Helical Tomotherapy and Melphalan As the Conditioning Regimen in Autologous Stem Cell Transplantation for Multiple Myeloma with Extramedullary Plasmacytoma: A Single Center Clinical Research

Abstract

Background Multiple myeloma(MM) is the second hematologic malignancy. Extramedullary myeloma indicates a poorer prognosis and survival. High dose Melphalan is the most widely used conditioning regimen. Helical tomotherapy(TOMO) is one of the most advanced intensity-modulated conformal radiotherapy technologies. We applied the combination of TOMO and Melphalan as the conditioning regimen in MM patients, and analyzed its efficacy and safety. Methods Clinical data were collected and compared between TOMO combined with melphalan group and non-TOMO group. SPSS V.25.0 was used for statistical analysis. Results Two methods were not significant difference by statistics analysis. The complete response rate of 100d in non-TOMO group significantly decreased compared to 1 month after transplantation (P=0.001). The 1-year PFS rate in the TOMO group was 86%, while non-TOMO group was 91%. There was no myeloma related death in the two groups within one year. TOMO group showed earlier enter platelet count below 20x109/L (P=0.003) and granulocyte deficiency (P=0.000). In terms of platelet implantation time,TOMO group was superior in platelet implantation time (P=0.041). No atrial fibrillation, heart failure, hepatic small vein occlusion, or transplant related death occurred during the transplantation period. Conclusion: The combination of TOMO and reduced dose Melphalan conditioning regimen is clinically feasible in terms of safety and efficacy evaluation. This scheme could improve the long-term survival of MM patients with extramedullary plasmacytoma.