Risk factors for adverse outcome in low rectal cancer

Table 1 Characteristics of 331 patients with low rectal cancer

Characteristic	APR (%)n = 172	SPS (%)n = 159	Pvalue
Median age (yr)	56.0	58.0	0.334
Median tumor size (cm)	4.0	4.0	0.301
Median distance of tumor from the anal verge (cm)	3.0	5.0	< 0.001
Gender (male)	115 (66.9)	96 (60.4)	0.220
Positive resection margins	23 (13.4)	10 (6.3)	0.032
Histopathologic grade			0.238
Well	34 (19.8)	27 (17.0)
Moderate	102 (59.3)	108 (67.9)
Poor	36 (20.9)	24 (15.1)
pTNM stage			0.445
I	20 (11.6)	22 (13.8)
II	63 (36.6)	69 (43.4)
III	73 (42.4)	56 (35.2)
IV	16 (9.4)	12 (7.6)
Mucin production	14 (8.1)	10 (6.3)	0.517
Adjuvant chemotherapy	34 (19.8)	29 (18.2)
Year of surgery			0.001
1994-2001	101 (58.7)	65 (40.9)
2002-2005	71 (41.3)	94 (59.1)

APR: Abdominoperineal resection; SPS: Sphincter-preserving surgery.

Table 2 Univariate analysis of 331 patients with low rectal cancer

Characteristic	No. of patients	5-year OS		5-year DFS
		%	P value	%	P value
Gender			0.987		0.768
Male	211	61.2		59.2
Female	120	59.6		58.9
Age (yr)			0.707		0.987
< 60	182	58.8		56.4
≥ 60	149	62.7		62.2
Tumor size (cm)			0.011		0.003
< 4	103	74.8		74.0
≥ 4	228	54.1		52.3
Distance of tumor from the anal verge (cm)			0.189		0.197
< 3.5	117	60.1		58.1
≥ 3.5	214	60.9		59.6
Type of surgery			0.018		0.013
APR	172	54.6		52.9
SPS	159	66.8		65.6
Resection margins			< 0.001		< 0.001
Negative	298	63.8		62.1
Positive	33	32.5		32.5
Histopathologic grade			0.006		0.002
Well	61	66.5		66.5
Moderate	210	63.6		61.9
Poor	60	43.6		41.6
pT stage			< 0.001		< 0.001
1-2	125	74.0		71.9
3-4	206	52.4		51.2
pTNM stage			< 0.001		< 0.001
I-II	174	75.4		73.3
III-IV	157	44.0		43.1
Mucin production			0.212		0.121
No	307	61.7		60.3
Yes	24	44.8		42.6
Anastomotic leakage1			0.310		0.386
No	153	67.6		66.3
Yes	6	50.0		50.0
Adjuvant chemotherapy			0.950		0.573
No	268	60.2		58.4
Yes	63	62.2		62.2

OS: Overall survival; DFS: Disease-free survival; APR: Abdominoperineal resection; SPS: Sphincter-preserving surgery.

¹Analysis of 159 patients who underwent sphincter-preserving surgery.

Table 3 Multivariate analysis of 331 patients with low rectal cancer

Characteristic	OS			DFS
	HR	95% CIfor HR	Pvalue	HR	95% CIfor HR	P value
Tumor size (cm)			0.131			0.067
< 4	1.000			1.000
≥ 4	1.327	0.920-1.915		1.388	0.977-1.971
Type of surgery			0.091			0.112
APR	1.000			1.000
SPS	0.754	0.544-1.047		0.778	0.572-1.060
Resection margins			0.031			0.012
Negative	1.000			1.000
Positive	1.644	1.047-2.582		1.728	1.129-2.644
Histopathologic grade			0.150			0.047
Well	1.000			1.000
Moderate	1.061	0.688-1.637	0.788	1.108	0.735-1.670	0.624
Poor	1.515	0.917-2.504	0.105	1.665	1.039-2.666	0.034
pT stage			0.003			0.006
1-2	1.000			1.000
3-4	1.781	1.212-2.616		1.669	1.162-2.396
pTNM stage			< 0.001			< 0.001
I-II	1.000			1.000
III-IV	2.153	1.515	3.058	1.839	1.332-2.540

OS: Overall survival; DFS: Disease-free survival; HR: Hazard ratio; CI: Confidence interval; APR: Abdominoperineal resection; SPS: Sphincter-preserving surgery.