Magnetic resonance imaging-based deep-learning radiomics score for survival prediction and risk stratification in pediatric hepatoblastoma receiving surgical resection

Table 1 Demographic characteristics of hepatoblastoma patients receiving surgical resection in the training and testing cohorts, n (%)

Variable	All subjects (n = 106)	Training set (n = 74)	Testing set (n = 32)	P value
Age, median (IQR)	2.1 (0.6)	2.1 (0.6)	2.0 (0.6)	0.397
Gender				0.478
Male	84 (79.2)	60 (81.1)	24 (75.0)
Female	22 (20.8)	14 (18.9)	8 (25.0)
Histological subtype				0.938
Mixed epithelial/mesenchymal	58 (54.7)	41 (55.4)	17 (53.1)
Fetal	44 (41.5)	30 (40.5)	14 (43.8)
Epithelial mixed	4 (3.8)	3 (4.1)	1 (3.1)
PRETEXT stage				0.275
I	3 (2.8)	1 (1.4)	2 (6.3)
II	52 (49.1)	35 (47.3)	17 (53.1)
III	51 (48.1)	38 (51.4)	13 (40.6)
Maximum tumor size, median (IQR), cm	5.1 (4.0)	5.1 (3.1)	5.5 (4.4)	0.964
Multifocality				0.870
Absent	65 (61.3)	45 (60.8)	20 (62.5)
Present	41 (38.7)	29 (39.2)	12 (37.5)
Local lymph node involvement				0.904
Absent	103 (97.2)	72 (97.3)	31 (96.9)
Present	3 (2.8)	2 (2.7)	1 (3.1)
Serum AFP concentration				0.419
≤ 1000 ng/mL	50 (47.2)	33 (44.6)	17 (53.1)
> 1000 ng/mL	56 (52.8)	41 (55.4)	15 (46.9)
DLBR score1, median (IQR)	0.002 (0.049)	0.002 (0.050)	0.002 (0.058)	0.625

¹Deep learning-based radiomics score was generated based on deep learning features related to specific events in hepatoblastomas.

PRETEXT: 2017 PRE-Treatment EXTent of tumor; AFP: Alpha-fetoprotein; DLBR: Deep learning-based radiomics; IQR: Interquartile range.

Table 2 Predication performance of clinical variables, deep learning-based radiomics score, and integrated nomogram models for prognostication of event-free survival in the training and testing cohorts of hepatoblastoma patients receiving surgical resection

Models	Training set				Testing set
	C-index (95%CI)	IBS (95%CI)	HR (95%CI)	P value	C-index (95%CI)	IBS (95%CI)	HR (95%CI)	P value
Clinical variables
Age	0.443 (0.435-0.450)	0.066 (0.054-0.077)	1.145 (0.546-2.402)	0.720	0.435 (0.426-0.443)	0.040 (0.028-0.052)	1.087 (0.468-2.527)	0.846
Gender	0.517 (0.510-0.524)	0.002 (-0.018-0.023)	1.178 (0.558-2.486)	0.668	0.500 (0.493-0.508)	0.003 (-0.000-0.007)	1.033 (0.423-2.523)	0.944
Histological subtype	0.545 (0.535-0.556)	-0.020 (-0.040 to -0.001)	1.672 (0.390-7.165)	0.377	0.569 (0.556-0.583)	-0.103 (-0.168 to -0.038)	0.784 (0.104-5.911)	0.549
PRETEXT stage	0.633 (0.624-0.642)	-0.963 (-1.063 to -0.863)	2.610 (1.318-5.167)	0.006	0.650 (0.639-0.660)	-1.368 (-1.490 to -1.246)	2.578 (1.181-5.629)	0.017
Maximum tumor size	0.576 (0.561-0.590)	-0.289 (-0.316 to -0.262)	1.108 (0.975-1.259)	0.116	0.622 (0.608-0.636)	-0.898 (-0.962 to -0.833)	1.186 (1.015-1.386)	0.031
Multifocality	0.632 (0.625-0.640)	-0.746 (-0.820 to -0.671)	1.621 (0.862-3.047)	0.134	0.603 (0.592-0.614)	-0.383 (-0.436 to -0.331)	1.309 (0.639-2.680)	0.462
Local lymph node involvement	0.508 (0.506-0.511)	-0.036 (-0.047 to -0.024)	1.289 (0.175-9.490)	0.803	0.511 (0.508-0.514)	-0.091 (-0.109 to -0.073)	1.630 (0.220-12.091)	0.633
Serum AFP concentration	0.620 (0.611-0.629)	-0.827 (-0.912 to -0.741)	2.873 (1.397-5.910)	0.004	0.647 (0.636-0.657)	-1.412 (-1.540 to -1.284)	3.194 (1.370-7.446)	0.007
DLBR score	0.610 (0.599-0.620)	0.246 (0.042-0.449)	0.000 (0.000-0.002)	< 0.001	0.642 (0.633-0.652)	0.378 (0.162-0.593)	0.000 (0.000-0.004)	< 0.001
Clinical modela	0.633 (0.624-0.643)	-0.923 (-1.022 to -0.825)	/	/	0.653 (0.643-0.664)	-1.384 (-1.508 to -1.261)	/	/
Integrated nomogram1	0.669 (0.661-0.677)	-0.634 (-0.894 to -0.375)	/	/	0.696 (0.688-0.704)	-0.760 (-1.017 to -0.503)	/	/

