Abstract
Objectives:
Hematological toxicities are a common sequelae of radiation therapy (RT), and pelvic RT is of particular concern as the pelvic marrow contributes nearly 50% of total body hematopoiesis. We evaluated the impact of pelvic RT on hematological toxicities in pediatric patients with pelvic genitourinary rhabdomyosarcoma (GU-RMS).
Methods:
A secondary evaluation of 448 pediatric patients (53.8% male) with intermediate-risk RMS in the ARST0531 trial included 65 with pelvic GU-RMS (who received pelvic RT). Multivariable logistic regression was used to compare cytopenias and complications (febrile neutropenia, infectious complications) between GU-RMS and non-GU-RMS. Primary analysis assessed toxicities over the study period (weeks 1–43), with secondary analysis evaluating T1 (weeks 1–15), T2 (weeks 16–30), and T3 (weeks 31–43).
Results:
GU-RMS patients did not have a significantly higher risk of cytopenias than non-GU RMS patients. Neutropenia was the most common, affecting 79.4% of subjects, with no significant difference between the GU (73.8%) and non-GU (80.4%) groups (OR 0.64, 95% CI 0.34–1.19, p = 0.16). Anemia rates were similar in the GU (36.9%; n = 24) and non-GU (35.2%; n = 135) groups (OR 0.96, 95% CI 0.54–1.70, p = 0.89). Thrombocytopenia occurred slightly more often in the GU group (33.8%) than the non-GU group (28.4%) but was not statistically significant (OR 1.49, 95% CI 0.81–2.73, p = 0.20). Pelvic RT for GU-RMS in T1 was linked to a significantly higher risk of thrombocytopenia compared to non-GU subjects (OR 2.79, 95% CI 1.25–6.23, p = 0.01), which declined over time (T2, T3). Rates of febrile neutropenia (3.1%–9.2%) and infectious complications (4.6%–15.4%) in GU patients did not differ significantly from those in non-GU cohorts (febrile neutropenia: 7.3%–13.05%; infectious complications: 5.5%–9.7%) across T1–T3.
Conclusions:
Hematological toxicities were comparable between pediatric GU and non-GU RMS patients. Pelvic RT for GU-RMS increased the risk of early thrombocytopenia, which diminished over time.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
