Table 1.

Lists the basic information for the two cohorts.

Variable	Training cohort	Validation cohort	p-value
Number of patients n (%)	2711 (70)	1163 (30)
Age of diagnosis	61 (52–71)	61 (53–71)	0.860
Sex n (%)			0.323
Male	1696 (62.6)	747 (64.2)
Female	1015 (37.4)	416 (35.7)
Race n (%)			0.146
White	2292 (84.6)	1003 (86.2)
Black	166 (6.1)	74 (6.3)
Other	253 (9.3)	86 (7.3)
Marital status n (%)			0.371
Married	1535 (56.6)	686 (58.9)
Single	571 (21.0)	227 (19.6)
Other	605 (22.4)	250 (21.5)
Size n (%)			0.456
≤2	1102 (40.6)	471 (40.5)
[2, 4]	871 (32.2)	355 (30.5)
≥4	738 (27.2)	337 (28.9)
AJCC stage n (%)			0.971
I	842 (31.1)	369 (31.7)
II	458 (16.9)	194 (16.6)
III	522 (19.3)	224 (19.3)
IV	889 (32.7)	376 (32.4)
Combined summary stage n (%)			0.229
Localized	1247 (45.9)	558 (47.9)
Regional	1093 (40.4)	435 (37.4)
Distant	371 (13.7)	170 (14.7)
Surgery n (%)			0.706
Yes	2156 (79.6)	911 (78.4)
No/unknown	555 (20.4)	252 (21.6)
Radiotherapy n (%)			0.541
Yes	1416 (52.3)	595 (51.2)
No/unknown	1295 (47.7)	568 (48.8)
Chemotherapy n (%)			0.084
Yes	852 (31.5)	371 (31.9)
No/unknown	1859 (68.5)	792 (68.1)
RX summ—scope reg LNSur n (%)			0.351
Yes	1559 (57.5)	650 (55.8)
No/unknown	1152 (42.5)	513 (44.2)
RX summ—surg/rad seq n (%)			0.783
No radiation	1707 (62.9)	742 (63.8)
Radiation prior to surgery	27 (0.9)	10 (0.8)
Radiation after surgery	956 (35.4)	405 (34.8)
Radiation before and after surgery	21 (0.8)	6 (0.6)
Income n (%)			0.537
<$55,000	496 (18.3)	216 (18.5)
[$55,000, $75,000]	1386 (51.2)	573 (49.3)
>$75,000	829 (30.5)	374 (32.2)

Note. RX summ—scope reg LN sur: regional lymph node dissection after surgery; RX summ—surg/rad seq: surgery and radiation sequence.