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Health condition · Clinically reviewed

Bowel cancer, screening, surgery and modern targeted care.

The 4th most common cancer in the UK and the 2nd biggest cancer killer. Caught early through FIT screening or acted on quickly, it is often curable.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a UK-registered clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, ESMO, the NHS Bowel Cancer Screening Programme and peer-reviewed sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including FIT screening from age 50, total neoadjuvant therapy and dostarlimab for MSI-high rectal cancer.

Key facts

Bowel cancer at a glance.

The essentials, in plain English. Who gets it, how it is found and how it is treated in the UK today.

  • What it is

    A cancer of the colon or rectum. In the UK it is the 4th most common cancer and the 2nd biggest cancer killer, with around 44,000 new diagnoses each year.

  • Types

    Adenocarcinoma accounts for 90 to 95 percent. Rarer types include neuroendocrine and carcinoid tumours, squamous cell (anal and low rectal), GIST, lymphoma and metastatic deposits.

  • Who gets it

    Median age at diagnosis is 72, but early-onset bowel cancer in people under 50 is rising and now a distinct clinical concern.

  • UK screening

    The NHS Bowel Cancer Screening Programme sends a home FIT kit every two years from age 60 to 74, expanding to age 50 by 2025. A positive test leads to colonoscopy.

  • Diagnosis

    Colonoscopy with biopsy is the gold standard. Staging uses MRI rectum, CT chest, abdomen and pelvis, and selective PET-CT.

  • Modern treatment

    Surgery, chemotherapy, radiotherapy, targeted agents and immunotherapy, tailored by stage, tumour location and molecular profile (MMR/MSI, KRAS, NRAS, BRAF, HER2, NTRK).

Why this guide matters

Early action changes outcomes.

Screening finds bowel cancer sooner. Molecular profiling makes treatment sharper. Immunotherapy has opened new options for a specific group.

  • Screening saves lives

    The NHS FIT programme is one of the most effective cancer screens in the UK. Take part when your kit arrives.

  • Molecular profiling shapes therapy

    MMR status, KRAS, NRAS, BRAF, HER2 and NTRK now guide which drugs will work, especially for advanced disease.

  • Immunotherapy is transforming care

    For MSI-high tumours, PD-1 blockers such as dostarlimab and pembrolizumab are producing remarkable early responses.

How the diagnosis is made

From first symptoms to a full staging plan.

The pathway a UK GP and colorectal team will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Symptom review and FIT

    A structured history, a symptom-based FIT test and baseline bloods (FBC for iron-deficiency anaemia, LFTs, U&Es, CEA) shape the urgency of referral.

  2. 02

    Assessing

    Two-week-wait referral

    Change in bowel habit for over three weeks, rectal bleeding, iron-deficiency anaemia, weight loss or a palpable mass trigger urgent suspected-cancer referral.

  3. 03

    Assessing

    Colonoscopy with biopsy

    The gold-standard test. Any suspicious lesion is biopsied and small polyps can be removed at the same visit.

  4. 04

    Confirming

    CT colonography or flexi-sig

    CT colonography is an alternative for frail patients or incomplete colonoscopy. Flexible sigmoidoscopy is used for distal disease.

  5. 05

    Confirming

    Staging imaging

    MRI of the rectum for rectal cancers (T stage, nodes, EMVI and circumferential resection margin), CT chest, abdomen and pelvis for distant disease, PET-CT when needed.

  6. 06

    Profiling

    Tumour molecular profiling

    Universal MMR and MSI testing, with KRAS, NRAS, BRAF, HER2 and NTRK for metastatic disease. Lynch screening for younger patients and strong family histories.

  7. 07

    Profiling

    Genetic counselling

    Considered when the person is young, has a strong family history or meets Amsterdam or Bethesda criteria. Panel testing checks Lynch, FAP, MUTYH, Peutz-Jeghers and juvenile polyposis genes.

Typical timeline: from referral to a staged, MDT-agreed plan in a few weeks.

Symptoms

What bowel cancer can look and feel like.

