Prognostic value of changes in serum carcinoembryonic antigen levels for preoperative chemoradiotherapy response in locally advanced rectal cancer

Table 5 Comparison of the non- pathologic complete response and pathologic complete response groups after the chemoradiotherapy following surgical resection

Variables	Non-pCR (n = 108)	pCR (n = 27)	P value
Pre-CRT tumor size (cm, mean ± SD)	4.7 ± 1.5	4.4 ± 1.3	0.246
Pre-CRT CEA, ng/mL			< 0.001
CEA ≤ 5	40 (37.0%)	25 (92.6%)
CEA > 5	68 (63.0%)	2 (7.4%)
Pre-CRT T stage			0.875
T3	84 (77.8%)	22 (81.5%)
T4	24 (22.2%)	5 (18.5%)
Pre-CRT N stage			0.004
N0	6 (5.6%)	7 (25.9%)
N+	102 (94.4%)	20 (74.1%)
Pre-CRT TNM stage			0.005
I	1 (0.9%)	0
II	6 (5.6%)	7 (25.9%)
III	101 (93.5%)	20 (74.1%)
Post-CRT CEA, ng/mL			0.008
≤ 5	81 (75.0%)	27 (100%)
> 5	27 (25.0%)	0
Downstaging after CRT			0.051
No	65 (60.2%)	10 (37.0%)
Yes	43 (39.8%)	17 (63.0%)
Differentiation			> 0.999
Well–Moderate	30 (27.8%)	7 (25.9%)
Poor + others1	78 (72.2%)	20 (74.1%)
Lymphovascular invasion			0.034
No	88 (81.5%)	27 (100%)
Yes	20 (18.5%)	0
Perineural invasion			0.151
No	96 (88.9%)	27 (100%)
Yes	12 (11.1%)	0

¹Mucinous, signet ring cell, pCR: Pathologic complete response; CRT: Chemoradiotherapy; SD: Standard deviation; CEA: Carcinoembryonic antigen; TNM: Tumor node metastasis.