Gastric cancer, also called stomach cancer, is usually diagnosed by upper gastrointestinal endoscopy and biopsy. Selected very early cancers can be removed through an endoscope, while other localised cancers need surgery. For many patients with resectable, locally advanced disease, chemotherapy is given before and after surgery. If the cancer has spread, treatment usually starts with medicines, and biomarkers such as HER2, PD-L1, MSI/MMR, and CLDN18.2 can change which treatment is offered. [1, 2]
By Dr Raman Narang, Consultant Medical & Hemato-Oncologist, New Delhi
Last clinically reviewed [Insert review date]
A CT report may describe stomach cancer as “operable,” yet the oncology team may recommend chemotherapy first. The decision depends on how deeply the cancer appears to have grown, whether nearby lymph nodes are involved, and whether further staging could reveal spread that would change the plan. If you are seeking gastric cancer treatment in Delhi, ask your team to explain the purpose and sequence of each treatment before you begin.
1. What are the symptoms, risk factors, and types of stomach cancer?
Early gastric cancer can cause few symptoms. Possible signs include persistent upper abdominal discomfort, feeling full after a small meal, unexplained weight loss, persistent vomiting, and iron-deficiency anaemia. A tumour near the junction with the oesophagus may cause difficulty swallowing. Vomiting blood or passing black, tarry stools warrants urgent medical assessment. These symptoms have several possible causes, and persistent or progressive symptoms deserve evaluation. [1, 2]
Helicobacter pylori (H. pylori) infection is an important risk factor, particularly for cancers arising away from the junction with the oesophagus. Other risk factors include tobacco use, certain long-standing changes in the stomach lining, and a family history of gastric cancer. A diagnosis at a young age or a family pattern of diffuse gastric cancer can prompt a discussion about genetic counselling. [1, 2]
Most stomach cancers are adenocarcinomas. Pathologists may describe them as intestinal-type or diffuse-type, and may note poorly cohesive or signet-ring cells. These features can affect staging and surgical planning. This page focuses on gastric adenocarcinoma. Gastric lymphoma, gastrointestinal stromal tumours (GISTs), and neuroendocrine tumours follow separate treatment pathways. [1, 2]
2. How is gastric cancer diagnosed and staged?
An upper gastrointestinal endoscopy with biopsy usually confirms the diagnosis. The endoscopy shows where the tumour sits and how much of the stomach it involves. The pathology identifies the cancer type, and biopsy tissue can also be used for biomarker testing when indicated. A contrast CT of the chest, abdomen, and pelvis helps assess nearby lymph nodes and look for distant spread. Endoscopic ultrasound can help assess tumour depth in selected cases, particularly when that information could change the treatment. [1, 2]
Some patients who appear to have removable cancer on CT are advised to have staging laparoscopy with peritoneal washings. During this keyhole procedure, the surgeon inspects the abdominal lining and collects fluid to check for cancer cells. Small deposits can be missed on CT. Finding cancer cells in the washings can change the stage and the treatment plan even when there are no visible deposits. This assessment is particularly relevant when chemotherapy before surgery is being considered. [1, 2]
The team also checks weight loss, food intake, anaemia, and physical fitness. If eating has become difficult, nutrition support can begin during staging.
3. How is early-stage gastric cancer treated?
Selected very early cancers confined to the inner lining of the stomach can be removed through an endoscope, often by endoscopic submucosal dissection (ESD). Eligibility depends on the lesion’s size, depth, and other features that affect the likelihood of lymph node spread. After removal, the pathologist checks the depth, margins, and whether cancer cells have entered small blood or lymphatic vessels. Those findings determine whether endoscopic treatment was sufficient or surgery should be discussed. [1, 2]
For early tumours that need surgery, an operation may be the first treatment. A partial gastrectomy removes part of the stomach. A total gastrectomy removes the whole stomach when the tumour’s location or extent requires it. The surgeon also removes regional lymph nodes for staging and cancer control. The final pathology helps determine whether further treatment is needed. [1, 2]
4. When is surgery done first, and when is chemotherapy given first?
The decision depends on the clinical stage, the likelihood of complete removal, and the patient’s fitness for both chemotherapy and surgery. Removing the tumour is one part of treatment. For deeper tumours or those involving regional lymph nodes, the team also considers the risk of microscopic spread. [1, 2]
| Clinical situation | What the team usually discusses |
|---|---|
| Very early tumour with a low risk of lymph node spread | Whether endoscopic removal can provide complete treatment. |
| Early, resectable cancer unsuitable for endoscopic removal | Surgery first, with the final pathology guiding the need for additional treatment. |
| Resectable, locally advanced cancer, often stage II or III | Perioperative chemotherapy, which starts before surgery and continues afterward when recovery allows. FLOT is a common option for patients fit enough to receive it. |
| Surgery already performed, with stage II or III disease found on pathology | Whether postoperative chemotherapy such as CAPOX is appropriate after adequate surgery and lymph node removal. |
| Locally advanced cancer that cannot be removed completely at diagnosis | Systemic treatment and, in selected cases, a later review of whether surgery or another local treatment has become feasible. |
Chemotherapy before surgery starts treating possible microscopic disease early. It may also shrink the tumour and allows the team to reassess before a major operation. When surgery is planned for locally advanced disease, the team usually aims for clear margins and appropriate regional lymph node removal, often called a D2 lymph node dissection. [1, 2]
Where does immunotherapy fit around surgery? The MATTERHORN trial supports adding durvalumab to perioperative FLOT, followed by durvalumab alone, for eligible patients with resectable gastric or gastro-oesophageal junction adenocarcinoma. The US FDA approved this approach in November 2025. For treatment in Delhi, the team should verify the applicable Indian prescribing indication, access, and individual suitability before recommending it. [3, 4]
Radiation is used selectively. It may be discussed after surgery in certain situations, such as a microscopically positive margin. It can also help control symptoms such as tumour bleeding in advanced disease. [1, 2]
