Generality assessment of a model considering heterogeneous cancer cells for predicting tumor control probability for stereotactic body radiotherapy against non-small cell lung cancer

Saga, Ryo*; Matsuya, Yusuke  ; Obara, Hideki*; Komai, Fumio*; Yoshino, Hironori*; Aoki, Masahiko*; Hosokawa, Yoichiro*

The curative effects after radiotherapy are evaluated by the index of tumor control probability (TCP), and the treatment regimen has been determined empirically based on clinical experiences. In recent years, in order to determine TCP for any treatment regimens based on cell experiments, it is necessary to consider the existence of radioresistant cancer stem cells, which are included in tumors at from a few to several tens of percent. Our previous study has proposed an integrated microdosimetric-kinetic (IMK) model that explicitly considers cancer stem cells, and successfully reproduced cancer cell death obtained from cell experiments and clinical TCP. However, the verification so far has been limited to comparison with the clinical data of Hirosaki University Hospital, and comparative verification with clinical data of other facilities has not been performed. In this study, we focused on the stereotactic radiotherapy against non-small cell lung cancer that prescribes a large dose at once, and compared the public data collected by meta-analysis with the IMK model. As a result, it was found that the IMK model considering cancer stem cells well reproduced the clinical TCP regardless of the observed facility type. This work would contribute to the development of technology for predicting curative effects of radiotherapy with high precision.