Prognostic Significance of the Diameter of Superior Rectal Vein for Locally Advanced Rectal Cancer

Figures & data

Figure 1. Flow diagram of enrolled patients between December 2014 to July 2017.

dSRV: Diameter of the superior rectal vein; TME: Total mesorectal excision.

Figure 2. Superior rectal vein (red arrow).

Figure 3. Bland–Altman plot showed good correlation between the observers in measuring diameter of the superior rectal vein.

Figure 4. The optimal cut-off value for diameter of the superior rectal vein was confirmed to be 3.6 mm by using X-tile software.

dSRV: Diameter of the superior rectal vein.

Table 1. Comparison of patient characteristics according to diameter of the superior rectal vein.

Characteristics	Overall dataset		p-value	Propensity score-matched group		p-value
	≤3.60 mm (N = 87), n (%)	>3.60 mm (N = 333), n (%)		≤3.60 mm (N = 82), n (%)	>3.60 mm (N = 82), n (%)
Age			0.046			0.592
≤65 years	59 (67.8)	262 (78.7)		59 (72.0)	63 (76.8)
>65 years	28 (32.2)	71 (21.3)		23 (28.0)	19 (23.2)
BMI (kg/m^2)			0.205			0.235
<18.5	8 (9.2)	16 (4.8)		7 (8.5)	3 (3.7)
18.5–23.9	52 (59.8)	213 (64.0)		49 (59.8)	61 (74.4)
24–27.9	21 (24.1)	92 (27.6)		20 (24.4)	14 (17.1)
≥28	6 (6.9)	12 (3.6)		6 (7.3)	4 (4.9)
Sex			0.000			0.753
Male	37 (42.5)	236 (70.9)		37 (45.1)	34 (41.5)
Female	50 (57.5)	97 (29.1)		45 (54.9)	48 (58.5)
Distance to anus (cm)			0.034			0.840
≤7 cm	74 (85.1)	246 (73.9)		69 (84.1)	67 (81.7)
>7 cm	13 (14.9)	87 (26.1)		13 (15.9)	15 (18.3)
Tumor length			0.001			0.161
≤5 cm	67 (77.0)	193 (58.0)		64 (78.0)	55 (67.1)
>5 cm	20 (23.0)	140 (42.0)		18 (22.0)	27 (32.9)
EMVI			0.718			0.875
+	38 (43.7)	154 (46.2)		36 (43.9)	38 (46.3)
-	49 (56.3)	179 (53.8)		46 (56.1)	44 (53.7)
Clinical TNM stage			0.332			0.167
II	8 (9.2)	20 (6.0)		7 (8.5)	2 (2.4)
III	79 (90.8)	313 (94.0)		75 (91.5)	80 (97.6)
Pathological tumor response			0.443			0.982
TRG 0	21 (24.1)	78 (23.4)		20 (24.4)	18 (22.0)
TRG 1	32 (36.8)	98 (29.4)		29 (35.4)	29 (35.4)
TRG 2	28 (32.2)	137 (41.1)		28 (34.1)	30 (36.6)
TRG 3	6 (6.9)	20 (6.0)		5 (6.1)	5 (6.1)
ypT			0.287			–
0	21 (24.1)	79 (23.7)		20 (24.4)	19 (23.2)
1	3 (3.4)	18 (5.4)		2 (2.4)	7 (8.5)
2	32 (36.8)	85 (25.5)		31 (37.8)	21 (25.6)
3	29 (33.3)	142 (42.6)		27 (32.9)	32 (39.0)
4	2 (2.3)	9 (2.7)		2 (2.4)	3 (3.7)
ypN (0/1–2)			0.890			0.195
0	64 (73.6)	249 (74.8)		59 (72.0)	67 (81.7)
1–2	23 (26.4)	84 (25.2)		23 (28.0)	15 (18.3)
Pathological TNM stage			0.653			0.354
pCR	20 (23.0)	76 (22.8)		19 (23.2)	17 (20.7)
I	25 (28.7)	82 (24.6)		23 (28.0)	23 (28.0)
II	18 (20.7)	90 (27.0)		17 (20.7)	26 (31.7)
III	24 (27.6)	85 (25.5)		23 (28.0)	16 (19.5)

BMI: Body mass index; EMVI: Extramural venous invasion; pCR: Pathological complete response; TNM: Tumor node metastasis; TRG: Tumor regression grade; ypT: post-neoadjuvant pathologic tumor stage; ypN: post-neoadjuvant pathologic node stage.

Figure 5. Pre- and post-propensity score matched Kaplan–Meier analysis survival curves for overall survival, disease-free survival and metastasis-free survival.

The first row shows the survival curve prior to propensity score matching.

SRV: Superior rectal vein.

Table 2. Significant factors in survival analysis.

Variables	Univariate analysis ^†	Multivariate analysis ^†		Univariate analysis ^‡	Multivariate analysis ^‡
	p-value	p-value	HR (95% CI)	p-value	p-value	HR (95% CI)
OS
dSRV	0.007	0.009	2.16 (1.22–3.84)	0.033	0.033	1.61 (1.04–2.49)
EMVI	0.001	0.003	2.48 (1.36–4.50)	0.007	0.008	3.29 (1.37–7.88)
ypT	0.005	0.513	1.15 (0.76–1.72)	NS	NS	NS
ypN	0.005	0.002	2.41 (1.38–4.20)	0.015	NS	NS
TRG	0.013	0.475	1.20 (0.73–1.20)	NS	NS	NS
DFS
dSRV	0.000	0.000	2.80 (1.80–4.36)	0.004	0.013	1.52 (1.09–2.10)
EMVI	0.003	0.030	1.65 (1.05–2.59)	0.015	0.052	1.85 (1.00–3.44)
ypT	0.001	0.063	1.23 (0.99–1.53)	NS	NS	NS
ypN	0.000	0.001	2.15 (1.36–3.39)	0.000	0.007	2.33 (1.26–4.33)
TRG	0.004	0.641	1.10 (0.75–1.61)	NS	NS	NS
MFS
dSRV	0.000	0.000	2.95 (1.83–4.76)	0.017	0.046	1.41 (1.01–1.97)
EMVI	0.007	0.057	1.61 (0.99–2.63)	0.014	0.050	1.92 (1.00–3.70)
ypT	0.001	0.046	1.28 (1.00–1.63)	NS	NS	NS
ypN	0.000	0.004	2.07 (1.26–3.39)	0.000	0.004	2.58 (1.36–4.92)
TRG	0.013	0.964	0.99 (0.65–1.51)	NS	NS	NS
LRFS
ypN	0.013	0.013	8.02 (1.56–41.37)	0.010	0.039	10.89 (1.13–104.85)

† Survival analysis for all 420 patients.

‡ Survival analysis for propensity score-matched group.

DFS: Disease-free survival; dSRV: Diameter of the superior rectal vein; EMVI: Extramural venous invasion; HR: Hazard ratio; LRFS: Local recurrence-free survival; MFS: Metastasis-free survival; NS: Not significant; OS: Overall survival; TRG: tumor regression grade; ypT: post-neoadjuvant pathologic tumor stage; ypN: post-neoadjuvant pathologic node stage.