Background: This work was to establish an uncomplicated tumour control probability (UTCP) model using Hepatocellular Carcinoma Stereotactic Body Radiation Therapy (HCC SBRT) clinical data in our institution. The model was then used to analyze the treatment outcome of the current dose prescription method and to seek the opportunity for improvement.
Methods: A tumour control probability (TCP) model was generated based on local clinical data using the maximum likelihood method. A UTCP model was then formed by combining the established TCP model with the normal tissue complication probability (NTCP) model based on the study by Dawson et al. The authors investigated the dependence of maximum achievable UTCP on tumor mean biological effective dose (BED) at various ratio between tumour mean biological effective dose (BED) and normal liver mean BED (T/N BED ratios). A new term uncomplicated tumour control efficiency (UTCE) was also introduced to analyze the outcome. A UTCE value of 1 implied that the theoretical maximum UTCP for the corresponding T/N BED ratio was achieved.
Results: The UTCE of the HCC SBRT patients based on the current dose prescription method was found to be 0.90±0.08. It was found that the UTCE could be increased to 0.99±0.03 by using a new dose prescription scheme, for which the UTCP could be maximized while keeping the NTCP value smaller than 5 %.
Conclusion: The treatment outcome of the current HCC SBRT in our institution was analyzed using a UTCP model established based on local clinical data. It was shown that there could be a potential to increase the prescription dose of HCC SBRT. A new dose prescription scheme was proposed to achieve better treatment outcome.