Cancer types · Common solid tumours
Gastric & Oesophageal Cancers
Gastric (stomach) and oesophageal cancers include adenocarcinomas and, in the oesophagus, squamous cell carcinomas. Histology and location shape both the questions and the relevant evidence.
In advanced disease, several biomarkers are commonly discussed, and some are assessed by immunohistochemistry rather than sequencing.
Clinical and molecular questions that often arise
- Is it adenocarcinoma or squamous cell carcinoma, and where exactly is it located?
- What are the HER2, PD-L1 and MSI or MMR results?
- Has Claudin 18.2 been assessed where relevant?
- Does age or family history raise a hereditary question?
Information that may be part of an individual assessment
- Endoscopy with biopsy.
- Immunohistochemistry for HER2, PD-L1 and MMR proteins, and Claudin 18.2 where relevant.
- Staging imaging, sometimes with endoscopic ultrasound or laparoscopy.
- Broader molecular profiling in selected situations.
Which investigations are appropriate is decided by the treating team for each person.
Molecular profiling and biomarker interpretation
Depending on the setting, molecular and biomarker questions in gastric & oesophageal cancers may involve:
- HER2 status
- PD-L1 combined positive score
- MSI-high or MMR-deficient status
- Claudin 18.2 expression
- Epstein–Barr virus status (subtype context)
- FGFR2b and other emerging biomarkers (research context)
Biomarkers, panels and available tests vary by subtype, disease setting, assay and guideline version. A detected alteration is not automatically actionable.
How KPCIRC pathways may apply
POAS
POAS may help organise multiple biomarker results, distinguish what is established from what is investigational, and set out trial and access questions.
Molecular Tumour Board
MTB discussion may help with complex staging, multimodality planning or discordant biomarker results.
Second opinion and progression review
A second opinion may help clarify the proposed sequence of surgery, chemotherapy and radiotherapy. Progression review can organise new findings after treatment.
Hereditary risk and screening
Hereditary diffuse gastric cancer (CDH1) and Lynch syndrome are among the inherited conditions associated with stomach cancer. Early age at diagnosis or a family history of gastric or related cancers may prompt risk assessment.
How to access the relevant pathway
Patients and families
- Talk to your treating oncologist about whether an additional review may help.
- Request a consultation and tell us which question you want answered.
- Share records only when asked, through the secure route.
Referring doctors
- Define the clinical question and the pathway: POAS, MTB, second opinion or progression review.
- Start a case enquiry without patient identifiers.
- Scope, fees and timing are confirmed before any review proceeds.
Questions and limitations
Why are several different tests needed?
Each biomarker answers a different question and some are measured by immunohistochemistry, not sequencing. Together they help describe the cancer.
Is a high PD-L1 score a guarantee that immunotherapy will work?
No. PD-L1 is one piece of evidence that depends on the assay and scoring method; it does not by itself establish benefit.
Does this page apply to my situation?
This page is educational. It explains common questions but cannot account for individual circumstances. Your treating clinician is best placed to interpret your reports and plan your care.
Educational content reviewed against the KPCIRC service scope. It is not a diagnosis, a treatment recommendation or a statement that a specialist or service is available for this cancer type.