Comparing different sources for stem cell transplantation for patients with lymphoma

This study compared the outcomes of patients with lymphoma who had an allogeneic stem cell transplant with different sources of stem cells. This study found that stem cells from a matching donor had better outcomes compared to those from unrelated cord blood.

Allogeneic stem cell transplantation is one type of stem cell transplant (SCT) used to treat lymphoma. This procedure requires a close tissue type match between the donor and the patient so that the donor’s immune cells do not attack the patient’s healthy cells. This immune attack is called GVHD. It is a common complication of SCT. 

Unfortunately, it can be difficult to find an exact tissue type match. For these patients, haploidentical transplantation can achieve a 50% match. These stem cells can come from a parent or sibling. Stem cells can come from the bone marrow or peripheral blood. Stem cells from donated umbilical cord blood (UCB) can also be used. Which of these stem cell sources leads to better transplant outcomes for patients with lymphoma is unclear.

This study had 740 patients with lymphoma. 38% (283 patients) had Hodgkin’s lymphoma (HL) and 62% (457 patients) had non-Hodgkin’s lymphoma (NHL). 526 patients had a haploidentical transplant (HT). Of these, 68% received stem cells from the donor’s bone marrow and 32% received cells from the donor’s blood. 214 patients had a UCB transplant. Patients were followed for 30 to 48 months. 

Overall, more patients in the HT group were still alive 4 years later compared to the UCB group (58% vs. 49%). More patients in the HT group also survived for 4 years without tumor growth or spread compared to the UCB group (46% vs. 36%).

The UCB transplant was significantly associated with a 1.55-fold higher mortality risk compared to HT. The UCB transplant also significantly increased the risk of tumor growth or spread by 1.44-fold. 

Significantly more patients in the UCB group developed GVHD after the transplant compared to the HT group (43% vs. 20%). Serious GVHD was also more common in the UCB group (18%) compared to the HT group (5%, donor marrow vs. 6%, donor blood). 

Significantly more patients in the UCB group still had GVHD 4 years later compared to the HT group (28% vs. 24%, donor marrow). The UCB transplant was significantly associated with a 1.53-fold higher risk of persistent GVHD compared to bone marrow HT.

This study found that donor stem cells from the bone marrow or peripheral blood had better outcomes than stem cells from UCB for patients with lymphoma. The authors suggest that umbilical cord blood may be recommended when a haploidentical relative is not available.

This study looked back in time to analyze data. More studies are needed to confirm these results.