HepQuant: Pilot Study to Assess the Role of Blood-based Biomarkers and Quantitative MR Imaging for Patients Receiving Radiation Therapy for Liver Cancer

Historically, the role of fractionated liver radiation therapy (RT) has been limited because of the potential for developing fatal radiation-induced liver disease (RILD), particularly in patients who already have poor liver function due to cirrhosis. Classic RILD generally occurs within 4 months following radiotherapy to the liver and consists of symptoms including fatigue, right upper quadrant pain, ascites, anicteric hepatomegaly, and elevation of liver enzymes especially alkaline phosphatase.

Technical advances in the delivery of RT, particularly using stereotactic body radiotherapy (SBRT) and proton therapy with respiratory gating and image guidance, have facilitated the safe use of radiation dose escalation in unresectable liver cancers. SBRT is a promising and attractive option for HCC patients with cirrhosis. Previous reported experiences have been largely kept to Child-Pugh (CP) A patients with significant liver reserves. The 1 to 2-year local control rate for CP A patients with early-stage tumor have generally been reported around 80-90%. Toxicities rates have also been acceptable with no classic RILD or grade 4 or 5 treatment related toxicities seen 3 months after SBRT. This impressive toxicity result is likely due to keeping with strict dosimetric constraints for the normal liver tissue. Dosimetric parameters reported in literature indicated mean liver disease (MLD) and V20 to be a significant predictor of RILD and elevated liver enzymes in CP A patients with primary HCC.

While there are no overt liver toxicities in CP A patients with primary liver cancer, 10 to 30% of patients will experience a decline in liver function 3 months after SBRT even without disease progression based on the referenced literature. Pre-treatment CP A6 has an increased risk of liver function decline when compared to CP A5. In addition, the tumor volume was also a significant predictor of liver function decline after SBRT.

Patients with CP B or C and primary HCC are more likely to experience liver toxicities as defined by worsening liver function. Dosimetric parameters to predict for fatal RILD for this group has also remained elusive. Yet, it is this particular group of patients that have the worst outcome due to limited treatment options as a result of poor liver reserve to tolerate currently available treatments. The median survival for patients with Child-Pugh B or C HCC treated with best supportive care or sorafenib is approximately 4-5 months according to the literature. Limited institutional experiences have shown that local treatment of these patients with SBRT can potentially improve survival; however, this also comes at a cost of significant potential toxicity. Current reported data are limited, but they do show that patients can experience liver function decline as early as 3 months.

The published experience with SBRT in the treatment of HCC clearly demonstrates a relationship of the underlying degree of hepatic impairment to risk for liver toxicity. However, the data also clearly demonstrate that CP class or score is insufficient to define risk or to monitor treatment effects. The proposed study will use blood-based biomarkers coupled with quantitative imaging (LiverMultiScan™) to fully characterize the effect of SBRT on the liver and the liver cancer.