1043 - The Influence of Cancer Primary Site on Outcomes after Preoperative Radiosurgery for Resected Brain Metastases: A XXX International Multicenter Cohort Study
Presenter(s)
R. S. Prabhu1, R. Russek2, Z. K. Vaslow3, J. K. Matsui4, N. Haghighi5, T. Dan6, M. V. Mishra7, E. S. Murphy8, S. Boyles9, H. K. Perlow10, J. D. Palmer11, C. Udovicich12, T. Patel13, Z. Wardak6, G. F. Woodworth14, A. Ksendzovsky15, K. Yang16, S. T. Chao17, A. Asher18, and S. H. Burri19; 1Atrium Health Levine Cancer, Wake Forest School of Medicine, and Southeast Radiation Oncology Group, Charlotte, NC, 2Atrium Health Levine Cancer, Charlotte, NC, 3Cone Health, Greensboro, NC, 4The Ohio State University College of Medicine, Columbus, OH, 5Peter MacCallum Cancer Centre, Melbourne, Australia, 6Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 7Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, 8Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, OH, 9Cone Health Cancer Center, Greensboro, NC, 10Department of Radiation Oncology, University Hospitals Cleveland Medical Center/ Seidman Cancer Center, Cleveland, OH, 11Department of Radiation Oncology, James Cancer Hospital/Wexner Medical Center, The Ohio State University, Columbus, OH, 12GenesisCare Melbourne, Malvern, Australia, 13Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX, 14Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 15University of Maryland, Baltimore, MD, 16Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, 17Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH, 18Carolina Neurosurgery and Spine Associates, Charlotte, NC, 19Southeast Radiation Oncology Group, Charlotte, NC
Purpose/Objective(s): Preoperative (preop) stereotactic radiosurgery (SRS) is a feasible alternative to postoperative (postop) SRS with potential benefits in adverse radiation effect and meningeal disease. The goal of this study was to determine if there is an association between the cancer primary site and oncologic outcomes after preop SRS for resected brain metastases (BM).
Materials/Methods: Patients with BM from solid cancers, of which at least 1 lesion was treated with preop SRS and underwent planned resection were included from 8 institutions. SRS to synchronous intact BM was allowed. Exclusion criteria included classically radiosensitive or non-solid cancers (including small cell lung cancer) and prior or planned whole brain radiotherapy (WBRT). Cancer primary site was categorized into 6 groups: non-small cell lung cancer (NSCLC), breast, melanoma, kidney, gastrointestinal (GI), and other. Intracranial outcomes were estimated using cumulative incidence with competing risk of death.
Results: The cohort consisted of 404 patients with 416 preop SRS treated index lesions. Primary site distribution was NSCLC for 192 patients (48%), breast 62 (15%), melanoma 50 (12%), kidney 29 (7%), GI 28 (7%), and other 43 (11%), respectively. The other category included predominantly gynecologic, sarcoma, and bladder/urothelial primary sites. Median interval between preop SRS and surgery was 2 days. Median cranial imaging follow-up interval was 9.5 months overall and 17.5 months for alive patients. There were baseline imbalances between primary site groups for age, graded prognostic assessment score, median index tumor volume, gender, and posterior fossa location. Univariate analyses results at 2-years by primary site are included in the table below. In multivariate analysis controlling for other prognostic factors, primary site was found to have significant association with risk of local recurrence (LR), distant brain failure (DBF), meningeal disease (MD), adverse radiation effect (ARE), and overall survival (OS). Relative to NSCLC, GI primary site was associated with significantly increased risk of LR; melanoma and kidney primaries with increased risk of DBF; breast, melanoma, and other primary sites with increased risk of MD; and melanoma with increased risk of ARE. Melanoma and kidney primary sites were associated with significantly improved OS compared to NSCLC.
Conclusion: Intracranial tumor control, ARE, and overall survival after preoperative SRS for resected brain metastases are highly influenced by cancer primary site in both univariate and multivariate analyses. Some of these findings may be related to inherent differences in primary site biology and/or differences in systemic therapy options and efficacy by cancer primary site. Additional confirmatory studies are needed.
| 2-year Outcomes | NSCLC | Breast | Melanoma | Kidney | GI | Other | p-value |
| LR | 13% | 23% | 11% | 4% | 19% | 11% | 0.3 |
| DBF | 36% | 35% | 55% | 56% | 52% | 37% | 0.04 |
| MD | 2% | 10% | 12% | 9% | 4% | 8% | 0.05 |
| ARE (any grade) | 9% | 7% | 8% | 3% | 8% | 5% | 0.6 |
| OS | 43% | 46% | 49% | 48% | 26% | 29% | 0.03 |