Stomach Cancer: Symptoms, Diagnosis and Current Treatment Options

What is stomach cancer?

The great majority of stomach cancers are adenocarcinomas. The tumour can be located in the upper part of the stomach, near the junction with the oesophagus (cardia), or in the lower parts of the stomach; the location affects both the symptoms and the surgical approach [3].

What causes stomach cancer? Risk factors

One of the most important risk factors is infection with Helicobacter pylori, which causes long-term inflammation of the stomach lining [1]. A diet rich in salted, smoked or improperly stored foods and low in vegetables and fruit, and smoking, also increase the risk. Atrophic gastritis, a family history of stomach cancer and inherited conditions such as hereditary diffuse gastric cancer or Lynch syndrome are other risk factors [1][2].

How common is stomach cancer?

According to World Health Organization data, stomach cancer is among the most common cancers worldwide, with about 1 million new cases in 2024, and is also among the top five causes of cancer-related death [4].

What are the symptoms of stomach cancer?

• Persistent indigestion, heartburn or pain in the stomach
• Feeling full quickly after eating little, loss of appetite
• Nausea, vomiting
• Difficulty swallowing (especially in tumours of the upper stomach)
• Unexplained weight loss, black stools, anaemia

In the early stage symptoms may be mild and non-specific; endoscopic evaluation is important for long-lasting digestive complaints [2].

How is stomach cancer diagnosed?

The diagnosis is made by biopsy taken during upper gastrointestinal endoscopy. For staging, thoracic-abdominal CT is used, and when needed endoscopic ultrasound and PET-CT; in locally advanced disease, diagnostic laparoscopy may be recommended to assess spread to the peritoneum [3].

Biomarker tests

In advanced disease, determining the status of HER2, PD-L1 (CPS), MSI/MMR and Claudin 18.2 in tumour tissue directly affects the choice of targeted drug and immunotherapy [3][5].

How is stomach cancer treated?

Treatment is planned according to the stage, the location of the tumour and the biomarker results. Assoc. Prof. Dr. Ali Oğul’s approach is to evaluate patient files in a multidisciplinary tumour board together with specialists in general surgery, gastroenterology, radiology and pathology.

Early and localised disease

Very early-stage selected tumours can be removed endoscopically. In localised disease, the standard approach is gastrectomy with lymph node dissection together with chemotherapy given before and after surgery (such as the perioperative FLOT protocol) [3][6].

Advanced disease

The mainstay of treatment is chemotherapy containing platinum and fluorouracil. In HER2-positive tumours, trastuzumab is added to chemotherapy. In HER2-negative tumours with PD-L1 expression, immunotherapy drugs such as nivolumab or pembrolizumab can be used together with chemotherapy. In Claudin 18.2-positive tumours, zolbetuximab is an option. In later lines, ramucirumab (together with paclitaxel) or, in HER2-positive disease, antibody-drug conjugates such as trastuzumab deruxtecan can be considered [3][5].

Latest regulatory updates for this cancer type: Stomach Cancer: Latest Developments

Side effects and follow-up during treatment

Chemotherapy can cause fatigue, nausea and a fall in blood counts. After stomach surgery, eating small, frequent meals, support from a dietitian and monitoring of vitamin B12 and iron levels are important. After treatment, follow-up is done with regular examination, blood tests and imaging.

Can stomach cancer be prevented?

Recognising and treating H. pylori infection, reducing salted and smoked foods, eating more vegetables and fruit and quitting smoking can lower the risk [1][2]. In people with a familial risk, endoscopic surveillance and genetic counselling may be considered.