Repeat Courses of Stereotactic Radiosurgery (SRS), Deferring Whole Brain Irradiation, for New Brain Metastases Following Initial SRS
Menée sur 95 patients atteints d'un cancer avec métastases cérébrales (nombre de métastases identifiées : 652 ; durée médiane de suivi : 15 mois), cette étude évalue l'efficacité, du point de vue du taux d'échec à 1 an, et la sécurité de plusieurs séances de radiochirurgie stéréotaxique ciblant les métastases
Résumé en anglais
Purpose : There is no standard of care for new brain metastases that develop following initial stereotactic radiosurgery (SRS), although whole brain radiotherapy (WBRT) has been historically recommended. We report the outcomes of repeat SRS, deferring WBRT, for distant intracranial recurrences and identify factors associated with prolonged overall survival (OS).
Patients and Methods : We retrospectively identified 652 metastases in 95 patients treated with 2 or more courses of SRS for brain metastases, deferring WBRT. Cox regression analyzed factors predictive for OS.
Results : Patients had a median of 2 metastases (range: 1-14) treated per course, with a median of 2 courses (range: 2 - 14) of SRS per patient. With a median follow-up following first SRS of 15 months (range: 3 – 98 months), the median OS from the time of the first and second course of SRS was 18 (95% CI 15 – 24) and 11 months (95% CI 6 – 17), respectively. On multivariate analysis, histology, graded prognostic assessment (GPA) score, aggregate tumor volume (but not number of metastases), and performance status correlated with OS. The 1-year cumulative incidence, with death as a competing risk, of local failure was 5% (95% CI 4-8). Eighteen (24%) of 75 deaths were from neurologic causes. Nineteen (20%) patients eventually received WBRT. Adverse radiation events developed in 2% of SRS sites.
Conclusion : Multiple courses of SRS, deferring WBRT, for distant brain metastases following initial SRS, appear to be a safe and effective approach. The GPA score, updated at each course, and aggregate tumor volume may help select patients in whom the deferral of WBRT might be most beneficial.
