Abstract P2-20-07: Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience

Background Leptomeningeal carcinomatosis (LMC) is a complication of advanced malignancies wherein metastatic disease invades the meninges of the central nervous system via contiguous spread from bone or brain metastases or hematogenous spread from systemic disease. Breast cancer is the most common solid tumor etiology of LMC. Approximately 5% of patients (pts) with breast cancer develop LMC. LMC has a median survival of 4 weeks when untreated and 8-16 weeks with treatment. The diagnosis of LMC remains challenging with only 60% of pts having cerebrospinal fluid (CSF) positive for malignant cells. There is no generally accepted standard of care for treatment of LMC but it may involve intrathecal or systemic chemotherapy, whole brain or spinal radiotherapy, or a combination of modalities. We aimed to assess detection and treatment strategies of LMC in pts with breast cancer treated at the Ohio State University Comprehensive Cancer Center-James (OSUCCC-James) to better characterize the disease and guide clinical care. Methods An IRB-approved single-institution retrospective protocol was developed. Medical records of 469 pts who had undergone a procedure related to LMC diagnosis or treatment were identified and reviewed to determine study eligibility. Comprehensive data was obtained through information warehouse and chart review was performed for the eligible 69 pts with breast cancer diagnosed with LMC and treated at the OSUCCC-James between January 1, 2005 and December 31, 2015. Descriptive statistics were used to summarize demographic and clinical characteristics. Overall survival (OS) was defined as time from LMC diagnosis to death or last known follow-up, and was generated using Kaplan Meier methods. Comparisons in OS between groups were analyzed using Log-rank tests. Results Sixty-nine female pts were included in the analysis with the following characteristics: median age 55.7 years (range: 48-60.6 years), Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 (86%; N=59), and Caucasian (78%; N=54). They had the following subtypes hormone receptor positive (HR +), and human epidermal growth factor receptor (HER2) negative (61%, N=42), triple negative (25%, N=17) and HER2 positive (10%, N=7). The most common sites of metastases included bone (42%), brain (28%), and lung (12%). The median time between the diagnosis of first metastasis and LMC was 0.9 years (range: 0-3.2 years). Of the 40 (58%) pts who underwent lumbar puncture, 21 (52%) pts had positive CSF cytology. Sixty-eight pts (99%) had MRI findings suggestive of LMC. The most common treatment modalities were systemic chemotherapy (N=14, 41%), radiotherapy (N=12, 35%), and intrathecal chemotherapy (N=14, 35%). Fifty-six pts (81%) had a change in systemic chemotherapy agent after diagnosis. The median OS of all pts was 2.4 months (95% confidence interval: 1.2-4.4). Pts with ER+/PR+/HER2- had a better OS (4.4 months, 95%CI 1.5, 6.1)) compared to those with HER2+ (1.3 months, 95%CI 0.2, 1.9) or ER-/PR-/HER2- (0.6 months, 95%CI 0.0, 15.8) subtypes (p-value=0.004). Pts with negative CSF cytology had a greater OS compared to those with positive CSF cytology (9.8 vs. 0.7 months, p=0.026) and pts who had a change in systemic treatment had a greater OS compared with patients who had no new treatment (2.5 months vs. 1.2 months, p =0.039). No significant difference was seen in OS between ECOG performance status groups. Conclusions LMC is a relatively rare yet devastating complication of breast cancer. Based on our institutional experience, LMC remains a clinical challenge and is associated with poor OS. Pts with triple negative and HER2 positive disease and those with high disease burden fare worse. Pts who had change in systemic therapy fare better. Dedicated clinical trials are urgently needed to improve outcomes. Citation Format: Hannah Rinehardt, Nicole Williams, Evan Morgan, Mahmooud Kassem, Marilly Palettas, Abdul Miah, Iyad Alnahhas, Pilar Guillermo Prieto Eibl, Anupama Suresh, Vinay Puduvalli, Pierre Giglio, Maryam Lustberg, Robert Wesolowski, Sagar Sardesai, Daniel Stover, Jeffrey VanDeusen, Jose Bazan, Bhuvaneswari Ramswamy, Anne Noonan. Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-20-07.