Is gastric carcinoma an infectious disease?
Article Abstract:
A brief discussion focuses on the problem of inferring causality when a disease occurs after exposure to a suspect agent or environmental factor. In particular, two studies in the October 17, 1991 issue of The New England Journal of Medicine found that past infection with Helicobacter pylori increases the risk of gastric carcinoma (stomach cancer); however, the majority of patients (76 percent in one report) without cancer were also infected with H. pylori. Causal relationships are difficult to infer when cause and effect (in this case, a disease) are separated by many years. The Bradford-Hill guidelines for causality in carcinogenesis are discussed. They take into account the complex nature of long-term causality. To what extent infection with H. pylori causes gastric carcinoma is debated. The causal ''puzzle'' concerning this issue is reconstructed; the studies cited showed that infection was present many years before the diagnosis of gastric carcinoma. It remains to be shown that curing the infection can reduce the risk of gastric carcinoma. Although between 30 percent and 70 percent of all adults (in the populations studied) harbored H. pylori, the populations at risk for stomach cancer are those whose children have a high prevalence of H. pylori infection. A parallel is drawn between the roles of H. pylori and salt in cancer. Excessive salt can cause gastritis (stomach inflammation), which is accompanied by increased rates of cell replication, an important event for carcinogenesis. Salt also enhances the actions of known carcinogens in the stomach. H. pylori appears to cause changes in polymorphonuclear lymphocytes (a type of white blood cell), and the changes cause these lymphocytes to release more oxygen radicals. The radicals can then cause mutations in gastric cells. However, these changes also occur in diffuse antral gastritis, which is not associated with stomach cancer. Infection with H. pylori is clearly not necessary and sufficient to cause stomach cancer, which is a disease of multifactorial etiology. Stomach cancer is probably related to H. pylori infection, excessive salt intake, and inadequate amounts of fresh fruit and vegetables in the diet. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1991
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Streptozocin-doxorubicin, streptozocin-fluorouracil, or chlorozotocin in the treatment of advanced islet-cell carcinoma
Article Abstract:
Streptozocin combined with doxorubicin may be more effective than streptozocin plus fluorouracil for treating advanced islet-cell cancer, a rare form of pancreatic cancer. Chlorozotocin alone may be as effective as streptozocin plus fluorouracil, and it causes less nausea and vomiting. A group of 105 patients with advanced islet-cell cancer received either streptozocin and doxorubicin, streptozocin and fluorouracil or chlorozotocin alone. Sixty-nine percent of the patients given streptozocin and doxorubicin had tumor regression compared to 45% of the patients in the streptozocin-fluorouracil group and 30% of the patients in the chlorozotocin group. The average time before the cancer progressed again was 20 months for patients in the streptozocin-doxorubicin group and 6.9 months for patients in the streptozocin-fluorouracil and chlorozotocin groups. The average survival time for patients in the streptozocin-doxorubicin group was 2.2 years, compared to 1.4 years for patients in the streptozocin-fluorouracil and chlorozotocin groups. Side effects of the drugs were vomiting and nausea, decreased production of blood cells and, with long-term treatment, kidney failure.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1992
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Urothelial carcinoma associated with the use of a Chinese herb (Aristolochia fangchi)
Article Abstract:
The Chinese herb Aristolochia fangchi may cause kidney cancer. Researchers describe 39 patients with end-stage kidney failure caused by a weight loss product made from Chinese herbs. All patients had their kidneys removed in preparation for a kidney transplant or dialysis. When the kidneys were examined, 18 cases of kidney cancer were found Nineteen patients had a precancerous condition called dysplasia and only two had normal kidneys. A manufacturing error had resulted in the incorporation of the herb Aristolochia fangchi, which is known to be carcinogenic, instead of the usual herb, Stephania tetrandra.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 2000
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