All About Gastric Cancer

Author: Christina Bach, LCSW, OSW-C, FAOSW
Content Contributor: Ryan P. Smith, MD, Eric Shinohara, MD, MSCI and Elizabeth Prechtel-Dunphy, MSN, CRNP, AOCN
Last Reviewed:

What is the stomach?

The stomach is the muscular organ that holds and stores food. It is found just below the lower part of the rib cage on the left side. It is connected to the mouth and throat by the esophagus. Using motion and acid, the stomach helps to partially digest food. The partially digested food is then emptied into the small intestine. The small intestine helps to absorb nutrients from the partially digested food.

What is gastric cancer?

Normally, cells in the body will grow and divide to replace old or damaged cells. This growth is highly regulated, and once enough cells are produced to replace the old ones, normal cells will stop dividing. Tumors occur when there is an error in this regulation and cells continue to grow uncontrolled. 

Gastric cancer, or stomach cancer, is cancer of the stomach. Gastric cancer occurs when cells in the lining of the stomach grow uncontrollably and form tumors that can invade normal tissues and spread to other parts of the body. Cancers are described by the types of cells from which they arise. About 90-95% of gastric cancers arise from the lining of the stomach, called adenocarcinoma. There are other cancers that can arise in the stomach, including gastrointestinal stromal tumors (GIST), lymphoma, and carcinoid tumors, among others. 

Am I at risk for gastric cancer?

Each year, about 26,560 new cases of gastric cancer are diagnosed in the United States. The average age at diagnosis is 68. The number of people being diagnosed with gastric cancer has gone down greatly since the 1930s. The exact reason is not known. One theory is that the use of refrigeration has led to less use of nitrites, "smoking" of foods, and other such forms of food preservation. 

Diets that consist of heavily salted, smoked, or pickled foods can increase your risk of gastric cancer. Diets rich in fruits, vegetables, and dietary fiber can reduce your risk of gastric cancer. Tobacco use and heavy alcohol use can also increase the risk of gastric cancers. It also appears that people with blood type A are at higher risk for gastric cancer for an unknown reason.

There does appear to be a genetic link in some cases of gastric cancer. Some genetic diseases that can be linked to a higher risk of gastric cancer include

  • Lynch syndrome (hereditary nonpolyposis colorectal cancer).
  • Familial adenomatous polyposis.
  • Peutz Jeghers syndrome.
  • Juvenile polyposis syndrome (JPS).
  • Hereditary diffuse gastric cancer (HDGC) is an inherited genetic abnormality that is associated with an increased risk of developing gastric cancer. HDGC is caused by a mutation on the CDH1 gene. It is not known how many families carry the CDH1 mutation. Families that have had several cases of gastric cancer, particularly if they are the diffuse type, should consider genetic testing and screening options.

Studies have also linked infection with Helicobacter pylori (H. pylori) with gastric cancer. H. pylori can cause gastric ulcers and chronic atrophic gastritis. This may explain the higher rate of gastric cancer in individuals who also have H. pylori. The exact role of H. pylori in the development of gastric cancer remains unclear. It is thought that H. pylori causes gastritis or inflammation of the stomach, which can lead to a loss of secretory cells in the stomach, also known as atrophic gastritis. This process can lead to gastric cancer. H. pylori has also been linked to lymphomas of the stomach.

Pernicious anemia, an autoimmune disease where the stomach does not produce stomach acid, has also been linked to gastric cancer. 

Keep in mind that just because you have a risk factor for gastric cancer, it does not mean that you are going to get gastric cancer. 

How can I prevent gastric cancer?

Because there is no one risk factor directly associated with gastric cancer, there is no specific way to prevent it. However, there are ways to prevent cancer in general. These include a balanced diet low in smoked foods, pickled foods and preserved or heavily salted meats and fish. You should try to eat a diet rich in fruits, vegetables, and lean proteins. Maintaining a healthy way of life and staying active can also help prevent cancer. 

Avoid tobacco use. If you use tobacco, you should quit as tobacco use has been shown to cause many types of cancer. If you need help quitting, you should speak with your healthcare provider.

Since H. pylori infections have been linked to the development of gastric cancers, quick treatment of H. pylori infections may decrease the number of gastric cancers. However, if treating H. Pylori actually reduces the risk of gastric cancer remains controversial. 

