By Gary Wolfe and Marleen Wolfe

Daily, it seems, news reports on disconcerting health trends in the United States emerge. In many cases, the key factor contributing to these trends is the American lifestyle of excess. We eat too much, neglect our bodies, overwork, spend too much time in the sun, abuse drugs and alcohol, and so on. Nevertheless, such self-criticism should not obscure the fact that in spite of our lifestyle, there have been dramatic reductions in the incidences and prevalence of numerous diseases. This good news rarely elicits media notice or public concern in the United States, even though some of these diseases are still widespread elsewhere in the world.

Consider stomach (gastric) cancer. According to statements from Brigham and Women’s Hospital in Boston, “Stomach cancer has decreased as the most common cause of cancer deaths in males in 1930 to one of the less common causes of cancer death today. This decrease in cancer death is almost entirely accounted for by a decrease in the incidence of the disease rather than improved treatment or better detection. Stomach cancer remains common in Asia and Japan, and first-generation immigrants to the US retain a high risk for the disease. The marked decrease in the risk of stomach cancer is unexplained since the cause of stomach cancer is unknown. Changes in diet, food preservation by refrigeration rather than salting, and smoking tobacco rather than chewing it, have all been cited as possibly contributing to the decline in incidence.”

Incidence Worldwide Versus in the United States
According to the National Cancer Institute (NCI), Washington, DC,“Stomach cancer was the most common form of cancer in the world in the 1970s and early 1980s.” Investigators at the John Wayne Cancer Institute of Saint John’s Health Center in Santa Monica, Calif, note,“Stomach cancer is now the ninth leading cause of death in men and the eleventh in women.”

Statistics from the American Cancer Society (ACS) based in Atlanta indicate that in 2003 approximately 22,400 new cases of stomach cancer occurred in the US, mainly among people in their 60s and 70s. Of these, the ACS says, “About 12,100 will die of this disease.” The disease thus presents an interesting conundrum: comparatively few Americans get stomach cancer, so the disease has a low profile. But, if they do contract the disease, more than half (about 54%, based on the ACS numbers) will die as a result.

Origins and Characteristics
Investigators at Hendrick Health System in Abilene, Tex, describe stomach cancer as a “disease in which the cells forming the inner lining of the stomach become abnormal and start to divide uncontrollably, forming a tumor. The cancer can develop in any of the five sections of the stomach (ie, cardia, fundus, antrum, prepyloric region, and pylorus), with symptoms and outcomes of the disease varying, depending on the location of the cancer.”

The John Wayne Cancer Institute report explains, “Ninety-five percent of stomach cancer begins as a mutation of the cells in the glandular tissue lining the stomach. Occasionally a tumor will develop in the lymph tissue or in the muscles of the stomach walls. Doctors universally refer to the spread of stomach cancer by stages: from the early stage 0 (in which the cancer is limited to its site of origin in the epithelial layer of cells in the stomach) up to the advanced stage IV (in which the cancer may have spread into a combination of one or more stomach layers, the main muscle layer of the stomach wall, the outermost layer of the stomach, more than 15 nearby lymph nodes, nearby organs (such as the spleen, liver, intestines, kidneys, and pancreas), and/or distant organs (such as lymph nodes, bones, lungs, and brain).”

Few Symptoms, Rarely Diagnosed Early
Symptoms of the disease, according to both the American Cancer Society and the John Wayne Cancer Institute, include: “weight loss and lack of appetite; abdominal pain and discomfort, often above the navel; abnormal sense of fullness in the upper abdomen and below the chest bone; heartburn, indigestion or ulcer-type symptoms; nausea and vomiting, with or without blood; and swelling of the abdomen, usually due to accumulation of fluid and cancer cells.” According to the John Wayne Institute, because stomach cancer has few symptoms, only 10% to 20% of cases are diagnosed before it has spread to other sites.

