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

Table 4 Comparison of the changes in the carcinoembryonic antigen level after curative resection

Variables	Group A (n = 27)	Group B (n = 43)	Group C (n = 65)	P value
Name of surgery				0.272
Low anterior resection	15 (55.6%)	22 (51.2%)	43 (66.2%)
Others1	12 (44.4%)	21 (48.8%)	22 (33.8%)
Differentiation				0.781
Well–Moderate	8 (29.6%)	13 (30.2%)	16 (24.6%)
Poorly + others2	19 (70.4%)	30 (69.8%)	49 (75.4%)
Lymphovascular invasion				0.444
No	22 (81.5%)	35 (81.4%)	58 (89.2%)
Yes	5 (18.5%)	8 (18.6%)	7 (10.8%)
Perineural invasion				0.005
No	21 (77.8%)	38 (88.4%)	64 (98.5%)
Yes	6 (22.2%)	5 (11.6%)	1 (1.5%)
Postoperative T stage				< 0.001
0–2	2 (7.4%)	11 (25.6%)	38 (58.5%)
3–4	25 (92.6%)	32 (74.4%)	27 (41.5%)
Postoperative N stage				0.538
N0	15 (55.6%)	27 (62.8%)	44 (67.7%)
N+	12 (44.4%)	16 (37.2%)	21 (32.3%)
Postoperative M stage				0.002
M0	24 (88.9%)	43 (100%)	65 (100%)
M1	3 (11.1%)	0	0
Postoperative TNM stage				< 0.001
0	0	3 (7.0%)	25 (38.5%)
I	2 (7.4%)	5 (11.6%)	8 (12.3%)
II	13 (48.1%)	19 (44.2%)	11 (16.9%)
III	9 (33.3%)	16 (37.2%)	21 (32.3%)
IV	3 (11.1%)	0	0
CEA on postoperative day 7	3.7 (2.8-5.2)	1.6 (1.1-2.2)	1.1 (0.7-1.7)	< 0.001
Tumor regression grade				< 0.001
0	1 (3.7%)	3 (7.0%)	26 (40.0%)
1	7 (25.9%)	23 (53.5%)	18 (27.7%)
2	11 (40.7%)	14 (32.6%)	17 (26.2%)
3	8 (29.6%)	3 (7.0%)	4 (6.2%)
Good response (TRG 0,1)				0.003
TRG 0, 1	8 (29.6%)	26 (60.5%)	44 (67.7%)
TRG 2, 3	19 (70.4%)	17 (39.5%)	21 (32.3%)
Pathologic complete response				< 0.001
pCR (-)	27 (100%)	41 (95.3%)	40 (61.5%)
pCR (+)	0	2 (4.7%)	25 (38.5%)

Group A: patients with pre- and post-CRT CEA levels > 5 ng/mL; Group B: patients with pre- and post-CRT CEA levels > 5 and ≤ 5 ng/mL, respectively; and Group C: patients with pre- and post-CRT CEA levels ≤ 5 ng/mL. Name of surgery,

¹others abdominoperineal resection, Hartmann’s operation, subtotal or total colectomy; Differentiation,

²others mucinous, signet ring cell. TNM: Tumor Node Metastasis; CEA: Carcinoembryonic antigen; TRG: Tumor regression grade.