Predicting pathological complete response to chemoradiotherapy using artificial intelligence-based magnetic resonance imaging radiomics in esophageal squamous cell carcinoma

Table 1 Demographic and clinical factors in pathological complete response and non-pathological complete response groups

	All (n = 70)	pCR (n = 15)	Non-pCR (n = 55)	P value
Age, median (range)	66 (45-78)	64 (52-76)	66 (45-78)	0.97
Gender
Male/female	60/10	12/3	48/7	0.48
Tumor site
Cervical/upper/middle/lower	5/14/33/18	1/5/6/3	4/9/27/15	0.60
TNM staging
cT1/2/3/4	0/2/19/49	0/0/3/12	0/2/16/37	0.56
cN0/1/2/3	1/17/29/23	0/1/5/9	1/16/24/14	0.06
cStage I/II/III/IVA	0/0/10/60	0/0/0/15	0/0/10/45	0.075
Total radiation dose
40 Gy/up to 60 Gy	59/11	11/4	48/7	0.19

pCR: Pathological complete response; TNM: Tumor node metastasis.

Table 2 Predictive performance and receiver operating characteristic curve analyses of the five radiomics features with the highest area under the curve values and the best performing artificial intelligence-based machine-learning model for pathological complete response

	AUC	Sensitivity	Specificity	Accuracy	Cut off	95%CI	P value
ADC skewness	0.77	0.67	0.82	0.79	0.37	0.61-0.88	0.005
GLCM entropy (b = 1000 second/mm²)	0.76	0.87	0.62	0.67	9.28	0.64-0.85	0.002
GLCM autocorrelation (b = 0 second/mm²)	0.76	0.53	0.93	0.84	5276.1	0.60-0.87	0.009
Skewness (b = 0 second/mm²)	0.73	0.87	0.42	0.64	0.72	0.61-0.84	0.006
Kurtosis (b = 0 second/mm²)	0.72	0.73	0.64	0.66	5.05	0.55-0.82	0.005
Machine learning radiomics model	0.85	0.80	0.85	0.81	NA	0.73-0.93	< 0.001

AUC: Area under the curve; CI: Confidence interval; ADC: Apparent diffusion coefficient; GLCM: Gray-level co-occurrence matrix; NA: Not applicable.

Table 3 Univariate and multivariate Cox regression analyses for relapse-free survival

	Univariate			Multivariate
	HR	95%CI	P value	HR	95%CI	P value
Radiomics features
ADC skewness	0.42	0.16-1.09	0.076
GLCM entropy (b = 1000 second/mm²)	0.25	0.11-0.56	0.001	0.32	0.14-0.75	0.009
GLCM autocorrelation (b = 0 second/mm²)	2.00	0.61-6.57	0.25
Skewness (b = 0 second/mm²)	0.60	0.29-1.22	0.16
Kurtosis (b = 0 second/mm²)	0.76	0.37-1.54	0.45
Pathological features
pT3 vs pT0-2	1.08	0.54-2.18	0.82
pN + vs pN -	3.14	1.48-6.63	0.003	2.20	1.00-4.80	0.042
Grade 3 or 2 vs grade 1	0.50	0.25-1.01	0.054

ADC: Apparent diffusion coefficient; GLCM: Gray-level co-occurrence matrix; pN: Positive lymph node status; HR: Hazard ratio; CI: Confidence interval.