Any-LM	Current leptomeningeal involvement, including LM alone and concurrent brain metastasis plus LM
AUROC	Area under the receiver operating characteristic curve
BM	Brain metastasis
BM-only	Brain metastasis without leptomeningeal metastasis
CEA	Carcinoembryonic antigen
CI	Confidence interval
CNS	Central nervous system
CSF	Cerebrospinal fluid
CTC	Circulating tumor cell
CYFRA21-1	Cytokeratin 19 fragment
FLIC	Firth logistic regression with intercept correction
hs-pAUC	Standardized high-specificity partial area under the receiver operating characteristic curve
IQR	Interquartile range
LM	Leptomeningeal metastasis
LUAD	Lung adenocarcinoma
MRI	Magnetic resonance imaging
OOF	Out-of-fold
RCS	Restricted cubic spline
WBC	White blood cell