Extremely long duration of chronic myeloid leukaemia with Ph1 negative and Ph1 positive bone marrow cells.

A male patient still surviving 17 years after the diagnosis of chronic myeloid leukaemic (CML) is described. A chromosome analysis of the bone marrow 16 years after the diagnosis revealed 84% Ph1 negative and 16% Ph1 positive cells, all containing the Y chromosome. The disease has been very sensitive to treatment with busulphan but bone marrow hypoplasia has not been induced. It is probable that in some CML patients with such a double cell population the prognosis may be extraordinarily good and that they run a considerable risk of being overtreated due to a pronounced sensitivity to alkylating drugs. Such rare cases should not serve as arguments for aggressive treatment of CML.