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The role of myeloablation for lymphoma.

To the Editor: Stiff et al. (Oct. 31 issue)1 report that autologous stem-cell transplantation improved progression-free survival among patients with high-intermediate-risk or high-risk aggressive non-Hodgkin’s lymphoma who had a response to induction therapy. This statement has limited clinical value because it does not translate into a survival advantage; moreover, only 150 patients in the study received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus rituximab (R-CHOP). The estimated 2-year progression-free survival among these patients was 63% in the control group and 73% in the transplantation group (hazard ratio, 1.56; 95% confidence interval [CI], 0.92 to 2.63; P = 0.10). This 10-percentagepoint difference in progression-free survival is not statistically significant, because the study was highly underpowered to allow a meaningful comparison. According to international statistical standards, a sample size much larger than 150 patients would have been necessary. Furthermore, findings from other studies addressing the same question have been reported. German2 and French3 studies showed no difference in survival rates. An Italian study 4 showed an 11-percentage-point difference in progressionfree survival in favor of autologous stem-cell transplantation, but it did not show a benefit in overall survival. Taken together, the available data do not support the continued use of high-dose chemotherapy and autologous stem-cell transplantation as consolidation treatment in aggressive B-cell lymphoma in the rituximab era.