OBJECTIVETo explore the clinical features and prognosis of primary acute myeloid leukemia (AML) with trisomy 8.

METHODSThe clinical data of 24 cases diagnosed as primary AML with trisomy 8 were collected. The clinical characteristics such as sex, age, subtype of FAB, blood routine and bone marrow blast at the first visit were analyzed and the relationship of the characteristics with CR rate and the prognosis was explored.

RESULTS12 out of 24 AML patients were diagnosed as M5 (50%), while M2, M3, M4 and M6 had 3 cases, respectively (12.5%); one case did not receive the chemotherapy. 23 cases received 1-2 cycles of standard induction chemotherapy. Among them 3 cases of M3 achieved complete response (CR) and survived until the last following up with 100% 5-year OS rate. Among 20 cases of non-M3, 12 cases achieved CR1 (60%), 4 cases achieved partial response (PR) (20%), 4 cases did not respond (NR); 5 cases relapsed in follow-up for 3 years after CR1 (41.7%), 3 cases achieved CR2 after re-induction chemotherapy, and 2 cases remained NR. Among 20 cases of non-M3, 1 case failed to be followed-up after diagnosis within 1 month. The mean follow-up time of 19 cases was 26.2 (1.5-84) months, 9 cases died (6 cases of M5, 1 case of M4 and 2 cases of M2), who achieved PR and NR, or relapsed after CR1; the 3-year DFS and OS were 21%, 31.5% respectively. 2 cases of non-M3 accepted allo-HSCT with HLA-matched sibling donor and kept disease-free survival until the last following up, and survived for 58 and 66 months respectively. Except for 3 cases of M3, 2 cases received allo-HSCT and the cases without chemotherapy, the other 18 cases with initial WBC count less than 10×10(9)/L had OS and DFS longer than those of 10 cases with initial WBC count no less than 10×10(9)/L (P<0.05, P<0.01). The OS of 10 cases with CR1 was longer than OS of those cases without CR1 (P<0.01).

CONCLUSIONThe incidence of trisomy 8 in M5 is higher than the other AML subtypes, and the prognosis of M5 is poor. The initial WBC count above 10×10(9)/L is a high-risk factor. M3 with trisomy 8 and RARA gene has a very good prognosis. Trisomy 8 may increase the risk of primary AML except for M3, so allo-HSCT with HLA-matched sibling donor should be carried out as much as possible after CR1. The gene mutation of FLT3, MLL, HOX11, C-kit, NPM1 may possess an important significance on prognosis.