What is stomach cancer?
Stomach cancer or gastric carcinoma refers to cancer of the stomach, the hollow organ in the upper abdomen. The stomach wall is made up of many layers, which protects the stomach from the action of digestive juices and stomach acid. The innermost layer is called the mucosa, cells of which make stomach acid and digestive juices. The next layer is called submucosa. After submucosa, a layer of muscle is found called muscularis. The outer 2 layers are called subserosa and serosa. There are different types of stomach cancers depending from which layer the tumor arises.
What are the types of stomach cancer?
- Adenocarcinomas, which form in mucosa layer. These are the most common and make up 90% of the cases of stomach cancer.
- Lymphomas, which begin in immune system cells. It is a rare type of stomach cancer.
- Carcinoids, which begin in hormone-producing cells.
- Gastrointestinal stromal tumors (GISTs), which begin in nervous system cells found in the stomach. Rare.
The location of these tumors defines the clinical stage of stomach cancer, which also affects the treatment choice.
What are the stages of stomach cancer?
- Stage 0 is the one, in which cancer is restricted to the inner lining of the stomach. If it spreads further, it will be treated as stage 1 cancer.
- Stage 1 can be sub-divided in stage 1A or stage 1B depending on the involvement of the second layer and regional lymph nodes.
- In stage 2, cancer penetrates the the second and distant lymph nodes, or the third layer and the lymph nodes in the area, or all 4 layers without affecting the lymph nodes.
- Stage 3 the cancer extends to the third layer and remote lymph nodes, or to the fourth layer and nearby tissues or lymph nodes.
- In stage 4, there is evidence that the cancer has extended to surrounding organs and tissue as well as to remote lymph nodes.
Stomach cancer in the early stages is easy to treat. However, treatment becomes difficult if cancer spreads to deeper layers or other organs.
What are the symptoms of stomach cancer?
The symptoms of stomach cancer may include:
- Bloating of the stomach after eating
- Feeling full quickly
- Stomach pain
- Vomiting, sometimes bloody vomit
- Weight loss
What causes stomach cancer?
The exact causes of stomach cancer are not known, though many factors can play a role in its development.
- Chronic infection with a bacteria called H. pylori causes stomach cancer in many patients.
- Heredity factors.
- Cigarette smoking increases the risk of all cancers, including stomach cancer.
- Alcohol abuse.
- Long term inflammation of stomach wall (gastritis) also increase the risk of developing stomach cancer.
- In many patients, gastric polyps develop into stomach cancer over time.
How is stomach cancer treated?
Treatment for stomach cancer depends on the type of cancer, stage of the cancer, and overall health of the patient.
Surgical options to remove all of the stomach cancer may include:
- In endoscopic mucosal resection, early-stage tumors from the stomach lining are removed.
- In subtotal gastrectomy, a portion of the stomach affected by cancer is removed; whereas in total gastrectomy, entire stomach is removed and esophagus is connected directly to the small intestine.
- In lymphadenectomy, lymph nodes are removed.
This approach can be used either before surgery (neoadjuvant radiation) or after surgery (adjuvant radiation). Radiation therapy is often used together with other cancer treatments like chemotherapy. Side-effects include diarrhea, indigestion, nausea and vomiting.
In this approach, combination of drugs (like 5‑fluorouracil, mitomycin, doxorubicin, leucovorin, or cisplatin) is used to kill cancer cells. Chemotherapy is recommended when cancer has spread beyond the stomach. Chemotherapy too can be given before or after a surgery.