Stereotactic radiosurgery for brain metastases from pelvic gynecological malignancies: oncologic outcomes, validation of prognostic scores, and dosimetric evaluation

Abstract

IntroductionStereotactic radiosurgery is a well-established treatment option in the management of brain metastases. Multiple prognostic scores for prediction of survival following radiotherapy exist, but are not disease-specific or validated for radiosurgery in women with primary pelvic gynecologic malignancies metastatic to the brain. The aim of the present study is to evaluate the feasibility, safety, outcomes, and impact of established prognostic scores.MethodsWe retrospectively identified 52 patients treated with radiotherapy for brain metastases between 2008 and 2021. Stereotactic radiosurgery was utilized in 31 patients for an overall number of 75 lesions; the remaining 21 patients received whole-brain radiotherapy. Kaplan-Meier survival analysis and the log-rank test were used to calculate and compare survival curves and univariate and multivariate Cox regression to assess the influence of cofactors on recurrence, local control, and prognosis.ResultsWith a median follow-up of 10.7 months, overall survival rates post radiosurgery were 65.3%, 51.3%, and 27.7% for 1, 2, and 5 years, respectively, which were significantly higher than post whole-brain radiotherapy (p=0.049). Five local failures (6.7%) were detected, resulting in 1 and 2 year local cerebral control rates of 97.4% and 94.0%, respectively. Univariate factors for prediction of superior overall survival were high performance status (p=0.030) and application of three prognostic scores, especially the Recursive Partitioning Analysis score (p=0.028). Uni- and multivariate analysis revealed that extracranial progression prior to radiosurgery was significant for inferior overall survival (p<0.0001). Radionecrosis was diagnosed in five women (16%); long-term neurotoxicity was significantly worse after whole-brain radiotherapy compared with radiosurgery (p=0.023).ConclusionStereotactic radiosurgery for brain metastases from pelvic gynecologic malignancies appears to be safe and well tolerated, achieving promising local cerebral control. Prognostic scores were shown to be transferable and radiosurgery should be recommended as primary intracranial treatment, especially in women with no prior extracranial progression and Recursive Partitioning Analysis class I.