Gastric cancer, also known as stomach cancer, occurs when malignant cells form in the lining of the stomach. It can develop slowly over many years and often goes unnoticed in its early stages. Common symptoms include persistent stomach pain, difficulty swallowing, and unexplained weight loss. Risk factors include Helicobacter pylori infection, smoking, and a diet high in salty or smoked foods. Early detection is crucial for better treatment outcomes. Doctors may use imaging tests, endoscopy, or biopsies to diagnose gastric cancer. Treatment options often include surgery, chemotherapy, and radiation therapy, depending on the cancer's stage and the patient's overall health.