What screening tests are available?

Currently, there is no approved routine screening test for gastric cancer in the U.S. If you have known risk factors such as atrophic gastritis (a chronic inflammation of the stomach lining), you may want to speak to your provider about the need for screening tests. Currently, screening for H. Pylori is not recommended in areas with a relatively low incidence of gastric cancer, such as in the United States.

In Japan, where gastric cancer is much more common, screening programs are used. A variety of tests have been used in these screening programs including upper gastrointestinal series (barium swallow), upper endoscopies, Helicobacter pylori antibody test, and serum pepsinogen tests. 

Families with a known HDGC mutation CHD1 should speak to their provider about having a screening endoscopy (EDG).

What are the signs of gastric cancer?

It is not common to have symptoms of stomach cancer until the cancer is quite advanced. If you do develop symptoms, you may have:

  • Weight loss can be related to poor appetite or early satiety (feeling full before finishing a meal). 
  • Discomfort and pain in the belly. 
  • Nausea and vomiting. 
  • Blood in vomit or stool. 
  • Heartburn. 
  • Enlarged belly from fluid buildup. 
  • Enlarged lymph nodes in the underarms, belly button, and clavicle (in advanced stages). 

The symptoms of stomach cancer can be the symptoms seen in many other illnesses such as peptic ulcer disease and gastritis. Often, treatment for these conditions will be tried first, as these are much more common than gastric cancer. If your symptoms continue, it is important to talk with your provider about further testing.

How is gastric cancer diagnosed? 

Upper endoscopy is used for the initial diagnosis and staging of patients with gastric cancer. Many times, ultrasound during endoscopy is also used to help identify how deep into the wall of the stomach the cancer has grown. In many cases, ultrasound can also identify if the cancer has spread to lymph nodes. Depth of stomach wall invasion and presence of lymph node spread are two very important pieces of information in determining treatment options.

Other procedures are needed to determine the stage of the disease. CT scans ("CAT scans") of the abdomen and chest may be done. This is to rule out spread to distant organs, like the liver and lungs, and also to see if the cancer has spread to lymph nodes close to the stomach that could not be seen by ultrasound. Other tests to rule out abdominal spread of disease outside of the stomach itself are PET scans and laparoscopy.

Laparoscopy is a surgical procedure that involves entering the abdominal cavity with a fiber-optic camera using small cuts in the skin. This allows your provider to see all the organs and tissues in the area of the stomach, the abdominal cavity, and the lining of the abdomen (omentum and peritoneum). A sample of abdominal fluid can be sent to cytology/pathology to check for cancer cells in the fluid. 

A biopsy is the removal of a piece of the tissue or fluid for testing to see if there are cancerous cells. After the biopsy, the tissue/fluid is sent to a pathologist who looks at the tissue under a microscope to see if the tumor is cancerous or not. This information is reported in a pathology report

Blood screening tests may also be done to check that overall blood counts are within normal limits, to check for anemia and that a patient's liver and kidneys are working properly.

All of these tests are important to determine the extent of the disease, which allows the disease to be staged. The stage provides a guideline for the best treatment of gastric cancer.

How is gastric cancer staged?

The stage of the cancer can be determined after your testing is done. The staging of a cancer describes how much cancer has grown within the stomach as well as if it has spread. This is very important in terms of what treatment is offered to each individual patient. The staging system used to describe gastric tumors is the "TNM system", as described by the American Joint Committee on Cancer. The TNM systems are used to describe many types of cancers. They have three components

  • T-describes the size/location/extent of the "primary" tumor in the stomach.
  • N-describes if the cancer has spread to the lymph nodes
  • M-describes if the cancer has spread to other organs (i.e.-metastases). 

The T, N, M, are then combined to come up with a stage from 0-IV, with IV being the most advanced. The staging system is very complex. The entire staging system is outlined at the end of this article. Though complicated, the staging system helps healthcare providers determine the extent of the cancer, and in turn, make treatment decisions for your cancer. 

How is gastric cancer treated?

Surgery

At this time, curative treatments for gastric cancer involve surgery (surgical resection of the cancer). The smallest amount of surgery that is possible while still taking out all of the cancer is what is usually done. Often, tumors that are in the part of the stomach closest to the esophagus (proximal stomach) are treated with a gastrectomy (removal of the entire stomach). A total gastrectomy is often used to also treat cancer involving the entire stomach. 

