Table 1.
Characteristics of patients in training and testing cohorts.
| Characteristic | Training cohort | Testing cohort | P ※ | ||||
|---|---|---|---|---|---|---|---|
| pLN+n = 54 | pLN−n = 69 | P | pLN+n = 27 | pLN−n = 36 | P | 0.892 | |
| Gender | 0.090a | 0.184a | 0.906a | ||||
| Male | 33(61.1) | 52(75.4) | 16(59.3) | 27(75.0) | |||
| Female | 21(38.9) | 17(24.6) | 11(40.7) | 9(25.0) | |||
| Age, years | 60(53−67) | 60(51.5−70.5) | 0.520c | 57.6 ± 12.7 | 59.3 ± 10.2 | 0.571b | 0.388b |
| CEA level | 0.508a | 0.052a | 0.324a | ||||
| Normal | 39(72.2) | 46(66.7) | 13(48.1) | 26(72.2) | |||
| Abnormal | 15(27.8) | 23(33.3) | 14(51.9) | 10(27.8) | |||
| CA19-9 level | 0.289a | 0.643a | 0.684a | ||||
| Normal | 47(87.0) | 64(92.8) | 24(88.9) | 34(94.4) | |||
| Abnormal | 7(13.0) | 5(7.2) | 3(11.1) | 2(5.6) | |||
| Location of primary tumor | 0.008a* | 0.128a | 0.397a | ||||
| Upper | 7(13.0) | 1(1.4) | 0(0) | 1(2.8) | |||
| Middle | 29(53.7) | 31(44.9) | 17(63.0) | 15(41.7) | |||
| Lower | 18(33.3) | 37(53.6) | 10(37.0) | 20(55.6) | |||
| Tumor length(cm) | 5.2 ± 2.2 | 5.3 ± .3 | 0.858b | 5.4 ± 2.0 | 4.8 ± 1.9 | 0.199b | 0.594b |
| Tumor thickness(cm) | 1.3(1.1−1.5) | 1.3(1.1−1.6) | 0.910c | 1.1(0.9−1.6) | 1.3(1.0−1.6) | 0.512c | 0.194c |
| Extramural depth of invasion(mm) | 5.0(2.0−7.3) | 4(0-6) | 0.126c | 5.0(3.0−8.0) | 4.0(0.3−8.0) | 0.212c | 0.268c |
| Maximum LN short diameter(mm) | 6.0(4.0−8.0) | 6.0(3.0−6.0) | 0.001c* | 7.0(5.0-9.0) | 5.0(3.3−6.8) | 0.004c* | 0.121c |
| Invasion of MRF | 0.708a | 0.504a | 0.598a | ||||
| Negative | 43(79.6) | 53(76.8) | 19(70.4) | 28(77.8) | |||
| Positive | 11(20.4) | 16(23.2) | 8(29.6) | 8(22.2) | |||
| MRI-reported lymph status | 0.063a | 0.059a | 0.271a | ||||
| Negative | 14(25.9) | 29(42) | 4(14.8) | 13(36.1) | |||
| Positive | 40(74.1) | 40(58) | 23(85.2) | 23(63.9) | |||
pLN-, pathological N0 stage; pLN +, pathological N1-N2 stage; CEA, carcinoembryonic antigen; CA19-9, carbohydrate antigen 19-9; MRF, mesorectal fascia; a, Chi-square test or Fisher’s exact test, data are number of patients, with percentages in parentheses; b, Independent sample t test, data are mean ± SD; c, Mann-Whitney U test, data are median, with Interquartile range in parentheses.* p value <0.05; ※The comparison between the training cohort and testing cohort. The threshold value for CEA level was 5ng/mL and >5 ng/mL, and the threshold value of CA 19-9 level was 39 U/mL and >39 U/ml, according to the normal range used in clinics.