Evaluating the Effectiveness of Small Fractionation Radiotherapy Regimens on the ACHN Renal Cell Carcinoma Cell Line

Background: Renal cell carcinoma is considered to be a radioresistant tumor. Consequently, radiotherapy is used mainly for palliation of metastases or local tumor growth. The aim of this study was to evaluate the efficacy of the radiation protocols with small fractions on cell killing of ACHN human renal cell carcinoma cell line. Methods: After cell culture, the ACHN cells were exposed to 6, 8 and 10 Gy of single fraction and 3 × 2, 4 × 2 and 5 × 2 Gy of two fractions. Viability was calculated using MTS assay [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]. Findings: Exposing cultured cells to small fractions of radiation resulted to a mean decrease of 70% in cell survival over 120 hours after radiation. Survival fraction reduced with increasing the dose per fraction. Two fractions 5 × 2 Gy showed significant effect on cell survival compared to single fraction 10 Gy (P = 0.02) Conclusion: Our results indicate that the small fraction is a valuable alternative to provide local tumor control.