Biological Response Assessment in Hepatocellular Carcinoma Post Stereotactic Body Radiotherapy

Abstract

Biological Response in Hepatocellular carcinoma (HCC) is measured in terms of serum alpha-fetoprotein (AFP) which is elevated in nearly 60% HCC patients at baseline and is directly related to the severity of the disease. This biological response is defined as the reduction of more than 50% from the baseline levels and is associated with an increased percentage of tumor necrosis and is directly related to increased loco-regional control. Patients diagnosed with HCC have very limited treatment modalities. With the recent advances in the field of radiation therapy and the development of Stereotactic Body radiotherapy (SBRT), the role of radiotherapy has increased as a loco-regional modality for HCC. In this single-arm prospective study, we evaluated the biological response post-SBRT in patients diagnosed with HCC. We conducted a prospective study that included patients diagnosed with HCC with baseline elevation of serum AFP, Child-Turcotte Pugh (CTP) Class A/B with a maximum score of 7. Patient's serum AFP levels were recorded at baseline, pre-treatment, and post-treatment. The biological response was measured at 3 months post-treatment and compared with the baseline serum AFP levels using Wilcoxon signed rank test. A total of 14 patients with HCC were recruited and received SBRT to the target lesion, with a dose between 30-42 Gy over 6 fractions treated on alternate days. Patients were assessed post-treatment at one month with triphasic CEMRI and serum AFP levels. 12 out of 14 patients (85.71%) had a biological response at 3 months follow-up and levels showed further decline unless a progression was found. The median (IQR) serum AFP level was 1131 ng/ml (359-5668 ng/ml) at baseline. Post-treatment serum AFP levels had a median (IQR) value of 156 ng/ml (15-372 ng/ml) showing a near reduction of 86% from baseline, which was significant. 2/14 pts (14.28%) showed no reduction or even increase in serum AFP levels post-treatment. This prospective single-arm study demonstrated the vital role of SBRT in the treatment of HCC and its importance in achieving a better disease control. The response was achieved in 86% of patients with marked reduction of nearly 90% in serum AFP levels as compared to the baseline and increased median OS and PFS as compared to patients not receiving radiotherapy. Further prospective studies are warranted to confirm our findings.