Birgitta Versluijs

23 Pulmonary complications of childhood cancer treatment Introduction With advances in therapeutic strategies, the number of childhood cancer survivors con- tinues to increase. The 5 years survival rate for children with cancer approaches 75%, and an estimated 1 in 600 young adults in western countries is a survivor of childhood cancer. This increase in survival is not without consequences. Treatment related com- plications can result in adverse sequelae, which may not become evident for many years They represent a major cause of morbidity with a large impact on quality of life, and predispose to increased mortality during adulthood. Large cohort studies in childhood cancer survivors show a high burden of disease in 40-85% of survivors, depending on treatment, follow up time and age at time of assessment. 1–3 Mortality among 5-year survi- vors of childhood cancer is 8-10 times higher when compared to the general population. Causes of death change over time; recurrence of primary disease is the leading cause in the first 15 years from diagnosis, but after that, most survivors die from secondary malig- nancies or cardiac or pulmonary disease. 4,5 Pulmonary complications of cancer treatment can be divided into acute (during treat- ment), early (within months after treatment) and late effects. Lung surgery, lung ir- radiation, certain chemotherapeutic agents and immune mediated phenomena after Haematopoietic Cell Transplantation (HCT) are all associated with pulmonary damage. Interactions of these treatment related effects with other factors like infections, growth and other organ dysfunction may further influence long term pulmonary outcome of children treated for cancer. Studies on this subject vary in design. Some use self-reported data on clinical symptoms in all survivors, others use data retrieved from screening programs for high-risk survi- vors with history taking and physical examination. Some studies use sibling controls, some compare treatment modalities within childhood cancer survivors, and others com- pare with data from the general population. Questionnaires and findings on medical as- sessment can be useful. Often pulmonary function tests are used as an objective test for lung damage, also detecting asymptomatic lung injury. Chronic health conditions can be classified using National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) grading from mild to life threatening/death (see Figure 1). Most studies present data from only one or few centres, definitions and classifications of PFT abnor- malities vary somewhat, and many studies are retrospective or cross-sectional. None- theless these studies help define the extent and patterns of pulmonary dysfunction in survivors of childhood cancer. Here we review the pulmonary toxicity of cancer treatment in children and focus on the non-acute, non-infectious adverse effects on the lungs. 2