Prognostic value of preoperative weight loss-adjusted body mass index on survival after esophagectomy for esophageal squamous cell carcinoma

Table 1 Clinical characteristics of the entire patient cohort

Characteristics	Values
Age in yr	59.8 ± 8.4
Sex
Male	1288 (83.4%)
Female	257 (16.6%)
BMI in kg/m2
< 18.5	212 (13.8%)
18.5-24.9	1144 (74.0%)
25.0-29.9	172 (11.1%)
≥ 30.0	17 (1.1%)
Weight change
Weight stable	986 (63.8%)
Weight loss	559 (36.2%)
Tumor location
Upper	133 (8.6%)
Middle	938 (60.7%)
Lower	386 (25.0%)
Cardia	88 (5.7%)
Histological grade
Well differentiated	57 (3.7%)
Moderately differentiated	625 (40.5%)
Poorly differentiated	789 (51.1%)
Others	74 (4.8%)
T stage
Tis	38 (2.5%)
T1	187 (12.1%)
T2	292 (18.9%)
T3	731 (47.3%)
T4a	297 (19.2%)
N stage
N0	891 (57.7%)
N1	374 (24.2%)
N2	217 (14.0%)
N3	63 (4.1%)
Surgical approach
Sweet	1256 (81.3%)
Ivor-Lewis	146 (9.4%)
McKeown	143 (9.3%)
Lymphovascular invasion
Yes	75 (4.9%)
No	1470 (95.1%)
Adjuvant therapy
Yes	575 (37.2%)
No	970 (62.8%)

Table 2 Optimal cut-off point for body mass index

Deciles of BMI	χ2	HR	95%CI	P value
1 vs 2-10	14.5	1.5	1.2-1.8	0.000
1-2 vs 3-10	15.9	1.4	1.2-1.6	0.000
1-3 vs 4-10	24.5	1.4	1.2-1.6	0.000
1-4 vs 5-10	21.6	1.4	1.2-10.6	0.000
1-5 vs 6-10	18.6	1.3	1.2-1.5	0.000
1-6 vs 7-10	15.1	1.3	1.1-1.5	0.000
1-7 vs 8-10	14.1	1.3	1.1-1.5	0.000
1-8 vs 9-10	7.5	1.3	1.1-1.5	0.006
1-9 vs 10	6.2	1.3	1.1-1.7	0.013

BMI: Body mass index; HR: Hazard ratio; 95%CI: 95% Confidence interval.

Table 3 Optimal cut-off point for preoperative weight loss

Deciles of PWL	χ2	HR	95%CI	P
ws vs all	19.2	1.3	1.2-1.5	0.000
ws + 10 vs 1-9	17.9	1.3	1.2-1.5	0.000
ws + 10-9 vs 1-8	20.3	1.4	1.2-1.6	0.000
ws + 10-8 vs 1-7	23.9	1.4	1.2-1.6	0.000
ws + 10-7 vs 1-6	26.1	1.5	1.3-1.7	0.000
ws + 10-6 vs 1-5	24.8	1.5	1.3-1.7	0.000
ws + 10-5 vs 1-4	34.4	1.6	1.4-1.9	0.000
ws + 10-4 vs 1-3	48.4	1.8	1.5-2.2	0.000
ws + 10-3 vs 1-2	35.5	1.9	1.5-2.3	0.006
ws + 10-2 vs 1	14.8	1.8	1.3-2.4	0.013

ws: weight stable; PWL: Preoperative weight loss; HR: Hazard ratio; 95%CI: 95% Confidence interval.

Table 4 Combined analysis of preoperative weight loss and body mass index (sample size)

	BMI in kg/m2
PWL, %	≥ 20	< 20
0-8.8	1033	351
≥ 8.8	70	99

PWL: Preoperative weight loss; BMI: Body mass index.

Table 5 Combined analysis of preoperative weight loss and body mass index (median overall survival, mo)

	BMI in kg/m2
PWL, %	≥ 20	< 20
0-8.8	45.3	29.5
≥ 8.8	23.5	17.4

PWL: Preoperative weight loss; BMI: Body mass index.

Table 6 Combined analysis of preoperative weight loss and body mass index (unadjusted estimated hazard ratios)

	BMI in kg/m2
PWL, %	≥ 20	< 20
0-8.8	1	1.289 (1.105-1.505)
≥ 8.8	1.913 (1.453-2.519)	2.02 (1.592-2.567)

PWL: Preoperative weight loss; BMI: Body mass index.

Table 7 Predictors of overall survival in univariable and multivariable analyses

Variables	Univariate analyses			Multivariate analyses
	HR	95%CI	P value	HR	95%CI	P value
Age	1.16	1.00-1.33	0.038	1.11	0.97-1.27	0.136
Sex, M/F	1.32	1.10-1.58	0.002	1.19	0.99-1.43	0.066
TNM stage	2.56	2.24-2.92	0.000	2.52	2.20-2.89	0.000
Adjuvant therapy	0.86	0.75-0.98	0.027	0.75	0.66-0.86	0.000
Group 1	1
Group 2	1.29	1.11-1.51	0.001	1.19	1.02-1.39	0.030
Group 3	1.96	1.62-2.37	0.000	1.63	1.35-1.98	0.000

HR: Hazard ratio; 95%CI: 95% Confidence interval.