Heart volume reduction during radiotherapy involving the thoracic region in children: An unexplained phenomenon

Publication date: Available online 24 April 2018
Source:Radiotherapy and Oncology
Author(s): Irma W.E.M. van Dijk, Jorrit Visser, Jan Wiersma, Jessica R. van Boggelen, Brian V. Balgobind, Elizabeth A.M. (Lieke) Feijen, Sophie C. Huijskens, Wouter E.M. Kok, Leontien C.M. Kremer, Coen R.N. Rasch, Arjan Bel
Background and purposeRadiotherapy involving the thoracic region is associated with cardiotoxicity in long-term childhood cancer survivors. We quantified heart volume changes during radiotherapy in children (<18 years) and investigated correlations with patient and treatment related characteristics.Material and methodsBetween 2010 and 2016, 34 children received radiotherapy involving the thoracic region. We delineated heart contours and measured heart volumes on 114 CBCTs. Relative volume changes were quantified with respect to the volume on the first CBCT (i.e., 100%). Cardiac radiation dose parameters expressed as 2 Gy/fraction equivalent doses were calculated from DVHs. Chemotherapy was categorized as treatment with anthracyclines, alkylating agents, vinca-alkaloids, and other.ResultsThe overall median heart volume reduction from the first to the last CBCT was 5.5% (interquartile range1.6–9.7%; p < 0.001). Heart volumes decreased significantly between the baseline measurement and the first week (Bonferroni's adjusted p = 0.002); volume changes were not significant during the following weeks. Univariate analysis showed a significant correlation between heart volume reduction and alkylating agents; however, no multivariate analyses could be done to further confirm this.ConclusionsWe found a significant heart volume reduction in children during radiotherapy. Elucidation of underlying mechanisms, clinical relevance, and possible long-term consequences of early heart volume reduction require a prospective follow-up study.



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