GI Endoscopy · 7 min read
Malignant Colon Obstruction: Uncovered SEMS, Not Balloon Dilation
The URL says dilation. For cancer, the tool is a stent. Balloons belong to short benign Crohn's and anastomotic strictures.
Do not treat a rigid colon cancer like a peptic esophageal stricture. ESGE 2020 (van Hooft, PMID 32259849) says do not dilate the tumor, including immediately before or after a stent. Uncovered SEMS is the endoscopic decompression tool for selected left-sided obstruction without perforation, in a unit that already does this. Bevacizumab is a reason to stop.
Experienced teaching points
Clinical Pearls
- CT first. No perforation, real obstruction, known or obvious mass. Do not place a prophylactic stent in an asymptomatic narrowing.
- Uncovered SEMS for palliation. Covered stents migrate more. ESGE prefers uncovered in both palliation and bridge discussions.
- Do not balloon the tumor to 'make room' for the stent. That is how series pick up extra perforations.
- Antiangiogenic therapy (bevacizumab and kin) is a reason not to stent. Weak evidence, strong enough to stop.
- Short fibrotic Crohn's or anastomotic strictures are a balloon problem. Dysplasia surveillance is a different page: IBD surveillance. Esophagus: esophageal dilation.
Clinical Bottom Line
| Situation | Tool |
|---|---|
| Malignant left-sided obstruction, no perforation | Uncovered SEMS as palliation, or as a bridge to elective resection after shared decision. Alternative is emergency surgery or a decompressing stoma (ESGE 2020, PMID 32259849). |
| Balloon dilation of the cancer | Do not. Not as therapy, and not as a prelude or afterthought to SEMS. Pooled series show extra perforations without a success gain. |
| Bevacizumab or other anti-VEGF | ESGE does not suggest colonic stenting while the patient is on antiangiogenic therapy. |
| Right colon | Evidence is thinner. Surgery is often the cleaner decompression. Do not treat proximal obstruction as a routine stent case. |
| Short benign Crohn's or anastomotic stricture | TTS balloon, not SEMS first. SEMS in benign colon migrates and embeds. |
Why is the balloon the wrong instinct?
A malignant apple-core is not a fibrotic ring. Radial stretch tears through tumor into peritoneum. ESGE 2020 is explicit: do not dilate the stricture in the setting of colonic stenting. Technical success of SEMS does not improve with a balloon, and perforation does.
The leftover stub on this URL treated balloon dilation as "absolutely contraindicated" theater and SEMS as a guaranteed colostomy-sparing miracle. Neither is how the guideline reads. SEMS is an option, in expert hands, after CT has shown obstruction without perforation. Prophylactic stenting of an asymptomatic narrowing is not.
Bridge or palliation?
Palliation: uncovered SEMS, because migration is lower and you are not coming back for an oncologic resection next week. Ingrowth happens. You can restented. Covered stents migrate.
Bridge to surgery in potentially curable left-sided obstruction: discuss SEMS versus emergency resection. ESGE allows SEMS as an alternative, then about 2 weeks to elective surgery. A decompressing stoma is valid if the patient is not a stent candidate or the unit does not stent. This is shared decision, not a mandate to avoid a bag at all costs.
Operator: colonoscopy plus fluoroscopy, done often enough to stay competent. Through-the-scope uncovered stents over a wire. If you cannot get a wire across without force, stop. That hole is worse than an operation.
What about benign colon strictures?
The slug promised dilation. Honor it for the benign case. Short fibrotic Crohn's and anastomotic strictures can be balloon-dilated. Long inflammatory strictures and suspected cancer cannot. SEMS is not first-line for benign colon disease. IBD dysplasia technique is the surveillance page, not this one.
Selected references
Last reviewed September 20, 2026. Written for clinicians staring at a left-sided apple-core obstruction and deciding between emergency surgery, a stent, and a balloon they should not use.
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