Lung Tumours in Rats After Inhalation of Radon and Treatment with Different Cofactors

Purpose: To determine the risks of lung tumors after inhalation of radon in combination with treatment with various cofactors.

Status: 1973- ongoing; data in ERAD

Treatment: Inhalation of radon (0.1-0.3 μm AMAD 6.2% unattached), treatment with radiation, radionuclides or different cofactors, for details see individual experiments below.

Dosimetry: Activity inhaled (dose from daughter products deposited 2-3 mGy/WLM), for Triton see 02.14

Endpoints: Life-span study (spontaneous death) with macroscopic/microscopic pathology unless otherwise stated below

Animal: Male Sprague-Dawley SPF rats of different ages as indicated below

Results: Several pharmaceutical active agents were given together with radon exposure to test whether, on the one hand, certain of these substances (eg cyclophosphamide, bleomycine, methotrexate) would reduce the incidence of cancer, or, on the other hand, whether such substances when used for different therapeutic purposes (eg rifampicine, BCG, isoniazide, endoxan, largactil, phenobarbitol) could act as cofactors for radon-induced cancer. None of the substances had any positive or negative effect on the rate of incidence of radon-induced lung cancer. Alcohol also had no effect whatsoever.