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Neurooncol Adv
Neurooncol Adv
noa
Neuro-Oncology Advances
2632-2498
Oxford University Press US

10.1093/noajnl/vdae090.056
vdae090.056
Final Category: Multimodality Approaches
AcademicSubjects/MED00300
AcademicSubjects/MED00310
MMOD-12 PATHOLOGIC INCIDENCE OF TUMOR POSITIVITY VS ONLY NECROSIS AFTER PRIOR RADIATION IN PATIENTS UNDERGOING SURGICAL EXCISION FOR PRESUMED BRAIN METASTASIS RECURRENCE: INSIGHT FROM A PROSPECTIVE MULTICENTER REGISTRY
Kotecha Rupesh Baptist Health of Miami, Miami/FL, USA

McDermott Michael Baptist Health of Miami, Miami/FL, USA

Lee Stuart ECU Health, Greenville/NC, USA

Peach Matthew ECU Health, Greenville/NC, USA

Richardson Angela Indiana University, Indianapolis/IN, USA

Floyd John UT San Antonio, San Antonio/TX, USA

Patel Toral UT Southwestern, Dallas/TX, USA

Wardak Zabi UT Southwestern, Dallas/TX, USA

Sloan Lindsey University of Minnesota, Minneapolis/MN, USA

Ferreira Clara University of Minnesota, Minneapolis/MN, USA

Neil Elizabeth University of Minnesota, Minneapolis/MN, USA

Hunt Matthew University of Minnesota, Minneapolis/MN, USA

Shen Colette University of North Carolina Health, Chapel Hill/NC, USA

Wasilewski Andrea Abbott Northwestern Hospital, Minneapolis/MN, USA

Wanebo John Barrow Neurological Institute, Scottsdale/AZ, USA

Smith Kris Barrow Neurological Institute, Scottsdale/AZ, USA

Chamoun Roukoz Univeristy of Kansas Medical Center, Kansas City/KS, USA

Robin Adam Henry Ford Health, Detroit/MI, USA

Lee Ian Henry Ford Health, Detroit/MI, USA

Leng Lewis Sutter Health, San Francisco/CA, USA

Patel Akash Baylor St. Luke’s Medical Center, Houston/TX, USA

Zhu James Texas Oncology - The Woodlands, Woodlands/TX, USA

Hanft Simon Westchester Medical Center, Westchester/NY, USA

Zeller Sabrina Westchester Medical Center, Westchester/NY, USA

Aizenberg Michelle University of Nebraska, Omaha/NE, USA

Rodriguez Analiz University of Arkansas Medical Center, Little Rock/AR, USA

Choutka Ondrej Saint Alphonsus, Boise/ID, USA

Hoang Kimberly Emory University, Atlanta/GA, USA

Nowlan Adam Piedmont Healthcare, Atlanta/GA, USA

McCracken David Piedmont Healthcare, Atlanta/GA, USA

Dunbar Erin Piedmont Healthcare, Atlanta/GA, USA

Brachman David GT Medical Technologies, Phoenix/AZ, USA

Garcia Michael GT Medical Technologies, Phoenix/AZ, USA

Patel Sita GT Medical Technologies, Phoenix/AZ, USA

8 2024
02 8 2024
02 8 2024
6 Suppl 1 2024 SNO/ASCO CNS Metastases Conference i18i18
© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

Abstract

PURPOSE/OBJECTIVE(S)

Determining true recurrence versus necrosis alone after previous radiation therapy (RT) for brain metastasis based on imaging alone is difficult. Proper diagnosis is essential, as further radiation is contraindicated in the setting of radiation necrosis without tumor (TUM-). To better understand the rate of pathologic tumor positivity (TUM+) vs TUM-, we examined frozen section results from a cohort of patients with prior same-site RT undergoing resection of presumed recurrent brain metastasis (RBM).

MATERIALS/METHODS

Rates of intraoperative frozen section pathology disclosing tumor +/- necrosis (TUM+) or necrosis without tumor (TUM-) were examined in patients undergoing resection for presumed RBM after prior same-site RT. All cases had been prospectively enrolled on a multi-institution registry for patients undergoing resection and intraoperative cesium-131 collagen tile brachytherapy (NCT04427384)(GammaTile, GT Medical Technologies, Tempe AZ, USA). Preoperative evaluation varied by center, and patient demographics, primary site, lesion size, and prior therapies were also examined.

RESULTS

From 10/2020 to 2/2024 60 patients (64 lesions) underwent resection and intraoperative frozen section pathologic evaluation. Per patient, primary sites were 53% lung, 15% melanoma, 13% breast, 7% renal, and 10% other. F:M ratio was 31:29; median age 62, maximum preoperative diameter 2.9 cm, and median time from prior RT 15.4 months. Across all histologies TUM+ was seen in 88% (53/60) and TUM- in 12% (7/60). Rates of TUM- by primary type were highest for lung (16%), breast (13%), and melanoma (11%). The TUM- rate for lung metastasis was 16% vs 7% for non-lung origin. All TUM- patients received RT and prior chemotherapy, immunotherapy, or both.

CONCLUSION

For all previously irradiated metastasis, pathology demonstrated a 12% rate of TUM-. As all cases necessitated surgery, the adverse event grading would be ≥ Gr 4. These findings highlight the importance of pathologic confirmation before undertaking re-irradiation for presumed radiographic recurrence.
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