A partial gastrectomy is the removal of only part of the stomach. Partial gastrectomies may be used in those with tumors that are further from the esophagus, in the distal portion of the stomach. 

It is important that an experienced surgeon performs this procedure, as it is a difficult surgery. When the stomach or a portion of the stomach is removed, the two ends must be rejoined. This is done in various ways, with the goal being to eliminate as many of the side effects of the surgery as possible. Side effects can include not being able to eat larger meals and dumping syndrome. Dumping syndrome occurs when the small intestine fills too quickly with undigested food as a result of the stomach (or part of the stomach) being removed. Symptoms include nausea, vomiting, bloating, diarrhea, and even shortness of breath. These symptoms can usually be managed with changes to the diet.

Although surgery is always needed for curative treatment, it is often not enough to achieve a cure in many cases. In most patients with more advanced cases of gastric cancer, including those with positive lymph nodes or tumors which have invaded the deep layers of the stomach or beyond, the cancer will come back if only surgery is done. To reduce risk or recurrence, chemotherapy and radiation may be used. This can be done before or after surgery, depending on the stage of the tumor.

Radiation

Radiation therapy uses high-energy x-rays to kill cancer cells. It does this by damaging the DNA in tumor cells. Normal cells in our body can repair radiation damage much quicker than cancer cells. While cancer cells are killed by radiation, many normal cells are not. This is the basis for the use of radiation therapy in cancer treatment. Radiation is delivered using large machines that produce high-energy x-rays. After radiation oncologists set up the radiation fields (the areas of the body that will be treated by radiation), treatment is begun. The number of treatments you may need will depend on your specific case. The treatment takes just a few minutes each day and is painless. The typical radiation field used in the treatment of gastric cancer includes portions of the upper abdomen. In other words, it is designed to kill tumor cells in the area that the surgery was performed. Typical side effects include nausea and vomiting (though this should be less of a problem since the stomach has already been removed) and diarrhea.

Chemotherapy

Chemotherapy refers to medications to treat cancer that are usually given intravenously (IV, into a vein) or in pill form to take by mouth.  Chemotherapy travels throughout the bloodstream and throughout the body to kill cancer cells. This is one of the big advantages of chemotherapy. If cancer cells have broken off from the tumor and are somewhere else inside the body, chemotherapy has the chance of killing them, while radiation does not. 

The standard chemotherapy used in the treatment of gastric cancer is called 5-FU (fluorouracil) and is given with another drug called leucovorin. This type of chemotherapy is given into a vein. Sometimes chemotherapy and radiation are used prior to surgery or after surgery (or before AND after surgery). Some of the chemotherapy agents used to treat gastric cancer include capecitabinecarboplatincisplatindocetaxelepirubicinirinotecanoxaliplatinpaclitaxel and the combination drug trifluiridine and tipiracil

Targeted Therapies

Targeted therapies can be used to treat gastric cancers that have specific targets on their cells. For example, trastuzumab can be used to treat gastric cancer cells that have a HER2 positive protein on them. Other targeted therapies include nivolumab, ramucirumab, fam-trastuzumab deruxtecan-nxki, entrectinib, larotrectinib, and pembrolizumab. Your tumor will be tested for certain markers to determine if targeted therapies are an option.

Clinical Trials                    

Clinical trials are extremely important in furthering our knowledge of this disease. It is through clinical trials that we know what we do today, and many exciting new therapies are currently being tested. Talk to your healthcare provider about participating in clinical trials in your area. You can also explore currently open clinical trials using the OncoLink Clinical Trials Matching Service. 

Follow-up Care and Survivorship

Once you complete treatment for gastric cancer you need to be closely followed by your oncology team. This close follow-up is needed for a couple of reasons. First, to see if you are having side effects related to your treatment. This includes making sure that you are not vomiting, not having diarrhea, and that you have healed from surgery. In addition, because of the removal of the stomach or a portion of the stomach, gastric cancer patients are prone to a certain type of anemia, resulting from not having enough vitamin B-12. You will have your B-12 level checked as this anemia does not usually happen until years after the surgery.

