Could Transfusion be Restricted for Acute Promyelocytic Leukemia in the Era of Diffetentiating Agents?

BACKGROUND: With the advent of differentiating agents (DA) like all-trans-retinoic-acid (ATRA), and arsenic trioxide (ATO), acute promyelocytic leukemia (APL) has become one of the best prognostic type of acute myeloid leukemia (AML) even in the under-developed countries. In Myanmar, APL is recognized as a common form of AML and managing APL in the resource limited setting particularly for aggressive transfusion support according to current guidelines is difficult and therefore transfusion requirement of APL treated in our center were analyzed with an aim to find evidence for restrictive transfusion policy.

MATHODS: Cases of APL complicated by disseminated intravascular coagulation (DIC) treated during November 2014 to April 2017 were retrospectively reviewed in this study. All cases were treated with combined ATRA and ATO and conventional chemotherapy was added in high risk patients and those who developed rapid rise in white cell counts. Recommended target platelet count of 30-50 x 10⁹/L and fibrinogen level of 100-150 mg/dl were maintained only for WHO grade 3 to 4 bleeding while the rest were transfused with platelet target of 20 x 10⁹/L and fixed dose of FFP 2 -4 units per day until bleeding subsided. Prophylactic platelet was given for counts below 10 x 10⁹/L.

RESULTS: Among 33 APL admitted during two and half year's period, 29 presented with evidence of DIC, of them 4 had already developed intracerebral haemorrhage at presentation and died within 24 hours. In remaining molecularly confirmed 25 patients with APL, 14 males and 11 females, with median age of 28 years (range 12 -58) with initial performance status of 3 to 4 in 8 cases (32%) were classified as low, intermediate and high risk in 1 (4%), 13 (52%) and 11 (44%) cases respectively. Presenting blood counts were median hemoglobin - 5.9 mg/dl (3.2 - 10.6), median white cell count 7.23 x 10⁹/L (0.43 - 110.8) and median platelet count 29 x 10⁹/L (2 - 121). Regarding coagulation profile median PT - 15.6 second (9.9 - 21), median APTT - 28.4 second (20 - 46), median fibrinogen 160 mg/dl (82 - 900) and median D-Dimer - 8700 ng/ml (1917 - 19166). Median lowest platelet was 6 x 10⁹/L (2 - 37) and median days of platelet count less than 10 x 10⁹/L and less than 20 x 10⁹/L were 4 days (0 - 10) and 8 days (2 - 26) respectively. Median number blood products transfused were of 6 units (3 - 12) of red cell, 10 units (6 - 15) of platelets and 10 unit (4 - 24) of FFP in total for each patient. Most bleeding and DIC subsided within first week and there were no haemorrhagic death during induction.

CONCLUSION: Restricted transfusion policy may be possible in APL provided close monitoring of clinical and laboratory parameters and transfusion of blood products are tailored according to the risk and clinical condition.