2025 Proffered Presentations
S196: LONG-TERM OUTCOMES AND COMPLICATION PREDICTION AFTER STEREOTACTIC RADIOSURGERY FOR PREVIOUSLY UNTREATED MENINGIOMAS
Rahul Kumar, MD, PhD1; Lucas P Carlstrom, MD, PhD2; Ramin A Morshed, MD3; Paul D Brown, MD1; Christopher S Graffeo, MD4; Michael J Link, MD1; Bruce E Pollock, MD1; 1Mayo Clinic, Rochester, MN, USA; 2Southern California Kaiser Permanente Medical Group, San Diego, California, USA; 3University of San Francisco, San Francisco, CA, USA; 4University of Oklahoma, Oklahoma City, OK, USA
Background and Objectives: Stereotactic radiosurgery (SRS) has been utilized as a primary and adjuvant treatment modality for patients with meningiomas. We seek to describe the long-term outcomes for patients that underwent SRS as primary treatment for sporadic intracranial meningiomas while exploring treatment-related outcomes as a function of radiosurgical parameters, including biological effective dose (BED).
Methods: A prospectively maintained database was reviewed for all patients with sporadic meningiomas who underwent SRS (Gamma Knife) as primary treatment modality at a single center from April 1997 to February 2022. Clinicodemographic data, tumor measurements, and radiosurgical treatment parameters were abstracted. BED was calculated utilizing published monoexponential fits as a function of treatment time and marginal dose. Primary outcomes included progression-free survival and treatment-related neurological sequalae.
Results: A total of 616 patients without prior surgery or radiotherapy underwent single-fraction SRS for treatment of 653 sporadic meningiomas at a single institution over a 25-year period. Median patient age at SRS was 59.1 years with 77.3% females. Median tumor volumes for 456 posterior fossa/skull base and 197 supratentorial lesions were 4.8 cm3 and 4.1 cm3, respectively. Median isodose line and number of isodose centers were 50% and 9, respectively. Median marginal and biological effective doses were 15.2 and 86.0 gray, respectively. With median and mean radiographic follow-up time of 6.50 and 7.43 years, median progression-free survival (PFS) estimates at 5, 10, and 15 years were 99.8%, 98.9%, and 92.9%. A total of 310 patients (50.2%) had lesions that decreased in size while 295 patients (48.0%) had lesions that remained stable. Local progression was noted in 7 patients (1.0%), marginal progression in 2 patients (0.4%, 1 patient with multiple lesions), and distant progression was observed in 2 patients (0.3%).
Treatment-associated neurological sequalae were noted in 56 patients (9.1%), of which 6 (1.0%) were permanent and/or required intervention. Cranial neuropathies and/or neuralgias accounted for 46.4% of all sequalae. Peri-lesional cerebral edema post-SRS was noted in 75 patients (12.2%), amongst which 24 (3.9%) required steroid therapy and 2 (0.3%) underwent surgical intervention. Univariable logistic regression and receiver operating characteristics revealed marginal superiority of BED (AUC: 0.61) compared to marginal dose (AUC: 0.54) in predicting treatment-related sequalae. Multiple random forest classification models also confirmed relative importance of BED over marginal dose in predicting treatment-related neurological sequalae.
Conclusion: SRS is highly efficacious and safe as primary treatment modality for sporadic intracranial meningiomas. Minimization of treatment-related sequalae remains an important incremental milestone to further enhance patient outcomes and may be achieved by refinement of treatment planning paradigms utilizing BED.
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