Which type of stem cell transplant is best for patients with T-cell lymphoma?

This study looked at the use of two types of stem cell transplant (SCT) in the treatment of T-cell lymphoma.  It found that both haploidentical and umbilical cord blood SCT were good options for these patients. 

T-cell lymphoma is a cancer affecting a certain type of blood cell called T-cells. T-cells are produced from stem cells. Stem cells are special cells found in the bones which are able to divide and produce different types of cells. 

Chemotherapy is the first treatment for T-cell lymphoma. Chemotherapy is used to kill the cancer cells. However, chemotherapy often destroys stem cells. When a patient's stem cells are destroyed like this they need a stem cell transplant (SCT) in order to produce new cells.

There are different types of SCT depending on where the transplanted stem cells come from. If the stem cells are taken from the patient's own bones (before treatment) this is called autologous (auto) SCT. If the stem cells are taken from a donor whose stem cells are a very close match to the patient's stem cells, this is called allogeneic (allo) SCT. If the stem cells are taken from the patient's close relative, that is only half-matched, this is called haploidentical (haplo) SCT. Another source of stem cells is the blood from the umbilical cord that can be frozen and preserved after birth. This is called umbilical cord blood (UCB) SCT.

Auto SCT is usually the first choice of treatment because there is less risk of side effects. However, the cancer can sometimes recur with this treatment. Allo SCT is usually the second choice. It is less likely to lead to recurrence than auto SCT. However, there is a risk of a severe type of allergic reaction called graft versus host disease (GVHD). This occurs when the transplanted stem cells attack the patient's body. It is difficult to find a closely matched donor for allo SCT. When a donor cannot be found quickly, haplo or UCB SCT are often used. It is not clear which of these types of SCT is best in patients with T-cell lymphoma.

This study involved 95 patients with T-cell lymphoma. 41 patients received haplo SCT. 54 patients received UCB SCT. Patients were followed up for an average of 21 months.

Overall survival after 2 years for the 2 groups combined was 59%. Progression-free survival over 2 years for the 2 groups combined was 53%.

Patients in the haplo SCT group tended to have a higher survival at 2 years (71%) compared to the UCB group (50%). This difference was not considered statistically significant. 

There were more SCT-related deaths in the UCB group (52%) compared to the haplo group (25%). The most common causes were infections (70%), side effects to medications (15%), and GVHD (15%).

This study showed that both haploidentical and umbilical cord SCT prolong progression-free survival time in patients with T-cell lymphoma. However, haploidentical SCT may be safer than umbilical cord SCT, as it led to fewer SCT-related deaths.

This study looked at a relatively small group of patients. Larger studies are needed to explore these results. This study was based on medical records data. The haploidentical and umbilical cord groups were not closely matched, so it is difficult to compare their outcomes accurately.