Effects of local one shot irradiation (3, 5, 10 Gy) on lung metastases of VX2 carcinoma transplanted in maxillary sinus of rabbits were observed.
Tumor growths were apt to be inhibited corresponding to given dosage. Some tumors among rabbits with single dose of 10 rabbits Gy regressed completely. However, when insufficient local irradiation for complete tumor regression was given, the incidence of pulmonary metastases in irradiated groups remarkably increased compared with non-irradiated group. If the implanted tumor was cured by the radiation, the incidence of pulmonary metastases was 0%. This evidence might suggest that non-curative irradiation to VX2 carcinoma implanted in maxillary sinus of rabbit resulted in an increased incidence of lung metastases. General conditions between irradiated and non-irradiated groups examined in this study were not significantly different, so it was suspected that local factors influenced by the radiation were also involved in this phenomenon, although further studies would be needed.
