Background: Rare cancers are the target for cancer control in the era of precision medicine. However, there are no generally accepted definitions of rare cancers, and the incidence and survival of patients with rare cancers are unknown. As part of the European RARECARE project, a definition was introduced wherein cancers are defined as rare when the crude incidence rate is less than 6 per 100,000 per year.
Objective: The aim of this study was to analyze the rare cancer incidence rate in Gangwon-do.
Methods: We applied the RARECARE definition to cancers listed as rare in 2018, and calculated crude incidence rates based on the primary site and histological groups, using data from the Gangwon-do Regional Cancer Registry between 1999 and 2020. Furthermore, Korean, and World standardized incidence rates were also calculated.
Results: Of the 219 entities in the second tier of RARECARE list, 205 (93.6%) entities were rare according to the definition, accounting for 10,971 cancers. Rare cancers constituted 60% of all newly diagnosed cancers in Gangwon-do, indicating the challenge faced by clinicians and the government in terms of patient support. The incidence rates of rare and common cancers in Gangwon-do and that in Europe were slightly different according to the EUROCARE classification.
Conclusion: The findings of this study highlight the considerable impact of rare cancers within Gangwon-do. It is anticipated that these insights will catalyze further discourse aimed at addressing the deficiencies in scientific understanding, the development of effective treatments, and the enhancement of clinical expertise in this area.