Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 8 Sept 2026Clinical review pending
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Bleeding, perforation or outlet obstruction
Gastric cancer may present with haemorrhagic shock, free perforation or persistent vomiting with profound dehydration and aspiration risk.
Action: Resuscitate, decompress obstruction under appropriate supervision, obtain urgent endoscopic and surgical input, and integrate emergency control with tissue diagnosis and oncological staging.
Synopsis
Recognise gastric cancer and its atrophy–metaplasia–dysplasia sequence, map and biopsy the stomach systematically, eradicate Helicobacter pylori where appropriate, and link stage to endoscopic or surgical treatment.
Most gastric cancers are adenocarcinomas developing through chronic inflammation, gland loss, intestinal metaplasia and dysplasia, although diffuse cancers may not form a discrete precursor field.
Helicobacter pylori is a major modifiable carcinogenic driver; autoimmune gastritis creates corpus-predominant atrophy, achlorhydria and B12 deficiency.
For suspected advanced gastric adenocarcinoma obtain at least eight viable biopsies; take only one or two targeted biopsies from a potentially endoscopically resectable lesion, and at least ten bite-on-bite samples when linitis plastica is suspected.
Key red flags
Iron-deficiency anaemia, early satiety, persistent vomiting, weight loss, dysphagia or a palpable epigastric mass requires prompt upper-GI assessment.
A gastric ulcer that appears benign still needs appropriate biopsy and follow-up to demonstrate healing and exclude an underlying cancer.
Diffuse infiltration
Poor distension, thickened folds and a rigid stomach suggest linitis plastica despite limited surface ulceration.
Investigation priorities
01
High-quality gastroscopy with lesion samplingFirst step
Inspect the entire stomach and establish cancer or precursor histology.
Biopsy confirms gastric adenocarcinoma and CT shows no distant metastases.
Review pathology, nutrition and performance status at the specialist MDT.
Perform staging laparoscopy for potentially curable gastric disease and sample suspicious deposits or washings according to protocol.
Key medicines
One current local first-line H pylori regimen: omeprazole, amoxicillin and metronidazoleFor a confirmed infection in an adult weighing at least 40 kg with normal hepatic function, GFR above 30 mL/min, no penicillin allergy and no metronidazole use in the previous year, one March 2026 NHS Somerset example is omeprazole 20 mg orally twice daily, amoxicillin 1 g orally twice daily and metronidazole 400 mg orally twice daily for 7 days. With the cited omeprazole 10 mg gastro-resistant tablets, each 20 mg dose is two tablets; swallow whole without chewing or crushing.Exclude penicillin/severe immediate beta-lactam hypersensitivity and nitroimidazole allergy. At GFR 10–30 mL/min the amoxicillin product limit is 500 mg twice daily; below 10 it is 500 mg daily. At GFR 30 or below, obtain an individually adjusted eradication regimen before prescribing rather than using this full-dose example. Hepatic impairment also requires an individual regimen/dose review: do not default to 20 mg omeprazole twice daily or full-dose metronidazole in severe disease. Omeprazole is contraindicated with nelfinavir; avoid combining it with clopidogrel and ask the prescriber/pharmacist to select a suitable acid-suppression alternative without stopping clopidogrel automatically. Take metronidazole with or after food, avoid alcohol during treatment and for 48 hours afterwards, and review warfarin/INR, lithium, methotrexate and other interactions. Check adherence and the eradication result when indicated before selecting treatment after failure.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 8 Sept 2026; clinical approval remains outstanding.