Construction of a clinical survival prognostic model for middle-aged and elderly patients with stage III rectal adenocarcinoma

Table 1 Baseline demographic and clinical characteristics of middle-aged and elderly patients with stage III rectal adenocarcinoma

	Training cohort (1944)		Validation cohort (829)		Overall (2773)
Variable	Quantity	SCALE	Quantity	SCALE	Quantity	SCALE	P value
Age (yr)							0.596
45-62	1107	56.94%	456	55.01%	1563	56.36%
62-75	588	30.25%	258	31.12%	846	30.51%
> 75	249	12.81%	115	13.87%	364	13.13%
Race							0.425
Other	146	7.51%	66	7.96%	212	7.65%
White	1511	77.73%	656	79.13%	2167	78.15%
Black	287	14.76%	107	12.91%	394	14.21%
Sex							0.051
Female	794	40.84%	305	36.79%	1099	39.63%
Male	1150	59.16%	524	63.21%	1674	60.37%
Grade							0.859
I/II	1642	84.47%	698	84.20%	2340	84.39%
III/IV	302	15.53%	131	15.80%	433	15.61%
Site							0.692
Rectosigmoid Junction	660	33.95%	275	33.17%	935	33.72%
Rectum	1284	66.05%	554	66.83%	1838	66.28%
Stage							0.138
III A	199	10.24%	90	10.86%	289	10.42%
III B	1394	71.71%	615	74.19%	2009	72.45%
III C	351	18.06%	124	14.96%	475	17.13%
Tumor size							0.204
≤ 68	1626	83.64%	677	81.66%	2303	83.05%
> 68	318	16.36%	152	18.34%	470	16.95%
CEA							0.558
Low	1074	55.25%	468	56.45%	1542	55.61%
High	870	44.75%	361	43.55%	1231	44.39%
TD							0.473
Neg	1481	76.18%	621	74.91%	2102	75.80%
Pos	463	23.82%	208	25.09%	671	24.20%
CRM							0.409
Pos	354	18.21%	162	19.54%	516	18.61%
Neg	1590	81.79%	667	80.46%	2257	81.39%
PNI							0.197
Neg	1551	79.78%	679	81.91%	2230	80.42%
Pos	393	20.22%	150	18.09%	543	19.58%
pLN							0.152
0	508	26.13%	204	24.61%	712	25.68%
1-6	1212	62.35%	546	65.86%	1758	63.40%
> 6	224	11.52%	79	9.53%	303	10.93%
DLNs							0.241
≤ 26	1675	86.16%	728	87.82%	2403	86.66%
> 26	269	13.84%	101	12.18%	370	13.34%
LNR							0.246
0-0.12	1146	58.95%	477	57.54%	1623	58.53%
< 0.31	463	23.82%	221	26.66%	684	24.67%
> 0.31	335	17.23%	131	15.80%	466	16.80%

CEA: Carcinoembryonic antigen; TD: Tumor engraftment; CRM: Circumferential resection margin; PNI: Perineural invasion; pLN: Positive lymph nodes; DLNs: Examined lymph nodes; LNR: Lymph node-positive rate.

