The doubling time of human tumours during radiotherapy:An analysis based on comparison between clinical and in vitro tumour cell radioresponsiveness

摘要

AbstractA correspondence between the effect of 2 Gy in vitro for human tumour cell lines and the clinical effect of radiotherapy of the corresponding tumours has earlier been described. In this analysis data on surviving fraction (SF) in vitro have been applied to clinical studies in a predictive model similar to the linear‐quadratic model for the calculation of isodoses. In addition, a proliferation factor describing exponential growth has been included. Different proliferation rates have been tested and the predicted probabilities for local control have been compared with the clinical local control rates of respective studies. The best correspondence between predicted and clinical results were found for a potential doubling time of 2–3 days during a whole treatment course, even for radiotherapy courses shorter than 3–4 weeks. The possible impact of hypoxia is discussed. © Wiley‐L