Late mortality in survivors of childhood cancer in Hungary

The Hungarian Pediatric Oncology Network provides centralized treatment and population-based registration for cases of childhood cancer since 1973. We collected and analized data on late mortality, secondary malignancies and cardiac diseases in survivors (> 5 years) of childhood cancer to evaluate long-term risks. We extracted all solid tumour cases (3,650 followed up for 5-39.3 years, diagnosis: 1973-2008) from the database of the Hungarian Childhood Cancer Registry and checked against the Population Registry. Among the 301 patients who died after 5 years (8.2%) the most common causes of death were progression of primary cancer (52.5%), secondary malignancies (16%) and cardiovascular diseases (8%). Late mortality rates (SMR, total: 35,006 pyrs) showed highly elevated risk of death (SMR: 10.7 95% CI 9-12.4) for the second 5 years of follow up and moderately elevated risk for 10-year survivors (SMR: 3.5 95% CI 3-4.1). Marked differences were detected in the pattern of causes of death between diagnostic groups of primary cancer; with highest risks beyond 10 years for CNS tumours, Hodgkin disease, osteosarcoma and advanced stage neuroblastoma. The longstanding mortality risk for 5-year survivors underlines the need for tailored long-term follow-up and monitoring of late consequences according to the context of different primary diseases of childhood cancer.