SECONDARY ACUTE PROMYELOCYTIC LEUKEMIA - CHARACTERISTICS AND PROGNOSIS OF 14 PATIENTS FROM A SINGLE INSTITUTION

The aims of this study were to analyze the characteristics and outcome of patients with secondary acute promyelocytic leukemia (APL) and com pare them to those with primary APL. One hundred and thirteen patients referred to our service with a diagnosis of APL were reviewed. Fourte en were classified as secondary APL. Nine were induced with chemothera py, and five with all-trans retinoic acid plus chemotherapy. Pretreatm ent characteristics, response to therapy and outcome of primary vs sec ondary APL were compared by standard statistical methods. Secondary AP L constituted 12% of all APL cases. Patients with secondary APL were s ignificantly older (median age 56 vs 36 years; P < 0.01) and had a low er incidence of hypofibrinogenemia (P < 0.01) than those with primary APL. The complete response (CR) rates were similar with secondary vs p rimary APL (CR rates 79 vs 69%), as were CR duration and survival. The CR rates at 5 years were 57 and 45%, respectively (P not significant) , and the survival rates 37 and 35%, respectively (P not significant). The incidence of secondary APL within APL disease (12%) was similar t o the incidence of secondary acute myeloid leukemia (AML) in karyotype s not known to be therapy-related (diploid, t(8;21), inversion 16: inc idences 9 to 12%), but was significantly lower than in karyotypes know n to be therapy-related (chromosome 5 or 7 abnormalities, 11q; inciden ces 30 and 33%). We conclude that secondary APL has general characteri stics and outcome similar to primary APL. It is more likely a second p rimary rather than therapy-related AML, and should be treated in a man ner similar to primary APL.