Causes and Risk Factors for Gastric Cancer
Gastric cancer, also known as stomach cancer, arises when cells lining the stomach undergo a transformation into malignant cells, leading to progressive growth and spread. While researchers have yet to identify the primary cause of this cell transformation, several factors have been recognized that increase the risk of developing gastric cancer. It is important to note that the presence of one or more of these factors does not guarantee the onset of the disease. Some risk factors, such as smoking, can be avoided, while others, like age and family history, are unavoidable. A detailed overview of the causes and risk factors associated with gastric cancer is outlined below:
Diet
The risk of gastric cancer is heightened among individuals who consume a diet high in salted, pickled, and smoked foods, as well as processed and red meats, and refined grains. In contrast, a diet rich in fresh fruits and vegetables can help reduce this risk. Interestingly, the increased use of refrigeration for food preservation has been linked to higher gastric cancer rates.
Smoking
Smokers are twice as likely to develop gastric cancer compared to non-smokers, especially types that originate in the upper stomach or near the esophagus. A study published in Gastroenterology and Hepatology from Bed to Bench in 1997 indicated that the risk of gastric cancer increases by 44% among current and former smokers. Further research conducted in 2007 revealed that male smokers face a 60% increased risk, while female smokers have a 20% higher risk.
Obesity and Overweight
The likelihood of developing gastric and esophageal cancers is increased among individuals who are obese or overweight, defined as having a Body Mass Index (BMI) of 30 or greater. Maintaining a healthy diet and engaging in regular physical activity are essential for reducing this risk.
Chemical Exposure
Repeated exposure to certain chemicals, such as those encountered in rubber manufacturing or lead, can escalate the risk of gastric cancer. Fortunately, numerous regulations have been enacted to limit exposure to these harmful substances, resulting in a decrease in the incidence of gastric cancer associated with chemical exposure.
Health Issues
The presence of specific health conditions can elevate the risk of gastric cancer. It is essential to understand that a history of these conditions does not automatically imply cancer development. Some relevant health issues include:
- Surgical History: Individuals who have undergone previous stomach surgery face a higher risk of gastric cancer.
- Megaloblastic Anemia: This type of anemia occurs due to an inability to absorb vitamin B12 adequately.
- Ménétrier’s Disease: Characterized by abnormal growth of stomach folds and reduced stomach acid production.
- Helicobacter Pylori Infection: This bacterial infection is a significant risk factor for gastric cancer, particularly if left untreated for an extended period. It can lead to atrophic gastritis and pre-cancerous changes in the stomach lining. Research from Vanderbilt University found that while nearly half of the global population may be affected by this infection, only 1-3% will develop gastric adenocarcinoma.
- Epstein-Barr Virus Infection: This virus has been detected in 5-10% of gastric cancer cases, though its direct role in cancer development remains unclear. These cases often grow slowly and have a lower chance of metastasis and are also linked to certain lymphomas.
- Gastroesophageal Reflux Disease: Individuals with this condition have an increased risk of esophageal and gastric cancers due to repeated acid exposure.
- Other Conditions: The risk is also heightened in individuals with Acquired Immune Deficiency Syndrome (AIDS) and diabetes.
Family History and Genetic Factors
A family history of gastric cancer can significantly raise the risk for close relatives. Additionally, certain hereditary disorders are linked to an increased likelihood of developing this form of cancer, including:
- Lynch Syndrome: This condition arises from mutations in multiple genes, increasing the risk for various cancers, including gastric and colorectal cancers.
- Genetic Mutations: Mutations in genes such as BRCA1 and BRCA2 are associated with a heightened gastric cancer risk.
- Li-Fraumeni Syndrome: Caused by mutations in the TP53 gene, this syndrome increases the likelihood of early-onset gastric cancer alongside other cancers.
- Peutz-Jeghers Syndrome: This syndrome leads to polyp formation in various organs, including the stomach, and heightens cancer risk.
- Familial Adenomatous Polyposis: Characterized by early-stage polyp development throughout the colon.
Other Factors
A range of additional factors may contribute to an increased risk of gastric cancer, such as:
- Age: The majority of gastric cancer cases occur in individuals over the age of 50.
- Gender: Men have double the risk of developing gastric cancer compared to women, as confirmed by a 2011 study from the University of Southern California.
- Ethnicity: Incidences of gastric cancer vary among different ethnic groups, with higher prevalence observed in Latino, African American, and Native American populations compared to non-Latino white individuals.
- Geography: Gastric cancer rates are elevated in certain regions, including Japan, China, and some European areas, while lower rates are noted in Central Asia and parts of North and West Africa.
- Blood Type: Individuals with type A blood may be at increased risk; however, the underlying cause remains undetermined.
- Excessive Alcohol Consumption.
Tips for Preventing Gastric Cancer
Several modifiable risk factors can be controlled or avoided, contributing to the prevention of gastric cancer. Below are some recommendations to help reduce the risk:
- Healthy Eating: Emphasize a diet rich in fresh fruits and vegetables, which are abundant in vitamins and fiber, while minimizing the intake of salted, pickled, and smoked foods. Maintaining a healthy weight is also crucial.
- Treating Stomach Conditions: Doctors may prescribe appropriate antibiotics to eliminate Helicobacter pylori infections, along with other medications to treat ulcers and lower the risk of gastric cancer.
- Consulting on Medications: Long-term use of certain drugs, such as aspirin and non-steroidal anti-inflammatory drugs, may damage the stomach, so it’s essential to discuss prolonged medication use with a healthcare professional.
- Quitting Smoking: Since smoking and alcohol consumption are significant risk factors for gastric cancer, avoiding these behaviors or seeking cessation support is vital.
- Estrogen Use: Women using estrogen for medical reasons have been found to have a potentially lower risk of developing gastric cancer.