Abstract
BACKGROUND: Secondary acute lymphoblastic leukemia (sALL) is rare in patients diagnosed with antecedent multiple myeloma (MM). This study aimed to elucidate the clinical features and outcomes of patients with sALL after MM. METHODS: We conducted this population-based study using the Surveillance, Epidemiology, and End Results (SEER) database and retrospectively reviewed patients with sALL following MM treatment at our institution. Cox regression analysis was performed to investigate the prognostic factors for survival in patients with sALL. RESULTS: We identified 64,629 cases of MM (including 18 sALL from the SEER Plus 9 database, and three sALL from our institution). Younger patients with MM and those who received chemotherapy were at a higher risk of developing sALL. The novel agent era witnessed an increased incidence of sALL (post-novel agent era vs. pre-novel agent era: 0.31% [10/32,640] vs. 0.25% [8/31,989]) and shorter latency time (post-novel agent era vs. pre-novel agent era [median]: 51.5 vs. 74.5 months, P = 0.516), though the difference was not significant. The median age at sALL onset was 65 (range: 47-78) years. Significant cytopenia and absence of BCR/ABL fusion genes were common features in this patient population. The treatment of sALL is complicated by old age and poor performance status. The median survival of patients with sALL is 18 months, whereas those who received chemotherapy had significantly prolonged survival. CONCLUSIONS: Patients with sALL combined with an antecedent MM, especially those with long-term exposure to immunomodulatory agents such as thalidomide or lenalidomide, should be cautiously evaluated and managed with a comprehensive approach.