Epidemiology, databases, and cancer registries

Abstract

Rare diseases are defined by their low prevalence. In Europe, a disease is considered rare if it affects fewer than 1 in 2000 people. A more specific definition exists for rare tumours, which are classified as malignancies with an incidence of fewer than 6 per 100,000 per year. This classification, established through EU-funded projects and the Joint Action on Rare Cancers (JARC). Population- based cancer registries provide essential epidemiological indicators—incidence, prevalence, survival, and mortality—allowing continuous assessment of the cancer burden in defined populations. Projects such as RARECARE, RARECAREnet and EUROCARE have contributed to understand ing rare cancer epidemiology across Europe. Rare gynaecological cancers, including non-epithelial ovarian tumours, epithelial tumours of the fallopian tube, and placental choriocarcinoma, exhibit varying incidence and survival figures, with older women often more affected and five-year survival generally lower than common gynaecologic cancers.