Paediatric oncology is a discipline of rare diseases, defined by incidence lower than five cases per 10,000 people. Around 1160 new cases of childhood malignancies are diagnosed every year in Poland (2016Poland ( -2017. The incidence rate is about 151 children per 1 million paediatric population a year. It is calculated that one out of 6600 children develops malignancy during one calendar year. Children with oncological diseases are treated in