Radiomics of rectal cancer for predicting distant metastasis and overall survival

Table 1 Patient and tumor characteristics in the training and validation sets

Characteristic	Training (n = 103)	Validation (n = 45)	P value
Age (yr)	60 ± 12	59 ± 11	0.513
Gender			0.156
Male	57	19
Female	46	26
Tumor size (long axis, mm)	49.4 ± 11.6	54.1 ± 14.6	0.040
Pathological T-stage			0.218
T1	11	2
T2	34	13
T3	55	29
T4	3	1
Pathological N-stage			0.018
N0	75	24
N1	18	12
N2	10	9
M-stage	0	0
Overall Stage (pTNM)			0.081
I	39	14
II	36	10
III	28	21
Pathological grade			0.222
Well	3	0
Moderate	78	32
Poor	22	13
CRM			0.788
Negativity	91	39
Positivity	12	6
Ki-67 (%)	52 ± 20	47 ± 21	0.261
Distant metastasis (+/-)	36/67	15/30	0.849
Distant metastasis1			0.394
Lung	16	13
Liver	19	8
Other (bone, brain, etc.)	6	6
Follow-up time (months)
DFS	29 ± 12	30 ± 12	0.638
OS	34 ± 5	34 ± 5	0.691

The data are presented as the mean ± the standard deviation.

¹A total of 51 patients had distant metastases within 3 years after surgery, and some of these patients had multiple organic metastases. CRM: Circumferential resection margin; DFS: Disease-free survival; OS: Overall survival.

Table 2 Comparison of the models between the metastasis group and the non-metastasis group, and between the death group and the survival group

	Metastasis	Non-metastasis	P value	Death	Survival	P value
3-yr1
n (%)	51 (34.5)	97 (65.5)		26 (17.6)	122 (82.4)
Rad-score	0.46 ± 0.21	0.32 ± 0.24	< 0.001	0.45 ± 0.20	0.35 ± 0.24	0.023
Clinical	0.52 ± 0.20	0.30 ± 0.21	< 0.001	0.55 ± 0.20	0.34 ± 0.22	< 0.001
Combined	0.60 ± 0.23	0.28 ± 0.26	< 0.001	0.62 ± 0.22	0.34 ± 0.28	< 0.001
2-yr1
n (%)	41 (27.7)	107 (72.3)		15 (10.1)	133 (89.9)
Rad-score	0.44 ± 0.20	0.34 ± 0.25	0.009	0.40 ± 0.17	0.35 ± 0.25	0.368
Clinical	0.51 ± 0.19	0.32 ± 0.23	< 0.001	0.63 ± 0.15	0.35 ± 0.22	< 0.001
Combined	0.56 ± 0.23	0.31 ± 0.28	< 0.001	0.65 ± 0.19	0.36 ± 0.29	< 0.001
1-yr1
n (%)	25 (16.9)	123 (83.1)		2 (1.4)	146 (98.6)
Rad-score	0.39 ± 0.19	0.36 ± 0.25	0.453	0.29 ± 0.36	0.37 ± 0.24	0.676
Clinical	0.55 ± 0.19	0.34 ± 0.22	< 0.001	0.75 ± 0.24	0.37 ± 0.23	0.258
Combined	0.56 ± 0.23	0.35 ± 0.29	0.001	0.60 ± 0.52	0.38 ± 0.29	0.302

The data are presented as the mean ± standard deviation.

¹During the time from surgery to the presence of distant metastasis or death.

Table 3 Diagnostic performance of the three models in both training and validation cohorts

		Training set			Validation set
1Time		Rad-score	Clinical	Combined	Rad-score	Clinical	Combined
3-yr	AUC	0.709	0.782	0.842	0.687	0.766	0.802
	SEN	88.89%	88.33%	91.67%	80%	100%	86.67%
	SPE	42.67%	58.21%	70.15%	56.67%	50%	80%
2-yr	AUC	0.700	0.760	0.816	0.609	0.720	0.691
1-yr	AUC	0.614	0.771	0.769	0.545	0.742	0.632

¹Time: The time from surgery to the presence of distant metastases. AUC: Area under the summary receiver operating characteristic curve; SEN: Sensitivity; SPE: Specificity.