Clinical significance of cancer-related fatigue in multiple myeloma patients.

Cancer-related fatigue (CRF) is one of the adverse events in multiple myeloma (MM) patients treated with cytotoxic agents, proteasome inhibitors (PIs), and immunomodulatory drugs (IMiDs) such as bortezomib, lenalidomide, and thalidomide. The aims of our study were to prospectively analyze the clinical significance of CRF, and to evaluate the cumulative incidence of CRF and the survival rates of 16 MM patients who were treated with PIs and IMiDs. Reactivation of salivary human herpes virus (HHV)-6 and HHV-7 was analyzed using real-time quantitative polymerase chain reaction (qPCR). CRF was evaluated using a visual analog scale (VAS). Eleven newly diagnosed multiple myeloma (NDMM) and five relapsed or refractory MM patients were enrolled in this study. The cumulative incidence of CRF was 54.9%. The treatment types were not associated with the CRF incidence. The cumulative incidence of reactivation of HHV-6 and HHV-7 was 73.1% and 45.6%, respectively. However, the reactivation of HHV-6 and HHV-7 was not related to CRF. The overall survival (OS) and progression-free survival (PFS) in NDMM patients with CRF was significantly shorter than in those without CRF. In conclusion, CRF was one of the major symptoms in MM patients, and predicted shorter OS and PFS in NDMM patients.