Prognostic value of early changes in artificial intelligence-based computed tomography-measured body composition in pediatric osteosarcoma receiving neoadjuvant chemotherapy

Table 1 Demographic and clinical characteristics, n (%)/median (interquartile range)

Variable	Overall (n = 133)
Age, years	15 (4)
Gender
Male	72 (54.1)
Female	61 (45.9)
Location
Axial	21 (15.8)
Pelvis	-14 (10.5)
Spine	-7 (5.3)
Limb	112 (84.2)
Distal femur	-52 (39.1)
Proximal tibia	-38 (28.6)
Proximal humerus	-14 (10.5)
Others	-8 (6.0)
Maxium tumor length, cm	10.0 (7.0)
BMI, kg/m2	18.36 (4.59)
Pre-chemotherapy indexes
VATI, cm2/m2	10.13 (11.80)
SATI, cm2/m2	16.57 (24.05)
SMI, cm2/m2	34.20 (12.75)
SMD, HU	45.66 (7.72)
Albumin, g/L	43.3 (5.4)
Platelet count, 109/L	238 (141)
Neutrophil count, 109/L	4.07 (3.20)
Lymphocyte count, 109/L	1.57 (0.91)
ALP, g/L	155 (153)
SII	642.6 (689.6)
PNI	51.15 (5.48)
Post-chemotherapy indexes
VATI, cm2/m2	10.41 (14.15)
SATI, cm2/m2	17.03 (25.44)
SMI, cm2/m2	34.05 (11.72)
SMD, HU	44.75 (8.06)
Albumin, g/L	39.9 (7.7)
Platelet count, 109/L	227 (145)
Neutrophil count, 109/L	5.96 (5.13)
Lymphocyte count, 109/L	1.33 (0.90)
ALP, g/L	125 (123)
SII	1240.1 (1341.0)
PNI	46.03 (10.55)
ΔVATI, cm2/m2/30 days	1.29 (5.57)
ΔSATI, cm2/m2/30 days	1.27 (7.94)
ΔSMI, cm2/m2/30 days	0.68 (3.85)
ΔSMD, HU/30 days	1.01 (3.36)
ΔSII, score/30 days	754.1 (1416.4)
ΔPNI, score/30 days	6.38 (9.16)
Histopathological response to neoadjuvant chemotherapy
Non-responder	20 (15.0)
Responder	113 (85.0)

Δ: Body compartment area change per 30 days. BMI: Body mass index; VATI: Visceral adipose tissue index; SATI: Subcutaneous adipose tissue index; SMI: Skeletal muscle index; SMD: Skeletal muscle density; HU: Hounsfield unit; ALP: Alkaline phosphatase; SII: Systemic immune-inflammation index; PNI: Prognostic nutritional index.

Table 2 Results of multivariant logistic regression analysis for the association between changes in body compartment measurements and histopathological response to neoadjuvant chemotherapy

Variable	P value1	Coefficient2	SE	Wald χ2	HR	95%CI
Age, years	0.031	0.254	0.118	4.640	1.289	1.023-1.625
Maxium tumor length, cm	0.067	0.073	0.040	3.352	1.075	0.995-1.162
Post-chemotherapy SII	0.032	-0.001	0.000	4.590	0.999	0.999-1.000
ΔSMD, HU/30 days	0.017	0.153	0.064	5.726	1.165	1.028-1.321
Constant	0.002	-5.993	1.939	9.558	0.002	-

¹Based on likelihood test adjusted for the other factors in the final mode.

²Estimated coefficient for the variable and the associated standard error.

Δ: Body compartment area change per 30 days; HR: Hazard ratio; CI: Confidence interval; SII: Systemic immune-inflammation index; SMD: Skeletal muscle density; HU: Hounsfield unit.

Table 3 Univariable and multivariable analysis for the association between changes in body compartment measurements and overall survival

Variable	Univariable analysis		Multivariable analysis
	HR (95%CI)	P value	HR (95%CI)	P value
Age	1.094 (0.949-1.261)	0.214
Gender		0.528
Male	Reference
Female	0.788 (0.375-1.654)
Location		0.885
Trunk	Reference
Limb	0.931 (0.354-2.449)
Maxium tumor length	1.020 (0.966-1.076)	0.478
BMI	1.038 (0.948-1.137)	0.421
Pre-chemotherapy indexes
VATI	1.004 (0.974-1.035)	0.783
SATI	1.000 (0.982-1.019)	0.966
SMI	1.033 (0.999-1.069)	0.057	1.041 (1.003-1.081)	0.033
SMD	1.035 (0.976-1.097)	0.250
ALP	1.001 (1.000-1.002)	0.043	0.999 (0.997-1.001)	0.172
SII	1.000 (1.000-1.001)	0.138
PNI	0.922 (0.872-0.976)	0.005	0.929 (0.872-0.989)	0.022
Post-chemotherapy indexes
VATI	1.000 (0.968-1.033)	0.996
SATI	0.999 (0.980-1.017)	0.874
SMI	1.018 (0.975-1.062)	0.418
SMD	1.026 (0.962-1.094)	0.441
ALP	1.002 (1.001-1.003)	0.001	1.003 (1.001-1.005)	0.007
SII	1.000 (1.000-1.000)	0.385
PNI	1.001 (0.955-1.050)	0.953
ΔVATI	1.005 (0.940-1.075)	0.881
ΔSATI	1.036 (0.998-1.076)	0.063	1.010 (0.970-1.051)	0.634
ΔSMI	1.032 (0.979-1.088)	0.240
ΔSMD	1.115 (1.042-1.193)	0.002	1.113 (1.035-1.197)	0.004
ΔSII	1.000 (1.000-1.001)	0.181
ΔPNI	0.970 (0.914-1.029)	0.313

Δ: Body compartment area change per 30 days. HR: Hazard ratio; CI: Confidence interval; BMI: Body mass index; VATI: Visceral adipose tissue index; SATI: Subcutaneous adipose tissue index; SMI: Skeletal muscle index; SMD: Skeletal muscle density; ALP: Alkaline phosphatase; SII: Systemic immune-inflammation index; PNI: Prognostic nutritional index.

Table 4 Kaplan-Meier analysis for the association between independent predictors and overall survival

Variable	Cut-off point	Group	Median survival time (95%CI)	Log rank test
Pre-chemotherapy SMI	48.86 cm2/m2	Low	88.297 (77.206-99.388)	0.066
		High	64.739 (43.620-85.858)
Pre-chemotherapy PNI	50.25	Low	72.654 (57.202-88.107)	0.002
		High	82.702 (73.927-91.478)
Post-chemotherapy ALP	380 g/L	Low	89.401 (78.820-99.981)	0.012
		High	44.397 (28.647-60.148)
ΔSMD	6.27 HU/30 days	Low	94.657 (86.277-103.037)	0.001
		High	43.356 (29.130-57.581)
Integrated index	-1.09	Low	94.319 (85.826-102.813)	0.010
		High	46.988 (33.710-60.267)

Δ: Body compartment area change per 30 days. CI: Confidence interval; SMI: Skeletal muscle index; PNI: Prognostic nutritional index; ALP: Alkaline phosphatase; SMD: Skeletal muscle density; HU: Hounsfield unit.