Malignant transformation of gastric ulcer

The stomach is located in the upper abdomen of the human body, shaped like the letter "J," and is an important digestive organ for food. Gastric cancer can arise in any part of the stomach, and its development process may span many years. The symptoms of gastric cancer and precancerous lesions are insidious and nonspecific, making early gastric cancer difficult to detect. In fact, only 5% to 10% of gastric cancer cases in China can be diagnosed at an early stage. The mortality rate of gastric cancer in China is 25.2 per 100,000 (male: 32.8 per 100,000, female: 17.0 per 100,000), accounting for 23.2% of all malignant tumor deaths, ranking first among malignant tumor deaths (males are 1.9 times that of females). The world age-adjusted mortality rate of gastric cancer in China is 40.8 per 100,000 for males and 18.6 per 100,000 for females, which are 4.2 to 7.9 times and 3.8 to 8.0 times higher than those in developed countries in Europe and America, respectively. The incidence of gastric cancer in China shows significant regional and urban-rural differences. A national sample survey of 263 sites found that the age-adjusted mortality rate of gastric cancer ranged from 2.5 to 153.0 per 100,000, with urban and rural areas at 15.3 per 100,000 and 24.4 per 100,000, respectively, the latter being 1.6 times that of the former. The main pathological type of gastric cancer is adenocarcinoma; other types include squamous cell carcinoma, adenosquamous carcinoma, carcinoid tumor, and small cell carcinoma, among others, which are relatively rare. Treatment strategies differ among different types of gastric cancer. In China, the incidence of gastric cancer is highest in the northwest, followed by the northeast and Inner Mongolia, then East China and coastal areas, and lowest in central-south and southwest China. Approximately 170,000 people die from gastric cancer each year, accounting for nearly one-quarter of all malignant tumor deaths, and more than 20,000 new gastric cancer patients are diagnosed annually. Gastric cancer is indeed a disease that seriously threatens public health. It can occur at any age but is most common in individuals aged 40 to 60, with a male-to-female ratio of about 2:1. Its etiology remains unclear and may be related to multiple factors, such as lifestyle habits, dietary patterns, environmental factors, genetic predisposition, and psychological factors, as well as chronic gastritis, gastric polyps, gastric mucosal dysplasia and intestinal metaplasia, remnant stomach after surgery, and long-term Helicobacter pylori (HP) infection. Gastric cancer can occur in any part of the stomach but is most commonly found in the gastric antrum, especially on the lesser curvature. Based on the depth of cancer tissue invasion, it is classified into early gastric cancer and advanced gastric cancer (middle and late-stage gastric cancer). Early symptoms of gastric cancer are often subtle, such as vague upper abdominal discomfort, dull pain, belching, acid regurgitation, loss of appetite, and mild anemia, some of which resemble symptoms of gastroduodenal ulcers or chronic gastritis. Some patients experience reduced or relieved pain after taking analgesics, anti-ulcer medications, or dietary adjustments, and thus may be overlooked without further examination. As the disease progresses, gastric symptoms become more pronounced, manifesting as upper abdominal pain, loss of appetite, wasting, weight loss, and anemia. In later stages, cancer metastasis often occurs, presenting with abdominal masses, enlarged left supraclavicular lymph nodes, melena, ascites, and severe malnutrition. Since gastric cancer is extremely common in China and highly harmful, related research suggests that its causes are associated with dietary habits and gastric diseases; therefore, understanding the basic knowledge of gastric cancer is of great significance for its prevention and treatment.