Table 2. Incidence of CNS PD in gefitinib and erlotinib treatment groups.

Characteristics	Gefitinib	Erlotinib	P
All patients, % (n)	29.9% (43/144)	11.5% (3/26)	0.06
Patients without CNS metastasis before EGFR-TKI, % (n)	24.5% (26/106)	4.8% (1/21)	0.04

CNS, central nervous system; PD, progressive disease; EGFR, epidermal growth factor receptor; TKI, tyrosine kinase inhibitor.