It is recommended that you follow up with your provider every 3 to 6 months following initial treatment for two years then every 6 to 12 months for years 3-5. Labs and imaging studies are done as needed. You will also need to be monitored for nutritional deficiencies.

Fear of recurrence, relationships and sexual health, the financial impact of cancer treatment, employment issues, and coping strategies are common emotional and practical issues experienced by gastric cancer survivors. Your healthcare team can identify resources for support and management of these challenges faced during and after cancer.

Cancer survivorship is a relatively new focus of oncology care. With nearly 17 million cancer survivors in the US alone, there is a need to help patients transition from active treatment to survivorship. What happens next, how do you get back to normal, what should you know and do to live healthy going forward? A survivorship care plan can be a first step in educating yourself about navigating life after cancer and helping you communicate knowledgeably with your healthcare providers. Create a survivorship care plan today on OncoLink.

Resources for Further Information

Gastric Cancer Foundation

GCF serves as a comprehensive resource for anyone with stomach cancer, their family, friends, or caregivers – after a new diagnosis, during treatment, and post-treatment. Also operates a Gastric Cancer Registry to assist in research.

No Stomach for Cancer

Empowering families by providing information on stomach cancer and a community of support.

Debbie's Dream Foundation: Curing Stomach Cancer

Raising awareness, funding research, and supporting patients through education, an online community, and a clinical trials matching service.

Appendix: Staging System for Gastric Cancer

AJCC TNM Staging Classification for Carcinoma of the Stomach, 8th Ed., 2017

Your provider can tell you the TNM staging for your tumor. T stands for the size/invasiveness of the primary tumor. The N describes lymph node involvement and the M describes if the cancer has spread. These numbers are combined to determine the stage of the cancer using the chart below.

Primary Tumor (T)

Description

TX

Primary tumor cannot be assessed

T0

No evidence of primary tumor

T1s

Carcinoma in situ; intraepithelial tumor without invasion of the lamina propria

T1

Tumor invades lamina propria or muscularis mucosae or submucosa

T1a

Tumor invades lamina propria or muscularis mucosae

T1b

Tumor invades submucosa

T2

Tumor invades muscularis propria (without perforation of the visceral peritoneum)

T3

Tumor penetrates subserosal connective tissue without invasion of visceral peritoneum or adjacent structures

T4

Tumor invades serosa (visceral peritoneum) or adjacent structures

T4a

Tumor invades serosa (visceral peritoneum)

T4b

Tumor invades adjacent structures

  

Regional Lymph Nodes (N)

Description

NX

Regional lymph node(s) cannot be assessed

N0

No regional lymph node metastasis

N1

Metastasis in 1-2 regional lymph nodes

N2

Metastasis in 3-6 regional lymph nodes

N3

Metastasis in 7 or more regional lymph nodes

N3a

Metastasis in 7-15 regional lymph nodes

N3b

Metastasis in 16 or more regional lymph nodes

  

Distant Metastasis (M)

Description

M0

No distant metastasis

M1

Distant metastasis

  

Histologic Grade

Description

GX

Grade cannot be assessed

G1

Well differentiated

G2

Moderately differentiated

G3

Poorly differentiated, undifferentiated

  

Clinical Staging

cT

cN

M

Stage 0

Tis

N0

M0

Stage I

T1

T2

N0

N0

M0

M0

Stage IIA

T1

T2

N1, N2, N3

N1, N2, N3

M0

M0

Stage IIB

T3

T4a

N0

N0

M0

M0

Stage III

T3

T4a

N1, N2, N3

N1, N2, N3

M0

M0

Stage IVA

T4b

Any N

M0

Stage IVB

Any T

Any N

M1

  

Pathologic Staging (pTNM)

pT

pN

M

Stage 0

Tis

N0

M0

Stage IA

T1

N0

M0

Stage IB

T1

T1

N1

N0

M0

M0

Stage IIA

T1

T2

T3

N2

N1

N0

M0

M0

M0

Stage IIB

T1

T2

T3

T4a

N3a

N2

N1

N0

M0

M0

M0

M0

Stage IIIA

T2

T3

T4a

T4b

N3a

N2

N1 or N2

N0

M0

M0

M0

M0

Stage IIIB

T1

T2

T3

T4a

T4b

N3b

N3b

N3a

N3a

N1 or N2

M0

M0

M0

M0

M0

Stage IIIC

T3

T4a

T4b

N3b

N3b

N3a or N3b

M0

M0

M0

Stage IV

Any T

Any N

M1

  

