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Health condition · Clinically reviewed

Stomach (gastric) cancer, H. pylori risk, staging and multimodal treatment.

Adenocarcinoma is the most common subtype. H. pylori eradication reduces risk. Modern staging + neoadjuvant FLOT chemotherapy + gastrectomy transform outcomes for resectable disease.

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Why trust this guide

  • 01

    Clinically reviewed

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

  • 02

    Sourced, not summarised

    Every claim is checked against NICE, AUGIS or ESMO — you can see the sources at the end.

  • 03

    Updated for 2026

    Reflects current UK guidance on H. pylori eradication, FLOT neoadjuvant chemotherapy and HER2/PD-L1 testing.

Key facts

Stomach cancer at a glance.

The essentials, in plain English — what it is, how common it is, what raises risk and how staging shapes treatment.

  • What it is

    Gastric adenocarcinoma is the most common subtype — cancer arising from the glandular lining of the stomach.

  • How common

    Around 6,500 new cases each year in the UK.

  • Modifiable risk

    H. pylori infection is a major modifiable risk factor — eradication reduces risk.

  • Inherited risk

    Family history matters — CDH1 mutations and Lynch syndrome raise risk and change screening.

  • How it is staged

    OGD + endoscopic ultrasound + CT chest/abdomen/pelvis, with staging laparoscopy for advanced disease.

  • Biomarkers guide care

    HER2 and PD-L1 status on the biopsy shape systemic treatment choices.

Why this guide matters

Early diagnosis changes everything.

H. pylori is modifiable, staging has improved, and FLOT chemotherapy plus modern surgery meaningfully change survival for resectable disease.

  • H. pylori is modifiable

    Testing and eradicating H. pylori removes a major, treatable driver of gastric cancer risk.

  • Alarm symptoms deserve urgent OGD

    Dyspepsia with weight loss, dysphagia or GI bleed must trigger a 2-week-wait endoscopy — not another PPI trial.

  • Biomarkers change treatment

    HER2 and PD-L1 status on the biopsy decide who benefits from trastuzumab or nivolumab alongside chemotherapy.

How the diagnosis is made

From first symptom to a clear plan.

The upper GI pathway UK MDTs now follow, in order — so you know what to expect and why each test matters.

  1. 01

    Assessing

    Symptom review + H. pylori status

    A careful history looking for alarm symptoms and dyspepsia, plus H. pylori testing where relevant.

  2. 02

    Assessing

    Urgent OGD + biopsy

    A 2-week-wait upper GI endoscopy with targeted biopsies of any suspicious lesion.

  3. 03

    Assessing

    Endoscopic ultrasound (EUS)

    EUS refines local T-stage and N-stage — especially for early tumours being considered for endoscopic resection.

  4. 04

    Confirming

    CT chest / abdomen / pelvis

    Contrast CT looks for nodal involvement, liver, lung and peritoneal spread.

  5. 05

    Confirming

    Staging laparoscopy

    For locally advanced tumours, laparoscopy detects peritoneal disease missed on CT.

  6. 06

    Planning

    HER2 + PD-L1 + MSI testing

    Biomarker testing on the biopsy — HER2, PD-L1 CPS and mismatch-repair — guides systemic therapy.

  7. 07

    Planning

    Upper GI MDT

    A specialist upper GI multi-disciplinary team agrees the treatment plan that fits your stage and biology.

Typical timeline: 4–8 weeks from alarm symptom to a treatment plan.

Symptoms

What stomach cancer actually shows up as.

Early gastric cancer can be silent. When symptoms do appear they can look like ordinary indigestion — here is what deserves urgent attention.

  • Dyspepsia + red flags

    Persistent dyspepsia with alarm features — weight loss, dysphagia or GI bleed — needs urgent OGD.

  • Weight loss

    Unintentional weight loss over weeks or months is an important pointer to upper GI cancer.

  • Vomiting

    New persistent vomiting, especially after meals, can signal a gastric outlet problem.

  • Iron-deficiency anaemia

    Unexplained iron-deficiency anaemia — particularly in men and post-menopausal women — warrants upper and lower GI investigation.

  • Epigastric pain

    Persistent upper-abdominal pain that does not settle with usual treatment deserves review.

  • Early satiety

    Feeling full quickly, or being unable to finish a normal-sized meal, is a subtle but important symptom.

  • Palpable mass

    A palpable epigastric mass on examination is an urgent finding.

  • Red flag

    Alarm dyspepsia — weight loss, dysphagia or GI bleed — triggers a 2-week-wait OGD referral.

Treatment

How stomach cancer is treated in the UK.

Treatment is chosen by stage and biology — from endoscopic resection of early lesions, to perioperative FLOT plus gastrectomy, to targeted and immune therapies for advanced disease.

  • Endoscopic submucosal dissection (early T1)

    Endoscopic removal for carefully selected early T1 tumours — spares the stomach entirely.

  • Subtotal gastrectomy

    Surgical removal of the lower stomach for distal tumours, preserving the upper part where possible.

