Development of a Prognostic Score in Patients With Advanced Breast Cancer Treated for Meningeal Carcinomatosis

Purpose: Meningeal carcinomatosis (MC) has a dismal prognosis in patients with breast cancer and requires invasive therapies. The aim of the present retrospective study was to determine a prognostic score for overall survival (OS) in patients with breast cancer and treated for MC. Methods: The data of 109 patients with proven breast cancer MC treated with at least one intrathecal (IT) injection of methotrexate or thiotepa at Institut Curie were retrospectively recorded from 2011 to 2019. We developed prognostic clinical scores for OS and 24-week survival. Results: The diagnosis and evaluation of MC were based on a combination of clinical, imaging, and laboratory studies. Three significant prognostic factors for OS were identified. Clinical response or stabilization after one month of IT therapy had a favorable independent prognostic value for both OS and 24-week survival. Additionally, a baseline CSF Cyfra 21-1 concentration lower than 79 ng/mL in the cerebrospinal fluid (CSF) and the absence of 1-month CSF malignant cells had borderline favorable independent prognostic value for OS and 24-week survival, respectively. We constructed 2-class and 3-class prognostic scores for each outcome, identifying a population with a very poor prognosis. Conclusions: To our knowledge, this is the first study to develop a response-based prognosis score for patients with breast cancer-related MC. This one-month prognostic score may help to determine which patient could actually benefit from prolonged IT therapy.