Defining cure in multiple myeloma: a comparative study of outcomes of young individuals with myeloma and curable hematologic malignancies

Advances in therapy in recent years have led investigators to challenge the dogma that multiple myeloma (MM) is incurable. We assessed overall (OS) and progression-free survival (PFS) of young patients ( ≤ 50 years) with MM and compared outcomes with follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and Hodgkin lymphoma (HL). All patients ≤ 50 years with newly diagnosed MM (n = 212), FL (n = 168), DLBCL (n = 195), and HL (n = 233) between 1 January 2005 and 31 December 2015 were included. Observed vs. expected survival was summarized by standardized mortality ratios (SMR). Compared to the background US population, excess mortality risk was seen at diagnosis in all four cancers, SMR 19.5 (15.2-24.5) in MM, 4.2 (2.3-7.2) in FL, 13.0 (9.2-18.4) in DLBCL, and 5.2 (2.6-9.3) in HL. We reasoned that cure would most likely occur in the first 3 years after diagnosis and be reflected by an overall survival probability similar to the background population. From the 36-month landmark, excess mortality risk was seen in MM (SMR 20.7 14.7-28.3) and FL (SMR 3.8 1.5-7.8), but not with DLBCL (SMR 3.1 0.8-8.0) or HL (SMR 0.9 0.0-5.1). MM patients have 20-fold excess mortality risk compared to the background population at diagnosis and at 3 years after diagnosis, suggesting that MM remains an incurable cancer.