evaluated. Groups were matched. SCA was characterized by a lack of clinical evidence of Cushing disease, yet with positive immunostaining for corticotroph. Median age was 55.2 years (13.7-87). All patients underwent at least one trans-sphenoidal tumor resection prior to SRS. SRS parameters were comparable as well.
Results: Median follow-up 40 months (6-163). Overall tumor control rate (TCR) 91.2% (n=280). In the SCA group, TCR were 82% (n=41) vs. 94.1% (n=289) for the control-NFA (p=0.0065). The SCA group showed a significantly higher incidence of new post-SRS visual deficit (p<0.0001) assigned to tumor progression and growth, post-SRS weakness and fatigue (p<0.0005), and post-SRS new pituitary deficit (p=0.001). In univariate and multivariate analysis, only the status of silent corticotroph staining (p=0.005, p=0.009 respectively) and margin dose (p<0.0005, p=0.0037 respectively) significantly influenced progression rate. A margin dose of =17 Gy was noted to influence the adenoma progression rate in the entire cohort (p=0.003).
Conclusions: Silent corticotroph staining represents an independent factor for adenoma progression and hypopituitarism after SRS. A higher margin dose may convey a greater chance of TCR.
Patient Care: The participants will be able to learn of approaches to adjusting SRS treatment for silent ACTH pituitary adenomas.
Learning Objectives: The participants will learn of the implications associated with silent ACTH features in pituitary adenomas treated with radiosurgery. These include assessments of radiologic, endocrine, and neurological outcome parameters.