Gastric cancer, commonly known as stomach cancer, is a common and serious form of malignant tumor that develops from cells in the glands that line the inner wall (mucosa) of the stomach. Stomach cancer is the third leading causes of cancer-related death in the world, and the 15th most common cancer in the United States. However, its incidence has been declining for two decades, thanks to campaigns to reduce its risks: high sodium diet (too much salt), alcohol consumption, smoking… For more information please see gastric cancer causes and risk factors.
Gastric cancer usually starts its development in the lining of the stomach wall. As the tumor grows, it invades the deep layer of the mucosa or submucosal layer. As this stage, it is an early stage tumor with higher chance of survival. Surgical treatment can be less aggressive and more successful. At early stage, warning signs are unspecific and no severe: mild pain, nausea, vomiting, impaired general condition … For more information, please see gastric cancer symptoms.
Although there are different types, adenocarcinoma constitutes up to 95% of all primary gastric cancers. This form of tumor develops in the glandular cells that line the inner surface of the stomach and other internal organs such as cervical canal. This is the type most commonly called “stomach cancer”. Gastric adenocarcinoma is a common medical condition in Japan, China, South America and Eastern Europe. In fact, the disease is the most common form of malignant tumor in Japan, affecting successively about 75 men and 35 women out of 100,000 populations.
Other rare tumors of the stomach are, among others, non-Hodgkin lymphoma, gastrointestinal stromal tumor (GIST), and Kaposi’s sarcoma. These cancers can require specific treatments. For more information, please see gastric cancer treatment.
How Cancer Forms in the Stomach?
The stomach, which is a part of the digestive system, is a muscular organ in the form of bag, housed in the upper abdomen. It is in it that foods mix with digestive juices (which made up of water, electrolytes, hydrochloric acid, enzymes, mucus and intrinsic factor) that are produced by glands in the lining of the stomach. These gastric juices help break down food in a semi-solid mixture which is then fed into the small intestine for assimilation.
Due to carcinogenic effects, the gastric cells sometimes undergo changes which make them grow or reproduce abnormally. These changes can cause the formation of non-cancerous tumors (or benign), such as gastric polyps, benign gastrointestinal stromal tumors (GIST), or lipomas. Gastric cancer treatment is more strong and toxic than therapies for non-cancerous tumors.
The stomach cells can also undergo precancerous changes. In these cases, the cells are not malignant but their risk of becoming cancerous is higher. Some common precancerous conditions that may transform into cancer include gastric adenomas or adenomatous polyps, and gastric epithelial dysplasia.
In some cases, the cellular modification leads to cancerous growth. This condition is called gastric cancer or stomach cancer. The cells that are more prone to become malignant are the glandular cells of the inner layer of the stomach wall, known as gastric mucosa, thus causing the development of stomach adenocarcinoma or gastric adenocarcinoma.
- World Health Organization. Cancer: Fact Sheet No 297. WHO. Available at http://www.who.int/mediacentre/factsheets/fs297/en/. Accessed May 21, 2015.
- Surveillance, Epidemiology, and End Results Program. SEER Stat Fact Sheets: Stomach Cancer. National Cancer Institute. Available at http://seer.cancer.gov/statfacts/html/stomach.html. Accessed May 21, 2015.
- Avital I, Pisters PWT, Kelsen DP, Willett CG. Cancer of the Stomach. In: DeVita VT, Lawrence TS, Rosenberg SA. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 9th ed. Philadelphia: Lippincott Williams & Wilkins; 2011:924-54.
- National Comprehensive Cancer Network. Gastric Cancer: Version 3.2015. NCCN. Available at http://www.nccn.org/professionals/physician_gls/pdf/gastric.pdf. Accessed May 21, 2015.
- Global Cancer Facts & Figures, 3rd ed. American Cancer Society. Available at http://www.cancer.org/downloads/STT/Global_Facts_and_Figures_2007_rev2.pdf. Accessed May 21, 2015.
- American Cancer Society. What are the key statistics about stomach cancer?. American Cancer Society. Available at http://www.cancer.org/cancer/stomachcancer/detailedguide/stomach-cancer-key-statistics. Accessed May 21, 2015.
- Correa P. Diet modification and gastric cancer prevention. J Natl Cancer Inst Monogr. 1992;75-8. [Medline].
- Dicken BJ, Bigam DL, Cass C, et al. Gastric adenocarcinoma: Review and considerations for future directions. Ann Surg. 2005;241(1):27-39.
- Fuchs CS, Mayer RJ. Gastric carcinoma. N Engl J Med. 1995;333(1):32-41.