An Estimation of Radiobiological Parameters for Head-and-Neck Cancer Cells and the Clinical Implications

Cancers

X. Sharon Qi¹  Qiuhui Yang²  Steve P. Lee¹  X. Allen Li² 

[1] Department of Radiation Oncology, University of California Los Angeles, 200 ULCA Medical Plaza, Los Angeles, CA 90024, USA;Department of Radiation Oncology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA

关键词: head-and-neck cancer;    linear-quadratic model;    sublethal damage repair halftime;    fraction dose delivery time;    intensity modulated radiation therapy;   

DOI  :  10.3390/cancers4020566

来源: mdpi

【 摘 要 】

In vitro survival measurements using two human head-and-neck cancer (HNC) cell lines were performed. The specially designed split-dose surviving fraction was obtained and fitted to the linear-quadratic formalism. The repair halftime (Tr), the potential doubling time (T_d), α/β and radiosensitivity α, were estimated. Other radiobiological models: EUD, BED, TCP, etc., were used to examine the potential treatment effectiveness of different IMRT techniques. Our data indicated the repair halftime of ~17 min based on two HNC cell lines. The combined α/β, α and T_d are α/β = 8.1 ± 4.1 Gy, α = 0.22 ± 0.08 Gy⁻¹, T_d = 4.0 ± 1.8 day, respectively. The prolonged IMRT dose delivery for entire HNC treatment course could possibly result in the loss of biological effectiveness, i.e., the target EUDs decreased by 11% with fraction dose delivery time varying from 5 to 30 min. We determined the sublethal damage repair halftime and other radiobiological parameters for HNC cells, and to evaluate treatment effectiveness of the prolonged dose delivery times associated with different IMRT techniques. The estimated repair halftime for HNC is relatively short and may be comparable to the step-and-shoot IMRT fraction dose delivery time. The effectiveness of IMRT treatment may be improved by reducing the fraction delivery time for HNC treatment.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.