Table 2.

Cumulative smoking dose and EGFR mutation

Smoking dose (pack‐years [PY])	Number	EGFR mutation (%)	P‐values*
0 (Never‐smokers)	375	223 (59.5)
0 < PY ≤ 10	29	12 (41.2)	0.070
10 < PY ≤ 20	42	12 (28.6)	0.0002
20 < PY ≤ 40	181	28 (15.5)	<0.0001
40 < PY ≤ 60	187	20 (10.7)	<0.0001
60 < PY	187	19 (10.1)	<0.0001

^* The difference was examined between pack‐year categories and never‐smokers. EGFR, epidermal growth factor receptor.