Correlation between baseline magnetic resonance imaging features and serum carcinoembryonic antigen levels in patients with primary rectal cancer

Table 2 Univariate analysis of magnetic resonance imaging features and serum carcinoembryonic antigen levels

Magnetic resonance imaging feature	n	Serum carcinoembryonic antigen level (ng/mL) (mean ± SD)	r value	P value
Tumor size (cm)			0.456	< 0.01
≤ 4	40	5.2 ± 1.8
> 4	40	8.3 ± 2.5
T-stage			0.387	< 0.01
T1-T2	30	4.8 ± 1.6
T3-T4	50	8.1 ± 2.9
Circumferential resection margin			0.325	< 0.05
Positive	28	8.9 ± 3.3
Negative	52	5.2 ± 2.1
Extramural vascular invasion			0.298	< 0.05
Yes	35	7.8 ± 2.7
No	45	5.3 ± 2.3
Lymph node metastasis			0.356	< 0.01
Yes	40	8.5 ± 2.8
No	40	4.9 ± 1.9