High-dose melphalan and autologous haematopoietic stem cell transplantation in multiple myeloma in Norway, 2008-2020.

BACKGROUND AND AIM: High-dose melphalan and autologous haematopoietic stem-cell transplantation (ASCT) is effective against multiple myeloma. The type of treatment patients receive before and after ASCT may affect time to relapse and survival. The aim of this study was to compare the treatments administered before and after ASCT at the four hospitals offering ASCT in Norway during the period 2008-2020.

MATERIAL AND METHOD: All patients who received ASCT as first-line treatment for multiple myeloma in Norway in the period 1 January 2008-31 December 2020 were included in the study. Data on demographics, disease and treatment were recorded. Patients were followed until disease progression, death or study completion.

RESULTS

Patients who received ASCT at St Olav's University Hospital received almost exclusively bortezomib-cyclophosphamide-dexamethasone as induction therapy, while bortezomib-lenalidomide-dexamethasone dominated at the three other hospitals after 2017. Maintenance therapy was given to 27 % of patients receiving ASCT in Oslo, compared with 2-16 % at the other centres. Median progression-free survival ranged from 29 to 38 months, and median overall survival ranged from 102 to 120 months across the centres.

INTERPRETATION: Significant variations were observed in the treatments administered before and after ASCT, especially after 2017. National guidelines allowed for multiple treatment options, which has resulted in heterogeneous treatment practices. These different treatment approaches may have contributed to differences in progression-free and overall survival.