Possibility of inducing glandular stomach cancer in rats exposed to asbestos

Our plain-English summary of Possibility of inducing glandular stomach cancer in rats exposed to asbestos, by F.M. Kogan, N.N. Vanchugova, V.N. Frasch (British Journal of Industrial Medicine, 1987).

The study

• Authors: F.M. Kogan, N.N. Vanchugova, V.N. Frasch
• Journal: British Journal of Industrial Medicine
• Published: 1987;44(10):682-6
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The possibility of glandular stomach cancer being induced was studied in 75 random bred white rats exposed to chrysotile asbestos. A perforated polyethylene capsule containing 100 mg asbestos and filler (beef fat and natural wax mixture 1:1) was introduced in an artificial bag placed on the greater curvature of the stomach. A capsule containing filler only was introduced in a similar way in 40 control rats. In the following 25 months, 18 tumors of the stomach and abdominal cavity were found in the rats treated with asbestos (eight adenomas, two adenocarcinomas, one carcinosarcoma, one forestomach cancer, one intestinal adenocarcinoma, two peritoneal mesotheliomas, and three abdominal lymphoreticulosarcomas.) Among the control rats no such tumors were found. The results of the experiment are discussed in connection with epidemiological data on stomach cancer in asbestos workers.

In plain English

In this animal experiment from the USSR, the authors surgically formed a small pouch in the stomach wall of young white rats. Inside it they placed a perforated polyethylene capsule holding 100 mg of chrysotile asbestos mixed with beef fat and natural wax. Control rats received a capsule with filler only. Results covered 75 asbestos-treated and 40 control rats that survived at least six months, in two series. In the first series, survivors were killed at month 17; in the second, rats were followed for life. The asbestos-treated rats had 18 tumours of the stomach and abdominal cavity, 8 benign and 10 malignant. These included three malignant glandular stomach tumours, one probable forestomach cancer, two peritoneal mesotheliomas and one small-intestine adenocarcinoma. No such tumours were found in the controls. The authors noted the operation was traumatic and that effects of adhesions, sutures and the clip's polyethylene coating could not be ruled out. They concluded there were grounds to consider the tumours in the stomach and adjacent part of the abdominal cavity induced by asbestos. They also said they were far from drawing practical conclusions from this experiment alone.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment (rats) with surgical implantation of an asbestos-containing capsule into a surgically formed stomach pouch, compared with control rats given filler-only capsules; run as two separate series
• Who was studied: Random bred white rats, 2-3 months old at operation, from the nursery of the Academy of Medical Sciences of the USSR. There were 75 asbestos-treated rats surviving to 6 months (26 in the first series, 49 in the second) and 40 controls (26 and 14). The research institute was in Sverdlovsk, USSR. The dates of the experiment are not given.
• Exposure: A perforated polyethylene capsule containing 100 mg chrysotile asbestos mixed with a filler (beef fat and natural wax, 1:1). It was placed in an artificial pouch ('small stomach') in the stomach wall and held with a soft wire clip. Controls had a capsule containing filler only.
• Main results:
  • Among the 75 asbestos-treated rats, 18 tumours of the stomach and abdominal cavity were found: 8 benign and 10 malignant
  • No such tumours were observed in the control rats. In the asbestos-treated rats, the tumours appeared between 1.5 and 2.5 years after the start of the experiment.
  • In the first series, surviving rats were killed at month 17. Only benign tumours of the glandular stomach and one malignant tumour of adjacent tissue were found. The table lists 5 benign tumours and 1 sarcoma among 26 rats.
  • In the second series, three malignant tumours were found in the glandular stomach within the small-stomach zone: two adenocarcinomas and one carcinosarcoma. One rat with stomach adenocarcinoma had a liver metastasis.
  • The second series also had one squamous cell carcinoma of the stomach, most probably originating in the forestomach
  • Two peritoneal mesotheliomas developed near the clip separating the small stomach from the main stomach
  • Also found were one adenocarcinoma of the small intestine and two fibrosarcomas near the clip
  • Tumours developed in the abdominal cavity in 24% of the asbestos-treated animals
  • No differences were seen between control and experimental groups in the number or histological type of tumours in other organs and tissues
• The authors' conclusion: The authors concluded that there were grounds to consider the stomach and adjacent abdominal tumours induced by asbestos, supported by the two mesotheliomas. They said the results support their epidemiological data suggesting continuous exposure to asbestos-containing dust may cause stomach cancer. They stated they were far from drawing practical conclusions from this experiment alone.
• Limitations the authors state:
  • A possible carcinogenic effect of adhesions, suture materials in the abdominal cavity, and the polyethylene coating of the clip cannot be ruled out
  • The operation was traumatic and many rats died soon after it
  • All animals, experimental and control, had pronounced abdominal changes (adhesions, gastritis, erosions), which the authors connect with the operative procedure
  • The authors did not draw practical conclusions from this single experiment

Topics

The National Library of Medicine indexes this study under subjects our site covers: Stomach cancer.

Medical terms in this study, explained in our Lexicon: Stomach Cancer, Chrysotile, Adenocarcinoma, Peritoneal Mesothelioma.

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