Acute Leukemias - Republican Scientific Medical Library

Treatment of Lymphoblastic Lymphoma in Adults
Nicola Gökbuget, Dieter Hoelzer
Contents
16.1 Introduction ................... 203
16.2 Immunophenotype .............. 204
16.3 Clinical Features ................ 204
16.4 Therapeutic Approaches .......... 204
16.4.1 Chemotherapy Regimens
Designed for NHL ........... 204
16.4.2 Chemotherapy Regimens
Designed for ALL ........... 204
16.4.2.1 MDACC ............ 207
16.4.2.2 GMALL ............ 207
16.4.3 Summary ................. 207
16.5 CNS Prophylaxis ................ 207
16.6 Mediastinal Tumors ............. 207
16.6.1 Prognostic Impact of Residual
Mediastinal Tumors .......... 208
16.6.2 Diagnostic Procedures ........ 208
16.6.3 Mediastinal Irradiation ........ 208
16.7 Prognostic Factors .............. 209
16.8 Results of Stem Cell Transplantation
in LBL ........................ 209
16.8.1 Autologous SCT ............ 209
16.8.2 Allogeneic SCT ............. 209
16.8.3 Auto Versus Allo SCT ......... 210
16.8.4 Auto SCT Versus Chemotherapy . 210
16.8.5 Summary ................. 211
16.9 Outcome of Salvage Therapy ...... 211
16.10 Summary and Future Prospects .... 211
References ......................... 212
16.1 Introduction
Lymphoblastic lymphoma (LBL) is a rare entity of non-
Hodgkin’s lymphoma (NHL) with an incidence of less
than 2% (1.7% for T- and less than 1% for B-lymphoblastic
lymphoma) within all NHL [1]. In the USA, the
population-based incidence was 0.2/100 000 in males
and 0.1/100 000 in females between 1978 and 1995. The
age distribution is bimodal with higher rates in individuals
younger than 20 and in those older than 50 years
[2]. LBL represents a distinctive lymphoma entity with
cytological and histological features similar to those of
acute lymphoblastic leukemia (ALL). LBL and ALL are
generally separated by an arbitrary cut-point of 25%
bone marrow (BM) infiltration. Patients with BM infiltration
below 25% are considered as LBL. In the new
WHO classification of lymphatic neoplasia both are
summarized as B- or T-precursor lymphoblastic leukemia/lymphoma
[3].
Despite the generally accepted viewpoint that ALL
and LBL represent different manifestations of the same
disease, a recent gene expression analysis showed that a
clear segregation of T-ALL and T-LBL based on differentially
expressed genes is possible. Thus the study
demonstrated an overexpression of the MLL-1 gene in
T-LBL and of CD47 in T-ALL. Furthermore, adhesion
molecules and extracellular matrix proteins were upregulated
in T-LBL. Some of the latter differences may
be due to mechanisms in stroma cells. However, there
is also evidence that important growth regulatory pathways
may be different in T-ALL and T-LBL, which may
partly explain the different clinical presentation of both
diseases [4].