The Evolving Landscape of Leptomeningeal Cancer from Solid Tumors: A Systematic Review of Clinical Trials

SIMPLE SUMMARY: Leptomeningeal carcinomatosis is a devastating complication of solid malignancies and can occur concurrently in patients with brain metastasis. Despite progress in the treatment of brain metastasis, the survival of patients with leptomeningeal cancer remains stagnant. In the present work, we aimed to conduct a systematic review to evaluate outcome measures, complications, adverse effects, and limitations of therapies explored, with the objective to critically evaluate previous treatments as well as discuss the landscape of ongoing clinical trials for leptomeningeal carciomatosis. ABSTRACT: Leptomeningeal carcinomatosis (LMC) is a fatal but uncommon complication occurring in 5–15% of patients with stage IV cancer. Current treatment options are ineffective at managing leptomeningeal spread, with a median overall survival (mOS) of 2–6 months. We aimed to conduct a systematic review of the literature to identify past and future therapies for LMC from solid tumors. Forty-three clinical trials (CTs) published between 1982–2022 were identified. Of these, 35 (81.4%) were non-randomized CTs and 8 (18.6%) were randomized CTs. The majority consisted of phase I (16.3%) and phase II CTs (65.1%). Trials enrolled patients with LMC from various primary histology (n = 23, 57.5%), with one CT evaluating LCM from melanoma (2.4%). A total of 21 trials evaluated a single modality treatment. Among CTs, 23.7% closed due to low accrual. Intraventricular (ITV)/intrathecal (IT) drug delivery was the most common route of administration (n = 22, 51.2%) vs. systemic drug delivery (n = 13, 30.3%). Two clinical trials evaluated the use of craniospinal irradiation for LMC with favorable results. LMC continues to carry a dismal prognosis, and over the years, increments in survival have remained stagnant. A paradigm shift towards targeted systemic therapy with continued standardization of efficacy endpoints will help to shed light on promising treatments.