Double Transplantation of One's Own Stem Cells Is Not Warranted for Multiple Myeloma
Adapted from the NCI Cancer Bulletin.The addition of a second (tandem) hematopoietic stem cell transplant (HSCT) procedure using one's own (autologous) blood cells does not appear to improve either event-free or overall survival in multiple myeloma, according to a meta-analysis of trials comparing single versus tandem transplants head-to-head published in the January 21, 2009, Journal of the National Cancer Institute (see the journal abstract). Researchers led by Dr. Ambuj Kumar at the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Fla., concluded that “the routine use of tandem transplant in its current form is not justified.”
This conclusion reflects another finding in their review: While the response rate improved 21 percent in patients receiving tandem treatments, the risk of treatment-related mortality (TRM) increased by 71 percent in this group. The data were drawn from six randomized controlled trials published or presented at meetings since 2003, in which a total of 1,803 patients were enrolled.
Multiple myeloma is a rarely curable malignancy of blood plasma cells that is nonetheless highly treatable, especially when certain patients are conditioned with different chemotherapy combinations before undergoing autologous HSCT. Tandem transplantation became feasible in the early 1990s, and these six trials were subsequently mounted to determine its value and safety in clinical practice.
While the earliest trial published in 2003 showed tandem transplantation improved overall and event-free survival, the authors of the current meta-analysis noted that the 2003 results “also indicated that tandem transplant may not benefit all patients equally,” and that the subsequent trials did not stratify patients according to biologic and genomic factors that are thought to influence risk. Therefore, they wrote, “it is not known if a benefit in terms of [overall survival] may exist” in a subgroup of patients receiving the tandem treatment, “or if a survival benefit might emerge as strategies to reduce TRM are improved.”