According to the American Cancer Society, approximately 28,000 cases of stomach cancer will be diagnosed in 2017 in the United States alone, which is less than many other cancers including breast, prostate and skin cancer. However, although not an extremely common form of cancer, it’s still vital to educate yourself about stomach cancer facts, so you understand the importance of routine physical examinations from your primary care physician. 

• Stomach cancer occurs when cancer cells form in the stomach, in particular, in the inner lining of the stomach. It’s possible these cells will develop into a tumor.
• One of the most important stomach cancer facts is that it progresses slowly and may not generate any symptoms until the later stages. 
• The exact cause of stomach cancer, also referred to as gastric cancer, isn’t known. A Helicobacter pylori infection appears to play a role in the onset of this cancer in many patients. The infection contributes to inflammation and damage to the inner layer of the stomach. A majority of people who have this infection don’t develop cancer, though. 
• As one of the more important stomach cancer facts, age is a factor in the development of stomach cancer. People who are affected the most frequently by this form of cancer tend to be over the age of 65. In fact, two-thirds of people diagnosed with stomach cancer are over the age of 65, with the average being 70 years of age. 
• men develop stomach cancer more frequently than women. 
• Your chance of developing stomach cancer is 1 in 125. 
• The number of new cases of stomach cancer in the United States has decreased over the last decade, which is speculated to be partially due to the increased number of antibiotics being prescribed since they kill off the  Helicobacter pylori bacteria. 
• Stomach cancer is more common in other less developed areas of the world. In fact, it’s one of the leading causes of cancer-related death around the world. It was the leading cause of cancer death in the United States up until the late 1930s. 
• People who eat a diet high in salted fish and meats, smoked foods and pickled vegetables tend to develop stomach cancer more frequently than someone who doesn’t consume these foods. 
• The most common symptoms of stomach cancer include unintended weight loss, a lack of appetite, pain or discomfort in the stomach, feeling full after eating only a small meal, heartburn, indigestion, nausea and swelling in the abdomen. Vomiting is a common symptom, and some people experience bloody emesis. 
• The overall five-year relative survival rate for all people with stomach cancer in the United States is 31-percent, meaning 31 out of 100 people diagnosed with the condition survive for at least five years after receiving a stomach cancer diagnosis. The survival rate of people with this type of cancer is low as a result of most cases first being detected when it’s in its advanced stages. 

Source

http://www.antonbilchikmd.com/stomach-cancer/facts-and-figures/

http://www.idph.state.il.us/cancer/factsheets/stomach.htm

https://www.cancer.org/cancer/stomach-cancer/detection-diagnosis-staging/survival-rates.html