Minimal Residual Cancer Detection in Hematopoietic Stem Cell Products and its Prognostic Significance in Patients with Breast Cancer, Lymphoma, or Multiple Myeloma

Background Despite the initial success of high-dose therapy and bone marrow transplant, the major reason for posttransplant failure is relapse of disease. Reinfusion of tumor cells may contribute to relapse in autologous stem cell transplants. We now have ultra-sensitive methods of tumor cell detection that can determine the presence of minimal residual cancer (MRC) in marrow and peripheral blood stem cells. Methods The author has conducted a critical review of the literature on this issue. Results The factors that are associated with an increase in contamination of the graft include (1) the number of cycles of induction therapy, (2) the type of mobilization regimen used, (3) the presence of tumor cells in the marrow, and (4) the number of phereses. A number of studies show that the presence of occult breast cancer in the marrow and/or stem cell product predicts for a poor posttransplant clinical outcome. The presence of clonogenic breast cancer or lymphoma cells in the graft is also associated with a very poor outcome. Published data regarding contamination in graft and outcome for patients with myeloma are limited. Conclusions Testing for minimal MRC in the oncology patient provides prognostic information that may be useful to the transplant physician.