Our next speaker is Dr. Dale Ding, who is the recipient of the LexCell Radiosurgery Award. Dr. Ding will be speaking about stereotactic radiosurgery for the management of acromegaly outcomes of a multicenter retrospective cohort study. Great, well thanks to the AANS and thanks for the award, the opportunity to present our work on behalf of the IGKRF. These are the lists of the contributing authors and contributing centers for this particular study. I have no personal disclosures, some of the co-authors do. So a transminodal resection of growth hormone secreting pituitary adenomas is the first line therapy for acromegaly, however, 20 to 40% of surgically treated patients fail to achieve endocrine remission. Medical therapy for these subset of patients requires lifelong management with IGF-1 lowering medications. It's not always effective and it can be quite expensive, especially over time. Stereotactic radiosurgery has an important role in the postoperative management of acromegaly patients with residual or recurrent tumor. So with that in mind, the aim of the study is to assess the outcomes of radiosurgery for acromegaly as well as to look at predictors in a multicenter international retrospective cohort study. We pooled data from 10 participating centers of the IGKRF. We identified patients with acromegaly who had at least six months of endocrine follow-up and we analyzed the baseline and outcomes data. We performed a standard set of statistics, including Kaplan-Meier analysis to look at actuarial rates of initial remission, recurrence for survival, and durable remission. We also looked at predictors of each of these endpoints and then the significant predictors in the univariate analysis were entered into a multivariate model. This is the study cohort that started with 398 patients. We excluded 20 for either for lack of documented endocrine outcome after SRS. We excluded an additional seven for endocrine follow-up less than six months. We arrived at our study cohort of 371 patients. This is some baseline and treatment data. The average age was 46. About 50% were female, approximately two and a half to three years from last resection to SRS. About 20% had a preexisting endocrinopathy. The mean tumor volume is 2.5 cubic centimeters. The mean margin dose is 24 gray, and the mean follow-up was 79 months. We looked at the pre-SRS medical therapy. About a third of the cohort was on some kind of IGF-1 lowering medication prior to SRS. 17% of those patients were taking multiple medications, and in about half of those patients, the medical therapy was held four to eight weeks prior to SRS. This is the distribution of medications. These are our results for the initial endocrine remission. We had a 69% remission at 10 years, 74% at 15 years. We looked at predictors of initial remission. These were the significant factors in the multivariate analysis. Pre-SRS, a lower pre-SRS IGF-1 level and cessation of medication were independent predictors of initial endocrine remission. Just under 10% of patients with initial remission had biochemical recurrence. This happened in a mean interval of 17 months after the initial SRS. This is the Kaplan-Meier plot for recurrence-free survival, 73% at 10 years. We looked at predictors of recurrence. The multivariate analysis showed that prior surgical resection and SRS maximum dose were negative predictors of recurrence. This is the Kaplan-Meier plot for durable endocrine remission. It was 43% at 5 years and close to 60% at 10 years. We looked at the predictors of durable remission. These were similar to the ones of initial remission. But in the multivariate analysis, only cessation of medication was an independent predictor. And those who had medications held were about two and a half times more likely to achieve durable remission than those who continued medical therapy. We looked at the new endocrinopathy rate in terms of adverse radiation effects. About a quarter of patients had some form of endocrinopathy. It was 41 patients, which is about 10% of the study cohort, had multiple new endocrinopathies. Only targeting of the whole cell with SRS was predictive of new endocrinopathy. With respect to new cranial neuropathy, just under 5% had any new cranial neuropathy after SRS. This is the distribution. As you can see, most of it was optic neuropathy. Two had multiple cranial neuropathies. Only SRS targeting of supercell or tumor was predictive of optic apparatus injury. Due to the small number of non-optic cranial neuropathies, there were no predictors of that in our analysis. There were no patients with new cranial neuropathy that had radiologic evidence of tumor growth. So in conclusion, radiosurgery affords durable endocrine remission for one half of patients with acromegaly, although one quarter will develop at least one new pituitary hormone deficiency after SRS. Since biochemical remission occurs in a modest proportion, long-term endocrine follow-up is critical after SRS for acromegaly. When deemed appropriate by the endocrinologist, acromegaly patients should be temporarily taken off IGF-1 lowering medications four to eight weeks prior to SRS to potentially improve its efficacy. These patients are typically restarted on those same medications four to eight weeks after the SRS procedure. Thank you.

stereotactic radiosurgery

acromegaly

residual tumors

recurrent tumors

endocrine remission