Survival in hematological malignancies in the Nordic countries through a half century with correlation to treatment.

Studies of survival in hematological malignancies (HMs) have generally shown an improvement over time, although most of these studies are limited by a short follow-up period. Using the NORDCAN database with data from Denmark, Finland, Norway and Sweden, we follow periodic increases in relative survival in seven HMs through half a century up to 2015-2019. Five-year survival improved in all seven HMs, reaching 90% for Hodgkin lymphoma (HL), myeloproliferative neoplasias and chronic lymphocytic leukemia (CLL), 60% for multiple myeloma (MM) and chronic myeloid leukemias (CMLs), 50% for the myelodysplastic syndromes and 30% for acute myeloid leukemia (AML). Improvements in survival over 50 years ranged from 20% to more than 50% units across the different HMs. The likely reasons for such progress include earlier diagnoses, improved risk stratification and advances in treatment. We observed differing temporal trends in improvements in survival. The gradual increases observed in HL, CLL and AML highlight the impact of optimization of existing therapies and improvements in diagnostics and risk stratification, whereas the rapid increases observed in the CMLs and MM highlight the impact of novel therapies. Recent therapeutic advances may further improve survival in HMs where survival remains low such as in AML.