Cancer-specific mortality in multiple myeloma: a population-based retrospective cohort study

Survival has improved in patients diagnosed with multiple myeloma (MM) over the last two decades; however, there remains a paucity of data on the causes of death in MM patients and whether causes of death change during the disease trajectory. We conducted a retrospective population-based study to evaluate the rates of MM-specific vs non-MM cause of death and to identify factors associated with cause specific death in MM patients, stratified into autologous stem cell transplant (ASCT) and non-ASCT cohorts. A total of 6677 patients were included, 2576 in the ASCT group and 4010 in the non-ASCT group. Eight hundred and seventy-three (34%) ASCT patients and 2787 (68%) non-ASCT patients died during the follow-up period. MM was the most frequent cause of death, causing 74% of deaths in the ASCT group and 67% in the non-ASCT group. Other cancers were the second leading cause of death, followed by cardiac and infectious diseases. Multivariable analysis demonstrated that a more recent year of diagnosis and novel agent use within 1 year of diagnosis were associated with a decreased risk of MM-specific death, whereas a history of previous non-MM cancer, older age, and the presence of CRAB criteria at diagnosis increased the risk of non-MM death. Our data suggests that despite improvement in MM outcomes in recent years, MM remains the greatest threat to overall survival for patients. Further advances in the development of effective MM therapeutic agents in both ASCT and non-ASCT populations and patient access to them is needed to improve outcomes.