Stem Cell Transplantation For Relapsed Or Refractory Disease

The use of conventional dose chemotherapy regimens as salvage therapy produces response rates of less than 10% and median overall of only around 9 months.819-21 Some studies have investigated the role of autologous stem cell transplantation in this situation.

In a retrospective study from Europe, 41 patients underwent high-dose therapy and autologous stem cell transplantation in second complete remission.36 The 3-year actuarial progression-free survival and overall survival for this group were 30 and 31%, respectively. The sensitivity of the disease to conventional dose therapy given prior to the transplant was predictive of outcome. The 5-year actuarial overall survival for those with chemosensitive relapse was 31% compared with 18% for those with chemorefractory disease.

Since patients in chemosensitive relapse have a superior outcome compared to those with chemore-fractory relapse, all relapsing patients should receive conventional dose salvage therapy in an attempt to induce a second remission prior to high-dose therapy. However, even in those patients with refractory disease, the reported long-term disease-free survival of 18% is superior to that achieved with conventional dose salvage, and these patients should also be offered high-dose therapy.

In view of the relatively young age of adult patients with LBL, it is anticipated that their regimen-related mortality after allogeneic transplantation is likely to be relatively low. If a graft-versus-lymphoma effect exists in this disease, then the low relapse rate observed in patients who survive allogeneic transplantation might result in improved overall survival compared with autologous transplantation. A retrospective, case-controlled analysis from the European Group for Blood and Marrow Transplantation (EBMT) comparing autologous with allogeneic stem cell transplantation reported a lower relapse rate for patients receiving allogeneic compared with autologous stem cell transplantation (2% vs 48%, respectively, p = 0.035).38 However, progression-free survival for both groups was equivalent because of the higher procedure-related mortality in the allogeneic group. Although one other series has reported a superior outcome for patients receiving HLA-matched allogeneic transplants, this was also a small retrospective series.23 Patients proceeding to allogeneic transplant are likely to be favorable in terms of age, performance status, and time in remission prior to transplant-all factors that might bias for improved survival.

The study mentioned above, from the International Bone Marrow Transplant Registry, compared outcomes for autologous and allogeneic stem cell transplantation in adult patients with LBL. No difference in survival was observed.37

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