T-cell lymphoblastic lymphoma and T-cell acute lymphoblastic leukemia: a separate entity?
T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) are considered the same disease, differing by the extent of bone marrow infiltration. According to recent gene expression profiling data, T-ALL and T-LBL can be separated by prediction analysis of microarrays showing an overexpression of MML1 in T-LBL and CD47 in T-ALL. Immunophenotypes of T-LBL and T-ALL are identical but differ in frequency, with a higher rate of cortical or mature immunophenotypes in T-LBL, which is probably related to the higher rate (> 90%) of mediastinal tumors. Treatment approaches in T-LBL changed from conventional non-Hodgkin lymphoma (NHL) protocols to intensive NHL protocols but recently to ALL-designed protocols. T-ALL remission rates are 90%, and overall survival (OS) has improved to 60%-70%. Mediastinal tumors resolve in most cases of T-ALL with chemotherapy only, whereas in T-LBL additional mediastinal irradiation seems to be beneficial. Strategies for stem cell transplantation (SCT) in T-LBL and T-ALL differ. Autologous SCT in complete remission (CR) in T-LBL gives a 70% survival rate, which is similar to chemotherapy alone. In T-ALL, the subtypes of early and mature T-ALL have a poor outcome with chemotherapy alone (< 30%) and might profit from an allogeneic transplantation in first CR (OS > 50%). There seems to be no need for transplantation in thymic T-ALL in first CR. Prognostic factors are published for T-ALL but not for T-LBL. MRD may guide further treatment strategies in T-ALL and probably also in T-LBL as indications for a SCT or for the evaluation of novel, particularly T-cell-specific, drugs.
Hoelzer
Dieter
D
Onkologikum Frankfurt, D- 60596 Frankfurt, Germany. hoelzer@em.uni-frankfurt.de
Gökbuget
Nicola
N
D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008482:Mediastinum / Q000473:pathology; D008495:Medical Oncology / Q000379:methods; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology; D011379:Prognosis; D012074:Remission Induction; D013601:T-Lymphocytes / Q000473:pathology