Effect of recombinant human granulocyte colony-stimulating factor on efficacy of radiation therapy in tumor-bearing rats.
The effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on radiation-induced neutropenia and on growth of transplanted tumors treated by irradiation was investigated using tumor-bearing rats as a model for radiation therapy. In a preliminary study using normal rats, neutropenia induced by upper hemi-body irradiation at 3 Gy/day 5 times a week for 3 weeks was prevented by consecutive subcutaneous injections of rhG-CSF at 100 micrograms/kg/day. Rats bearing Walker-256, a mammary tumor, were scheduled to receive upper hemibody irradiation at 3 Gy/day for 15 times in 3 weeks if white blood cell (WBC) counts were maintained above 3,000/microliters. In control tumor-bearing rats not receiving rhG-CSF, irradiation was often withheld because of the decrease in WBC counts below 3,000/microliters. In contrast, a decrease in WBC counts below 3,000/microliters was rarely found in tumor-bearing rats injected daily with rhG-CSF. The average number of radiation treatments in control rats and rats treated with rhG-CSF was about 8 and 14, respectively, out of the scheduled 15 treatments in 3 weeks. Treatment with rhG-CSF made it possible to complete the radiation therapy regimen and thus inhibit the growth of the transplanted tumor more effectively. These results suggest that rhG-CSF may be useful to ensure radiation therapy on schedule in cancer patients.
Kabaya
K
K
Pharmaceutical Research Laboratory, Kirin Brewery Co., Ltd., Gunma, Japan.
Watanabe
M
M
Kusaka
M
M
Akahori
H
H
Seki
M
M
Fushiki
M
M
D000818:Animals; D002279:Carcinoma 256, Walker / Q000473:pathology / Q000532:radiotherapy*; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use*; D006801:Humans; D007958:Leukocyte Count / Q000187:drug effects / Q000528:radiation effects*; D008325:Mammary Neoplasms, Experimental / Q000473:pathology / Q000532:radiotherapy*; D009503:Neutropenia / Q000517:prevention & control*; D009504:Neutrophils / Q000187:drug effects / Q000528:radiation effects*; D011878:Radiotherapy / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000627:therapeutic use; D013997:Time Factors
D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor