OBJECTIVESTo explore MICM classification and adverse prognostic factors in adolescents with acute lymphoblastic leukemia (ALL).

METHODSThe MICM classification, clinical characteristics of 80 adolescents with ALL admitted to our hospital from January 1998 to December 2002 were retrospectively analyzed. Survival data were estimated by the Kaplan-Meier method and the prognostic factors were analyzed with the COX regression model.

RESULTSIn the 80 patients, B-ALL and T-ALL accounted for 69.12% and 26.47%, respectively. The percentage of Ph(+)ALL was 18.37% (9/49), and that of hyperdiploidy was 4.08%. Patients at diagnosis with high leukocyte counts (> 50 x 10(9)/L) accounted for 27.94%. Among the 78 cases treated with VDP(L) or CODP(L) regimens, 73 (91.03%) obtained CR in 4 weeks. After a median follow-up of 24 months, the estimated 3-year disease-free survival (DFS) rates of patients receiving chemotherapy or allo-HSCT were (32.55 +/- 16.50)% and (69.58 +/- 8.72)%, respectively (P < 0.05). In COX analysis, high initial leukocyte counts (> 50 x 10(9)/L) and Philadelphia chromosome positivity were adverse prognostic factors for long-term survival.

CONCLUSIONSMICM classification has important clinical and prognostic significance in the risk-directed therapy of adolescents with ALL. The adverse prognostic features for these patients were high leukocyte counts, less incidence of chromosome hyperdiploidy and Ph chromosome positivity.