Late effects of thoracic irradiation in children

Purpose: To summarize the literature regarding the late effects of radiotherapy to the thorax in childhood and adolescence with special emphasis on cardiac and pulmonary impairment. Material und Methods: The literature was critically reviewed using the PubMed (R) database with the key words "late effects", "late sequelae", "child", "childhood", "adolescence", "radiation", "radiotherapy", "thorax", "lung", "heart", and "pulmonary". Results: 17 publications dealing with radiation-induced pulmonary and cardiac late sequelae in children could be identified and were analyzed in detail. 29 further publications with additional information were also included in the analysis. Pulmonary function impairment after mediastinal irradiation arose in one third of all pediatric patients, even when treatment was performed with normofractionated lower doses (15-25 Gy). Whole lung irradiation was regularly followed by pulmonary function impairment with differing rates in several reports. However, clinically symptomatic function impairment like dyspnea was less frequent. Irradiation of up to 25 Gy (single doses <= 2 Gy) to the heart showed little or no cardiac toxicity in analyses of irradiated children (median follow-up 1.3-14.3 years). Doses of > 25 Gy (single doses <= 2-3.3 Gy) led to several cardiac dysfunctions. However, new data from adults with longer follow-up may indicate threshold doses as low as 1 Gy. Impairment of skeletal growth, breast hypoplasia, and secondary malignancy were further potential late sequelae. Conclusions: Several retrospective reports described radiation-associated late sequelae in children. However, there is still a lack of sufficient data regarding the characterization of dose-volume effects.