Peritumoral edema measurements provide additional information to RANO-BM based assessment of lung cancer brain metastases after Gamma Knife therapy (P10-13.002)

Abstract

<h3>Objective:</h3> In our study, we aimed to better understand the correlation between post-GK peritumoral edema and CE lesion. <h3>Background:</h3> Gamma Knife (GK) has become standard of care to treat brain metastases (BM), however there is little understanding of the posttreatment volumetric changes of peritumoral edema of BM due to paucity of tools for volumetric segmentation in neuroradiology clinical practice. Recently PACS-integrated tools have become available in select clinical practices, facilitating the comparison of volumetric treatment response curves of peritumoral edema to response curves of RANO-BM based measurements of the contrast-enhancing (CE) tumor core. <h3>Design/Methods:</h3> Patients with NSCLC BM ≥10 mm on post-contrast T1-weighted image and treated with GK had volumetric measurements for up to seven follow-ups using a PACS-integrated tool that segments the FLAIR hyperintense volume surrounding the CE lesion. The 2D and volumetric measurements were compared by creating response curves with incorporation of clinical information including steroid timing. <h3>Results:</h3> Fifty NSCLC BM were included with a median pretreatment metastasis volume of 8.5 cm³ (IQR 1–47 cm³, n=36). A significant decrease was measured at 0–90 days post-GK (median 1.2 cm³, IQR 0.5–6.1 cm³, n=31). The time of peak median peritumoral volume increase was at &gt;365 days (median 1.4 cm³, IQR 0.4–8.1 cm³, n=19). There was a positive correlation between longest diameter (LD) and peritumoral edema volume (r_s=.75, p&lt;.05). At 181–270 days post-GK 50% of BM showed incongruent response course for LD and peritumoral edema volume. The congruence/incongruence ratio of edema to enhancing portion of BM changed over follow-up time. <h3>Conclusions:</h3> Volumetric edema assessment of BM post-GK provides critical additional information as compared to RANO-BM based response curves. <b>Disclosure:</b> Miss Kaur has nothing to disclose. Mr. Cassinelli Petersen has nothing to disclose. Mr. Von Reppert has nothing to disclose. Mr. Jekel has nothing to disclose. Dr. Varghese has nothing to disclose. Dr. Dixe de Oliveira Santo has nothing to disclose. Dr. Omuro has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Merck. Dr. Omuro has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ono Therapeutics. Dr. Omuro has received personal compensation in the range of $0-$499 for serving as a Consultant for Kiyatec. Dr. Omuro has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Pyramic. Dr. Omuro has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Curevac. Dr. Omuro has received personal compensation in the range of $0-$499 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Current Opinion in Neurology. The institution of Dr. Omuro has received research support from NIH. The institution of Dr. Omuro has received research support from Agios. The institution of Dr. Omuro has received research support from Arcus Biosciences. The institution of Dr. Omuro has received research support from NIH. The institution of Dr. Omuro has received research support from NIH. The institution of Dr. Omuro has received research support from Denovo Biopharma. Dr. Chiang has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for monteris medical inc. Dr. Aboian has a non-compensated relationship as a Principal Investigator with Visage Imaging that is relevant to AAN interests or activities.