Is long term storage of cryopreserved stem cells for hematopoietic stem cell transplantation a worthwhile exercise in...

Stem cell units (SCUs) that are cryopreserved prior to both autologous and allogeneic hematopoietic stem cell transplants (for donor lymphocyte infusion) remain unused or partially used several times, and become an increased burden to blood banks/SCU repositories. Because of the scarcity of data regarding the duration for which the storage is useful, there is no general consensus regarding disposal of SCUs.

We conducted a retrospective audit of SCU utilization in 435 patients who planned to undergo either autologous stem cell transplantation (auto-SCT) (N=239) or allogeneic stem cell transplantation (allo-SCT) (N=196) at a tertiary cancer care center between November 2007 to January 2015.

Our cohort consisted of 1,728 SCUs stored for conducting auto-SCT and 729 SCUs stored for conducting donor lymphocyte infusions (DLIs) after allo-SCT. Stem cells were not infused in 12.5% of patients who had planned to undergo auto-SCT, and 80% of patients who underwent allo-SCT never received DLI. Forty-one percent of SCUs intended for use in auto-SCT remained unutilized, with a second auto-SCT being performed only in 4 patients. Ninety-four percent of SCUs intended for carrying out DLIs remained unused, with only minimal usage observed one year after undergoing allo-SCT.

The duration of storage of unused SCUs needs to be debated upon, so that a consensus can be reached regarding the ethical disposal of SCU.