Gastric carcinoma represents the most common gastric neoplasm accounting for 95% of all gastric tumors . Besides, it is one of the most common cancer in the world and a major cause of morbidity and mortality. It cause 30% of the cancer deaths in high risk areas, such as China and Japan. The peak of incidence of gastric carcinoma is estimated from between 50 and 70 years and its prevalence is variable in different countries. This pathological condition has a greater impact in certain geographical areas, such as Japan, Latin America and Eastern Europe. In fact, the prevalence of gastric carcinoma is very high in Japan, where the mortality rate is about 110 cases/100.000 inhabitants while a value of 50/100.000 has been estimated in Italy. Males are affected more commonly than females, with most patients presenting in the sixth decade.
Gastric carcinoma represents an aggressive tumor with a 5 year survival rate less than 20%. Superficial carcinoma forms are called “early gastric cancer” and have a better prognosis, with a 5 year survival rate of more than 90%. In fact, the 5 year survival rates range from 3% in case of stage IV to 85-90% in case of stage I, depending on tumor stage.
Among etiological factors, some dietary habits have been identified, such as hot or salty food. Unlike the esophageal carcinoma, alcohol and smoking do not seem to influence the incidence of gastric carcinoma. Atrophic gastritis, gastric ulcers, intestinal metaplasia, reflux esophagitis, gastric polyps, Menetrier disease, partial gastrectomy, pernicious anemia, achlorhydria and hypochlorhydria represent risk conditions and may predispose to the development of adenocarcinoma of the stomach. In 30% of cases gastric carcinoma is located on antrum, in 30% on gastric body and in other 30% on fundus or cardia; the remaining 10% is represented by diffuse infiltrating gastric lesions which affect all gastric walls at the time of diagnosis. Macroscopically, superficial forms, also called early gastric cancer, and advanced forms can be identified. Early gastric cancer is limited to the mucosal or submucosal layers and is characterized by variable incidence values from between 30% in Japan and 2 - 6% in other countries. Early gastric cancer can be difficult to recognize and can appear as a small, circumscribed, sometimes ulcerated thickening of the gastric wall.
The advanced gastric carcinoma reaches the muscolaris propria and four different kinds can be identified: polypoid, ulcerating, ulcerating infiltrating and infiltrating forms, also called linitis plastica. Generally, in case of advanced gastric carcinoma, wall thickening exceeds 1 centimeter, with a variable extension, or a vegetating mass with irregular surfaces and a wide retracted base due to the invasion of the adjacent gastric wall can be identified. The Jarvi and Lauren classification usually identifies intestinal or diffuse histological forms, the latest representing about the 80-90% of all gastric forms. The remaining 10-20% are represented by a third gastric form which collect all the other histological kinds. The intestinal form is usually moderately differentiated and originates from intestinal metaplasia areas; diffuse form represents an undifferentiated form which originated from gastric epithelium.
In most of the cases gastric carcinoma has a preferential diffusion towards the cardia or it follows a contiguity, lymphatic or haematic mechanism. Usually, the intestinal form is less infiltrating, rarely can have a peritoneal involvement and can give hepatic metastatic nodules. On the contrary, diffuse gastric carcinoma rapidly involves adjacent structures and peritoneum.
gastric carcinoma symptoms
However, metastatic diffusion usually depends on the extension and the depth of infiltration of the primary tumor. The most common metastatic sites are represented by lymph nodes (80% of cases), liver (40%), peritoneum (30%), lung (20%), pancreas (17%), retroperitoneum (12%), adrenal glands (10%), ovaries (5%) and diaphragm (5%). Symptoms from gastric carcinoma are often non specific and also completely absent for a long time and tumor can be already advanced at the time of the diagnosis. Epigastric pain syndrome, dyspepsia, anemia, weight loss and weakness represent the most common symptoms.
Prognosis and therapy of gastric carcinoma
Prognosis and therapy of gastric carcinoma depend on the stage of the disease at the time of the diagnosis and the first challenge for clinicians is to define the extent of the tumor in order to plan the best treatment . Besides, an early diagnosis and accurate staging are crucial for the choice of an accurate therapeutic approach and can also influence the survival rate ). Surgery remains the main therapeutic option and the choice of the most suitable treatment is determined by preoperative staging, which is based on diagnostic imaging. Radiation therapy or chemotherapy are reserved in selected cases.