Translational study for stereotactic body radiotherapy against non-small cell lung cancer, including oligometastases, considering cancer stem-like cells enable predicting clinical outcome from data

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

When treating non-small cell lung cancer (NSCLC), stereotactic body radiotherapy (SBRT) with high-dose irradiation is often utilized. The fractionation schemes and curative effects can be evaluated by mathematical models for predicting cell survival curve. Such model parameters can be determined from in vitro experiment, but they are empirically determined based on experiences in clinics. As such, there is a large gap between in vitro and clinical study. As such background, translational study between in vitro cell survival and clinical curative effects is necessary. In this study, explicitly considering existence of cancer stem-like cells (CSCs), we developed an all-in-one model for predicting both in vitro cell survival and clinical curative effects (integrated microdosimetric-kinetic (IMK) model) and performed retrospective evaluation of clinical outcomes following SBRT for NSCLC in Hirosaki University Hospital. As a result, the IMK model successfully reproduced both in vitro cell survival and the tumor control probability with various fractionation schemes (i.e., 6-10 Gy per fraction). The developed model would contribute on precisely understanding the impact of CSCs on curative effects after SBRT for NSCLC with high precision.