Prognostic value of complete remission with superior platelet counts in acute myeloid leukemia

Complete remission (CR) in acute myeloid leukemia (AML) is defined as having ≤5% leukemic blast cells in the bone marrow and return of normal hematopoiesis after the first induction cycle. There is a subset of patients, however, who achieve reduction of leukemic blast cells with a subnormal platelet count, designated as CR with incomplete platelet recovery (platelet count, ≤100,000/mcL; normal, 150,000-450,000/mcL), which is associated with inferior outcomes when compared with CR. Furthermore, there is another subset of patients with CR but superior platelet counts (≥400,000/mcL) whose prognostic significance is unclear.

To establish whether CR with superior platelet counts is associated with better outcomes and can be used as a separate entity for prognostication.

A retrospective chart review of 104 cases of AML was conducted. The highest platelet count during days 25-35 from initiation of induction chemotherapy (designated as day 30 platelet count) was documented. A multivariate analysis for other factors such as age, sex, risk categories, day 14+ plasma cell count (average plasma cell percentage at days 14-21), infections, allogeneic bone marrow transplant, and remission status was done.

Day 30 platelet count was found to be an independent predictor of survival in AML. On the multivariate analysis, the subgroup with superior platelet counts (≥400,000/mcL) was found to be associated with better outcomes.

Results need to be validated in a larger cohort.

CR with superior platelet recovery (≥400,000/mcL) is a unique subcategory in itself and has prognostic significance. This may help better assess response to chemotherapeutic agents and aid in further decision-making regarding treatment.