Table 2 Univariate Cox regression analysis

Variable	OS			CSS
	HR	95%CI	P value	HR	95%CI	P value
Age (yr)			< 0.001			< 0.001
45-62
62-75	1.684	1.32-2.148	< 0.001	1.649	1.649-1.255	< 0.001
> 75	3.102	2.372-4.057	< 0.001	2.687	2.687-1.964	< 0.001
Race			0.3			0.4
Other
White	0.752	0.519-1.091	0.134	0.7399	0.739-0.485	0.163
Black	0.682	0.432-1.076	0.009	0.7474	0.747-0.449	0.262
Sex			0.08			0.3
Female
Male	1.209	0.9731-1.502	0.087	1.139	1.139-0.8914	0.297
Grade			< 0.001			< 0.001
I/II
III/IV	1.214	2.02-1.214	< 0.001	1.788	1.788-1.352	< 0.001
Site			0.3			0.4
Rectosigmoid Junction
Rectum	0.894	0.718-1.114	0.319	0.889	0.889-0.693	0.356
Stage			< 0.001			< 0.001
III A
III B	2.399	1.446-3.979	< 0.001	3.225	3.225-1.651	< 0.001
III C	3.941	2.316-6.706	< 0.001	6.037	6.037-3.027	< 0.001
Tumor size size			< 0.001			< 0.001
≤ 68
> 68	1.651	1.279-2.131	< 0.001	1.663	1.663-1.245	< 0.001
CEA			< 0.001			< 0.001
Low
High	1.724	1.395-2.131	< 0.001	1.576	1.576-1.239	< 0.001
TD			< 0.001			< 0.001
Neg
Pos	2.009	1.612-2.504	< 0.001	2.072	2.072-1.614	< 0.001
CRM			< 0.001			< 0.001
Neg
Pos	2.205	1.756-2.77	< 0.001	2.551	2.551-1.981	< 0.001
PNI			< 0.001			< 0.001
Neg
Pos	2.092	1.665-2.629	< 0.001	2.222	2.222-1.718	<0.001
pLN			< 0.001			<0.001
0
1-6	1.379	1.039-1.831	0.026	1.711	1.711-1.21	0.002
> 6	2.27	1.594-3.233	< 0.001	2.924	2.924-1.927	< 0.001
DLNs			0.02			0.07
≤ 26
> 26	1.412	1.072-1.858	0.014	1.348	1.348-0.981	0.066
LNR			< 0.001			< 0.001
0-0.12
< 0.31	1.405	1.088-1.815	0.009	1.64	1.64-1.228	< 0.001
> 0.31	2.261	1.755-2.914	< 0.001	2.594	2.594-1.944	< 0.001

OS: Overall survival; CCS: Cancer-specific survival; HR: Hazard ratios; CEA: Carcinoembryonic antigen; TD: Tumor engraftment; CRM: Circumferential resection margin; PNI: Perineural invasion; pLN: Positive lymph nodes; DLNs: Examined lymph nodes; LNR: Lymph node-positive rate.

Table 3 Multivariate Cox regression analysis.

Variable	OS			CSS
	HR	95%CI	P value	HR	95%CI	P value
Age (yr)
45-62
62-75	1.773	1.384-2.272	< 0.001	1.731	1.311-2.286	< 0.001
> 75	3.427	2.601-4.516	< 0.001	2.976	2.157-4.106	< 0.001
Grade
I/II
III/IV	1.188	0.914-1.545	0.198	1.281	0.96-1.709	0.092
Stage
III A
III B	1.680	1.005-2.809	0.047	2.369	1.204-4.662	0.013
III C	1.770	0.968-3.24	0.064	2.960	1.391-6.297	0.005
Tumor size
≤ 68
> 68	1.669	1.277-2.18	< 0.001	1.638	1.209-2.219	0.001
CEA
Low
High	1.426	1.148-1.772	0.001	1.261	0.986-1.612	0.064
TD
Neg
Pos	1.525	1.204-1.933	< 0.001	1.520	1.164-1.985	0.002
CRM
Neg
Pos	1.538	1.204-1.963	< 0.001	1.773	1.351-2.328	< 0.001
PNI
Neg
Pos	1.550	1.204-1.996	< 0.001	1.520	1.147-2.015	0.004
pLN
0
1-6	1.096	0.784-1.532	0.592	1.378	0.925-2.053	0.115
> 6	0.895	0.497-1.612	0.712	1.076	0.57-2.031	0.821
DLNs
≤ 26
> 26	1.254	0.928-1.694	0.141
LNR
0-0.12
< 0.31	1.279	0.953-1.717	0.101	1.330	0.963-1.839	0.084
> 0.31	1.871	1.298-2.697	< 0.001	1.809	1.22-2.684	0.003

OS: Overall survival; CCS: Cancer-specific survival; HR: Hazard ratios; CEA: Carcinoembryonic antigen; TD: Tumor engraftment; CRM: Circumferential resection margin; PNI: Perineural invasion; pLN: Positive lymph nodes; DLNs: Examined lymph nodes; LNR: Lymph node-positive rate.