To the Editor Dr Turcotte and colleagues1 found that cumulative incidence rates of subsequent malignancies at 15 years after initial childhood cancer diagnosis were lower among survivors treated in more recent treatment eras and that lower risk was associated with reduced therapeutic radiation dose.
Although the authors analyzed maximum radiation treatment dose to any body region as well as median dose for chemotherapy agents, it is not clear how many children treated with hematopoietic cell transplantation (HCT) were included. Before autologous or allogeneic HCT, a myeloablative conditioning regimen is commonly used with higher doses of chemotherapy and radiation, including total body irradiation, in a shorter period than conventional chemotherapy. Such a conditioning regimen could influence the incidence of subsequent malignancies in the study population.
Tanimoto T, Tsuda K, Mori J. Temporal Changes in Subsequent Malignancies Among Childhood Cancer Survivors. JAMA. 2017;317(23):2451. doi:10.1001/jama.2017.6020