RationaleCancer is rare in children and adolescents. About 1 in 500 individuals develop cancer before the age of 15 years, and about 1 in 350 before the age of 20 years .
The causes of most childhood cancers remain unidentified.
Cancers that develop in children present special morphological features rarely seen in adults . To address these particularities in population-based data, for several decades childhood cancers have been grouped according to a specific classification system [1, 3]. The latest edition is the International Classification of Childhood Cancer, 3rd edition , based on the coding system of the International Classification of Diseases for Oncology, 3rd edition (ICD-O-3) . In contrast, all-age cancer statistics are usually presented according to the site codes of the International Statistical Classification of Diseases and Related Health Problems (ICD), of which the latest revision is ICD-10 .
Treatment of childhood cancer has improved considerably in Europe since the 1960s, so that on average up to 80% of patients survive for at least 5 years after the diagnosis . The outcome varies according to sex, age, tumour type, and other factors. Improved survival is determined by early diagnosis, a fast referral system, best practices defined in standardized therapeutic protocols, high-quality care, and efficient follow-up.
Despite this successful management, cancer is still the second most common cause of death in individuals aged 1-19 years, as it is in adults, but contributes to a higher proportion of (quality of) life lost per case than does cancer in adults.
These are all reasons why specific studies of cancer in children and adolescents are needed.
Impact of ACCIS:
- Better knowledge of the nature of tumours, due to large population-based series enabling the precise description of occurrence and outcome, even for rare tumours
- Etiological research, by unveiling the geographical differences, time trends, and subgroup-specific variations in incidence
- Public health planning and evaluation, by providing strategic figures on incidence and survival
- Improvement of referral patterns and standardization of therapies, by detecting differences in survival
- Evaluation of the consequences of childhood cancer, by providing data on long-term survival and second cancers in the survivors
- Standardization of diagnostics, treatment, and classification of tumours
- Harmonization of cancer registration techniques.