Two hundred fifty-three children with newly diagnosed T-cell acute lymphoblastic leukemia (ALL), who were treated uniformly with modified LSA2L2 therapy, were evaluated using univariate and recursive partition analyses to define clinical or biologic features associated with risk of treatment failure. Overall event-free survival (EFS) at 4 years was 43% (SE = 4%). Factors examined included white blood cell (WBC) level, age, gender, race (black v other), presence of a mediastinal mass, hepatomegaly, splenomegaly, marked lymphadenopathy, hemoglobin level, platelet count, blast cell expression of antigens such as the common acute lymphoblastic leukemia antigen (CALLA, CD10), HLA-DR, and T-cell-associated antigens (CD3, CD4, CD8, CD7, CD5, and THY). Univariate analysis showed that age ≤5 or ≤7 years, WBC level <10, <25, <50 or <100 x 103/μL, and blast cell expression of CD4, CD8, or CALLA were associated with significantly better EFS, while hepatomegaly and splenomegaly were associated with worse EFS. Recursive partitioning analysis showed that the most important single favorable prognostic factor was a WBC level <50 x 103/μL and, for patients with WBC counts below this level, the most important predictor of EFS was blast cell expression of the pan-T antigen defined by the monoclonal antibody (MoAb), L17F12 (CD5). For patients with higher WBC levels, the most important predictor of EFS was blast cell expression of THY antigen. The recursive partitioning analysis defined three groups of patients with widely varied prognoses identified as follows: (1) those with a WBC count <50 x 103/μL who lacked massive splenomegaly and had blasts expressing CD5 had the best prognosis (66%, SE = 7%, EFS 4 years, n = 84); (2) those with (b1) WBC counts <50 x 103/μL with either massive splenomegaly or who had blasts lacking CD5 expression, or (b2) WBC counts >50 x 103/μL with expression of the THY antigen had an intermediate prognosis (39%, SE = 7% EFS at 4 years, n = 94); (3) those with WBC counts >50 x 103/μL and whose blasts lacked expression of THY antigen had the poorest outcome (EFS = 19% at 4 years, SE = 8%, n = 63). A three-way comparison of EFS according to these groupings showed significant differences among the three patient groups (P < .001). The recursive partitioning was able to classify 241 (95%) of the patients. Twelve patients could not be grouped because of missing data. We conclude that this prognostic factor analysis provides information of potential importance for design of randomized clinical trials for children with T-cell ALL (T-ALL), because appropriate stratification depends on results of such analysis to ensure comparability of patient groups. In this study, recursive partitioning analysis provides prognostic insight that was not obtained by the stepwise Cox regression method. However, these results should be considered tentative until confirmed in a prospective clinical trial.
|Original language||English (US)|
|Number of pages||8|
|State||Published - 1990|
ASJC Scopus subject areas
- Cell Biology