Stomach cancer comes in many forms and can be caused by a variety of factors. Dr. Niraj D. Jani, chief of the division of gastroenterology at Greater Baltimore Medical Center, discusses who is at risk and what can be done to prevent and treat stomach cancer.
What is stomach cancer and what causes it?
Stomach cancer, also known as gastric cancer, is one of the leading causes of cancer deaths in the world. Luckily, the incidence has been declining over the past several decades. Primary cause of gastric cancer is Helicobacter pylori, or H. Pylori infection, which is a bacteria found in the stomach that leads to inflammation, ulcers and intestinal-type gastric cancer. Other causes of gastric cancer include exposure to foods high in nitrates, genetic causes, and chronic inflammation in the stomach.
Are there different types of stomach cancer?
There are several different types of stomach cancer, including adenocarcinoma, which arises from an abnormal gastric cell, and gastric lymphoma, which originates in the stomach. Some cancers are also show up as muscular tumors in the GI tract and neuroendocrine stomach cancer are tumors caused by abnormal hormonal cells. Gastric adenocarcinoma is the most common type, accounting for 90 percent of gastric cancers. It can appear as an intestinal form or a diffuse form, and the latter is most often associated with genetics. Cancers in the lower parts of the stomach were once more common, but now those in the upper part are more common. Lymphoma, specifically mucosa-associated lymphoma, accounts for 3 percent of gastric cancers and are linked to infection with H. Pylori. Linitis plastica, a gastric cancer that causes a rigid, thickened stomach, is more common in younger individuals.
The Esophageal Cancer Action Network in Baltimore plans to file a citizen's petition Monday with the U.S. Food and Drug Administration to require cancer warnings on the labels of over-the-counter reflux medications
Most patients with gastric cancer may initially not show any symptoms or have mild symptoms. As the cancer progresses, common symptoms are weight loss, upper abdominal pain, loss of appetite, early satiety, fullness, nausea, and dark blood in the stool. If the cancer is in the first part of the stomach or near the gastro-esophageal junction, patients may have difficulty swallowing or [dealing] with food getting stuck. Patients may also have unexplained anemia as an initial presenting symptom.
What are the risk factors of stomach cancer?
Risk factors include older age and race —African-Americans are more at risk than Caucasians —and living in certain geographic locations. There are environmental, dietary and genetic causes that have been linked to gastric cancer. There is also substantial evidence that links gastric cancer with high-salt diets and salted foods such as cured meats, salted fish and vegetables. There is also a link between diets high in nitrates and gastric cancer. Diets that are high in fried food, processed meat, fish and alcohol (and low in vegetables, fruits, milk, and vitamin A) have been associated with an increased risk of gastric carcinoma in several studies. In 2015, the World Health Organization's International Agency for Research on Cancer reviewed the evidence linking intake of processed meat with a variety of cancer sites and concluded that there was a positive association between consumption of processed meat and stomach cancer.
Obesity, tobacco use and occupational exposures such as mining, working with metals and rubber have all been linked to gastric cancer. H. Pylori found in the stomach has been linked to ulcers and different forms of gastric cancer. Epstein-Barr virus, a form of the herpes virus, and pernicious anemia has also been associated with gastric cancer in 5 to 10 percent of cases. Pernicious anemia is when the gastric cells don’t produce a factor needed to absorb Vitamin B12. There is also a link between low socioeconomic class and increased risk for gastric cancer. Most gastric cancers are sporadic but in 10 percent of cases, there are genetic causes.
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We do not exactly know why men are more prone to gastric cancer than women. One study found that estrogen was protective in the development of gastric cancer in mice by inhibiting inflammatory markers and immune cells that causes inflammation of the stomach lining, a precursor for gastric cancer.
What is the average age that people get stomach cancer and why are older people more likely to get it?
The median age of presentation of gastric cancer is 72 years old. There is no clear reason for why gastric cancer is seen more in older patients, but [it] could be due to chronic toxin or inflammatory exposure over time, which then leads to the start of cancer.
Treatment for gastric cancer depends on stage of diagnosis. Early gastric cancer may be treated endoscopically or require complete surgical resection. For mucosa-associated lymphoma, eradication of H. Pylori is the goal with medical treatment. Chemotherapy and radiation have also been used for more advanced gastric cancer.