Written and medically reviewed by: Assoc. Prof. Cengiz Dibekoğlu, MD, General SurgeryLast updated:
Stomach (Gastric) Cancer
Staging, biomarkers, perioperative therapy, and gastrectomy
HER2, PD-L1, CLDN18.2, and MSI/MMR are different tests. When they matter depends on the stage of disease.
Early gastric cancer can feel like ordinary indigestion — the question I hear most is how long to keep taking acid medicine alone. I do not lock perioperative sequencing before staging laparoscopy and peritoneal cytology when indicated. Gastric cancer care starts with accurate staging; many locally advanced tumors receive chemotherapy around the time of surgery. Gastrectomy includes the appropriate lymph nodes. Symptoms that persist or worsen need endoscopy. Biomarkers guide systemic therapy especially in advanced disease: HER2, PD-L1, and CLDN18.2 mainly shape metastatic drug choice, while MSI/MMR can matter earlier. Laparoscopic or robotic gastrectomy is considered only when the same cancer operation can be done safely.
Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Figure summary
- Labeled on this figure: Esophagus · Stomach · Duodenum.
- Related figures on this page: Diagnosis, Treatment, Operations, Robotic.
Figure labels (English)
- Esophagus
- Stomach
- Duodenum
Educational figures
Tap a figure to enlarge. These English illustrations mirror the Turkish hub gallery for this condition.
Diagnosis Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Treatment Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Operations Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Robotic Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Perioperative pathway
Neoadjuvant then surgery then adjuvant when indicated.
Biomarkers by stage
HER2 / PD-L1 / CLDN18.2 mainly shape advanced systemic choices.
MSI/MMR
Separate clinical meaning, including earlier settings.
Minimally invasive options
Laparoscopic / robotic gastrectomy in selected cases.
What to know
- Key note inside
How biomarkers affect treatment
HER2, PD-L1 CPS, and CLDN18.2 mainly influence advanced/metastatic drug choice. MSI/MMR may matter in localized disease as well. Not every marker is mandatory at every stage.
- MSI/MMR → stage-dependent meaning
- HER2 / PD-L1 / CLDN18.2 → mainly advanced disease
- Timing is set in tumor board
Staging before locking sequence
CT staging, endoscopy, and — when indicated — staging laparoscopy with cytology prevent operating into unresectable peritoneal disease.
Surgery types
Subtotal versus total gastrectomy depends on tumor location and oncologic margins. Lymphadenectomy extent follows oncologic standards, not incision size.
Nutrition is part of treatment
Prehabilitation, feeding routes, and vitamin supplementation after gastrectomy are planned with the resection — not left as an afterthought.
- Key note inside
When major resection is not offered
Unresectable spread or performance status that cannot tolerate major surgery changes the goal toward systemic therapy and symptom control — stated honestly.
What happens next
What patients notice — and which warning signs need urgent care
- 1
Gastric Cancer Symptoms
What patients notice — and which warning signs need urgent care
Read this chapter - 2
Gastric Cancer Diagnosis
How clinicians confirm the problem and stage the next steps
Read this chapter - 3
Gastric Cancer Treatment
How treatment options are matched to risk, stage, and goals
Read this chapter - 4
Gastric Cancer Operations
Operations: what the procedure aims to do and who it fits
Read this chapter - 5
Laparoscopic Gastrectomy
Minimally invasive gastrectomy when staging and anatomy fit
Read this chapter - 6
Robotic Gastric Cancer Surgery
Robotic: what the procedure aims to do and who it fits
Read this chapter - 7
Life After Gastric Surgery
Nutrition, vitamins, and recovery after gastrectomy
Read this chapter
Evidence
Scientific sources
Show sources · 3International guidelines for gastric cancer staging, multimodal therapy, and surgical pathways.
Evidence
Scientific sources
- 1. Gastric cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-upESMO · 2022 · DOI: 10.1016/j.annonc.2022.07.004Open source →
- 2. NCCN Guidelines — Gastric CancerNCCN · Current versionOpen source →
- 3. ESMO Gastrointestinal Cancer Guidelines (topic hub)ESMO · Living / eUpdateOpen source →
Last reviewed: 21 August 2026. Links go to publisher pages.
Appointment / info
Pathology with biomarker reports, endoscopy notes, and staging imaging accelerate an honest perioperative plan.
This page is for education. It is not medical advice and does not replace a visit with your physician.
Medical editor: Assoc. Prof. Cengiz Dibekoğlu, MD · English patient-education hub.