Gastric cancer, also known as stomach cancer, is the development of cancerous cells in the lining of the stomach. Although it can develop anywhere in the stomach, gastric cancer most often affects the body of the stomach. Gastric cancer is the second most prevalent cause of cancer-related mortality in the world (738,000 deaths per year) and the fourth most common disease in terms of new cases (989,600 in 2008). Geographical variation significantly affects the occurrence. More than 50% of newly discovered cases are identified in developing nations. 

Gastric cancer is the development of cancerous cells in the lining of the stomach. It is the fourth most common cause of cancer-related death in the world.

Symptoms

The majority of patients do not experience any symptoms when gastric cancer is in its early stages. However, symptoms only appear when the disease has progressed significantly. The most prevalent signs and symptoms include:

• Unintentional weight loss

• Persistent abdominal (belly) pain

• Epigastric fullness

• Nausea

• Vomiting

• Loss of appetite

• Dysphagia (difficulty in swallowing)

• Dyspepsia (indigestion)

• Early satiety and/or iron deficiency anemia.

• Occult gastrointestinal bleeding, with or without iron deficiency anemia.

• Overt bleeding in the form of melena (passage of black, tarry stools) or hematemesis (vomiting of blood) can be seen in less than 20% of cases.

Diagnosis

The medical history, physical examination, and imaging tests can be suggestive of the diagnosis of gastric cancer. Nonetheless, the diagnosis must be confirmed by evaluation of the biopsy specimen and histopathological diagnosis. The methods employed in the diagnosis of gastric cancer include:

• Upper gastrointestinal endoscopy: It can detect gastric cancers at an early stage. Magnifying endoscopy with narrow-band imaging has been reported to be accurate and reliable for the early identification of gastric cancer.

• Barium swallow / upper gastrointestinal series: An upper gastrointestinal (GI) series, often known as a barium swallow, is a diagnostic procedure that examines the upper part of the digestive system, including the esophagus, stomach, and duodenum. These examinations help determine the stage and early identification of gastric cancer.

• Imaging modalities: These include endoscopic ultrasound (the most accurate and sensitive diagnostic procedure for patients suspecting gastric cancer), computed tomography (CT, used for staging gastric cancer), magnetic resonance imaging (MRI, used in the clinical diagnosis and treatment of gastric cancer), and 18F-Fluorodeoxyglucose-positron emission tomography (FDG-PET, used to evaluate the extent of cancer).

• Staging laparoscopy (SL): It is a quick, minimally invasive procedure that needs a small incision. It can provide an accurate diagnosis of peritoneal dissemination and extra-serosal invasion.

• Histopathological examination of the biopsy specimen: It involves the removal of cells or tissues of the suspicious area. A tissue sample may be collected from regions where cancer may have spread and tested for HER2 genes, proteins, and the presence of Helicobacter pylori infection. It is also screened for high tumor mutational load.

Management

A multidisciplinary treatment approach before any treatment decision is mandatory in gastric cancer patients which comprises:

• Surgery: Surgery is frequently used to treat gastric cancer at all stages which include subtotal gastrectomy (removal of the cancerous portion of the stomach, surrounding lymph nodes, and nearby organ or tissue fragments) and total gastrectomy (entire stomach is removed). The spleen might be taken out in both procedures.

• Endoscopic mucosal resection: Endoscopic mucosal resection is a minimally invasive technique that removes the tumor through the lumen of the stomach.

• Chemotherapy: The most frequently prescribed drug for the treatment of gastric cancer is fluorouracil (5-FU), which may occasionally administer in combination with doxorubicin and mitomycin C. Chemotherapeutic drugs are coupled with tumor antigen-specific antibodies to enable direct delivery of the medications to the tumor.

• Radiation therapy: In patients with advanced gastric cancer, preoperative radiation therapy is primarily utilized to reduce tumor burden. It has been utilized, primarily as an adjuvant treatment along with chemotherapy.

• Chemoradiation: Combining chemotherapy and radiation therapy increases the effectiveness of both treatments. Adjuvant chemoradiation may compensate for inadequate surgery.

• Targeted therapy: Targeted therapies for the treatment of gastric cancer include monoclonal antibodies (Trastuzumab and ramucirumab) and multi-kinase inhibitors (Regorafenib) that are used to treat stage IV gastric cancer that cannot be surgically removed or has recurred.

• Immunotherapy: Immune checkpoint inhibitors including anti-programmed cell death-1 (PD-1) or anti-programmed cell death ligand-1 (PD-L1) monoclonal antibodies have been shown to extend survival in advanced gastric cancer. The immunotherapies that are improving outcomes in advanced gastric cancer include pembrolizumab and nivolumab.

In general, there has been a tremendous improvement in the understanding and therapeutics of gastric cancer. Numerous environmental and genetic factors can affect the development of gastric cancer. Greater knowledge of these elements holds the prospect of preventing gastric cancer and producing cutting-edge treatments.