Stomach cancer

Stomach cancer is a malignant tumor condition of the gastric mucosa. The tumor originates from the pancreatic ducts of the gastric mucosa in most patients. Specialists refer to this as adenocarcinoma of the stomach. 

If the tumor is located at the opening from the esophagus to the stomach, specialists call this adenocarcinoma of the esophagogastric junction (AEG). Depending on the exact location, it is treated as either esophageal cancer or stomach cancer. 

What causes stomach cancer? More information is available on the German Cancer Research Center’s Cancer Information Service website (in German).

For many patients, stomach cancer in its early stages does not exhibit symptoms. If the patient experiences initial symptoms, they are often atypical and could be linked to a different illness. 

Doctors recommend an image of the stomach and the esophagus be taken if the following symptoms are present: 

• difficulties swallowing 
• recurrent vomiting 
• persistent loss of appetite 
• unexplained weight loss 
• atypical, dark stool known as tarry stool due to bleeding

Anyone with persistent symptoms should have them investigated. General Practitioners can already narrow down what is causing the symptoms and, if necessary, initiate further diagnostic steps with specialists. 

Researchers are still not completely sure why some people become ill with stomach cancer and others do not. Most likely, various factors play a role, as is the case with other cancer diseases. Some risk factors for stomach cancer are known. Infections and other underlying conditions of the stomach often play a role. Lifestyle also appears to play a role. 

The following risk factors apply to stomach cancer: 

• chronic gastritis due to an infection of the stomach with the bacteria helicobacter pylori 
• an infection with Epstein-Barr virus 
• smoking 
• excessive alcohol consumption 
• a diet high in salt and consumption of foods preserved with salt
• consumption of meat products 
• prior stomach surgery 
• close relatives such as parents, siblings, or children with stomach cancer 
• some hereditary syndromes, such as Lynch syndrome 

As a general rule, not everyone who lives with one or more of these risk factors becomes ill with stomach cancer. And, conversely, people without these risk factors have no guarantee that they will remain healthy. 

Looking for more information about the risk factors of stomach cancer? The correlation between risk factors and the occurrence of stomach cancer is discussed in detail on the German Cancer Research Center’s Cancer Information Service website (in German). 

Around 14,500 people get stomach cancer every year in Germany. Men are more often affected than women. The risk of becoming ill also increases with age. On average, men become ill with this cancer at the age of 71 and women at the age of 75. 

The progression of stomach cancer depends on the size of the tumor, its stage, and how aggressive it is, among other things. The tumor is initially located in the uppermost layer of the stomach lining (mucosa) only. If it continues to grow, it penetrates the deeper layers of the stomach wall. Over time, the tumor can spread to nearby tissue, to lymph nodes, and to other organs. 

Tumors that spread (metastases)

Via the bloodstream or the lymph stream that transports tissue fluid, cancer cells can make their way to other organs in the body and form what are known as metastases. In stomach cancer, metastases occur most often in the lymph nodes, the peritoneum (the membrane lining the abdominal cavity), the liver and the lungs. But other organs can also be affected. 

Some diseases of the stomach increase the risk of becoming sick with stomach cancer later on. They include long-term infections of the gastric mucosa, such as chronic gastritis or a gastric ulcer.

The stomach bacteria Helicobacter pylori is the cause of these illnesses in most patients. The bacteria reside in the gastric mucosa and damage it. People with a Helicobacter pylori infection can be treated with antibiotics. This lowers the risk of stomach cancer. 

The following groups of people can be tested for Helicobacter pylori: 

• people with chronic inflammation of or changes to the gastric mucosa
• people with close relatives (parents, children, or siblings) who have stomach cancer

In Germany, approx. 3 out of 10 adults are infected with helicobacter pylori. Of course, not every person infected with the bacteria has stomach cancer. This is why specialists do not recommend testing everyone for the bacteria.

A gastroscopy is used by doctors to reliably diagnose stomach cancer. During the examination, a flexible tube about as thick as a finger (endoscope) is inserted through the mouth, into the esophagus and then the stomach. 

A small camera is located on the tip of the endoscope, which transmits images from inside the body onto a monitor. The doctor can evaluate changes in the gastric mucosa and remove tissue samples from areas that look suspicious. 

The examination is only slightly inconvenient for patients. However, many people find a gastroscopy unpleasant. A sedative or short-acting anesthetic can be requested for the examination. Complications from a gastroscopy are rare. 

The tissue samples are sent to a special lab and viewed under a microscope. Typically, it takes a few days before the results are available. 

Cancer diagnosis – what’s next? 

If the diagnosis is stomach cancer, additional tests are needed. Doctors determine whether the tumor has already spread and metastases have already formed. Specialists use the term staging for these examinations. 

• First, the doctor performs an ultrasound on the abdomen to look for metastases in the liver. 
• A computed tomography (CT) scan of the chest, abdomen, and pelvis makes it possible to locate metastases in other organs. Furthermore, it allows doctors to find out how deep the tumor has grown into the stomach wall. Another option is magnetic resonance imaging.
• Other possible tests that can be used if necessary are an endoscopic ultrasound of the stomach, ultrasound of the throat, laparoscopy (a minimally invasive abdominal exam) and bone scintigraphy. 

The attending physicians then create a treatment plan based on the staging results. 

For more information about the progress and possible risks of the various examination methods, visit the website of the Cancer Information Service of the German Cancer Research Center (in German). 