Post-Neoadjuvant Therapy (ypTNM)

ypT

ypN

M

Stage I

T1

T2

T1

N0

N0

N1

M0

M0

M0

Stage II

T3

T2

T1

T4a

T3

T2

T1

N0

N1

N2

N0

N1

N2

N3

M0

M0

M0

M0

M0

M0

M0

Stage III

T4a

T3

T2

T4b

T4b

T4a

T3

T4b

T4b

T4a

N1

N2

N3

N0

N1

N2

N3

N2

N3

N3

M0

M0

M0

M0

M0

M0

M0

M0

M0

M0

Stage IV

Any T

Any N

M1

  

References

SEER Statistics, Stomach Cancer, https://seer.cancer.gov/statfacts/html/stomach.html

NCCN Clinical Practice Guidelines, Gastric Cancer, www.nccn.org (log in required)

American Cancer Society, Stomach Cancer, https://www.cancer.org/cancer/stomach-cancer.html

Boku, N. (2014). HER2-positive gastric cancer. Gastric Cancer, 17(1), 1-12.

Cervantes, A., Roda, D., Tarazona, N., Roselló, S., & Pérez-Fidalgo, J. A. (2013). Current questions for the treatment of advanced gastric cancer. Cancer Treatment Reviews, 39(1), 60-67.

Fock, K. M. (2014). Review article: the epidemiology and prevention of gastric cancer. Alimentary Pharmacology & Therapeutics, 40(3), 250-260.

Lordick, F., Allum, W., Carneiro, F., Mitry, E., Tabernero, J., Tan, P., ... & Cervantes, A. (2014). Unmet needs and challenges in gastric cancer: the way forward. Cancer Treatment Reviews, 40(6), 692-700.

McLean, M. H., & El-Omar, E. M. (2014). Genetics of gastric cancer. Nature Reviews Gastroenterology & Hepatology, 11(11), 664-674.

Mickle, M. (2011). Gastric Cancer. In Yarbro C.H, Wujcik, D. & Gobel, B.H. (2011). Cancer Nursing (pp. 1683-1695. Sudbury, MA: Jones and Bartlett.

Orditura, M., Galizia, G., Sforza, V., Gambardella, V., Fabozzi, A., Laterza, M. M., ... & Lieto, E. (2014). Treatment of gastric cancer. World Journal of Gastroenterology, 20(7), 1635-1649.

Oliveira, C., Pinheiro, H., Figueiredo, J., Seruca, R., & Carneiro, F. (2015). Familial gastric cancer: genetic susceptibility, pathology, and implications for management. The Lancet Oncology, 16(2), e60-e70.

Plummer, M., Franceschi, S., Vignat, J., Forman, D., & de Martel, C. (2015). Global burden of gastric cancer attributable to Helicobacter pylori. International Journal of Cancer, 136(2), 487-490.

Rahman, R., Asombang, A. & Ibdah, J. (2014). Characteristics of gastric cancer in Asia. World Journal of Gastroenterology, 20(16), 4483-4490.

Rugge, M., Fassan, M., & Graham, D. Y. (2015). Epidemiology of gastric cancer. In Gastric Cancer (pp. 23-34). Springer International Publishing.

Takahashi, T., Saikawa, Y., & Kitagawa, Y. (2013). Gastric cancer: current status of diagnosis and treatment. Cancers, 5(1), 48-63.

Terashima, M., Iwasaki, Y., Mizusawa, J., Katayama, H., Nakamura, K., Katai, H., ... & Hirao, M. (2015). 2221 Randomized phase III trial of gastrectomy with or without neoadjuvant S-1 plus cisplatin for type 4 or large type 3 gastric cancer; short-term safety and surgical results: Japan Clinical Oncology Group Study (JCOG 0501). European Journal of Cancer, (51), S406.

Tramacere, I., Negri, E., Pelucchi, C., Bagnardi, V...Boffetta, P. (2012). A meta-analysis on alcohol drinking and gastric cancer risk. Annals of Oncology, 23(1), 28-36.

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