Table 1.

Demographic, clinicopathologic, and treatment characteristics of study patients

	Training cohort (n = 828)		Validation cohort (n = 312)
Characteristics	No. of patients	%	No. of patients	%
Age, years
Median	67		70
Range	26–95		32–94
Gender
Male	647	78.1	234	75.0
Female	181	21.9	78	25.0
Race
White	767	92.6	288	92.3
Black	31	3.7	13	4.2
Other	30	3.6	11	3.5
Histology
Sarcomatoid	226	27.3	63	20.2
Fibrous	80	9.7	27	8.7
Epithelioid	412	49.8	165	52.9
Biphasic	110	13.3	58	18.6
Differentiation
Well or moderately	28	3.4	7	2.2
Poorly	49	5.9	18	5.8
Undifferentiated	18	2.2	5	1.6
NOS	733	88.5	282	90.4
Chemotherapy
Yes	491	59.3	195	62.5
No	337	40.7	117	37.5
Radiotherapy
Yes	222	26.8	63	20.2
No	606	73.2	249	79.8
Primary tumor location
Bilateral	15	1.8	3	1.0
Left‐sided	313	37.8	109	34.9
Right‐sided	500	60.4	200	64.1
Clinical stage
I	128	15.5	59	18.9
II	151	18.2	53	17.0
III	267	32.2	91	29.2
IV	282	34.1	109	34.9
N stage
N0	540	65.2	201	64.4
N1	111	13.4	100	32.1
N2	142	17.1	4	1.3
N3	11	1.3	2	0.6
NX	24	2.9	5	1.6
T stage
T1	164	19.8	73	23.4
T2	218	26.3	90	28.8
T3	220	26.6	67	21.5
T4	222	26.8	79	25.3
TX	4	0.5	3	1.0
M stage
M0	718	86.7	256	84.9
M1	102	12.3	47	15.1
MX	8	1	0	0.0
Type of surgery
Palliative	568	68.6	235	75.3
Radical	218	26.3	71	22.8
NOS	42	5.1	6	1.9
Lymph node dissection
1–3 removed	65	7.9	21	6.7
≥ 4 removed	271	32.7	89	28.5
None/unknown	492	59.4	202	64.7

NOS, not otherwise specified.