Not every symptom is cancer. But persistent symptoms should always be checked - especially in combination.

  • Change in bowel habit

    Persistent looser or more frequent stools for more than three weeks, often the earliest symptom.

  • Rectal bleeding

    Fresh red blood mixed with the stool, or darker blood, especially without an obvious external cause.

  • Iron-deficiency anaemia

    Especially in right-sided colon cancer, where blood loss is slow and hidden. Often picked up on a routine blood test.

  • Abdominal pain or mass

    Crampy pain, bloating or a palpable lump, sometimes with signs of partial obstruction.

  • Tenesmus

    A constant feeling of needing to open the bowels even when empty, typical of rectal cancer.

  • Weight loss and fatigue

    Unexplained weight loss and persistent tiredness are non-specific but important signals.

  • Early-onset presentation

    Bowel cancer under 50 is rising. Persistent symptoms in a young adult still deserve investigation.

  • Red flag - obstruction

    Severe abdominal pain, vomiting, bloating and no stool or wind is a surgical emergency. Attend A&E.

Treatment

How bowel cancer is treated in the UK.

Surgery, chemotherapy, radiotherapy, targeted agents and immunotherapy - the mix depends on stage, tumour location and molecular profile, agreed by a colorectal MDT.

  • Colonic resection

    Right, left, extended or subtotal hemicolectomy, most often laparoscopic or robotic. The tumour and its lymph node basin are removed together.

  • Adjuvant chemotherapy

    FOLFOX or CAPOX for three months after surgery in high-risk stage II and stage III disease, based on IDEA trial evidence.

  • Total mesorectal excision

    The standard rectal operation - low anterior resection where sphincters can be saved, or abdominoperineal resection with a permanent stoma if not.

  • Neoadjuvant radiotherapy

    Short-course radiotherapy (5 x 5 Gy) or long-course chemoradiation (capecitabine with 50.4 Gy) before rectal surgery to shrink the tumour and improve margins.

  • Total neoadjuvant therapy

    RAPIDO and PRODIGE 23 established TNT - all chemotherapy and radiotherapy before surgery - as practice-changing for locally advanced rectal cancer.

  • Dostarlimab or pembrolizumab

    For MSI-high or mismatch-repair-deficient rectal cancer, neoadjuvant immunotherapy has produced complete responses in nearly every patient in early trials.

  • Metastatic chemotherapy

    Doublet or triplet regimens (FOLFOX, FOLFIRI, FOLFIRINOX) with bevacizumab, or cetuximab or panitumumab for RAS and BRAF wild-type left-sided tumours.

  • Targeted and later-line

    Encorafenib with cetuximab for BRAF V600E, trastuzumab plus tucatinib for HER2, sotorasib or adagrasib for KRAS G12C, larotrectinib or entrectinib for NTRK, regorafenib, trifluridine-tipiracil and fruquintinib as later options.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, European society standards and landmark trials, current at the time of last review.

Key references

Guidelines and trials we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or colorectal team knows your history and imaging and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Colorectal cancer (NG151).

  • NICE. Suspected cancer: recognition and referral (NG12).

  • ESMO. Clinical practice guidelines for localised and metastatic colorectal cancer.

  • NHS Bowel Cancer Screening Programme. FIT and colonoscopy pathway.

  • Cercek et al. PD-1 blockade in mismatch repair-deficient locally advanced rectal cancer. NEJM 2022.

  • Bowel Cancer UK. Patient information and support.

Red flags

When to act sooner, not later.

These features raise the priority of investigation or need same-day care. If in doubt, contact NHS 111 or attend A&E.

  • Bowel obstruction

    Severe abdominal pain, vomiting, distension and no stool or wind is a surgical emergency. Attend A&E without delay.

  • Heavy rectal bleeding

    Significant fresh bleeding, dizziness or fainting needs urgent assessment.

  • Perforation

    Sudden severe abdominal pain with fever and a rigid abdomen suggests perforation and needs emergency care.

