What is Gastric Cancer?
Gastric cancer, or cancer of the stomach, is the fifth most common cancer and the third largest cause of cancer deaths around the world, although the rate has been decreasing globally since the middle of the last century. In the United States, the number of stomach cancer cases has also gone down over the past few decades. However, the number of cancers occurring at the junction of the stomach and esophagus has increased during the same period.
Two main types of gastric cancer exist: intestinal (well-differentiated) and diffuse (undifferentiated). They are different in how they appear, develop, and the genetic traits they possess. The only hopeful treatment that can possibly cure patients with stomach cancer is a surgical operation that removes the cancer and some lymph nodes near the stomach.
Recent research indicates that applying treatments before and after the surgery can enhance a patient’s chance of survival. Unfortunately, if a patient’s cancer cannot be surgically removed, is very advanced, or has spread to other parts of the body, the only option available is therapy that aims to extend their life and alleviate symptoms, often called palliative care.
What Causes Gastric Cancer?
There are several factors that researchers believe increase the risk of stomach cancer. These include a diet high in salt, smoked or cured foods, and N-nitroso compounds (found in some food), and low in vitamins A and C. Drinking contaminated water and having a high body mass index (BMI) might also raise your risk, alongside frequent heartburn or smoking. Certain occupations, like working in rubber manufacturing, tin mining, metal processing, and coal, too, have a higher than average risk. Infections from bacteria called Helicobacter pylori or the Epstein-Barr virus are also linked to an increased risk, as is exposure to radiation or having previously had surgery on the stomach.
On the other hand, several studies have indicated that consuming high amounts of fiber, fruits, and vegetables could possibly lower your risk of developing stomach cancer. Taking aspirin and other non-steroidal anti-inflammatory drugs might also reduce the risk of certain cancer types in the junction between your stomach and esophagus. Contrary to popular belief, alcohol does not seem to raise the risk of stomach cancer. In fact, some studies suggest drinking wine daily could potentially be protective, though this isn’t certain. Chronic use of certain heartburn medications, such as histamine-2-receptor antagonists or proton pump inhibitors, also doesn’t appear to raise the risk of stomach cancer.
Some personal factors might play a role too. People with type A blood, for instance, seem to have a higher risk of a certain type of stomach cancer. Similarly, people with pernicious anemia (an autoimmune disease that causes inflammation and damage to stomach cells), stomach ulcers, hypertrophic gastropathy (swollen stomach lining), and gastric polyps (small growths in the stomach) might also have an increased risk.
Most cases of stomach cancer occur randomly, but 5% to 10% are in people with a family history of the disease. There are a few genetic disorders that can raise the risk for stomach cancer, such as hereditary diffuse gastric cancer (HDGC), gastric adenocarcinoma, proximal polyposis of the stomach (GAPPS), and familial intestinal gastric cancer (FIGC). That being said, these are rare. There are also genetics-related conditions, like hereditary non-polyposis colon cancer, familial adenomatous syndrome, Peutz Jeghers syndrome, juvenile polyposis syndrome, Li-Fraumeni syndrome, hereditary breast and ovarian cancer syndrome, and Cowden’s syndrome, that can slightly increase the risk of stomach cancer.
There is a definite link between stomach cancer and infection with H. pylori bacteria, as well as with eating processed meats, according to the World Health Organization. Researchers are also looking at certain gene variants and how they might interact with a H. pylori infection to potentially cause stomach cancer.
Risk Factors and Frequency for Gastric Cancer
The number of people getting stomach cancer is going down around the world. However, this decrease is not the same everywhere, especially in places like China and Japan. In the United States, it’s estimated that 28,000 new cases will be diagnosed, with almost 11,000 deaths expected in 2017. The decrease in stomach cancer is probably due to finding and treating its causes, as well as changes in lifestyle such as diet and environmental factors.
Unfortunately, it is still common in parts of the world that don’t have good food storage or clean water. Most stomach cancer happens in developing countries. It is twice as common in men as in women, and black men get it more often than white men. The people least likely to get it are white people in Western societies who have a high socioeconomic status.
- Changes in lifestyle have been shown to affect stomach cancer rates, with second and third-generation immigrants in the United States showing lower rates of the disease.
- Nutritional, socioeconomic, and medical factors are believed to influence the likelihood of developing stomach cancer more than genetic predisposition, as seen in studies on Japanese immigrants.
