Stomach cancer, also known as gastric cancer, is the development of cancerous cells in the stomach lining. This disease has the factors of age, the diet a person follows, and stomach diseases as risk factors. Stomach cancer is diagnosed with the help of procedures like a physical exam of the patient, endoscopy, and biopsy of the affected tissue.

The stages of stomach cancer are determined by the degree to which the cancerous cells have grown and how far cancer has spread in the stomach tissue, the lymphatic system, and to the other organs in the body. Stomach cancer is classified into five stages from 0 to 4 according to the same:

Stage 0
In stage 0, there is a presence of abnormal cells in the innermost lining of the stomach wall. These abnormal cells may turn into cancer and spread to the nearby healthy tissue. This stage is called the carcinoma in situ.

Stage I
Stage 1 is classified into 1A and 1B:

• Stage 1A : At this stage, the disease has affected the innermost lining (mucosa) of the stomach wall, and the cancer cells may have spread to the submucosa, which is the adjoining layer of tissue to the mucosa.
• Stage 1B : At this stage, the cancer cells may have spread into the submucosa, have affected one or two lymph nodes, and have also affected the muscle layer of the stomach wall.

Stage ll
Stage ll stomach cancer is classified into Stage ll A and Stage ll B:

• Stage ll A : At this stage, cancer has spread to the subserosa of the stomach wall (layer of connective tissue next to the muscle layer) or one to two lymph nodes in the muscle layer or to 3 or 6 lymph nodes in the submucosa.
• Stage ll B : Cancer has spread to the outermost layer of the stomach wall or 1 to 2 lymph nodes in the subserosa or 3 to 6 lymph nodes in the muscle layer or 7 or more lymph nodes in the submucosa.

Stage III
Stage III stomach cancer is classified into stage III A, stage III B, and stage III C:

• Stage III A : At this stage, cancer has spread to 1 to 6 lymph nodes in the serosa, 3 to 6 lymph nodes in the subserosa, or 7 or more lymph nodes in the muscle layer.
• Stage III B : The stage III B cancer is found in 7 or more lymph nodes of the subserosa or the serosa or in the nearby organs like spleen, liver, pancreas, kidney, adrenal glands, colon, or the small intestine.
• Stage III C : Stage III C cancer has spread to 16 or more lymph nodes in the subserosa or the serosa. It has also spread to the nearby organs like the small intestine, pancreas, adrenal gland, spleen, kidney, colon, or diaphragm.

Stage IV
The stomach cancer has spread to the distant organs in the body like the lungs, liver, and distant lymph nodes at this stage.

The treatment of stomach cancer depends on the stage of cancer and the organs affected by it. The different treatment options are surgery, chemotherapy, radiation therapy, and targeted therapy.