The changes in imaging following proton beam therapy for pediatric hepatoblastoma

Surgical resection or liver transplantation is the cornerstone of curative treatment for hepatoblastoma (HBL). For unresectable HBL, liver transplantation has proven to be a definitive curative option, with long-term survival rates ranging from 30 to 95% in previous studies. However, some patients may not meet the surgical or medical criteria for transplantation. Traditionally, radiotherapy (RT) has not been a standard treatment for HBL due to the risk of high-dose radiation damage to normal liver tissue. Proton beam therapy (PBT), a type of RT, leverages the Bragg peak phenomenon, concentrating the majority of its energy within the last few millimeters of its range. This results in a significantly reduced radiation dose beyond this point, thereby minimizing potential harm to distal radiosensitive structures. PBT has emerged as an alternative treatment option for hepatocellular carcinoma in non-surgical adult patients, but its effects and post-treatment changes in HBL remain under-documented. In this preliminary investigation, we aimed to examine the post-PBT following imaging changes in both HBL and the surrounding liver parenchyma in pediatric patients. What Is Known: • HBL is the most common primary malignancy of liver in children. • In HBL, liver transplantation is indicated for patients with tumors that cannot be managed by surgical resection. What Is New: • PBT may prove to be a promising treatment option for unresectable HBL, with the potential to preserve normal liver tissue. • Understanding the imaging changes in post-PBT tumors and the associated focal liver reaction at various time points is crucial for accurately assessing treatment response and guiding appropriate alternative treatment options.