Beyond the tumor region: Peritumoral radiomics enhances prognostic accuracy in locally advanced rectal cancer

Table 4 Variable parameters and permutation feature importance of Model based on integrated clinical-radiological-omics

Variable	β	HR (95%CI)	P value	Relative importance weight 1	Relative importance weight 2
Intratumoral radiomic score1	0.936	2.55 (1.43-4.54)	0.001	0.3510
Log.sigma50.mm.3D GLDM DependenceVariance	1.267	0.28 (0.10-0.79)	0.016		0.6047
Wavelet.HHL_firstorder_RootMeanSquared	0.621	1.86 (0.95-3.64)	0.069		0.0388
Wavelet.LHL_GLSZM_LargeAreaLowGrayLevelEmphasis	1.024	0.36 (0.12-1.04)	0.059		0.9806
Peritumoral radiomic score1	0.948	2.58 (1.90-3.51)	< 0.001	1.0000
Wavelet.LLH_GLCM_ClusterShade	0.007	1.01 (1.00-1.01)	0.008		0.5858
Wavelet.LLL_GLSZM_LargeAreaLowGrayLevelEmphasis	0.016	1.02 (1.01-1.03)	0.002		0.1473
Log.sigma30.mm.3D_firstorder_90Percentile	0.654	1.92 (0.93-3.99)	0.080		0.5038
Wavelet.LHL_GLCM_Correlation	0.878	0.42 (0.22-0.78)	0.007		0.0226
Wavelet.HLH_firstorder_Kurtosis	0.889	0.41 (0.22-0.77)	0.005		0.3817
Wavelet.HHH_NGTDM_Contrast	0.774	2.17 (1.02-4.62)	0.045		0.0430
Square_GLDM_DependenceVariance	0.865	2.37 (1.21-4.65)	0.012		1.0000
BMI				0.0943	0.5510
< 18.5		1 (Ref.)
18.5-24	0.337	0.71 (0.32-1.62)	0.418
> 24	0.673	0.51 (0.22-1.17)	0.111
MRF status				-0.0867	-0.3670
Negative		1 (Ref.)
Positive	0.332	1.39 (0.69-2.82)	0.355
ypN stage				-0.0510	-0.0208
ypN0		1 (Ref.)
ypN1	0.857	2.36 (1.14-4.87)	0.021
ypN2	0.958	2.61 (0.85-7.97)	0.093
TRG				0.1019	0.8614
1-2		1 (Ref.)
3-5	0.691	2.00 (1.03-3.87)	0.040

¹Intratumoral and peritumoral radiomic scores calculated by combining radiomic feature values weighted by their coefficient β values (radiomic features are listed in the present table).

The β, hazard ratio, and P value were calculated using multivariable Cox regression analysis. The relative importance weight of a variable was calculated using permutation feature importance, measuring the change in the model’s concordance index after random shuffling of each feature’s value, with the importance scaled relative to the maximum observed change. HR: Hazard ratio; BMI: Body mass index; CI: Confidence interval; GLCM: Grey level co-occurrence matrix; GLDM: Grey level dependence matrix; GLSZM: Grey level size zone matrix; HHH: High-high-high; HHL: High-high-low; HLH: High-low-high; LHL: Low-high-low; LLH: Low-low-high; LLL: Low-low-low; MRF: Mesorectal fascia; NGTDM: Neighboring grey tone difference matrix; TRG: Tumor regression grade; ypN stage: Pathological N stage after neoadjuvant chemoradiotherapy.