Radiation therapy for the human renal cell carcinoma transplantable to the nude mice

Efficacy of radiation therapy was studied using human renal cell carcinoma strain (AM-RC-3) implantable in nude mice. Cobalt 60 γ-ray was used dosage of 5 Gy, 10 Gy, 15 Gy and 20 Gy in single, localized exposures to subcutaneously implanted tumors of the lower right femoral region. Therapeutic efficacy was determined using the Battelle Columbus Standard and evaluation of histological changes based on National Cancer Research Institute (Shimosato's classifications). Conclusions based on the obtained data are as follows. The T RW/C RW ratio on the tumor growth curve was 42% or less for all radiation dose groups, except for the 5 Gy group; doses other than 5 Gy are believed effective. Doses of 15 and 20 Gy were particularly effective and the respective groups had RW of 0.96 and 0.95. Although Grade IIa and IIb changes were observed in the 15 and 20 Gy dose groups, respectively two weeks after irradiation; and four weeks after irradiation all groups exhibited microscopic tissue formations that could be considered regrowth of tumor cells. Determination of histopathological effectiveness two weeks after irradiation is thought most suitable. Radiation therapy is appropriate as an adjuvant treatment in cases of renal cell carcinoma and should be used in combination with other therapies. (author)