Efficacy of uncovered self-expandable metallic stent for colorectal obstruction by extracolonic malignancy

Table 1 Baseline characteristics of 72 patients with colorectal obstructions caused by extracolonic malignancy, n (%)

Characteristics	Value
Age (yr, mean ± SD)	56.1 ± 11.8
Male	34 (45.9)
Primary malignancy
Gastric cancer	44 (61.1)
Pancreaticobiliary cancer	11 (15.3)
Ovary cancer	6 (8.3)
Uterine cancer	2 (2.8)
Bladder cancer	6 (8.3)
Breast cancer	2 (2.8)
Esophageal cancer	1 (1.4)
Obstruction site
Rectum	19 (26.4)
Sigmoid colon	19 (26.4)
Descending colon	1 (1.4)
Splenic flexure	15 (20.8)
Transverse colon	16 (22.2)
Hepatic flexure	2 (2.8)
Ascending colon	0
Degree of obstruction (scope passing)
Partial	8 (11.1)
Near total	64 (88.9)
Peritoneal carcinomatosis	51 (70.8)
Previous chemotherapy	63 (87.5)
Previous radiotherapy	12 (16.7)
Stent diameter (mm, median)	24 (24-24)
Stent length (cm, median)	10 (8-12)
Stent length ≤ 10 cm	38 (58.5)

Table 2 Clinical outcomes of stent insertion

Technical success (%)	65/72 (90.3%)
Cause of technical failure (n = 7)
Long segment obstruction	3
Severe peritoneal adhesion	2
Total obstruction (unable to guidewire passage)	2
Clinical success (%)	57/65 (87.7%)
Cause of clinical failure (n = 8)
Insufficient expansion of stent	4
Multiple obstruction	2
Colon perforation (after 2 d)	2

Table 3 Baseline characteristics according to success or failure of stent insertion, n (%)

	Success group (n = 57)	Technical failure group (n = 7)	P value	Clinical failure group (n = 8)	P value
Age (yr, mean ± SD)	56.2 ± 12.4	58.3 ± 7.9	0.660	53.9 ± 11.1	0.623
Male	23 (40.4)	4 (57.1)	0.443	7 (87.5)	0.020
Primary malignancy			0.352		0.255
Upper abdominal cancer	42 (73.7)	5 (71.4)		8 (100.0)
Lower abdominal cancer	12 (21.1)	2 (28.6)		0
Extra abdominal cancer	3 (5.3)	0		0
Obstruction site			0.110		0.017
Left colon	35 (63.2)	2 (28.6)		1 (12.5)
Right colon	21 (36.8)	5 (71.4)		7 (87.5)
Degree of obstruction			0.359		1.000
Partial	6 (10.5)	1 (14.3)		1 (12.5)
Near total	51 (89.5)	6 (85.7)		7 (87.5)
Peritoneal carcinomatosis	42 (73.7)	4 (57.1)	0.391	5 (62.5)	0.675
Previous chemotherapy	49 (86.0)	7 (100.0)	0.582	7 (87.5)	1.000
Previous radiotherapy	9 (15.8)	2 (28.6)	0.593	1 (12.5)	1.000
Stent length ≤ 10 cm (%)	36 (63.2)	NA	NA	2 (25.0)	0.058

Upper abdominal cancer: Gastric cancer and pancreaticobiliary cancer; Lower abdominal cancer: Ovarian cancer, uterine cancer, and bladder cancer; Left colon: From the rectum to descending colon; Right colon: From the splenic flexure to ascending colon.

Table 4 Results of stent occlusion

Stent occlusion	16/57 (28.1%)
Duration to stent occlusion (days, median)	51 (14-158)
Cause of stent occlusion
Tumor ingrowth	12 (75.0%)
Tumor overgrowth	4 (25.0%)
Management of stent occlusion
Stent reinsertion	13 (81.3%)
Surgery	3 (18.8%)

Table 5 Baseline characteristics according to stent occlusion, n (%)

	Patent stent group (n = 41, 71.9%)	Stent occlusion group (n = 16, 28.1%)	P value
Age (yr, mean ± SD)	56.2 ± 12.4	58.3 ± 7.9	0.660
Male	15 (36.6)	8 (50.0)	0.354
Primary malignancy			0.231
Upper abdominal cancer	28 (68.3)	14 (87.5)
Lower abdominal cancer	11 (26.8)	1 (6.3)
Extra abdominal cancer	2 (4.9)	1 (6.3)
Obstruction site			0.198
Left colon	28 (68.3)	8 (50.0)
Sigmoid colon	13 (31.7)	8 (50.0)
Obstruction			1.000
Partial	4 (9.8)	2 (12.5)
Near total	37 (90.2)	14 (87.5)
Peritoneal carcinomatosis	31 (75.6)	11 (68.8)	0.739
Previous chemotherapy	35 (85.4)	14 (87.5)	1.000
Previous radiotherapy	6 (14.6)	3 (18.8)	0.700
Stent length ≤ 10 cm	21 (51.2)	15 (93.8)	0.003

Upper abdominal cancer: Gastric cancer and pancreaticobiliary cancer; Lower abdominal cancer: Ovarian cancer, uterine cancer, and bladder cancer; Left colon: From the rectum to descending colon; Right colon: From the splenic flexure to ascending colon.

Table 6 Long-term outcomes of stent success group

Long-term outcomes	n = 57
Survival time after 1st stent insertion (months, median)	4.7 (0.8-25.5)
Oncological treatment after stent without surgery	23 (40.4%)
Chemotherapy only	22
Chemotherapy + Radiotherapy	1
Duration to oncological treatments after stent insertion (d, median)	15 (2-163)
Surgery after clinical success (except stent occlusion)	15 (26.3%)
Multiple obstruction	7
Colon perforation	7
Stent fracture	1 (53 d after stent)
Duration to surgery after stent insertion (d, median)	25 (7-385)