The incidence of gastric cancer varies between countries. Stomach cancer is common all over the world but especially in East Asia, South America, and Eastern Europe. The incidence is 2 times higher in men compared to women. It is often diagnosed between the ages of 60-80 years. It is more common in societies with low socioeconomic status.
What Are the Risk Factors?
Helicobacter pylori infection frequently causes gastritis, peptic ulcer, and gastric maltomas. In countries with high gastric cancer incidences, the incidence of HP infection is usually high.
Gastroesophageal reflux is coming up of the gastric acid from the stomach to the esophagus, increasing the risk of developing cancer in the esophagus and gastric junction (cardia). The risk of gastric cancer is high in people who have previously undergone a partial gastric excision due to any reason, including peptic ulcer. Stomach polyps (adenomas) can transform into cancer. Chronic atrophic gastritis and intestinal metaplasia are precancerous lesions.
Obesity contributes to developing gastric cancer by facilitating gastroesophageal reflux leading to Barrett’s esophagus formation in the gastroesophageal junction.
The risk of cancer is increased 3-folds in individuals having first-degree relatives with gastric cancer. High levels of dietary salt intake and consumption of brined and smoked foods increase the risk of stomach cancer. Gastric cancer risk may increase with the consumption of foods containing high quantities of nitrate or nitrite, including brined meat.
Gastric cancers have been shown to be associated with smoking in up to 20% of the patients and smoking has been shown to increase the risk of gastric cancer by 1.5 times. The relationship between alcohol consumption and gastric cancer development has not been established, yet. Studies report conflicting results about this subject.
Prostate cancer, breast cancer, bladder cancer or testicular cancer, and a previous history of ovarian cancer, breast cancer or cervical cancer in women increases the risk of developing cancer in the stomach.
Immunocompromised people due to HIV, AIDS, drugs taken after organ transplants, and infections are at twice a higher risk of having stomach cancer compared to other individuals. These conditions may increase the risk of infection including Helicobacter pylori infections.
What Are the Presenting Complaints of Gastric Cancer Patients?
Gastric cancer symptoms are often vague and not specific. At the initial phases of the disease, 70% of the patients suffer from complaints of pain or discomfort in the upper abdomen. These complaints are then followed by weight loss, nausea, vomiting, hematemesis (the vomit looks like coffee grounds), melena (tarry stool), severe anorexia, and bloating. Cardia tumors may present with complaints of dysphagia (difficulty swallowing).
How Is Stomach Cancer Diagnosed?
The diagnosis of stomach cancer is made based on the findings obtained from the following assessments and tests:
1. Physical Examination: The doctor will examine your abdomen for any pain and swelling. The doctor will also check if there are lumps or palpable nodes between the left neck and the shoulder because the disease may have spread to the lymph nodes in that region in patients with advanced disease.
2. Endoscopic Examination: This examination of the esophagus helps evaluate the esophagus, stomach, and some parts of the small intestine. A biopsy is taken from the region where abnormalities are detected during endoscopy. The collected tissue samples are then submitted to the laboratory for further examination.
How Is Staging Performed In Stomach Cancer?
Preoperative staging plays an important role in the diagnosis in patients with gastric cancer. Staging helps select the specific surgical approach and identify the patients, who will not benefit from surgery.
Contrast computed tomography (CT) is the most common diagnostic method. However, endosonography (EUS) can also be used to screen for regional spread. CT provides information about both the local and systemic stages of the disease. This way, the layers of the stomach and the lymph nodes are visualized in detail and information is obtained about the spread of the disease throughout the gastric wall and the metastases to the lymph nodes.
How Is Treatment Carried Out In Stomach Cancers?
The aim of surgical intervention in gastric cancer should be complete resection to leave no residual tumor tissue. As a general rule, lymphatic dissection is also performed during gastric resection. In the preoperative evaluation, preoperative chemotherapy (neoadjuvant) should be considered for regressing the stage of the disease before surgery if complete tumor resection is not possible. Removal of the stomach is called gastrectomy.
Stage IA – mucosal cancer: Patients with early gastric cancer in this group can be treated with local excision because the likelihood of lymphatic metastasis is less than 5%. Endoscopic treatment methods can also be used in these patients. These methods include endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD).
Stage IB (submucosal Ca) II and IIIA tumors: These patients are diagnosed with more lymph node metastases compared to stage IA patients. Patients benefit most from radical surgery such as systemic lymphadenectomy.
Stage IIIB and IV tumors: These stages indicate the presence of locally advanced tumors that may also be associated with distant metastases. Complete tumor removal cannot be achieved by surgical resection in these tumors. Neoadjuvant treatments should be performed before surgery.
Laparoscopic surgery provides the same quality outcomes as open surgery. Even, it is possible to better visualize the tissue in detail owing to the closer view.
Selection of the surgical technique in gastric cancer patients mainly depends on tumor location. In distal cancers, subtotal (70-80% of the stomach is excised) or total (removal of the whole stomach) gastrectomy is performed. In gastric tumors located in the middle of the stomach, total gastrectomy is always performed. The tumors located in the proximal 1/3 of the stomach, the distal part of the esophagus and the whole stomach is usually removed.
Prognosis varies between countries.