Summary
Multiple myeloma (MM) is the second most common hematologic malignancy diagnosed in adults in the United States (U.S.). Current reports suggest that approximately 5%–7% of all MM patients develop a second primary malignancy (SPM) at some point during their disease course.1 As novel MM therapies translate into improved long-term outcomes, it is conceivable that extended survival will lead to more time to develop SPMs. Although there is significant literature regarding the incidence of SPMs in MM,1 there is a relative paucity of data regarding prognosis and mortality after SPM development. Available data on mortality after SPM development are either from European countries that lack the racial-ethnic diversity of the U.S.,2, 3 are from retrospective single center studies, or do not include the modern era of anti-cancer therapeutics or International Myeloma Working Group (IMWG) imaging modalities.4 Therefore, critical prognostic information on SPMs in MM patients within the U.S. in the modern era is not available. The American Society of Clinical Oncology's (ASCO) CancerLinQ Discovery® (CLQD) MM data set was utilized to determine outcomes of real-world MM patients in the U.S. who developed SPMs in the modern treatment era.