Diagnosis and Prognosis of Stomach Cancer
The diagnosis and prognosis of stomach cancer includes the following:
Review of Medical History
Your doctor will ask you about the symptoms you’ve been experiencing, as well as:
- Medical history (concentrating on various medical conditions or previous surgeries that may increase your risk of developing stomach cancer)
- History of tobacco and alcohol use
- Dietary intake
- The presence of stomach cancer or other associated conditions in your family
- Any occupational exposures you may have had
Your doctor will perform a complete physical examination, concentrating on the abdominal exam. He or she will check whether you have any of the following:
- Tenderness or discomfort during the exam
- Free fluid within the abdomen
- Masses that can be felt
- An enlarged or abnormally hard liver
Further testing to help with the diagnosis includes the following:
Fecal Occult Blood Test
This is a simple test that can be done in your doctor's office. After a rectal exam (the insertion of one gloved, lubricated finger into the rectum to feel for abnormalities), the doctor wipes a small sample of stool onto a slide. Chemicals are added, which will reveal if there is any blood in your stool. This test does not definitively diagnose the presence of stomach cancer because several other conditions can cause blood to appear in the stool. But, if there is blood in the stool, it should increase your doctor's suspicion and should prompt him or her to order more tests.
Upper Gastrointestinal (GI) X-ray Study
(Barium Swallow Study)
After you drink a thick, chalky solution containing barium, a series of x-rays are taken. The barium helps outline your gastrointestinal tract, making any abnormalities stand out more clearly.
Fiberoptic Esophagogastroduodenoscopy (Endoscopy)
In this test, a thin, flexible scope is passed through your mouth, down your esophagus, and into your stomach and the first part of your small intestine (duodenum). Your doctor can then examine your gastrointestinal tract for abnormalities. Tiny tools can also be passed down this scope to take biopsy samples (samples of tissue). These samples are examined under a microscope to check for the presence of cancer cells.
Cytology is the study of cells. The cytology of cancer cells differs significantly from normal cells, and physicians use the unique cellular features seen on biopsy samples to determine the diagnosis and assess the prognosis of a cancer.
In the case of stomach cancer, cytology involves looking at cells in fluid or from a thin needle biopsy, under the microscope. The pathologist may be able to make the diagnosis of cancer with this small sample and may be able to tell your doctor the specific type of cancer and how aggressive it may look.
Staging is the process by which physicians determine the prognosis of a cancer that has already been diagnosed. Staging is essential for making treatment decisions (such as surgery or chemotherapy). Several features of the cancer are used to arrive at a staging classification, the most common being the size of the original tumor, extent of local invasion, and spread to distant sites (metastasis). Low staging classifications (0-1) imply a favorable prognosis, whereas high staging classifications (4-5) imply an unfavorable prognosis.
Staging of stomach cancer cells considers several factors:
- How deeply the cancer cells have penetrated the layers of the stomach
- If cancer is present in the lymph nodes surrounding the stomach
- If there are cancer cells in neighboring organs and tissue
- If cancer has invaded distant organs or tissues within the body
Tests used to stage stomach cancer include the following, which may be done in your doctor's office or at an outpatient clinic:
Blood tests—Blood tests can reveal symptoms of cancer or its spread, such as anemia
or problems with liver function.
—A chest x-ray is a series of standard x-ray images of your chest. It is important to examine the lungs for metastatic cancer.
Abdominal computed tomography (CT) scan
—An abdominal CT scan can reveal the following:
- Presence of a tumor
- Lymph node enlargement, which may be a sign of cancer spread
- Abnormalities in other organs or tissues throughout the abdomen that might indicate metastases
Pelvic computed tomography (CT) scan—A pelvic CT scan can demonstrate metastatic spread of stomach cancer by identifying any of the following:
- Enlarged lymph nodes
- Presence of tumors in the ovaries or other organs
- Other tissue abnormalities
Endoscopic ultrasonography—An endoscope (thin, flexible, lighted scope) is passed through the mouth, down the esophagus, and into the stomach and intestine. A tiny ultrasound unit at the tip of the endoscope bounces sound waves off of the adjacent organs to generate ultrasound images of the intestinal tract and surrounding tissues.
