Relapsed multiple myeloma: who benefits from salvage autografts?

Background Multiple myeloma is incurable despite the advance of autologous stem cell transplant (ASCT) and novel agents (thalidomide, bortezomib, lenalidomide). The role of ASCT as salvage therapy in relapsed myeloma remains unclear. Aim To identify and refine the predictors of survival following salvage ASCT for relapsed multiple myeloma, so that they can be applied clinically for patient selection. Methods Retrospective review of patients treated salvage ASCT for relapsed myeloma at our centre from 1992 to 2011. Results Following an initial ASCT at diagnosis, 30 patients underwent salvage ASCT for subsequent relapse, with the median time to first relapse/progression being 30.2 months. All patients received reinduction, then melphalan-based conditioning with salvage ASCT. Non-relapse mortality at 100 days following salvage ASCT was 3%. The median overall survival and progression-free survival following salvage ASCT were 45 and 22 months respectively. The progression-free interval (PFI) after initial ASCT predicted survival outcomes in a time-dependent manner. With PFI following initial ASCT of <18, 1836 and 36 months, the median progression-free survival following salvage ASCT was 4.2, 13.8 and 49.1 months respectively (P < 0.0001). The median overall survival was 10.7, 30.9 and 86.1 months respectively (P < 0.0001). Conclusions Salvage ASCT is an effective and safe treatment option in selected patients and should be considered in patients relapsing 36 months after their initial ASCT. The time-dependent relationship between PFI and salvage ASCT outcome is important when stratifying patient groups who may benefit from this procedure.