Most chemotherapy regimens for multiple myeloma are 28 days for 1 chemotherapy cycle, which means 1 chemotherapy session in 28 days. Myeloma cells are more sensitive to chemotherapy drugs, especially the combination chemotherapy of multiple drugs is still the most basic treatment for multiple myeloma. At least 4-6 courses of treatment need to be repeated, and even some patients need 6-12 courses or more to kill most of the chemotherapy-sensitive cells. Most of the remaining tumor cells are in the inactive or quiescent stage, which are often not sensitive to chemotherapy, so it is not suitable for patients to continue chemotherapy at this stage, and it is not beneficial for patients to continue chemotherapy. At this time, some patients can also be considered for hematopoietic stem cell transplantation.