Table 1. Patients characteristics.

Characteristics	N non-missing	Overall (N=969)	1st comparison				2nd comparison
			Lobectomy (N=846)	Sub-lobar resection (N=123)	P value*		SND (N=455)	LS-ND (N=98)	NS (N=416)	P value*
Age	969				0.002					0.009
≤70 years		597 [62]	537 [63]	60 [49]			297 [65]	48 [49]	252 [61]
>70 years		372 [38]	309 [37]	63 [51]			158 [35]	50 [51]	164 [39]
Gender	969				0.753					0.426
Female		311 [32]	270 [32]	41 [33]			154 [34]	27 [28]	130 [31]
Male		658 [68]	576 [68]	82 [67]			301 [66]	71 [72]	286 [69]
Smokers	969				0.547					0.043
No		370 [38]	320 [38]	50 [41]			180 [40]	26 [27]	164 [39]
Yes		599 [62]	526 [62]	73 [59]			275 [60]	72 [73]	252 [61]
pTNM stage	969				0.251					<0.001
Ia		641 [66]	554 [65]	87 [71]			271 [60]	71 [72]	299 [72]
Ib		328 [34]	292 [35]	36 [29]			184 [40]	27 [28]	117 [28]
Vascular invasion	815				0.08					<0.001
No		643 [79]	567 [80]	76 [72]			342 [78]	59 [65]	242 [85]
Yes		172 [21]	143 [20]	29 [28]			98 [22]	32 [35]	42 [15]
Histologic predominant pattern	959				0.196					0.127
Lepidic		124 [13]	102 [12]	22 [18]			54 [12]	17 [17]	53 [13]
Common variants		762 [79]	671 [80]	91 [74]			365 [81]	79 [81]	318 [78]
NOS—other variants		73 [8]	63 [8]	10 [8]			34 [8]	2 [2]	37 [9]
Histologic grade	955				0.131					0.542
G1		202 [21]	170 [20]	32 [27]			90 [20]	17 [18]	95 [23]
G2		484 [51]	422 [51]	62 [52]			238 [53]	51 [53]	195 [48]
G3		269 [28]	243 [29]	26 [22]			124 [27]	29 [30]	116 [29]

*, χ² test or Fisher’s exact test. NS, lymph node sampling; LS-ND, lobe-specific lymph node dissection; SND, systematic nodal dissection.