Possible Influences and Causes
Factors noted by the ACS as possible causes of stomach cancer include: “bacterial infections, diet, tobacco and alcohol abuse, earlier stomach surgery, gender (males over females by two to one), ethnicity (highest rates are in Asian/Pacific Islanders and it is more common in Hispanics and African Americans than in non-Hispanic Whites), age (sharp increase in those over 50 years of age), type A blood, family history of stomach cancer, stomach polyps (notably adenomatous polyps), and geography.”

The ACS also reports, “Some doctors think that an important factor in the decline of the disease is the use of antibiotics to treat infections in children. These drugs can kill the bacterium (Helicobacter pylori) that may be a major cause of this disease.” In addition, according to the National Cancer Institute, “Evidence is strong that salt intake is a major determinant of stomach cancer risk.”

The geographical aspect of stomach cancer is especially intriguing. For example, the National Cancer Institute states, “Stomach cancer incidence rates for the racial/ethnic populations in the SEER (Surveillance, Epidemiology, and End Results) regions can be grouped broadly into three levels. Those with high age-adjusted incidence rates are Koreans, Vietnamese, Japanese, Alaska natives and Hawaiians. Those with intermediate incidence rates are white Hispanic, Chinese, and black populations. Filipinos and non-Hispanic whites have substantially lower incidence rates than the other groups. These patterns hold for both men and women when rates are available for both sexes.”

The Hendrick Health System reports, “In Japan, stomach cancer appears almost ten times as frequently as in the US.” Likewise, the American Cancer Society notes, “Japanese people living in Japan have a very high rate of stomach cancer. If they move to the US, the rate goes down after a number of years, but it still remains higher than that of people born in the US.”

Another factor possibly contributing to the disease, according to reports from the Methodist Health Care System in Houston, is Ménétrier disease. As described by the National Digestive Diseases Information Clearing House, “Ménétrier disease (also called giant hypertrophic gastritis, protein-losing gastropathy, or hypertrophic gastropathy) causes giant folds of tissue to grow in the wall of the stomach. The tissue may be inflamed and may contain ulcers. The disease also causes glands in the stomach to waste away and causes the body to lose fluid containing albumin.”

Yet another possible cause cited by the Methodist Health Care System is “exposure to environmental factors, such as dust and fumes in the workplace”. Moreover, this organization reports, “Recent studies have concluded that a diet high in red meat, particularly if the meat is barbecued or well done, contributes to stomach cancer.”

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Detection and Treatment
Techniques that the American Cancer Society says are used to detect stomach cancer include: “upper endoscopy, barium upper GI (gastrointestinal) radiography, ultrasonography, CT (computed tomography) scan, PET (positron emission tomography) scan, MRI (magnetic resonance imaging) scan, chest X-rays, laparoscopy, and blood testing (ie, for CBC and fecal occult blood)”. Modes of treatment cited by the ACS include “surgery (endoscopic mucosal resection, subtotal gastrectomy, or total gastrectomy), chemotherapy, and radiation therapy; all followed by regular exams and tests.”

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According to Laura Shapiro, director, Oncology, for Siemens Global Solutions Group, “To our knowledge, there are no imaging systems designed specifically to screen for stomach cancer. Systems used for diagnosing stomach cancer would likely be the same ones used for diagnosing other cancers.”

Shapiro notes, “One very promising trend that we have seen is the emergence of non-invasive diagnostic methods such as molecular imaging and the use of magnetic resonance (MR) spectra specific to the cancer type. This approach might someday permit physicians to definitively diagnose stomach cancer – or some other type of cancer – and to determine the extent to which it has progressed without necessarily having to do a biopsy.”

For more information, contact:

• American Cancer Society (www.cancer.org)
• Brigham and Women’s Hospital (www.brighamandwomens.com)
• Hendrick Health System (www.ehendrick.com)
• John Wayne Cancer Institute (www.jwci.org)
• Methodist Health Care System (www.methodisthealth.com)
• National Cancer Institute (www.cancer.gov)
• National Digestive Diseases Information Clearing House (digestive.niddk.nih.gov)
• Siemens Medical Products, 1551 Valley Street Parkway, Malvern, Penn 19355; (610) 448-1668; www.siemensmedical.com

Gary Wolfe and Marleen Wolfe are contributing writers for Clinical Lab Products.