Initial SRS for patients with 5-15 brain metastases: results of a multi-institutional experience
Menée à partir de données portant sur 2 089 patients présentant une ou plusieurs métastases cérébrales, cette étude multicentrique évalue, du point de vue de la survie globale et du développement de nouvelles métastases, l'efficacité d'une radiochirurgie stéréotaxique en fonction du nombre initial de métastases cérébrales (1, 2 à 4 ou 5 à 15)
Résumé en anglais
Background : Several studies evaluating stereotactic radiosurgery (SRS) for patients with >4 brain metastases (BM) demonstrated similar outcomes after treatment of 1, 2-4, and 5-15 BM; others found clinically significant survival decrements in the latter group. In this review of eight academic centers, we compared outcomes of patients undergoing initial SRS for 1, 2-4, and 5-15 BM.
Methods : A total of 2,089 patients treated with initial SRS for brain metastases were included. Overall survival (OS) was estimated using the Kaplan-Meier method and compared using the log-rank test. Patient and disease characteristics were evaluated for association with OS and cumulative incidence (CI) of distant brain failure (DBF) using stepwise multivariable Cox proportional hazards and competing risk regression modeling.
Results : In this series, 989 (47%) patients had 1 metastasis, 882 (42%) had 2-4 metastases, and 212 (10%) had 5-15 metastases treated. Median OS for the 1, 2-4, and 5-15 BM groups was 14.6, 9.5, and 7.5 months, respectively (log-rank p<0.01). Univariate and multivariable analyses revealed no difference in survival between 2-4 and 5-15 BM. DBF at 1 year was 30%, 41%, and 50%, respectively (Gray’s p<0.01). Two-year CI of salvage SRS decreased with increasing number of BM (1: 21% v. 2-4: 19% v. 5-15: 13%, p<0.01), but no difference in salvage WBRT was observed (1: 12% v. 2-4: 15% v. 5-15: 16%, p=0.10). At the time of DBF, median brain metastasis velocity was 3.9, 6.1, and 11.7 new metastases per year in the 1, 2-4 and 5-15 BM groups, respectively (p<0.01).
Conclusions : Patients treated with initial SRS for 5-15 brain metastases experienced similar survival to those with 2-4 brain metastases. Lower rates of salvage SRS were observed in the 5-15 BM group, with no difference in rates of salvage WBRT.
