Predictive value of carcinoembryonic antigen and carbohydrate antigen 19-9 related to downstaging to stage 0–I after neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Figures & data

Table 1 Characteristics of locally advanced rectal cancer patients

Characteristics values	Counts
Age (years, median [range])	56 (24–85)
Gender (male/female)	444/230
cT classification
cT1	1
cT2	35
cT3	253
cT4	385
cN classification
N0	61
N+	613
cStage
II	55
III	619
Pretreatment CA19-9 (U/mL, median [range])	11.855 (0–1,000)
Pretreatment CEA (U/mL, median [range])	4.1 (0.2–1,000)
ypT classification
ypT0	148
ypT1	38
ypT2	171
ypT3	270
ypT4	47
ypN classification
ypN0	477
ypN1	149
ypN2	28
ypStage
pCR	136
I	169
II	164
III	178
IV	27
Posttreatment CA19-9 (U/mL, median [range])	10.62 (0–173.2)
Posttreatment CEA (U/mL, median [range])	2.5 (0.2–308)

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; pCR,.

Figure 1 ROC curve analysis of CEA and CA19-9 for downstaging with locally advanced rectal cancer after nCRT.

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; nCRT, neoadjuvant chemoradiotherapy; ROC, receiver operating characteristic.

Figure 2 ROC curve analysis of CEA and CA19-9 for pCR with locally advanced rectal cancer after nCRT.

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; nCRT, neoadjuvant chemoradiotherapy; pCR, pathological complete response; ROC, receiver operating characteristic.

Table 2 Characteristics for downstaging with locally advanced rectal cancer after nCRT

Variables	Sum	Downstaging	Not downstaging	P-value
Age (years)				0.796
<65	534	243	291
≥65	140	62	78
Gender				0.634
Male	444	198	246
Female	230	107	123
cT classification				0.494
cT1	1	0	1
cT2	35	18	17
cT3	253	120	133
cT4	385	167	218
cN classification				0.146
N0	61	33	28
N+	613	272	341
cStage				0.379
I	55	28	27
III	619	277	342
ypT classification				<0.0001
ypT0	148	141	7
ypT1	38	33	5
ypT2	171	131	40
ypT3	270	0	270
ypT4	47	0	47
ypN classification				<0.0001
ypN0	477	305	172
ypN1	149	0	149
ypN2	48	0	48
ypStage				<0.0001
pCR	136	136	0
I	169	169	0
II	164	0	164
III	178	0	178
IV	27	0	27
Pretreatment CEA (U/mL)				<0.0001
<5.05	383	214	169
≥5.05	291	91	200
Pretreatment CA19-9 (U/mL)				<0.0001
<12.6	357	189	168
≥12.6	317	116	201
Posttreatment CEA (U/mL)				<0.0001
<2.45	336	185	151
≥2.45	338	120	218
Posttreatment CA19-9 (U/mL)				0.066
<11.3	365	177	188
≥11.3	309	128	181
Pre–post-CEA ratio				<0.0001
<1.56	328	181	147
≥1.56	346	124	222
Pre–post- CA19-9 ratio				<0.0001
<1.28	438	223	215
≥1.28	236	82	154

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; nCRT, neoadjuvant chemoradiotherapy; pCR, pathological complete response.

Table 3 Characteristics for pCR with locally advanced rectal cancer after nCRT

Variables	Sum	pCR	Not pCR	P-value
Age (years)				0.442
<65	534	111	423
≥65	140	25	115
Gender				0.182
Male	444	83	361
Female	230	53	177
cT classification				0.136
cT1	1	0	1
cT2	35	8	27
cT3	253	62	191
cT4	385	66	319
cN classification				0.572
N0	61	14	47
N+	613	122	491
cStage				0.752
II	55	12	43
III	619	124	495
Pretreatment CEA (U/mL)				<0.0001
<2.85	251	71	180
≥2.85	423	65	358
Posttreatment CEA (U/mL)				<0.0001
<2.45	336	91	245
≥2.45	338	45	293
Pre–post-CEA ratio				0.006
<1.07	193	52	141
≥1.07	481	84	397
Pre–post-CA19-9 ratio				0.012
<0.92	240	61	179
≥0.92	434	75	359

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; nCRT, neoadjuvant chemoradiotherapy; pCR, pathological complete response.

Table 4 Multivariate analyses of predictors for downstaging with locally advanced rectal cancer after nCRT

Variables	Regression coefficient	SE	P-value	OR [95% CI]
Pretreatment CA19-9<12.6	0.379	0.177	0.33	1.46 (1.032–2.067)
Posttreatment CEA <2.45	0.696	0.184	<0.0001	2.007 (1.398–2.879)
Pre–post-CEA ratio <1.56	0.441	0.208	0.034	1.555 (1.034–2.34)
Pre–post-CA19-9 ratio <1.28	0.38	0.194	0.049	1.463 (1.001–2.137)
Constant	−1.436

Abbreviations: CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; nCRT, neoadjuvant chemoradiotherapy.

Figure 3 ROC curve analysis of 4-factor scoring system for downstaging with locally advanced rectal cancer after nCRT.

Abbreviations: nCRT, neoadjuvant chemoradiotherapy; ROC, receiver operating characteristic.