2239 - Liver Volume Dynamics and Survival After Proton or Photon Radiotherapy in Hepatocellular Carcinoma
Presenter(s)
K. C. Tran1,2, R. C. E. Hsieh1,2, and P. Y. Chen2; 1Departments of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan City, Taiwan, 2Department of Radiation Oncology, Chang Gung Memorial Hospital at Linkou, Taoyuan City, Taiwan
Purpose/Objective(s): To investigate prognostic significance of postirradiation liver volume changes and identify predictors of liver regeneration in patients with hepatocellular carcinoma (HCC) undergoing definitive radiotherapy.
Materials/Methods: We retrospectively analyzed 366 patients with HCC treated with proton (n=302) or photon radiotherapy (n=64) between 2014 and 2024. Non-tumorous liver volume on CT or MRI was measured longitudinally at baseline and at 3, 6, and 12 months after radiotherapy. Patients with progressive disease were excluded from subsequent longitudinal volumetric analyses from the time of recurrence.
Results: Mean liver volumes at 3, 6, and 12 months after radiotherapy were 106.7%, 107.4%, and 110.6% of pretreatment volumes, respectively; 254 (69%) patients demonstrated increased liver volume, whereas 112 (31%) showed decreased liver volume. After a median follow-up of 41 months, patients with postirradiation liver volume increase had significantly longer median survival (45 vs 17 months, P<.001) than those with decreased liver volume, along with a lower incidence of a Child-Pugh score increase of =2 at 3 months after radiotherapy (4.3% vs 28.6%, P<.001). On multivariate analysis, Child-Pugh class A (P=.012), absence of tumor vascular thrombosis (TVT; P=.019), no alcohol consumption (P<.001), lower percentage of liver volume receiving =5 Gy (V5; P=.013), and use of proton radiotherapy (P<.001) independently predicted a higher likelihood of postirradiation liver regeneration. The incidence of postirradiation liver volume increase was 83%, 60%, and 2% among patients with V5 ranges of 0–40%, 40–70%, and 70–100%, respectively (P<.001). Patients treated with protons had significantly lower V5 (35.5% vs 61.5%, P<.001) and greater 1-year relative liver volume (113% vs 91%, P<.001) than those treated with photons.
Conclusion: Postirradiation liver volume increase was associated with improved survival. Better baseline liver function, absence of TVT, no alcohol consumption, lower V5 (<40%), and proton radiotherapy were associated with a higher likelihood of postirradiation liver regeneration.