ESTRO 2024 - Abstract Book

S2042

Clinical - Paediatric

ESTRO 2024

1 Maria Sklodowska-Curie National Research Institute of Oncology, Department of Radiation Oncology, Warsaw, Poland. 2 Children's Memorial Health Institute, Department of Oncology, Warsaw, Poland. 3 Mother and Child Institute, Department of Oncology and Surgical Oncology for Children and Youth, Warsaw, Poland. 4 Medical University of Warsaw, Clinical Department of Pediatric Oncology, Hematology, Clinical Transplantology and Pediatrics, Warsaw, Poland

Purpose/Objective:

Neuroblastoma 4S is a rare subtype of metastatic neuroblastoma that typically affects children under 12 months. It is characterized by metastases in the liver, skin, or bone marrow [1]. Although the prognosis for patients with neuroblastoma 4S is generally favorable, due to a high rate of spontaneous regression, the rapid progression of liver metastases can pose a life-threatening risk due to organ insufficiency [2,3]. In such critical cases, immediate chemotherapy or radiation therapy becomes imperative. The current standard of radiotherapy involves liver irradiation administered in fractions of 150 cGy, providing reasonable disease control with a total dose ranging between 450 and 600 cGy [4]. Nevertheless, in recent years, there has been a decrease in the use of radiotherapy due to apprehensions regarding potential toxicity, particularly in the context of children under the age of one year. Some pediatric oncology centers have even completely discontinued the use of radiotherapy, even for patients who do not respond to chemotherapy [4–6].

This study aims to reevaluate radiotherapy's role in treating neuroblastoma 4S, assessing its effectiveness and toxicity.

Material/Methods:

We evaluated the use of radiotherapy in patients with neuroblastoma 4S, conducting a systematic review and an institutional retrospective analysis. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included original studies published between 1941 and 2023 that investigated the effects of irradiation on hepatomegaly in patients with neuroblastoma 4S. The papers had to provide a minimum follow-up of 6 months and allow the extraction of individual data related to irradiation's efficacy and toxicity. In addition, we performed a retrospective analysis using the patient database at our institution. This analysis aimed to identify individuals diagnosed with neuroblastoma 4S who underwent radiotherapy from 1994 to 2023. Ultimately, we gathered and analyzed individual data from both the patients in the literature and those within our institution. This analysis encompassed an evaluation of treatment effectiveness and toxicity.

Results:

We analyzed 164 patients with neuroblastoma 4S from the literature, spanning 32 published papers covering the period from 1941 to 2022. In addition, our institutional cohort comprised 16 patients with neuroblastoma 4S who were treated between 1994 and 2023. In summary, 60 of 180 (33%) patients received radiation therapy alone for the treatment of liver metastases, while in 120 (67%), additional chemotherapy was administered. Our data revealed that 81% of patients (13 of 16) responded to low-dose radiotherapy of 450 cGy in three fractions. This treatment led to liver shrinkage and the resolution of associated symptoms. Unfortunately, three patients who did not respond to this therapy died shortly afterward due to disease progression and subsequent cardiopulmonary insufficiency. According to the systematic review, the 1-year survival rate was 80%, and the 5-