۱- INTRODUCTION

۲- PATIENTS AND METHODS

۳- RESULTS

۴- DISCUSSION

References

Abstract

Acute undifferentiated leukemia (AUL) is rare and defined by the absence of bona fide myeloid and lymphoid markers. Little is known about its incidence, survival and optimal management in the recent time period. Based on a case observed in our clinic, we queried the Surveillance, Epidemiology, and End Results database between 2000 and 2016. A total of 1,888 cases of AUL were diagnosed (1.34 per million person-years). The incidence of AUL has significantly decreased over time. Compared to other acute leukemias, patients with AUL have the highest median age (74 years); in contrast to acute myeloid leukemia (AML, 65) and acute lymphoblastic leukemia (ALL, 12). Excluding patients with preexisting malignancies, 1,444 patients with AUL were analyzed for survival. Only 35% of AUL patients had received chemotherapy. Comparatively, 94% of ALL and 71% of AML cases received chemotherapy. Among AUL patients who received chemotherapy, the median survival was 12 months as opposed to 1 month in the group who did not receive chemotherapy (or unknown status). Among adults, AUL patients had the worst prognosis, with a median overall survival (OS) of 9 months, compared to 27 months in ALL and 13 months in AML. Among children, the median OS was superior for all three groups of leukemias, the OS of AUL patients being better than in AML and very similar to ALL. On multivariate analysis, older age and time period were associated with worse outcome. We describe here the largest series of cases with AUL published to date.

INTRODUCTION

The last three or four decades have seen significant progress in the diagnosis and treatment of acute leukemias. No longer a universally fatal disease, acute leukemia has become treatable and, in many instances, curable. Using immunologic and molecular markers, many different prognostic types of acute leukemia are recognized. Acute undifferentiated leukemia (AUL) is rare and has neither lymphoid nor myeloid lineage specific markers. In the 2016 update of the World Health Organization (WHO) classification of myeloid neoplasms, AUL is listed as a subcategory of mixed phenotype acute leukemia. In an earlier epidemiologic study, an incidence of 1.6 cases per 1 million person-years was described. Based on a case of AUL observed in our clinic, we queried the Surveillance, Epidemiology, and End Results (SEER) registry database and reviewed the pertinent literature.