Distant Brain Recurrence in Patients With 5 or More Newly Diagnosed Brain Metastases Treated With Stereotactic Radiosurgery (SRS) or Fractionated Stereotactic Radiation Therapy (FSRT) Alone

Abstract

Background To assess the clinical outcomes in patients with greater than 4 newly diagnosed brain metastases treated with focal stereotactic radiotherapy alone. Methods All patients with five or more brain metastases who received focal radiotherapy without whole brain radiation or resection were included in this retrospective analysis. Distant brain failure (DBF), overall survival (OS) and toxicity were reported. Results Thirty-six patients met inclusion with median clinical follow-up of 6.3 months (range: 1.1, 51.4). Twenty-nine patients received stereotactic radiosurgery (SRS) to a median dose of 20 Gy (16-20), and 7 received fractionated stereotactic radiotherapy (FSRT) to a median dose of 30 Gy (25, 30) in five fractions. The median lesion number and total brain metastases volume was 6 (5, 14) and 1.55 cc (0.12, 32.96), respectively. The Kaplan-Meier estimate of DBF at six-month was 58%, and survival probability at 1 year was 49%. Twenty percent of patients experienced systemic death without CNS relapse. Eight percent experienced grade 3 toxicity with no grade 4 or 5 toxicity. Neither tumor volume nor number predicted DBF. Conclusions DBF, OS and treatment toxicity were similar to historical controls with fewer than five metastases treated with focal radiation. Focal stereotactic radiotherapy alone without whole brain RT is a reasonable treatment strategy for five or more brain metastases.

Outcomes in Patients With 4 to 10 Brain Metastases Treated With Dose-Adapted Single-Isocenter Multitarget Stereotactic Radiosurgery: A Prospective Study

“…Other factors must be considered, including histology, control of systemic disease, existing systemic therapy options, and predicted survival. 34,35 For example, Fiveash et al analyzed outcomes of SRS in patients with 5 or more brain metastases and demonstrated that neither tumor volume nor tumor number were predictive of distant failure in multivariate analysis. 35 Risk of distant brain failure in 6 months in our study was 58%, which is comparable to historical controls, where risk of distant brain failure in patients following SRS alone was similar and ranged from 35-64% 3,29,35 .…”

“… 33 , 34 For example, Barrett et al 35 analyzed outcomes of SRS in patients with 5 or more brain metastases and demonstrated that neither tumor volume nor tumor number were predictive of distant failure in multivariate analysis. Risk of distant brain failure in 6 months in our study was 58%, which is comparable with historical controls, where risk of distant brain failure in patients after SRS alone was similar and ranged from 35% to 64% 3 , 28 , 35 In addition, Nam et al demonstrated no differences in distant brain failure between those who had 1 to 3 versus 4 to 10 brain metastases. 36 More than half of our patients did not experience a distant recurrence (21 of 40), and the cumulative incidence at 1 year for distant recurrence was 35.8%.…”