^aThe clinical model was constructed by significant clinical variables, 2017 PRE-Treatment EXTent of tumor stage, and serum alpha-fetoprotein concentration, which were evaluated by multivariate Cox regression analysis with a P value less than 0.05 in the training cohort.

¹The integrated nomogram model was composed of significant clinical variables and the deep learning-based radiomics score.

PRETEXT: 2017 PRE-Treatment EXTent of tumor; AFP: Alpha-fetoprotein; DLBR: Deep learning-based radiomics; CI: Confidence interval; IBS: Integrated Brier score; HR: Hazard ratio.

Table 3 Time-dependent area under the receiver operating characteristic curve value of clinical variables, deep learning-based radiomics score, and integrated nomogram models for prognostication of event-free survival in the training and testing cohorts of hepatoblastoma patients receiving surgical resection

Models	Training set			Testing set
	1-year AUC (95%CI)	3-year AUC (95%CI)	5-year AUC (95%CI)	1-year AUC (95%CI)	3-year AUC (95%CI)	5-year AUC (95%CI)
Clinical variables
PRETEXT stage	0.615 (0.496-0.733)	0.631 (0.526-0.736)	0.625 (0.522-0.729)	0.653 (0.523-0.784)	0.649 (0.530-0.768)	0.639 (0.521-0.756)
Serum AFP concentration	0.586 (0.465-0.708)	0.632 (0.528-0.736)	0.624 (0.521-0.728)	0.635 (0.503-0.766)	0.663 (0.549-0.777)	0.650 (0.536-0.765)
DLBR score	0.539 (0.406-0.672)	0.589 (0.471-0.707)	0.609 (0.493-0.724)	0.588 (0.430-0.746)	0.615 (0.480-0.750)	0.641 (0.509-0.772)
Clinical model	0.607 (0.484-0.730)	0.637 (0.533-0.742)	0.631 (0.528-0.734)	0.650 (0.516-0.783)	0.660 (0.544-0.777)	0.649 (0.533-0.765)
Integrated nomogram	0.606 (0.471-0.742)	0.654 (0.537-0.771)	0.660 (0.544-0.775)	0.661 (0.509-0.814)	0.678 (0.548-0.808)	0.685 (0.556-0.813)

PRETEXT: 2017 PRE-Treatment EXTent of tumor; AFP: Alpha-fetoprotein; DLBR: Deep learning-based radiomics; CI: Confidence interval; AUC: Area under the receiver operating characteristic curve.

Table 4 Kaplan-Meier analysis of deep learning-based radiomics score stratified by significant clinical variables for prognostication of event-free survival in the training and testing cohorts of hepatoblastoma patients receiving surgical resection

Variable	DLBR score group	Training dataset			Testing dataset
		Mean survival time, month	95%CI, month	Log-rank test	Mean survival time, month	95%CI, month	Log-rank test
DLBR score				< 0.001			< 0.001
Low score	/	104.83	93.85-115.81		106.73	94.27-119.19
High score	/	71.58	58.61-84.55		61.74	46.55-76.92
PRETEXT stage				< 0.001			< 0.001
I + II	Low score	107.21	96.65-117.78	0.005	111.95	102.30-121.61	< 0.001
	High score	84.64	65.49-103.79		73.50	50.16-96.84
III	Low score	93.30	71.48-115.12	0.012	93.63	69.51-117.74	0.003
	High score	63.11	46.49-79.74		53.88	34.40-73.37
Serum AFP concentration				< 0.001			< 0.001
≤ 1000 ng/mL	Low score	106.58	95.37-117.79	0.021	111.95	102.30-121.61	0.001
	High score	87.12	66.36-107.89		73.58	47.39-99.78
> 1000 ng/mL	Low score	96.10	76.09-116.12	0.005	93.63	69.51-117.74	0.003
	High score	63.58	47.69-79.46		55.32	36.93-73.71

PRETEXT: 2017 PRE-Treatment EXTent of tumor; AFP: Alpha-fetoprotein; DLBR: Deep learning-based radiomics; CI: Confidence interval.