Background and objective: T-cell acute lymphoblastic leukemia (ALL) includes 4 immunological subtypes: pro-T, pre-T, thymic or cortical and mature. In some studies, pro-T and mature subtypes have a poor prognosis. The objective of this study was to describe the clinical characteristics, the result of treatment and the prognosis of the immunological subtypes of T-cell ALL in 81 adult patients included in 2 protocols of the Spanish PETHEMA group (ALL-96 and ALL-93).
Patients and method: Between 1993 and 2003, 81 adult patients from 22 Spanish hospitals were included in two PETHEMA protocols: ALL-96 for standard-risk patients, and ALL-93 for high- risk patients. The main clinical and biological parameters as well as the rate of response to treatment, the frequency of complete remission , disease free survival and overall survival were compared in each T-cell ALL subtype.
Results: Of the 64 evaluable patients the distribution of the immunological subtypes was: 3 pro-T, 17 pre-T, 22 thymic or cortical and 22 mature. Patients with mature T-ALL had higher frequency of central nervous system involvement and myeloid antigen expression than those of the remaining subgroups. Patients with mature T-cell ALL had a slow rate of response to treatment in comparison with patients wit pre-T and mature T-cell ALL but this did not translate to significant differences in frequency of complete remission (77% vs 94%), disease free survival (42% vs 46%) and overall survival (29% vs 47%).
Conclusions: Although patients with mature T-cell ALL had a slow rate of response to treatment and their survival tended to be shorter, in the present study there were no statistically significant differences in the prognosis of the different subtypes of T-cell ALL.