Table 1.

Clinicopathological characteristics of RCC patients with lung metastases.

Characteristic	Primary cohort (n = 976)		Validation cohort (n = 393)		P value
	No. of patients	%	No. of patients	%
Age (years)					0.72
Median	60		60
Range	54-68		54-68
Sex					0.252
Male	705	72.2	271	69
Female	271	27.8	122	31
Race					0.937
White	831	85.1	335	85.2
Black	64	6.6	24	6.1
Other	81	8.3	34	8.7
Grade					0.928
I	29	3	10	2.5
II	188	19.3	77	19.6
III	405	41.5	158	40.2
IV	354	36.3	148	37.7
Laterality					1
Left	480	49.2	193	49.1
Right	496	50.8	200	50.9
T					0.859
T1a	19	1.9	6	1.5
T1b	82	8.4	29	7.4
T2a	89	9.1	43	10.9
T2b	83	8.5	36	9.2
T3	572	58.6	224	57
T4	131	13.4	55	14
N					0.875
N1	304	31.1	120	30.5
N0	672	68.9	273	69.5
Surgery					0.659
No surgery	231	23.7	84	21.4
PN	19	1.9	8	2
RN	726	74.4	301	76.6
Tumor size (mm)					0.356
Median	95		100
Range	75-120		75-120
Pathological type					0.582
pRCC	28	2.9	12	3.1
ccRCC	697	71.4	288	73.3
RCC, NOS	168	17.2	53	13.5
sRCC	8	0.8	3	0.8
chRCC	63	6.5	30	7.6
CDC	12	1.2	7	1.8
Brain metastasis					0.421
Yes	116	11.9	40	10.2
No	860	88.1	353	89.8
Bone metastasis					<0.001
Yes	116	11.9	78	19.8
No	860	88.1	315	80.2
Liver metastasis					0.523
Yes	131	13.4	47	12
No	845	86.6	346	88
Insurance status					0.93
Yes	936	95.9	378	96.2
No	40	4.1	15	3.8
Marital status					0.115
Unmarried	155	15.9	57	14.5
Married	642	65.8	280	71.2
Negative married	179	18.3	56	14.2

Abbreviations: ccRCC: clear cell renal cell carcinoma; pRCC: papillary renal cell carcinoma; chRCC: chromophobe renal cell carcinoma; sRCC: sarcomatoid renal cell carcinoma; CDC: collecting duct carcinoma.