Impact of Synchronous Multiple Primary Malignant Tumors on Newly Diagnosed Hematological Malignancies

The existence of synchronous multiple primary malignant tumors was not a significant risk factor for patients with newly diagnosed hematological malignancies. It is important to provide adequate treatment to both hematological malignancies and solid tumors appropriately. Hematological malignancies are occasionally observed with synchronous multiple primary malignant tumors (sMPMTs) at diagnosis. We aimed to clarify the impact of sMPMTs on newly diagnosed hematological malignancies and determine the optimal treatment strategies. We analyzed the outcomes of 649 patients with hematological malignancies, including 19 patients with sMPMTs (2.9%), and compared the outcomes between patients with and without sMPMTs. The overall survival (OS) and disease-free survival (DFS) rates for patients with sMPMTs were 77% and 70%, respectively, at 2 years; these rates were not statistically different from those for patients without sMPMTs (P = .17 and P = .64, respectively). Multivariate analysis showed that the presence of sMPMTs was not a significant prognostic factor for OS, DFS, or relapse (hazard ratio [HR] 1.48, 95% confidence interval [CI] 0.65-3.38, P = .35; HR 0.97, 95% CI 0.46-2.10, P = .97; and HR 0.79, 95% CI 0.29-2.14, P = .65). In patients with sMPMTs, the order of treatment was not a significant prognostic factor. However, discontinuation of treatment was a marginally favorable factor and might reflect a selection bias. The presence of sMPMTs was not a significant risk factor for patients with newly diagnosed hematological malignancies. It is important to provide adequate treatment for both hematological malignancies and solid tumors at the physician's discretion.