T-cell acute lymphoblastic leukemia (T-ALL)

Rare but very aggressive, comprising 1-2% of all non-Hodgkin’s lymphomas.

Accounts for <2000 new diagnoses per year in  both adults and children.

More common in children than adults with most presentations in the teenage years.

Tends to affect older children, adolescents and young adults.

3:1 male predominance.

Disproportionately affects black children.

Patients classically present with the mediastinal mass, nonspecific symptoms, and evidence of local invasion, such as tracheobronchial and superior vena cava obstruction.

A malignancy of thymic T-cell progenitors before they become effector T cells.

30-40% of cases have a normal and 15-20% of cases have a failed type of karyotype.

Patients with a mediastinal mass and a bone marrow biopsy specimen made up of less than 25% malignant lymphoblastic meet the criteria for a diagnosis of acute lymphoblastic lymphoma, while patient with a biopsy containing more than 25% malignant lymphoblasts are diagnosed with acute lymphoblastic leukemia.

NOTCH-1 mutations occur in about half of patients with T-cell ALL.

Prognostic value of genetic abnormalities in T-cell ALL less clear then for a B-cell disease.

Overexpression of intracellular Notch-1 in lymphocyte precursors has a significant role in pathogenesis.

Prognosis better for children than adults.

Cure rate for children and young adults is 75% or better.

Patients respond better to leukemia regimens than they do to lymphoma regimens.

T-cell acute lymphoblastic lymphoma and leukemia are indistinguishable as both carry specific CD3 or CD7with TdT coexpression.

Patients with T-cell acute  lymphoblastic lymphoma respond better to leukemia regimens then they do to lymphoma regimens.

Current intensified acute lymphoblastic leukemia type regimens provide a complete response rate of more than 90% and overall survival rate of more than 70%.

The total duration of therapy for T-ALL is 2 1/2 to 3 1/2 years starting with 6 to 8 months of chemotherapy.

Initial therapy is most intensive and given primarily as an outpatient.

The only marker of the disease is independently prognostic and is the response to therapy.

Patients with residual disease 52 to 3 months of treatment have a significantly lower chance of being cured.

After the initial intensive chemotherapy, low intensity maintenance therapy continues.

Over the course of treatment patients are treated with more than 10 different medications.

The cure rate for T-ALL is approximately 85 to 90%.

Lymphoma regimens produce a complete response rate of 55-79% of patients, and an overall survival rates are 30-50%.

Leave a Reply

Your email address will not be published. Required fields are marked *