# Obstruction and T4 disease in bowel cancer

Source: https://onco.cc/terms/obstructing-colorectal-cancer/  
OnCo record `obstructing-colorectal-cancer` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Sometimes a bowel cancer is found only when it blocks the bowel or has grown through its outer wall into the peritoneum or a neighbouring organ. Both change the plan: a blockage may be relieved with a stent so that surgery can be done calmly a few weeks later, and a tumour that has grown outside the bowel may be given chemotherapy first.

## Summary

Obstruction. Colorectal cancer often presents with a blockage that needs urgent decompression, and where a primary tumour is left in place in metastatic disease, around 20 in 100 people develop obstruction, perforation, bleeding or pain needing surgery (NICE NG151, the table on the asymptomatic primary tumour, on low-quality evidence). NICE asks teams to consider stenting for people being treated with palliative intent (1.3.1) and to offer either stenting or emergency surgery to those in whom cure is still possible (1.3.2). The CReST trial randomised 245 patients from 39 hospitals with left-sided obstruction to a stent followed by elective surgery one to four weeks later, or to surgical decompression. Stenting was attempted in 96.7 percent and relieved obstruction in 82.4 percent. Among the 89 percent treated with curative intent there was no significant difference in 30-day postoperative mortality (3.6 against 5.6 percent) or hospital stay (median 19 against 18 days), but stoma formation fell from 67.9 to 47.5 percent, with no difference in perioperative morbidity, critical care use, quality of life, three-year recurrence or mortality (Hill 2022).

T4 disease. T4a means the tumour has grown through the outer lining of the bowel wall into the peritoneum; T4b means it has grown into a nearby organ (Cancer Research UK). Both carry a higher risk of recurrence, and T4b often needs resection of more than the bowel. NICE NG151 (1.3.16) says to consider preoperative systemic anticancer therapy for cT4 colon cancer, on the strength of the FOxTROT trial, in which patients with radiologically staged T3 to T4, N0 to N2, M0 colon cancer were allocated to six weeks of oxaliplatin and fluoropyrimidine before surgery plus eighteen after, or twenty-four weeks after surgery alone; 96 percent of those allocated to preoperative treatment started it (FOxTROT Collaborative Group 2023). T4 disease, obstruction, fewer than twelve examined nodes and lymphovascular invasion are also the features that make a stage II colon cancer high-risk and bring adjuvant chemotherapy into the discussion; the parent record carries those rows.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: bowel obstruction from cancer; obstructing colorectal cancer; large bowel obstruction; colonic stent; bridge to surgery; T4 colon cancer; locally advanced colon cancer
- Tags: gi; colorectal

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Bowel_obstruction
- NICE NG151: colorectal cancer, recommendations (Lynch 1.1, local disease 1.3, biomarkers 1.4, metastatic disease 1.5, ongoing care and support including follow-up 1.6): https://www.nice.org.uk/guidance/ng151/chapter/Recommendations
- Hill, Br J Surg 2022: CReST, colorectal endoscopic stenting trial for obstructing left-sided colorectal cancer (245 patients): https://doi.org/10.1093/bjs/znac141
- FOxTROT Collaborative Group, J Clin Oncol 2023: preoperative chemotherapy for operable colon cancer, mature results (699 patients allocated to preoperative chemotherapy, randomised 2:1): https://doi.org/10.1200/jco.22.00046
- CRUK: TNM staging for bowel cancer: https://www.cancerresearchuk.org/about-cancer/bowel-cancer/stages-types-and-grades/TNM-staging

## Connected records

- cancers: [Colon cancer (adenocarcinoma of the colon)](https://onco.cc/cancers/colon-cancer/), [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Rectal cancer](https://onco.cc/cancers/rectal-cancer/)
- terms: [Colectomy](https://onco.cc/terms/colectomy/), [Conversion therapy in bowel cancer](https://onco.cc/terms/conversion-therapy-colorectal/), [Emergency presentation (route to diagnosis)](https://onco.cc/terms/emergency-presentation/), [Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/), [Liver-limited metastatic bowel cancer](https://onco.cc/terms/liver-limited-metastatic-colorectal/), [Lymphovascular invasion (LVI)](https://onco.cc/terms/lymphovascular-invasion/), [TNM staging](https://onco.cc/terms/tnm-staging/)
- technologies: [CT (computed tomography)](https://onco.cc/technologies/ct/)

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