Exploring the association between bone marrow dosimetry and hematologic toxicity in esophageal cancer chemoradiotherapy

Abstract

Abstract: Introduction: Esophageal cancer (EC) is a lethal neoplasm with high incidence and mortality rates in Brazil and worldwide, especially among males. Chemoradiotherapy plays na essential role in curative treatment; however, radiation-associated toxicity can compromisse the bone marrow, leading to hematological alterations such as anemia, neutropenia, and thrombocytopenia. Therefore, it is crucial to assess the impact of radiotherapy on hematopoietic function to improve therapeutic strategies and minimize adverse effects. Materials and Methods: This is a retrospective study conducted with 70 patients diagnosed with clinical stage I-III esophageal cancer, treated with curative-intent chemoradiotherapy at the Radiotherapy Service of INCA between 2012 and 2016. Data were extracted from the dose-volume histogram (DVH), including maximum dose, mean dose, and irradiated volumes (V5, V10, V20, V30, and V40) of the bone marrow, as well as the planning target volume (PTV). Toxicity was classified based on the evaluation of pre- and post-treatment hematological parameters, following the Common Terminology Criteria for Adverse Events (CTCAE v. 4.0). Results: Lymphocytes count was the most affected hematological parameter, with more patients classified in grades 3 and 4 of toxicity. However, statistical analysis indicated no significant association between irradiated volumes and severe hematological toxicity (p > 0.05 for V5-V40, maximum dose, and mean dose). Conclusion: The radiation dose administered in the thoracic region was not significantly associated with severe hematological toxicity, despite the radiosensitivity of the bone marrow. Monitoring hematological parameters during treatment remains essential to ensure patient safety.