RESUMO
BACKGROUND: No international standards include vitamin D levels at diagnosis or during treatment. It is included in the Children's Oncology Group long-term follow-up guidelines. However, bone health complications (like osteopenia and atraumatic fractures) can occur at diagnosis or during treatment as well. CASES: In this small case series, we illustrate the complexity of bone health complications among our broad paediatric oncology population. If the vitamin D level is low we supplement the patient with one standard oral dose (150 000 units for 1-2 year olds, 300 000 units for 2-5 year olds and 600 000 units for >5 year olds). We do not adjust depending on diagnosis. CONCLUSION: Because of the potentially negative outcomes on short, medium and long term, we recommend checking vitamin D levels on diagnosis for all newly diagnosed patients. It is a simple, low cost test and one dose of oral supplementation can easily treat the deficiency.