When selecting the best treatment option, doctors primarily take the following factors into account:

• Tumor location and characteristics on the cellular level
• The tumor stage: how far has the tumor grown into the stomach’s tissue and how far have the cancer cells spread in the body?
• The general heath of the individual: what is their nutritional condition and are there any underlying health conditions?
• The patient’s wishes and needs

Localized tumor (early-stage carcinoma)

Endoscopic treatment: very small tumors on the surface can often be removed endoscopically. The procedure is similar to a gastroscopy in which a tube is inserted through the esophagus into the stomach. If the doctor discovers during the procedure that the tumor cannot be completely removed, an operation may be necessary in certain cases.

Locally advanced tumor

Surgery

If the tumor is at an advanced stage but still confined to the stomach, an operation is performed to remove as much of the tumor as possible. Depending on the tumor’s size, stage, and location, part of the stomach or the entire stomach is removed. The operation is the only way to cure stomach cancer that has penetrated through the mucous membrane and into the deeper layers of the stomach.

Pre- and post-operative chemotherapy

In addition to surgery, most patients with an advanced tumor that is limited to the stomach also receive chemotherapy. It is typically started before the operation and continued after. The goal is to shrink the tumor before the operation to lower the likelihood of a relapse after the operation.

Chemoradiotherapy

Radiation is recommended for only a small number of people with cancer because stomach cancer does not respond well to radiation. Chemoradiotherapy is considered if an operation is not possible, and stopping the disease from advancing and curing the cancer to the greatest extent possible is the goal.

Metastases

In some people with stomach cancer, tumors have already spread around the body and can even be found in distant organs and tissues. A cure is no longer possible if the disease is already at an advanced stage.

Doctors then try to slow the spread of the tumor clusters with chemotherapy and stop their growth for as long as possible. Depending on the characteristics of the tumor’s tissue, medication can be prescribed in addition to chemotherapy. This medication is used to stop the growth of cancer cells. Treating distressing symptoms is also important in this situation.

For details about stomach cancer treatments and the associated side effects, visit the German Cancer Research Center’s Cancer Information Service website (in German).

Stomach cancer is physically and psychologically difficult. Patients need time to recover after treatment. Patients whose stomachs were partially or completely removed must also adapt to a new way of eating. 

Rehabilitation can help them make the transition to daily life. It also helps to prevent long-term side effects of the illness or its treatment. 

Anyone wishing to enter rehab can discuss it with the doctors treating them. They will certify the need for rehabilitation. Questions about rehabilitation can be answered by medical social work services at the hospital and at the local cancer consultation office, and by health insurance providers. 

Looking for more information about rehabilitation after oncological disorders and contact information for socio-legal advice? The website of the German Cancer Research Center’s Cancer Information Service provides further details (in German). 

Most patients with stomach cancer must regularly schedule aftercare appointments at their doctor’s office or the hospital after treatment. The objectives of these aftercare appointments are to monitor the general condition of the patient and offer supportive measures for side effects of the illness or its treatment. Furthermore, they are designed to detect signs of a relapse early on. 

Another aspect of aftercare is monitoring the nutritional condition of the patient. For example, patients experiencing difficulties in getting proper nutrition can receive nutritional counseling. Psychological counseling is also available as part of aftercare. 

During aftercare, the doctor examines the patient regularly, initially at shorter intervals and then longer ones. If the tumor was removed endoscopically, multiple gastroscopies are part of aftercare. After an operation or chemoradiotherapy, doctors look for new symptoms that may have appeared. 

If the stomach cancer is advanced and cannot be cured, specialists recommend regular progress monitoring. This involves checking the patient’s general condition and blood values. Imaging techniques are also used. This makes it possible to monitor how the disease is progressing. Adverse symptoms can be recognized early on and treated to provide the best quality of life possible. 

Many people with stomach cancer have already lost a lot of weight by the time they are diagnosed. Additionally, treatment makes it difficult to get enough calories and important nutrients. Many who undergo extensive stomach surgery find it difficult to adjust their nutrition to their new situation. 

Nutrition before treatment

Surgery often has an adverse effect on a patient’s nutritional condition. Therefore, it is important to have their nutritional condition assessed before the operation. If necessary, patients can be given liquid nutrition (“astronaut food”) for several days before surgery. 

Nutrition after treatment

Immediately after surgery, many patients are artificially fed. They are either fed nutrients intravenously directly into the bloodstream or through a tube in the part of the stomach that remains or the upper part of the intestine. Fairly shortly thereafter, the patient can cautiously start to eat normally again. Some weight loss is normal during this time. However, few patients ever return to their original weight. 

Patients whose stomachs have been completely removed are no longer able to absorb vitamin B12 from their food. Even if only part of the stomach has been removed, their nutritional intake may be insufficient. They require B12 injections at regular intervals in this case.

Doctors from a variety of disciplines work together closely to treat stomach cancer. Hospitals with a great deal of experience in treating patients with stomach cancer can demonstrate this through certification. The German Cancer Society regularly checks the hospitals for compliance with certain professional requirements. 

You can find the addresses of the certified centers on the OncoMAP website.  

Do you have further questions about dealing with the condition in everyday life and additional support options? You can find information about this on the website of the Cancer Information Service of the German Cancer Research Center (in German).

For questions about stomach cancer, contact the Cancer Information Service by dialing 0800 - 420 30 40 (toll free) or send an email to krebsinformationsdienst@dkfz.de