- There has been a change in the types of stomach cancer being diagnosed. The intestinal type is becoming less common but is still the most common type (70%), usually occurring in men over 50 with certain environmental risk factors.
- On the other hand, the diffuse or infiltrative type of stomach cancer is less common (30%), tends to occur in younger people of both sexes, and usually has a worse prognosis.
- An increase in stomach cancer occurring near the food pipe (esophagus) and a decrease in the lower part of the stomach has been observed in the United States. The most common sites for stomach cancer in Western countries are the upper smaller curve of the stomach, and the point where the esophagus meets the stomach.
- In contrast, non-proximal stomach cancers are more common in Japan. Stomach cancer cases in Japan have a better outcome than in the United States, largely due to early detection through regular screenings.
Signs and Symptoms of Gastric Cancer
Most patients in the United States are already at an advanced stage of gastric cancer when they first seek medical care, hence their symptoms are often severe. Common symptoms of gastric cancer can include weight loss, constant stomach pain, difficulty swallowing, vomiting blood, loss of appetite, nausea, feeling full quickly, and indigestion. If the cancer has spread locally or to distant parts of the body, symptoms can also include significant stomach pain, accumulation of fluid in the abdomen, weight loss, fatigue, and possible blockage of the stomach’s exit.
On physical examination, a doctor might be able to feel a hard mass in the abdomen, which indicates advanced disease. Signs of the cancer spreading to the lymph system can include swollen lymph nodes above the collarbone on the left side, a lumpy growth around the belly button, and a swollen lymph node in the left armpit. The spread of cancer to the lining of the abdomen can result in various physical changes, such as a mass in the ovary, a mass in the space between the rectum and the back of the uterus, fluid build-up in the abdominal cavity, and an enlarged liver.
Additionally, some patients may experience unusual symptoms or conditions associated with but not directly caused by the cancer. These can include skin changes like scattered, wart-like growths or darkened skin patches, blood abnormalities like the destruction of red blood cells or increased clotting, kidney issues like nephropathy, and rare autoimmune conditions like inflammation of small and medium-sized blood vessels. However, these diverse manifestations are not exclusive to gastric cancer patients.
- Weight loss
- Constant stomach pain
- Difficulty swallowing
- Vomiting blood
- Loss of appetite
- Nausea
- Feeling full quickly
- Indigestion
- Significant stomach pain (in advanced stages)
- Accumulation of fluid in the abdomen (in advanced stages)
- Blockage of the stomach’s exit (in advanced stages)
Testing for Gastric Cancer
If your doctor suspects you may have stomach cancer, you’ll likely be asked to undergo a type of test called an upper endoscopy. This procedure is a bit more intensive and also more expensive than a simple barium study (another type of medical test), but it’s an effective way to get tissue samples of any suspicious areas in the esophagus, stomach, or small intestine. It’s important to have the area of concern, like a stomach ulcer for example, biopsied multiple times to increase the chance of an accurate diagnosis. An endoscopy is particularly useful in areas with a high incidence of stomach cancer, like Japan, as it aids in detecting disease at early stages with potentially higher cure rates.
The American Joint Committee on Cancer, and the Union for International Cancer Control have developed a classification scheme to stage stomach cancer. This staging method is centered on the size of the tumor, presence of cancer in nearby lymph nodes, and whether the cancer has spread to other areas of the body (metastasis). This staging is helpful in predicting a patient’s 5-year survival rate after surgery, with or without additional treatments before surgery (neoadjuvant therapy).
Before surgery, it’s important to conduct tests to rule out metastasis (the spread of cancer to other parts of the body) and to assess whether the cancer can be surgically removed (resectability). A computerized tomography (CT) scan of the tummy and pelvis is often the first step to rule out spread of the disease. However, a CT scan may not accurately determine the size of the tumor, status of nearby lymph nodes, and tiny cancer spread in the belly lining. In such cases, an ultrasound examination done through the endoscope (endoscopic ultrasound) is more helpful in staging accurately though it may depend on the technician’s expertise. If areas of small-scale spread (metastasis) are suspected, they should be biopsied. If there’s suspicion of cancerous fluid in the belly (malignant ascites), a sample may be taken for testing. Also, a CT scan of the chest is usually preferred to a regular X-ray for checking lung spread.
