Stomach Cancer (Gastric Cancer)
Stomach cancer or gastric cancer is a malignant tumour arising from the inner lining (mucosa) of the stomach wall. It is one of the leading causes of cancer-related mortality worldwide, ranking particularly high in East Asia, Eastern Europe and parts of South America. The disease most commonly develops in the antrum (lower part of the stomach) and is strongly associated with Helicobacter pylori infection, chronic gastritis, dietary factors (high salt and processed food intake) and prolonged smoking. Gastric cancer progresses insidiously symptoms are often absent or vague in early stages, which is why the majority of cases are diagnosed at an advanced stage.
Symptoms
In its early stages, stomach cancer may be entirely asymptomatic or mimic common benign conditions such as gastritis or peptic ulcer disease. As the tumour grows, patients typically present with persistent upper abdominal pain or discomfort, early satiety, progressive dysphagia (difficulty swallowing) if the tumour involves the gastro-oesophageal junction, unexplained and significant weight loss, nausea and vomiting sometimes containing blood or dark material and black tarry stools (melaena) indicating upper gastrointestinal bleeding. In advanced disease, a palpable abdominal mass, ascites, or a hard enlarged lymph node above the left clavicle (Virchow's node) may be detected on examination.
Diagnosis
Upper GI Endoscopy (OGD Oesophagogastroduodenoscopy) is the cornerstone of diagnosis allowing direct visualisation of the gastric mucosa, targeted biopsy of suspicious lesions and histopathological confirmation of malignancy. CT scanning of the chest, abdomen and pelvis is performed for staging assessing local tumour invasion, regional lymph node involvement and distant metastasis, particularly to the liver and peritoneum. Endoscopic Ultrasound (EUS) provides high-resolution assessment of tumour depth (T-staging) and is essential for surgical planning. PET scan may be used selectively to detect occult metastatic spread. Serum tumour markers including CEA, CA 19-9, and CA 72-4 are measured at baseline and used to monitor treatment response over time.
Treatment
Treatment strategy is determined by tumour stage, location and the patient's overall performance status. For resectable disease, surgery remains the only potentially curative option. Total or subtotal gastrectomy removal of the entire stomach or the affected portion along with regional lymph nodes (D2 lymphadenectomy) is the procedure of choice, with reconstruction using a Roux-en-Y jejunal loop to restore continuity. For tumours at the gastro-oesophageal junction an Oesophagogastrectomy may be required. In locally advanced cases, perioperative chemotherapy (given both before and after surgery the FLOT regimen being current standard) significantly improves resection rates and overall survival. Radiotherapy may be used as adjuvant treatment in selected cases, particularly where surgical margins are close. For metastatic or unresectable Stage IV disease, palliative chemotherapy with or without targeted agents (such as trastuzumab for HER2-positive tumours) aims to control disease progression and preserve quality of life. Palliative surgical bypass or endoscopic stenting may be offered to relieve obstruction and restore the ability to eat comfortably.