Study of radiotherapy with simultaneous administration of interferon using established human renal cell carcinoma heterotransplanted into nude mice

Using human renal cell carcinoma heterotransplanted into nude mice (strain nomenclature, JRC 11), the effects of the combined use of radiotherapy and interferon (natural human interferon-alpha ; IFN-alpha, 3 x 105 I.U., i.M.) were examined. The radiotherapeutic device used was an 8 MeV (10 Gy.) linear accelerator. IFN administration was started one hour before radiotherapy and carried out on consecutive days. Combined use of radiotherapy and IFN was compared with radiotherapy alone and with IFN alone. Combined use of radiotherapy and IFN-alpha was shown to have significant anti-tumour effects compared with either therapy starting after 4 weeks of treatment. The ratio of TRW/CRW was 5.1 %, indicating effectiveness. However the combined treatment group showed regrowth after Week 5 of the treatment, and reached the same tumour volume was reached after Week 7. The ratio of TRW/CRW was 122 %. Additionally, there was grade IIb histological change which indicated that the therapy was ineffective at the time of the most inhibitory phase of this combined therapy. Thus further study is needed to identify a more effective modality of treatment. (author)