Comparison between RECIST 1.1, Choi and PERCIST 1.0 criteria to evaluate response to SBRT of liver metastasis

Background: Currently there are no guidelines for follow-up and assessment of response in tumors undergoing liver stereotactic body radiation therapy (SBRT). We analyzed imaging characteristics of liver metastasis treaded by SBRT and compared the accuracy of different imaging criteria (RECIST 1.1, Choi and PERCIST 1.0) to assess treatment response. Methods: Eighty-eight liver metastasis treated with SBRT at our institution, University Hospital HM Sanchinarro, were analyzed. We retrospectively reviewed images of all CT and PET-CT studies performed to these patients at baseline and every three months after SBRT treatment during the first year. Lesion size (cm) and attenuation coefficient values (HU, Hounsfield Units) were measured. 18F-FDG uptake value was collected if PET-CT was made. Surrounding liver tissue attenuation coefficient values and eventual dilation of the biliary ducts were also analyzed. Results: In our retrospective, observational study statistical analysis shown significant differences in the assessment of response of liver metastasis treated with SBRT using different criteria in the four reviews (P<0.001). PERCIST criteria were the most sensitive to assess response. Regarding “non-metabolic” criteria, Choi criteria showed better results in the assessment of response to SBRT than RECIST 1.1. Attenuation coefficient values of perilesional parenchyma did not vary significantly along the first year except in the first quarter (P<0.016), and we did not find dilation of the bile duct after SBRT with greater frequency than in other cases. Conclusions: PERCIST were the most suitable criteria to assess response to SBRT of liver metastasis in our series. Among the rest, Choi were more appropriate than RECIST 1.1.