Stomach cancer is the fourth leading cause of cancer deaths around the world. It is not as common as other cancers in United States and accounts for less than 2% of cancer deaths among Americans. As with any cancer, routine screening or identifying the early signs of cancer are key to early detection and treatment. Sometimes stomach cancer is discovered incidentally while investigating for other conditions.
Read more on what is stomach cancer.
What Happens In Stomach Cancer?
When genetic material in cells becomes mutated, these cells can multiply rapidly and not die as cells normally would. These abnormal cells are cancerous. It invades and destroys healthy tissue around the site where it arises. It can also spread into neighboring organs or via the circulation to distant sites where it damages and destroys healthy tissue.
In stomach cancer, these abnormal cells (cancer) arises in the stomach (primary cancer). It can also occur at the junction where the esophagus (food pipe) and stomach meets and is then referred to as gastroesophageal cancer. Sometimes cancer cells may arise elsewhere and then reach the stomach where it gives rise to cancerous lesions. This is known as secondary or metastatic cancer.
There are different types of stomach cancer depending on which type of stomach cell becomes cancerous. The most common type of stomach cancer is adenocarcinoma. It accounts for about 9 in 10 cancers of the stomach and arises from the glandular cells in the inner stomach lining. Gastric adenocarcinoma is highly aggressive.
Read more on types of stomach cancer.
Why do some people develop stomach cancer?
The exact reason why the genes of certain cells becomes defective and results in cancer is not always clear. There are known risk factors which means that some people are more likely to develop stomach cancer than others. Some of these risk factors are known to directly cause damage of stomach cell genes.
These risk factors include:
- Family history of stomach cancer
- Tobacco smoking
- Helicobacter pylori infection
- Chronic gastritis for any other reason
- Frequently consuming foods that are preserved (salted or smoked) or contaminated with aflatoxin.
- A diet that is low in fruit and vegetables.
- Pernicious anemia
However, it is important to note that stomach cancer arise in people without any of these risk factors. Similarly some people may have several of the abovementioned risk factors and not develop stomach cancer. It is important to speak to a doctor about cancer risk and whether routine screening is advisable.
How To Spot Stomach Cancer
Most patients stomach cancer present with advanced disease. This is one of the reasons why stomach cancer can be so difficult to treat. Early stomach cancer has little to no symptoms that are seen with later stages. In fact early diagnosis often occurs incidentally when investigations are being conducted for other upper digestive conditions.
This is one of the earliest and most common signs of stomach cancer. However, it is vague and can be associated with various esophageal, stomach and duodenal conditions. Indigestion is a term to describe several common digestive symptoms like a bloated feeling, stomach ache, abdominal discomfort, heartburn and nausea.
Usually indigetsion is short lived and lasts for a few minutes to a few hours. In acute cases it is usually a result of overeating, alcohol consumption, eating too fast or with certain foods. However, indigestion may persist for long periods in early stomach cancer before other symptoms arise. It also does not ease significantly if at all when common indigestion drugs are used.
Nausea and Vomiting
Nausea, with or without vomiting, is another common but non-specific symptom of cancer. Every person experiences bouts of nausea many times in life due to an upper digestive disturbance and sometimes for no obvious reason. However, persistent nausea that is unelated to eating should always be investigated. The nausea in stomach cancer persists for long periods of time.
Vomiting may or may not occur with the nausea. Initially the vomiting may occur mainly after a meal. However, vomiting can become a frequent symptom as the cancer progresses. In more advanced stages, bleeding from the tumor may cause bloody vomiting (hematemesis). Sometimes this can also appear as dark coffee grounds in the vomit rather than fresh red blood.
Early fullness is another common sign of stomach cancer. A person feels full after a few bites of food and may therefore be unable to consumer portion sizes as the previously did. Even a small amount of food may cause a bloated sensation. Eventually this can become severe enough to affect eating habits drastically and compromises nutrition.
Difficulty swallowing (dysphagia) is another sign of stomach cancer. It can occur in the early stages of the disease but is more prominent as the cancer advances. Difficulty swallowing occurs for several reasons and not only with obstruction of the end part of the stomach (gastric outlet obstruction) which is a late complication of stomach cancer.
Loss of Appetite
Loss of appetite is another common non-specific symptom of stomach cancer. It can occur anywhere in the course of the disease and persists for long periods of time. Other symptoms like nausea, vomiting, bloating, abdominal pain and stomach ache may be responsible for the loss of appetite.
However, even without these symptoms a person may experience a loss of appetite for prolonged periods and have to ‘force’ themselves to eat. It is further aggravated by cancer treatments and becomes very severe in the late stages of the stomach cancer.
Blood in the Stool
Bleeding from the tumor may also cause changes in the stool. The blood is degraded as it passes out of the stomach and through the bowels (small and large intestines). It causes the stool to become dark and tarry. This is known as melena. However, it is important to note that melena occurs in many different diseases and is not a definitive sign of stomach cancer.
Unintentional Weight Loss
Most cancers cause unintentional weight loss, especially in the late stages and when metastasis (cancer spread) occurs. However, unintentional weight loss may occur earlier in cancers of the digestive tract. This is in part due to reduced eating as a result of symptoms like nausea, heartburn, abdominal discomfort, nausea, vomiting and early fullness.