  • New iron-deficiency anaemia

    Unexplained iron-deficiency anaemia in men and postmenopausal women warrants urgent lower-GI investigation.

  • Persistent symptoms under 50

    Ongoing change in bowel habit, rectal bleeding or unexplained weight loss in a younger adult should still be investigated. Early-onset bowel cancer is rising.

  • Strong family history

    Multiple first-degree relatives with bowel or Lynch-related cancers should trigger a discussion about genetic testing and earlier surveillance.

  • Positive FIT result

    A positive screening or symptomatic FIT should lead to colonoscopy on an urgent pathway.

  • Ulcerative colitis flares

    Long-standing ulcerative or Crohn colitis raises cancer risk. Surveillance colonoscopy on schedule matters.

  • Post-treatment red flags

    New pain, weight loss, rising CEA or new symptoms during surveillance need prompt review by the colorectal team.

Living with it

Screening, lifestyle and a team behind you.

Four things that make the biggest difference - taking part in screening, small consistent lifestyle changes, using the specialist team and keeping up with follow-up.

A quiet reminder

One in twenty of us will get bowel cancer.

Doing the FIT test at home and mentioning symptoms early gives you the best possible chance of a curable diagnosis.

  1. 01 Screening

    Do the FIT test

    When the NHS bowel screening kit arrives, use it. It is a simple stool test at home that saves lives by catching cancers early.

  2. 02 Lifestyle

    Small changes add up

    Less processed and red meat, more fibre, less alcohol, no smoking, regular movement and a healthy weight all measurably lower risk.

  3. 03 Support

    Lean on the team

    Colorectal nurse specialists, stoma nurses and charities such as Bowel Cancer UK are there from diagnosis onwards.

  4. 04 Follow-up

    Stick with surveillance

    Five years of follow-up with CEA, CT and colonoscopy picks up recurrence early, when treatment options are widest.

Frequently asked

Everything we get asked about bowel cancer.

Quick answers on screening, symptoms, genetics, surgery and modern targeted therapy.

  • What is bowel cancer?

    Bowel cancer, also called colorectal cancer, is a cancer of the colon or rectum. Around 90 to 95 percent are adenocarcinomas that start in the gland cells of the bowel lining. It is the 4th most common cancer in the UK and the 2nd biggest cancer killer, with about 44,000 new diagnoses each year.

  • What are the main symptoms?

    A persistent change in bowel habit for more than three weeks, rectal bleeding, iron-deficiency anaemia, abdominal pain, a feeling of incomplete emptying (tenesmus), unexplained weight loss and fatigue. Right-sided cancers often show up as anaemia rather than obvious bleeding.

  • How does UK bowel cancer screening work?

    The NHS Bowel Cancer Screening Programme sends a free home FIT kit every two years to people aged 60 to 74, expanding to age 50 by 2025. FIT looks for tiny amounts of blood in the stool. A positive result leads to a colonoscopy for further assessment.

  • Do I need genetic testing?

    It is worth considering if you were diagnosed young, have multiple relatives with bowel or Lynch-related cancers, or meet Amsterdam or Bethesda criteria. Panel testing looks for Lynch syndrome (MLH1, MSH2, MSH6, PMS2, EPCAM), FAP, MUTYH-associated polyposis and other inherited syndromes.

  • What does modern treatment look like?

    It depends on stage and location. Colon cancer is usually treated with surgery, often laparoscopic or robotic, with chemotherapy afterwards for higher-risk disease. Rectal cancer often needs neoadjuvant radiotherapy or chemoradiation, then total mesorectal excision. Metastatic disease uses chemotherapy with targeted agents and, for MSI-high tumours, immunotherapy.

  • What is the news about immunotherapy for rectal cancer?

    A landmark 2022 New England Journal of Medicine trial showed that dostarlimab, a PD-1 inhibitor, produced a complete clinical response in every patient with mismatch-repair-deficient locally advanced rectal cancer treated, avoiding surgery and radiotherapy. Larger trials are ongoing, but this has changed practice for the small but important MSI-high group.

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