Table 1.

Patient characteristics

Patient characteristics	Total number n=81 (%)	Matched n=22 (%)	Non-matched n=59 (%)	P value (matched vs. non-matched)
Median age, years (range)	54 (22-74)	54 (37-74)	54 (22-73)	/
Sex
Female	37 (45.7%)	11 (50%)	26 (44.1%)	0.6
Male	44 (54.3%)	11 (50%)	33 (55.95)
Smoking status
Never	61 (75.3%)	18 (81.8%)	43 (72.9%)	0.4
Former	20 (24.7%)	4 (18.2%)	16 (27.1%)
Histology type
Adenocarcinoma	79 (97.5%)	22 (100%)	57 (96.6%)	1.0
Adenosquamous	2 (2.5%)	0	2 (3.4%)
EGFR mutation status
19DEL	39 (48.1%)	13 (59.1%)	26 (44.1%)	0.2
21L858R	34 (42.0%)	9 (40.9%)	25 (42.4%)
Others*	8 (9.9%)	0	8 (13.5%)
Concurrent brain metastases
Yes	59 (72.8%)	13 (59.1%)	46 (78%)	0.09
No	22 (27.2%)	9 (40.9%)	13 (22%)
No. of extracranial metastases
0–1	48 (59.3%)	15 (68.2%)	33 (55.9%)	0.3
≥2	33 (40.7%)	7 (31.8%)	26 (44.1%)
ECOG-PS
0–1	44 (54.3%)	11 (50%)	33 (55.9%)	0.6
≥2	37 (45.7%)	11 (50%)	26 (44.1%)
No. of prior systemic therapies	3 (1-7)	2 (1-7)	2 (1-4)	0.4
Prior brain radiotherapy
Yes	25 (30.9%)	6 (27.3%)	19 (32.2%)	0.7
No	56 (69.1%)	16 (72.7%)	40 (67.8%)
LM status
PD on pre-existing LM	49 (60.5%)	11 (50%)	38 (64.4%)	0.2
First diagnosis of LM	32 (39.5%)	11 (50%)	21 (35.6%)
Progression mode on osimertinib
CNS-only progression	67 (82.7%)	18 (81.8%)	49 (83.1%)	1.0
Systemic progression	14 (17.3%)	4 (18.2%)	10 (16.9%)

*EGFR G719X, L747P, S768I, and exon 20 insertion

ECOG-PS Eastern Cooperative Oncology Group-performance status, TKI Tyrosine kinase inhibitor, osimer osimertinib, LM leptomeningeal metastases; PD progression