5. How is metastatic gastric cancer treated?
When cancer has spread to the liver, abdominal lining, distant lymph nodes, or other organs, systemic treatment is usually the main approach. The goals are to control the cancer, relieve symptoms, and help patients live longer where possible. Chemotherapy often includes a fluoropyrimidine and a platinum drug. Biomarker results help determine whether to add immunotherapy or a targeted drug. [1, 2]
| Biomarker | How it can change treatment |
|---|---|
| HER2 | HER2-positive cancers may be treated with trastuzumab and chemotherapy. In eligible patients, PD-L1 results can also inform whether pembrolizumab is added. |
| PD-L1 combined positive score (CPS) | Helps guide whether to add immunotherapy to chemotherapy. The relevant threshold depends on the regimen and applicable prescribing indication. |
| MSI-high or mismatch repair deficiency (dMMR) | Can identify tumours for which immunotherapy is particularly relevant. This finding may also affect discussions about treatment for localised disease. |
| CLDN18.2 | In eligible patients with CLDN18.2-positive, HER2-negative advanced gastric or gastro-oesophageal junction adenocarcinoma, zolbetuximab with chemotherapy may be a first-line option, depending on local access and indication. |
If the cancer progresses, the next treatment depends on the first regimen, biomarker results, and overall fitness. Options may include paclitaxel with ramucirumab or, in selected patients with HER2-positive disease previously treated with trastuzumab, trastuzumab deruxtecan. Supportive care can begin alongside cancer treatment. It may address nausea, pain, anaemia, poor intake, or symptoms caused by bleeding or a blockage at the stomach outlet. [1, 2]
What I look for clinically before recommending treatment
I review the biopsy and original scan images together. If the cancer appears removable, I ask whether staging laparoscopy could reveal spread that would change the plan. I also want to know how much weight the patient has lost and what they can eat today. For advanced disease, I check whether the biopsy has enough tissue for the biomarkers that could change the first treatment. If vomiting, bleeding, or poor intake needs attention now, I discuss how to manage it while treatment is being planned.
How the next step is decided
| If the reports show… | The next discussion is about… |
|---|---|
| A very superficial lesion | Whether endoscopic removal is appropriate |
| A deeper tumour or suspicious regional nodes without visible distant spread | Whether staging laparoscopy is needed and whether chemotherapy should come before surgery |
| Cancer already removed by surgery | The final stage, margins, lymph nodes, and value of postoperative chemotherapy |
| Spread to the abdominal lining or another distant site | Biomarker-guided systemic treatment and symptom support |
What to bring to a gastric cancer consultation in Delhi
- Upper GI endoscopy report and images, including the tumour’s location.
- Biopsy or surgical pathology report and details for obtaining the tissue block.
- CT or MRI reports and the original scan images, if available.
- Staging laparoscopy and peritoneal washings reports, if performed.
- HER2, PD-L1, MSI/MMR, and CLDN18.2 results, if already tested.
- Details of recent weight loss, current food intake, vomiting, and any previous treatment.
Frequently asked questions
Does every patient with stomach cancer need the whole stomach removed?
Some patients can have a partial gastrectomy, depending on the location and extent of the tumour. Selected very early lesions can be removed endoscopically. [1, 2]
Why do I need a laparoscopy if my CT scan shows no spread?
Small deposits on the abdominal lining can be difficult to see on CT. Laparoscopy and washings can identify disease that changes whether surgery is appropriate. [1, 2]
Can a patient receive immunotherapy for gastric cancer?
Yes, in selected settings. The decision depends on the stage, the treatment combination, biomarker results where relevant, and the locally applicable indication. [1–4]
Can I eat normally after gastrectomy?
Eating often changes after surgery. Smaller, more frequent meals may help. The team can advise on weight monitoring, dietetic support, and replacement of nutrients such as vitamin B12, particularly after total gastrectomy. [1, 2]
Before treatment, ask your team which finding determines the first step and what would change the sequence. If surgery is planned, ask how much of the stomach may need to be removed and how nutrition will be supported during recovery.
This page is for general education. Individual treatment decisions require review of your pathology, imaging, nutritional status, and overall health by your treating team.
Clinical references
- European Society for Medical Oncology. Pan-Asian Adapted ESMO Clinical Practice Guidelines for the Diagnosis, Treatment and Follow-up of Patients with Gastric Cancer.
- National Cancer Institute. Gastric Cancer Treatment (PDQ), Health Professional Version.
- MATTERHORN phase III trial. Perioperative Durvalumab Plus FLOT for Resectable Gastric and Gastro-oesophageal Junction Adenocarcinoma.
- US Food and Drug Administration. FDA Approves Durvalumab for Resectable Gastric or Gastroesophageal Junction Adenocarcinoma. November 2025.