Purging of autografts: methods and clinical significance

High-dose chemoradiotherapy with autologous haematopoietic progenitor cell support is being used with increasing frequency to treat patients with a variety of malignancies. The most common reason for the ultimate failure in patients treated with high-dose therapy with stem cell support is not lack of engraftment, toxicity of therapy, or infection, but rather relapse of disease. There is solid evidence that reinfusion of autografts containing clonogenic tumour cells can contribute to relapse and influence patient outcome after high-dose treatment. In patients undergoing high-dose treatment, tumour cell contamination can be observed in histologically normal bone marrow or peripheral blood by sensitive micrometastatic detection techniques. Consequently, methods for detection of minimal residual disease in the autografts, together with techniques to remove tumour cells from the harvest are considered to be important in patients receiving high-dose therapy with stem cell support.