PB1843: ACUTE MYELOID LEUKEMIA WITH PHILADELPHIA CHROMOSOME: EXPERIENCE OF SFAX HEMATOLOGY DEPARTMENT

Abstract

Background: Acute myeloid leukemia with Philadelphia chromosome (AML Ph+) is recently been listed in the 2016 revised World Health Organization (WHO) classification of myeloid malignancies as a provisional entity. Aims: A rare entity whose treatment is not yet established. we are studying the characteristics of a series of patients with AML Phi+. Methods: It’s a retrospective study over 15 years (2005-2019) which includes patients with AML Phi+, diagnosed and treated in the clinical hematology department of Hedi Chaker Sfax Hospital / TUNISIA. We are interested in studying the clinical and biological characteristics, the different treatments received and overall survival (OS). Known patients followed for Chronic Myeloid Leukemia (CML) and who are transformed into blast phase are excluded. Results: Among 264 cases of newly diagnosed AML, we collected 5 cases of AML Phi+ (1.8%). The average age was 43 years (range: 34 to 54). Sex-ratio was 1.5. On initial examination, splenomegaly was found in all cases. WBC counts less than 10 G/l, from 10 to 100 G/L and more than 100 G/L were observed respectively in 20, 40 and 40% of cases. Myelemia was found in 4 cases (80%) and basophilia greater than 2% was noted in 3 cases (60%). Cytogenetic study showed the presence of a t (9.22) in all cases, which was isolated in 1 case. The BCR-ABL transcript was of the p190 type in 2 cases and p210 in 2 cases, while the molecular study was not done in the remaining case. Four patients were treated with tyrosine kinase inhibitor (TKI) alone with the achievement of complete remission (CR) in 3/4 of the cases while one patient was treated with the combination TKI and chemotherapy with good evolution. Allograft was not done for all patients, in 2 cases for the absence of an HLA compatible siblings donor. The median follows up was 108 months. Relapse was observed in 2 patients with CR2 in both cases. The five years OS was 80%. Summary/Conclusion: Phi+ AML in our series is higher than that reported in the literature (1.8 vs <1%) this could be explained by the underestimation of the total number of AML in our country because some patients with AML (>55 years old) are not treated. The major question that arises in front of each phi+ AML is: is it a newly phi+ AML or a CML diagnosed at a blast phase? Previous abnormalities of the blood count, significant myelemia, blood basophilia >2% and the presence of associated cytogenetic abnormality tends towards CML diagnosed at a blast phase while the BCR-ABL transcript type is non-specific. By referring to these data, we can deduce that for our series most probably it is a newly phi+ AML in 2 cases. The major problem posed in the different series is the absence of standardized treatment due to the rarity of the pathology.