Search

2527 Background: Isolated central nervous system (CNS) progression on first-line systemic therapy with Trastuzumab (T) and Pertuzumab (P) for HER2-positive metastatic breast cancer (MBC) is a therapeutic challenge. Our aim was to describe the clinical outcome and current treatment strategies for such patients in a large retrospective cohort. Methods: Patients (pts) were selected among all MBC pts included in the French Epidemiological Strategy and Medical Economics (ESME) database involving 18 specialized cancer centers (NCT03275311). CNS progression-free survival (CNS-PFS), progression-free survival (PFS) and overall survival (OS) from diagnostic of brain metastases (BM) were estimated using the Kaplan-Meier method. Results: Between January 2008 and December 2016, 995 pts were treated with first-line T and P for their HER2-positive MBC. They were 55 years old in median, with tumors expressing hormone-receptors in 62%. A total of 132 pts (13%) experienced isolated CNS progression on T and P, with a median time from metastatic diagnosis to CNS progression of 12 months. It was the first CNS progression for 108 pts (82%) while 24 (18%) already had BM at time of metastatic relapse. After CNS progression, T and P were continued for 58% of pts (n = 73). The remaining 47 pts were switched to another HER2-directed therapy (T-DM1 for 57%, T alone or combined with chemotherapy for 36% and lapatinib for 21%). Among those 132 pts, 37% received whole-brain radiotherapy, 18% stereotactic radiation therapy, and 11% surgery. Systemic treatment was combined with CNS-directed therapy for 50% of pts. Median follow-up is 21 months (95%CI: 14.9-25.5) from the diagnosis of CNS metastases. Median OS (mOS) of the 132 pts is 35 months (95%CI: 29.2-53,6), and median PFS 7 months (95%CI: 6.3- 9.2). A total of 77 pts (58.3%) experienced a new CNS progression with a median CNS-PFS of 9 months (95%CI: 7.6-12,0). Patient who stayed on T and P had a significantly better OS in comparison to pts who were switched to another systemic HER2-directed therapy (mOS not evaluable vs23 months), whereas PFS and CNS-PFS were similar between groups. Conclusions: In this real life setting, isolated CNS progression occurred among 13% of pts with HER2+ MBC on first-line treatment with T and P, after a median time of 12 months. Following current ASCO recommendations, continuation of T and P after CNS-directed therapy, seemed to be adequate. Nevertheless, time to subsequent progression is short and better therapeutic options are needed.

2526 Background: Despite clinical implications, the complexity of brain metastases (BM) immune microenvironment in breast cancer (BC) patients is poorly understood. Multiplex immunofluorescence (mIF), a novel imaging technique allowing simultaneous visualization and quantification of several IF labeled proteins while maintaining spatial information, holds promise to comprehensively describe BCBM immune microenvironment, potentially providing valuable information to improve treatment. Methods: Clinical data and archival BM samples were collected for 60 BC patients undergoing neurosurgery (2003-2018) at three institutions. BM immune contexture was characterized using a custom mIF panel, including cell subtyping (CD4, CD8, FOXP3, CD68), activation (Granzyme B) and localization (keratin for tumor recognition) markers. Mean immune cell density (cells/mm2) for each sample was determined by digital image analysis and classified in tumor and stroma areas. Associations between immune subpopulations, BC subtype and overall survival from BM diagnosis (OS) were studied. Results: Up to date, 30 BCBM samples have been analyzed; 33% HR+/HER2-, 20% HR-/HER2+, 10% HR+/HER2+, 37% HR-/HER2-. At a median follow-up of 46 months, BC subtype was the only clinical variable associated with OS (longest for HER2+ and shortest for HR-/HER2-, log-rank p = 0.002). In the total sample area, no significant difference in immune cell densities was observed according to BC subtype. In the tumor area, HR+/HER2- tumors showed higher densities of CD8+ and CD68+ cells compared to other subtypes (p = 0.036 and p = 0.016, respectively). In stroma, HR-/HER2- tumors presented numerically higher densities of CD4+ and FOXP3+ cells and higher ratio of CD4/CD8 and FOXP3/CD8 ratio (not statistically significant). Higher CD4/CD8 and FOXP3/CD8 ratio in the stroma was significantly associated with worse OS, even after correction by BC subtype (Table). Conclusions: In BCBM, immune infiltrate differs according to BC subtype. Preliminary results suggest that a more tolerogenic immune microenvironment is associated with worse OS and might represent a target for optimization of immunotherapy for these patients. Updated results for all 60 patients will be presented. [Table: see text]

e13005 Background: This work describes oncological patterns of care and survival for all patients (pts) with newly diagnosed histologically confirmed glioblastoma (GB) in metropolitan France in 200...

e13051 Background: National brain tumor registries exist only in few countries, and systematic brain tumor declaration is not mandatory in many countries. Here we propose an easy method to build a ...

2067 Background: Diffuse WHO grade II and III gliomas (DGII/IIIG) are rare tumors (incidence ≤ 2/105person-years). Specific epidemiological studies are very rare. The main objective of this work is to study the geographical distribution of all newly diagnosed and histologically confirmed DGII/IIIG in metropolitan France. Methods: The methodology is based on a multidisciplinary national network already established by the French Brain Tumor DataBase. Personal addresses at the moment of the surgical procedure for all DGII/IIIG cases were collected for the years 2006-2009. For each area, the incidence of DGII/IIIG was analyzed and standardized on age and sex distribution of the French population (pop). Results: The total number of patients with newly diagnosed and histologically confirmed DGII/IIIG was 4790 (1220, 1190, 1228, and 1152 for years 2006-2009). The Table shows the number of tumors by histology, sex and median age at diagnosis. The overall crude rate was 19.4/106. To enable international comparisons, standardized rates were calculated as follows: 19.8/106 (reference pop, Europe), 18.8/106 (reference pop, US 2000), and 16.0/106 (reference pop, world). The geographic distribution by regions in France showed significant differences. For example, the standardized rates (for 106person-years, 95% confidence intervals, reference pop: France) for Auvergne, Champagne-Ardenne, and Basse-Normandie, were 30.9 (26.4-35.5), 28.5 (24.0-33.0), and 13.9 (10.9-17.0), respectively. Conclusions: To our knowledge, this work is the first to study the geographical distribution of DGII/IIIG across one entire country, and it shows significant heterogeneity. These results will enable to look for different environmental and genetic factors in these different regions. [Table: see text]