Autologous stem cell transplantation (ASCT) with immunologically purged progenitor cells in patients with advanced stage follicular lymphoma after early partial or complete remission: toxicity, follow-up of minimal residual disease and survival.

The role of autologous stem cell transplant (ASCT) in indolent lymphomas is a controversial issue. From 1994 to 1999, we performed ASCT with immunologically purged progenitor cells in 15 patients with advanced stage follicular lymphoma (FL) after early partial or complete remission. Results of the purging strategy and follow-up of minimal residual disease after transplant were analyzed with PCR amplification of bcl-2/IgH rearrangement for the t(14;18) translocation. A comparison of transplanted patients with a group of controls was carried out to evaluate differences in progression-free survival and overall survival. Eighty percent of patients received one chemotherapy regimen before ASCT and were in first remission. All the patients received cyclophosphamide plus hyperfractionated total body irradiation as the conditioning regimen. Nine patients were transplanted with bone marrow (BM) and six with peripheral blood progenitor cells (PBPC). Engraftment was delayed in one patient transplanted with BM. Two patients died during the transplant procedure. Ten of 12 evaluable patients were PCR positive in the BM for bcl-2 rearrangement at diagnosis. Six of them (60%) were still positive after chemotherapy, and one patient was transplanted with a positive hematopoietic product after purging. With a median follow-up of 27 months, six of eight evaluable patients still remain PCR negative in the BM. With a median follow-up of 4.7 years from diagnosis, progression-free survival was 83% (95% CI: 63-100). The risk of disease progression of non-transplanted patients was 19.2 times higher than that of transplanted patients (P = 0.01), but no differences were found in overall survival. Regarding patients in first remission, the risk of relapse was 12.6 times higher in non-transplanted than in transplanted patients (P = 0.04). This procedure seems to offer a good chance to achieve a PCR-negative state and prolonged freedom from recurrence. According to these results, prospective randomized trials are warranted.