Childhood T-cell acute lymphoblastic leukemia: the Dana-Farber Cancer Institute acute lymphoblastic leukemia consortium experience.
OBJECTIVE
T-cell acute lymphoblastic leukemia (T-ALL) accounts for 10% to 15% of newly diagnosed cases of childhood acute lymphoblastic leukemia (ALL). Historically, T-ALL patients have had a worse prognosis than other ALL patients.


METHODS
We reviewed the outcomes of 125 patients with T-ALL treated on Dana-Farber Cancer Institute (DFCI) ALL Consortium trials between 1981 and 1995. Therapy included four- or five-agent remission induction; consolidation therapy with doxorubicin, vincristine, corticosteroid, mercaptopurine, and weekly high-dose asparaginase; and cranial radiation. T-ALL patients were treated the same as high-risk B-progenitor ALL patients. Fifteen patients with T-cell lymphoblastic lymphoma were also treated with the same high-risk regimen between 1981 and 2000.


RESULTS
The 5-year event-free survival (EFS) rate for T-ALL patients was 75% +/- 4%. Fourteen of 15 patients with T-cell lymphoblastic lymphoma were long-term survivors. There was no significant difference in EFS comparing patients with T-ALL and B-progenitor ALL (P =.56), although T-ALL patients had significantly higher rates of induction failure (P <.0001), and central nervous system (CNS) relapse (P =.02). The median time to relapse in T-ALL patients was 1.2 years versus 2.5 years in B-progenitor ALL patients (P =.001). There were no pretreatment characteristics associated with worse prognosis in patients with T-ALL.


CONCLUSIONS
T-ALL patients fared as well as B-progenitor patients on DFCI ALL Consortium protocols. Patients with T-ALL remain at increased risk for induction failure, early relapse, and isolated CNS relapse. Future studies should focus on the identification of and treatment for T-ALL patients at high risk for treatment failure.
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002051:Burkitt Lymphoma / Q000188:drug therapy / Q000473:pathology; D016543:Central Nervous System Neoplasms / Q000473:pathology / Q000556:secondary*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis