AIM OF DATABASE: The Danish National Lymphoma Registry (LYFO) was established in order to monitor and improve the diagnostic evaluation and the quality of treatment of all lymphoma patients in Denmark.

STUDY POPULATION: The LYFO database was established in 1982 as a seminational database including all lymphoma patients referred to the departments of hematology. The database became nationwide on January 1, 2000.

MAIN VARIABLES: The main variables include both clinical and paraclinical variables as well as details of treatment and treatment evaluation. Up to four forms are completed for each patient: a primary registration form, a treatment form, a relapse form, and a follow-up form. Variables are used to calculate six result quality indicators (mortality 30 and 180 days after diagnosis, response to first-line treatment, and survival estimates 1, 3, and 5 years after the time of diagnosis), and three process quality indicators (time from diagnosis until the start of treatment, the presence of relevant diagnostic markers, and inclusion rate in clinical protocols).

DESCRIPTIVE DATA: Approximately 23,000 patients were registered in the period 1982-2014 with a median age of 65 years (range: 16-100 years) and a male/female ratio of 1.23:1. Patients can be registered with any of 42 different subtypes according to the World Health Organization classifications.

CONCLUSION: LYFO is a nationwide database for all lymphoma patients in Denmark and includes detailed information. This information is used for both epidemiological research and clinical follow-up as well as for administrative purposes.