Prognostic Factors For Survival In Patients Treated With Stereotactic Radiosurgery For Recurrent Brain Metastases After Prior Whole Brain RadiotherapyKeywords: brain metastasis, outcome, gamma knife, radiosurgery, brain tumorInteractive ManuscriptAsk Questions of this Manuscript: What is the background behind your study? What is the purpose of your study?To evaluate prognostic factors for survival after stereotactic radiosurgery (SRS) for “recurrent” (new, progressive, or recurrent) brain metastases after prior whole brain radiotherapy (WBRT). Describe your patient group.We retrospectively reviewed patients treated 1991-2007 with Gamma Knife SRS for recurrent brain metastases after WBRT, excluding patients who had prior SRS or prophylactic WBRT. Describe what you did. Prognostic factors were analyzed overall and by primary site using log-rank tests, univariate and backward stepwise multivariate Cox proportional hazards analyses, and recursive partitioning analysis (RPA), including age (<65 vs. =65; <50 vs. =50 for breast cancer), KPS (<70 vs. =70), primary tumor control, extracranial metastases, number of brain metastases treated (1, 2-3, 4-6, =7), total SRS target volume by quartile, and interval from WBRT to SRS by quartile. Describe your main findings. 310 patients were studied, including 90 breast, 113 nonsmall cell lung, 31 small cell lung, 42 melanoma, 11 kidney, and 23 miscellaneous primaries. The median age was 56, KPS 80, number of brain metastases 3, interval from WBRT to SRS 8.1 months, minimum prescribed SRS dose 17.0 Gy, and total target and treated volumes 5.8 and 8.8 ml; 76% of patients had primary tumor control and 60% had known extracranial metastases. The median survival time was 8.4 months overall–12.0 vs. 7.9 months for single vs. multiple brain metastases treated (p<0.001). There was no clear relationship between number of metastases and survival after excluding single-metastasis patients; median survival times were 7.9, 6.6, and 9.7 months for 102, 72, and 60 patients with 2-3, 4-6, and =7 brain metastases, respectively (log-rank p=0.12; Cox p=0.76). Prognostic factors differed by primary site, including age<50 and longer interval from WBRT to SRS in breast, single brain metastasis, KPS>=70, and controlled primary in nonsmall cell lung, and smaller total target volume in melanoma patients, by multivariate analysis. The RPA will be presented. Describe the main limitation of this study.This is a retrospective study. Describe your main conclusion.Prognostic factors differed by primary site among patients treated with SRS for recurrent brain metastases after WBRT. Describe the importance of your findings and how they can be used by others.Although survival was significantly longer for single-metastasis patients, the median survival time of 7.9 months for those with multiple metastases seems sufficiently long for salvage SRS to be worthwhile. No evidence was found for a cutoff for number of brain metastases appropriate for salvage SRS. To evaluate prognostic factors for survival after stereotactic radiosurgery (SRS) for “recurrent” (new, progressive, or recurrent) brain metastases after prior whole brain radiotherapy (WBRT). We retrospectively reviewed patients treated 1991-2007 with Gamma Knife SRS for recurrent brain metastases after WBRT, excluding patients who had prior SRS or prophylactic WBRT. Prognostic factors were analyzed overall and by primary site using log-rank tests, univariate and backward stepwise multivariate Cox proportional hazards analyses, and recursive partitioning analysis (RPA), including age (<65 vs. =65; <50 vs. =50 for breast cancer), KPS (<70 vs. =70), primary tumor control, extracranial metastases, number of brain metastases treated (1, 2-3, 4-6, =7), total SRS target volume by quartile, and interval from WBRT to SRS by quartile. 310 patients were studied, including 90 breast, 113 nonsmall cell lung, 31 small cell lung, 42 melanoma, 11 kidney, and 23 miscellaneous primaries. The median age was 56, KPS 80, number of brain metastases 3, interval from WBRT to SRS 8.1 months, minimum prescribed SRS dose 17.0 Gy, and total target and treated volumes 5.8 and 8.8 ml; 76% of patients had primary tumor control and 60% had known extracranial metastases. The median survival time was 8.4 months overall–12.0 vs. 7.9 months for single vs. multiple brain metastases treated (p<0.001). There was no clear relationship between number of metastases and survival after excluding single-metastasis patients; median survival times were 7.9, 6.6, and 9.7 months for 102, 72, and 60 patients with 2-3, 4-6, and =7 brain metastases, respectively (log-rank p=0.12; Cox p=0.76). Prognostic factors differed by primary site, including age<50 and longer interval from WBRT to SRS in breast, single brain metastasis, KPS>=70, and controlled primary in nonsmall cell lung, and smaller total target volume in melanoma patients, by multivariate analysis. The RPA will be presented. This is a retrospective study. Prognostic factors differed by primary site among patients treated with SRS for recurrent brain metastases after WBRT. Although survival was significantly longer for single-metastasis patients, the median survival time of 7.9 months for those with multiple metastases seems sufficiently long for salvage SRS to be worthwhile. No evidence was found for a cutoff for number of brain metastases appropriate for salvage SRS. Project Roles:
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