—Tiny incisions are made in the abdomen, allowing a scope to be passed into the abdomen. Your doctor can use this scope to examine the lining of your abdomen (peritoneum) and your liver, as well as other abdominal organs and tissue. Tiny tools can be passed through the laparoscope to take biopsy samples; the tissue samples will be checked for cancer cells.
Peritoneal lavage—Saline solution (salt water) is washed through your abdomen and then suctioned out. The saline is then examined under a microscope for the presence of cancer cells.
Once all the information has been collected, your healthcare provider will put it all together to determine the stage of your cancer. A common system used for staging is called the TNM system. This system characterizes three aspects of stomach cancer: information about the tumor (T), the lymph nodes (N), and the presence of distant metastasis (M). The higher numbers reflect a greater degree of abnormality and spread.
Stomach Tumor (T)
Evaluation of the stomach tumor determines which layers of the stomach have been invaded by cancer cells. There are five layers to the stomach. From the most interior layer to the most exterior layer, the layers of the stomach are: the mucosa (which lines the inside of the stomach), the submucosa, the muscularis (the largest, muscular layer), the subserosa, and the serosa (the outermost layer that lines the outside of the stomach).
The T stages are as follows:
- TX: Tumor cannot be evaluated.
- T0: There is no evidence of tumor.
- Tis: Cancer cells are present only in the mucosa.
- T1: Cancer cells are present in the submucosa.
- T2a: Cancer cells are present in the muscularis propria.
- T2b: Cancer cells are present in the subserosa.
- T3: Cancer cells are present all the way through to the serosa, but not in any adjacent tissues or organs.
- T4: Cancer cells have invaded neighboring tissues or organs.
Lymph Nodes (N)
The N stages are as follows:
- NX: Nodes cannot be evaluated.
- N0: There are no cancer cells in the lymph nodes surrounding the stomach.
- N1: There are cancer cells in 1-6 of the lymph nodes surrounding the stomach.
- N2: There are cancer cells in 7-15 of the lymph nodes surrounding the stomach.
- N3: There are cancer cells in more than 15 of the lymph nodes surrounding the stomach.
Distant Metastasis (M)
The M stages are as follows:
- MX: Presence of metastasis cannot be evaluated.
- M0: There is no distant metastasis.
- M1: There is distant metastasis, such as to distant lymph nodes, or the liver, lungs, brain, and/or bone.
Once the T, N, and M categories have been determined, the information is grouped together to determine your stage. The groupings are described in this table.
Stomach Cancer Staging Based on T, N, and M Categories
||T, N, and M categories
||Tis, NO, MO
||T1, N0, M0
||T1, N1, M0
|T2a or T2b, N0, M0
||T1, N2, M0
|T2a or T2b, N1, M0
|T3, N0, M0
||T2a or T2b, N2, MO
|T3, N1, M0
|T4, N0, M0
||T3, N2, M0
||T1-3, N3, M0
|T4, N1-3, M0
|Any T, Any N, M1
Prognosis is a forecast of the probable course and/or outcome of a disease or condition. Prognosis is most often expressed as the percentage of patients who are expected to survive over 5 or 10 years. Cancer prognosis is a notoriously inexact process. This is because the predictions are based on the experience of large groups of patients suffering from cancers at various stages.
Using this information to predict the future of an individual patient is always imperfect and often flawed, but it is the only method available. Prognoses provided in this monograph and elsewhere should always be interpreted with this limitation in mind. They may or may not reflect your unique situation.
Most patients (about 66%) are at Stage III or Stage IV at the time of diagnosis. The remaining 34% are evenly divided between Stages I and II. Because stomach cancer is usually at a relatively advanced stage at the time of diagnosis, only about 22% of patients with stomach cancer survive for 5 years after diagnosis.
Survival rates for patients who are diagnosed in the earlier stages of stomach cancer depend in part on the location of the stomach cancer. The 5-year survival rate for patients who have cancer in the part of their stomach closest to the esophagus is 10% to 15%. The 5-year survival rate for patients who have cancer in the part of their stomach closest to the intestine is about 50%.
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