Table 4. EGFR mutation subtypes .

Exon Mutation Subtype	N (%)	Stage at Presentation
Exon 19 deletion	63 (44)	Stage 1 = 48 (76%)
		Stage 2 = 7 (11%)
		Stage 3 = 8 (13%)
Exon 20 insertion	7 (5)	Stage 1 = 4 (57%)
		Stage 2 = 0 (0%)
		Stage 3 = 3 (43%)
G719A	2 (1)	Stage 1 = 2 (100%)
		Stage 2 = 0 (0%)
		Stage 3 = 0 (0%)
L858R	49 (35)	Stage 1 = 34 (70%)
		Stage 2 = 5 (10%)
		Stage 3 = 10 (20%)
G719×	6 (4)	Stage 1 = 6 (100%)
		Stage 2 = 0 (0%)
		Stage 3 = 0 (0%)
L861Q	8 (6)	Stage 1 = 7 (88%)
		Stage 2 = 0 (0%)
		Stage 3 = 1 (12%)
T790M	2 (1)	Stage 1 = 2 (100%)
		Stage 2 = 0 (0%)
		Stage 3 = 0 (0%)
Multiple mutations	5 (4)	Stage 1 = 4 (80%)
		Stage 2 = 1 (20%)
		Stage 3 = 0 (0%)