Overall Survival Analyses following Adjuvant Chemotherapy or Nonadjuvant Chemotherapy in Patients with Stage IB Non-Small-Cell Lung Cancer

Table 2

Baseline characteristics of the propensity-score matched population.

	Nonadjuvant chemotherapy (n = 2187)	Adjuvant chemotherapy (n = 2187)	value	Standardized difference
Gender			0.952	0
Male	1005 (46.0%)	1003 (45.9%)
Female	1182 (54.0%)	1184 (54.1%)
Age			0.887	<0.001
<60	576 (26.3%)	564 (25.8%)
61–75	1308 (59.8%)	1322 (60.4%)
≥75	303 (13.9%)	301 (13.8%)
Race			0.678	0.030
White	1855 (84.8%)	1836 (84.0%)
Black	181 (8.3%)	187 (8.6%)
Others	151 (6.9%)	164 (7.4%)
Marital status			0.682	−0.022
Divorced	249 (11.4%)	266 (12.2%)
Married	1333 (59.9%)	1328 (60.7%)
Others	605 (27.7%)	593 (27.1%)
Laterality			0.950	0.003
Left	842 (38.5%)	840 (38.4%)
Right	1345 (61.5%)	1347 (61.6%)
Grade			0.598	0.023
Well/moderate	1163 (53.2%)	1132 (51.8%)
Poor/undifferentiated	903 (41.3%)	935 (42.7%)
Unknown	121 (5.5%)	120 (5.5%)
Pathological subtype			0.845	0.017
Adenocarcinoma	1045 (47.8%)	1027 (47.0%)
Squamous cell carcinoma	407 (18.6%)	411 (18.8%)
Others	735 (33.6%)	749 (34.2%)
Visceral pleural invasion			0.829	<0.001
No	869 (39.7%)	862 (39.4%)
Yes	1318 (60.3%)	1325 (60.6%)
Tumor size (mm)			0.994	<0.001
≤20	469 (21.4%)	470 (21.5%)
21–30	475 (21.7%)	472 (21.6%)
31–40	1243 (56.9%)	1245 (56.9%)
Surgical procedure			0.686	0.013
Lobectomy	1823 (83.3%)	1814 (82.9%)
Segmentectomy	364 (16.7%)	373 (17.1%)
No. of resected lymph nodes			0.288	−0.023
0	182 (8.3%)	214 (9.8%)
1–3	388 (17.7%)	370 (16.9%)
≥4	1518 (69.4%)	1495 (68.4%)
Unknown	99 (4.6%)	108 (4.9%)