  • Total gastrectomy

    Complete removal of the stomach for proximal or diffuse tumours, with reconstruction.

  • Neoadjuvant FLOT chemotherapy

    Pre-operative FLOT (5-FU, leucovorin, oxaliplatin, docetaxel) is now standard for resectable disease.

  • Trastuzumab (HER2-positive)

    Anti-HER2 antibody added to chemotherapy for HER2-positive advanced or metastatic disease.

  • Nivolumab (PD-L1 CPS ≥5, first-line)

    PD-1 immunotherapy with chemotherapy in first-line advanced disease when PD-L1 CPS is 5 or higher.

  • Palliative chemotherapy

    Systemic chemotherapy to control symptoms and extend life in advanced disease.

  • Best supportive care

    Symptom control, nutrition support and palliative care when active treatment is no longer appropriate.

What this guide is based on

The sources behind every number on this page.

UK and European guidance, specialist society standards and patient-organisation resources, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or upper GI team knows your history and can tell you which parts apply to you.

  • National Institute for Health and Care Excellence (NICE). Oesophago-gastric cancer: assessment and management (NG83).

  • Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland (AUGIS).

  • European Society for Medical Oncology (ESMO). Gastric cancer clinical practice guidelines.

  • No Stomach for Cancer — patient information and hereditary diffuse gastric cancer resources.

Red flags

When stomach cancer becomes an emergency.

These are the situations that need action today — not next week — whether at diagnosis, during treatment or in advanced disease.

  • Perforated gastric ulcer

    Sudden severe upper-abdominal pain with peritonism — call 999 or attend A&E immediately.

  • Massive haemorrhage

    Vomiting blood or passing melaena with faintness needs emergency admission for endoscopy.

  • Malignant gastric outlet obstruction

    Persistent vomiting, dehydration and inability to keep food down — needs urgent hospital review.

  • Peritoneal disease

    New ascites or abdominal distension in known gastric cancer suggests peritoneal spread — needs same-day assessment.

  • Neutropenic sepsis

    Fever within a chemotherapy cycle is a medical emergency — go straight to your acute oncology unit.

  • Anastomotic leak

    Fever, tachycardia or severe pain after gastrectomy needs urgent surgical review.

  • Malnutrition

    Rapid weight loss or inability to eat needs early dietitian input and consideration of nutritional support.

  • Post-op dumping syndrome

    Sweating, palpitations, diarrhoea or dizziness after eating — treatable, but flag it to your team.

  • Palliative-stage crisis

    Uncontrolled pain, bleeding or vomiting in advanced disease — contact your palliative care team the same day.

Living with it

A long-term journey, with structured support.

Four things that make the biggest difference day to day — nutrition, supplements, follow-up and family screening.

A quiet reminder

Ask for a dietitian early.

Specialist upper GI dietetics protects your weight and strength — before, during and after treatment.

  1. 01 Nutrition

    Eat little and often

    After gastrectomy, small frequent meals and specialist dietitian input protect your weight and strength.

  2. 02 Supplements

    B12 and iron for life

    Total gastrectomy means lifelong vitamin B12 injections, and iron levels need regular monitoring.

  3. 03 Reviews

    Structured follow-up

    Regular upper GI oncology follow-up with imaging as needed keeps recurrence and complications in check.

  4. 04 Family

    Consider genetics

    Strong family histories or diffuse-type cancers should trigger a genetics referral to test for CDH1 and Lynch syndrome.

Frequently asked

Everything we get asked about stomach cancer.

Quick answers on H. pylori, endoscopy, FLOT chemotherapy, HER2/PD-L1 and when to worry.

  • What is stomach cancer?

    Gastric adenocarcinoma — cancer arising from the glandular lining of the stomach — is the most common subtype. Around 6,500 new cases are diagnosed each year in the UK.

  • Does H. pylori cause stomach cancer?

    H. pylori is a major modifiable risk factor for gastric cancer. Eradicating H. pylori infection reduces the risk, which is why it is tested for and treated when found.

  • What is FLOT chemotherapy?

    FLOT is a combination of 5-fluorouracil, leucovorin, oxaliplatin and docetaxel. Given before and after surgery (perioperative), it is now standard neoadjuvant treatment for resectable gastric cancer in the UK.

  • Why do HER2 and PD-L1 matter?

    HER2-positive gastric cancers can be treated with trastuzumab added to chemotherapy. Tumours with PD-L1 CPS of 5 or higher may benefit from nivolumab immunotherapy in first-line advanced disease.

  • Is stomach cancer inherited?

    Most cases are not inherited, but CDH1 mutations (hereditary diffuse gastric cancer) and Lynch syndrome raise risk significantly and change how relatives are screened. Strong family histories deserve a genetics referral.

  • When should I ask for urgent tests?

    Persistent dyspepsia with alarm symptoms — unintentional weight loss, dysphagia, GI bleed or a palpable mass — triggers a 2-week-wait OGD in the UK. Sudden severe pain or vomiting blood is a 999 emergency.

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