TUMORS FOLLOWING ADMINISTRATION OF THOROTRAST. A REVIEW OF THE LITERATURE
This review considers various aspects of tumorigenesis by Thorotrast, irtroduced about 1928 as a new roentgen contrast medium. As a colloidal solution of 25% ThO/sub 2/ containing 25% carbohydrate, 50% water, and small amounts of preservatives, 20 ml of Thorotrast is equivalent in radioactivity to about one mu g radium. After systematic injection, Thorotrast is deposited in the reticuloendothelial system and only insignificant amounts are excreted. Soon after its introduction, warnings were published against its radioactIvity and possible tumor-producing potentialities. As early as 1938 it was shown in lab animals that Thorotrast injected systemically or interperitoneally could induce tumors. In 1947 the first case of Thorotrast tumor in man was described, and now about 70 cases of such malignant tumors have been reported. According to the mode of administration, tumors following injection of Thorotrast may be divided into three groups: (1) tumors due to extravascularly deposited Thorotrast, (2) tumors due to Thorotrast deposited in natural cavities, (3) tumors due to Thorotrast injected intravascularly and deposited in the reticuloendothelial system. Three corresponding tables are provided showing the following data for the reported cases (type and site of tumor, diagnostic use of Thorotrast and its dose, aex and age of the patient, and latent period of tumorigenesis). Since the latent period is very long, it is difficult to observe all patients for a long enough period since many of them die from old age or disease long before the tumors are due to appear; hence it is not surprising that only 68 cases of malignant tumor following Thorotrast have been reported. It is proposed that the following criteria must be satisfied before a tumor appearing in a patient having received Thorotrast can be accepted as induced by this subatance: thorotrast particles should be found in the immediate vicinity of the tumor; the latent period should be sufficientiy long; and the radiation dose should be sufficiently high. Cases of leukemia attributed to Thorotrast have also been described but are not included in this review In the 1st group described above, Thorotrast particles are found in the tumor which appears as a fibrosing foreignbody granuloma, called thorotrastoma; only three cases of malignant tumors belonging to this group have been descrihed. In Group two, 26 cases of malignant tumors were reported. In Group 3, with 33 malignant tumors ascribed to Thorotrast deposited in the reticuloendothelial system, almost all were localized in the liver or bile ducts. The meam latent period between injection of Thorotrast and appearance of malignant tumors is 17.7 yr. The mean age of the patients at the time of diagnosis of the tumor or death waa approximates 52 yr and the sex (female/male) ratio 15/19. (BBB)
- Research Organization:
- Karolinska Institutet, Stockholm
- NSA Number:
- NSA-17-038826
- OSTI ID:
- 4629002
- Journal Information:
- Radiographica, Journal Name: Radiographica Vol. Vol: No. 4
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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