Table 1. Common LMD etiologies.

Primary-Specific Characteristics of LMD
Primary Cancer	Prevalence of LMD	Prognosis	Additional Treatment Modalities
Melanoma	30–75%	Median: 6.9 months	BRAF inhibitors (Vemurafenib and Dabrafenib) and Checkpoint inhibitors (Ipilimumab and Nivolumab) improved survival (16.9 weeks vs. 2.9 weeks) in prospective studies
NHL	5–30%	Median: 2.6 months	IT Rituxumab in Phase 1 studies. Prophylaxis with IT chemotherapy.
NSCLC	9–25%	Median: 3.5 months	EGFR TKI improved survival if EGFR+ in multiple case reports
Breast Cancer	5%	Median: 4.2 months (longer if hormone receptor positive)	High-Dose MTX trial (NCT02422641) pending. IT Trastuzumab if HER2+.