Proton Beam Therapy with Pencil Beam Scanning is Safe and Effective for Advanced Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma: A Single Center Experience

Abstract

Background Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) are the two most common primary liver tumors. Proton Beam Therapy (PBT) is a non-surgical treatment that spares adjacent tissues compared to photon radiation, limiting damage to nearby structures. We present a single center experience on liver toxicity, tumor response, and survival in patients with HCC and iCCA treated with PBT with Pencil Beam Scanning (PBS).MethodsConsecutive patients receiving PBT for HCC or iCCA were reviewed. PBT was delivered with hypofractionated or stereotactic body radiation therapy using PBS. Tumor size was approximated by clinical target volume (CTV). Liver toxicity was determined by changes in MELD-Na and albumin-bilirubin (ALBI) grade. Tumor response was determined by imaging at six to eight weeks post-therapy.Results44 consecutive patients were included, 22 patients in each group. 35% of patients had multifocal disease and median CTV was 232.5cc. Overall survival was 82%. For both cancer types, tumor size, laboratory values, and total radiation dose were not associated with liver toxicity. All iCCA patients had stable or improved ALBI grade following treatment, however there were 4 deaths. Among HCC patients, ALBI grade was stable in 83%, average MELD-Na score remained stable, and there was only one death.ConclusionsOur results indicate that PBT for unresectable HCC and iCCA is safe and effective, even for large and multifocal tumors. Liver function was preserved even in those with baseline cirrhosis who received biologically effective doses ≥80.5 Gy. Overall survival was 86.4%, similar between HCC and iCCA.