Purpose: To analyze published clinical data of local tumor control probability (TCP) for stereotactic body radiotherapy (SBRT) treatment of early stage hepatocellular carcinoma (HCC) and to understand the relationship between TCP and biological effective dose (BED) for early stage T1 and T2 HCC.
Methods: We collected the clinical data of 1-, 2-, 3-, 4-, and 5-year actuarial or Kaplan-Meier TCP from more than 40 selected studies for SBRT of early stage HCC cancer in the literature. For the considered three models (the linear-quadratic (LQ) model, the universal survival curve, and the regrowth model which takes into account of the tumor growth as a function of follow-up time after radiotherapy), the independent model parameters are to be determined from a fit to the TCP data using the least chi-square (χ2) method. As a starting point, BED was calculated at the corresponding isocenters using the LQ model with α/β=10 Gy to evaluate the relationship between the TCP and BED.
Results: The preliminary results show that there exists a correlation between the TCP and BED in Figure 1. Analyses of the three radiobiological models being investigated are underway.
Conclusion: Preliminary results show local TCP correlates with BED for SBRT of early hepatocellular carcinoma. The study will analyze the TCP data using the above three radiobiological models.