In instances where other tests show no spread of the disease, a different kind of scan, known as a positron emission tomography combined with computed tomography imaging (PET-CT), may be used in specific situations, such as in T2N0 cancer stage (a specific stage of cancer). Blood tests for certain markers, while available, have limited use, as these can be increased due to other health conditions too. Before surgery, a Test called laparoscopy coupled with testing for cancer cells in fluid inside abdomen (peritoneal cytology) could be done to confirm absence of spread, especially for cancers at stages higher than T1b. If cancer cells are found in the fluid inside the belly (positive peritoneal cytology), surgery is generally not recommended as the risk of recurrence is high.
About 12%-27% of stomach cancers have been found to have a particular gene alteration known as the human epidermal growth factor receptor 2 (HER2). Too much of the HER2 protein can cause cancer cells to grow and divide, leading to an aggressive form of the disease. It’s often seen more among the so-called “intestinal” type of stomach cancer (33%) than the “diffuse” type (8%), with slightly lower rates found in the US. Testing for this gene alteration is recommended for all stomach cancers that have spread beyond the stomach (metastatic), given that it can guide the use of certain treatments. In recent times, drugs that boost the body’s own immune defenses to fight cancer (immunotherapy) have been approved for use in stomach cancers, especially if they possess a certain feature known as “microsatellite instability”. Despite testing positive for Epstein-Barr virus (EBV) being associated with a better outlook in stomach cancer, routine testing for it isn’t yet recommended.
Treatment Options for Gastric Cancer
sorry, Error during response generation.
What else can Gastric Cancer be?
When trying to identify conditions related to stomach problems or issues with the esophagus, doctors would consider a list of possibilities. These include:
- Acute gastritis (sudden stomach inflammation)
- Atrophic gastritis (chronic stomach inflammation that damages stomach lining)
- Bacterial gastroenteritis (bacterial infection causing stomach flu)
- Chronic gastritis (long-term stomach inflammation)
- Esophageal cancer (cancer in the food pipe)
- Esophageal stricture (narrowing of the food pipe)
- Esophagitis (inflammation of the food pipe)
- Non-Hodgkin lymphoma (cancer in the lymphatic system)
- Peptic ulcer disease (ulcer in the stomach or upper part of the small intestine)
- Viral gastroenteritis (viral infection causing stomach flu)
What to expect with Gastric Cancer
The severity and outlook of stomach cancer align with how far the tumor has spread. This includes if the cancer has reached the lymph nodes or if the tumor has grown beyond the stomach wall. The grade of the tumor, or how abnormal the cancer cells look and how quickly they grow, can also give some indication about the person’s outlook.
Just over half of patients can expect a cure from stomach cancer that is localized or contained to the lower part of the stomach. However, this early-stage disease only makes up between 10% and 20% of all cases diagnosed in the United States. The remaining stomach cancer patients are found to have cancer that has spread either locally or to remote parts of the body. The overall survival rate after 5 years varies greatly from essentially zero for patients with widely spread disease, to almost 50% for patients with cancer in the lower part of the stomach that can be surgically removed.
Even when the cancer seems to be localized, the 5-year survival rate for patients with cancer in the upper part of the stomach is only between 10% to 15%. Treatment for patients with widespread stomach cancer can help alleviate symptoms and may extend life to some extent, but long remission periods are rare.
Possible Complications When Diagnosed with Gastric Cancer
Gastric cancer, or stomach cancer, can result in several complications. For example, it might cause people to lose their appetite and shed weight. Another common issue is ascites, which is a condition where fluid accumulates in the abdomen. This build-up can create a feeling of pressure on the stomach and may even contribute to shortness of breath.
Furthermore, in advanced stages of gastric cancer, it can spread to other parts of the body, a process known as metastasis. The lungs, liver, or bones are typical targets for these metastases. Also, treatments like radiation therapy and chemotherapy, while beneficial, may cause side effects in some patients. To summarize:
- Loss of appetite and weight loss
- Ascites or fluid build-up in the abdomen
- Feeling of pressure on the stomach
- Shortness of breath
- Metastases to the lungs, liver, or bones
- Adverse effects from radiation therapy and chemotherapy
Preventing Gastric Cancer
It’s crucial to know that stomach cancer is a very serious illness. Unfortunately, it often has a low rate of survival and patients may not have a positive outlook. The nature of this disease, the available treatments and their potential side effects, along with the patient’s chances of survival, should be understood. If the treatments don’t work, the patient may need hospice care – a type of care that focuses on pain and symptom management, rather than curing the disease. Along with these issues, family counseling and support are also important aspects of managing this condition.
