The Effect of Radiation from Filtered Radon Implants on the Growth of Carcinoma and Sarcoma in Animals

Abstract

It is only within comparatively recent years that the therapeutic value of radium and x-rays in the treatment of malignant neoplasms has been definitely established. Numerous clinical studies have shown that in certain types of tumors irradiation has been of little benefit because of the exceptional resistance of these tumors to radiation or because their location was such that in order to deliver a lethal dose to the tumor, the adjacent normal tissue must be over-irradiated. The authors have made a study of the effect of radiation from filtered radon implants on the growth of carcinoma and sarcoma in animals, in order to determine the minimal lethal closes for these tumors. Materials and Methods The Flexner-Jobling rat carcinoma and the Sugiura rat sarcoma were selected for the preliminary study. The behavior of these tumors in the hosts has been reported elsewhere. It may be of interest, however, to summarize their manner of development, since this may have a bearing upon the present investigation. The grafts of Flexner-Jobling rat carcinoma grew progressively and rapidly. Many of them reached the size of a walnut before ulceration. The transplants took in about 80 per cent of all cases. They showed only occasional spontaneous absorption, such cases representing about 20 per cent of the positive transplants.1 As the tumors grew larger, they became soft, due to central degeneration and necrosis. Later they ulcerated, usually about seven weeks after the implantation, though sometimes as early as the fourth week, and subsequently caused the death of the animals from toxemia, septicemia, and nutritional failure. About 10 per cent of the animals showed metastases ninety days after tumor implantation.