Cerebrovascular Diseases in Childhood Cancer Survivors: Role of the Radiation Dose to Willis Circle Arteries

Publication date: 1 February 2017
Source:International Journal of Radiation Oncology*Biology*Physics, Volume 97, Issue 2
Author(s): Chiraz El-Fayech, Nadia Haddy, Rodrigue Sètchéou Allodji, Cristina Veres, Fara Diop, Amar Kahlouche, Damien Llanas, Angela Jackson, Carole Rubino, Catherine Guibout, Hélène Pacquement, Odile Oberlin, Cécile Thomas-Teinturier, Pierre-Yves Scarabin, Jean Chavaudra, Dimitry Lefkopoulos, Maurice Giroud, Yannick Bejot, Valérie Bernier, Christian Carrie, Ibrahima Diallo, Florent de Vathaire
Background and PurposeThe aim of this study was to investigate the role of radiation dose received to the circle of Willis (WC) during radiation therapy (RT) and of potential dose-response modifiers on the risk of stroke after treatment of childhood cancer.MethodsWe evaluated the risk factors for stroke in a cohort of 3172 5-year survivors of childhood cancer who were followed up for a median time of 26 years. Radiation doses to the WC and brain structures were estimated for each of the 2202 children who received RT.ResultsFifty-four patients experienced a confirmed stroke; 39 were ischemic. Patients not receiving RT had a stroke risk similar to that of the general population, whereas those who received RT had an 8.5-fold increased risk (95% confidence interval [CI]: 6.3-11.0). The excess of incidence of stroke increased yearly. The dose of radiation to the WC, rather than to other brain structures, was found to be the best predictor of stroke. The relative risk was 15.7 (95% CI: 4.9-50.2) for doses of 40 Gy or more. At 45 years of age, the cumulative stroke incidence was 11.3% (95% CI: 7.1%-17.7%) in patients who received 10 Gy or more to the WC, compared with 1% expected from general population data. Radiation doses received to the heart and neck also increased the risk. Surgery for childhood brain cancer was linked to hemorrhagic strokes in these patients.ConclusionThe WC should be considered as a major organ at risk during RT for childhood brain cancers. The incidence of radiation-induced ischemic stroke strongly increases with long-term follow-up.



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