We have examined the role of early allogeneic
hematopoietic stem cell transplantation in patients with chronic phase
chronic myelogenous leukemia (CML) who enter a complete cytogenetic remission with
imatinib mesylate. Three kinds of data were used to examine the effect of the outcome of current BCR-ABL inhibitor treatment compared to early allogeneic
stem cell transplantation: (1) the life expectancy of the general population of the United States as a function of age, (2) the life expectancy of CML patients as a function of the age of patients treated with
imatinib mesylate (
imatinib) who achieve a complete cytogenetic remission, and (3) the life expectancy of patients with CML treated with matched-related or matched-unrelated
stem cell transplantation as a function of age, derived from data provided by the Center for International Blood and Marrow Transplant Research (CIBMTR). We also considered separately the transplant results of the Fred Hutchinson
Cancer Research Center (FHCRC), which are substantially better than the "average" outcome from the CIBMTR. We have calculated the projected life expectancy from the age at which patients with CML enter complete cytogenetic remission with
imatinib and that of those who receive allogeneic
stem cell transplantation. The outcome with
imatinib therapy of newly diagnosed patients with CML has been documented for only 4 and 1/2 years, whereas transplant data were available for up to 25 years. Thus, in order to compare life expectancy and 10-year survival probability, it was necessary to extrapolate the
imatinib data. A basis for extrapolation is offered and conservative estimates have been used for comparison. Our best estimate is that patients receiving
imatinib who have a complete cytogenetic remission have a higher projected probability of 10-year survival than patients who are transplanted, based on results provided by the CIBMTR, and have about the same probability compared to the data from the Fred Hutchinson
Cancer Center for patients in the 30- to 60-year-old range. The mathematical approach used here permits reexamining the analysis using future data on BCR-ABL inhibitor
therapy or allogeneic
stem cell transplantation therapy or both.