The Swedish childhood cancer quality registry for risk-based long-term follow-up after childhood cancer: structure, content, and development over time

Background Survival after childhood cancer has increased dramatically during the last 50–60 years. Today, approximately 86% of childhood cancer patients in Sweden survive more than 5 years, and most of them reach adulthood. The intense multimodal cancer treatment is unfortunately associated with a risk of late complications during childhood or later in adult life. A registry for monitoring late complications is an important tool to support structured long-term follow-up. In Sweden this is available through the SALUB database, a part of the Swedish childhood cancer quality registry. The aim of this study is to describe the SALUB database and assess its coverage, its capacity to identify treatment-defined risk groups for late complications, and the completeness of long-term follow-up data. Methods A cohort of patients who had reached at least 19 years of age, were born before 01/07/2006, and had received or were assumed to have received systemic cancer treatment or radiotherapy was identified in the Swedish childhood cancer quality registry. Database coverage was assessed by individual-level linkage, using personal identity numbers, between the SALUB database and the diagnosis-based databases. Subpopulations were assessed to explore changes over time, identify treatment-defined risk group, and assess the completeness of follow-up data. Results The coverage was 73% (3,780/5,171) in the overall cohort and 94% (803/853) in patients born between 2002 and 2006. The number of individuals at risk for cardiotoxicity and gonadal toxicity were easily identified. A total of 1,809 patients had at least one follow-up record meeting the inclusion criteria. Data completeness varied markedly across organ systems. Conclusions The SALUB database has high coverage among younger survivors and enables identification of individuals according to treatment-defined risks of late complications. However, lower coverage in older survivors and incomplete follow-up data currently limit some of its potential applications. Continued development of the database will strengthen its role in risk-based survivorship care, health care planning, and research.