Therapy related leukemia is most commonly acute myeloid leukemia.
Therapy related leukemia this is complication of treatment that can develop months to years or even decades after exposure to cytotoxic agents or radiotherapy or both.
Therapy related leukemia accounts for 10-20% of acute myelogenous leukemia cases.
Risk of AML 0.25-1.0% per year beginning 2 years after the start of chemotherapy and lasts 5-7 years after its cessation.
Induced leukemia-the risk is dose dependent and increases exponentially with age after the age of 40 years.
Induced leukemia-differences in the ages of patients and differences in the accumulative doses of alkylating agents explain the wide variations in risk from study to study.
Certain alkylating agents like melphalan, platinum compounds, and topoisomerase II inhibitors like etoposide reported to confer a five fold increase risks for therapy related myelodysplasia or AML.
Several chemotherapy agents that include alkylating agents, topoisomerase inhibitors, and tax anew are associated with the development of acute myelogenous leukemia and myelodysplastic syndrome.
Alkylating agents and topoisomerase II inhibitors induce therapy related leukemia.
Chromosome changes of the same type in primary AML occur in most cases os of chemotherapy-induced myelodysplasia and AML.
Deletions in chromosomes 5q or 7q are characteristic of myelodysplasia and AML that occur with alkylating agents.
Chromosomal changes in AML related to topoisomerase II inhibitors are rearrangement abnormalities without gain or loss of chromosomal material.
Alkylating agents or radiation related and topoisomerase II inhibitor related acute myelogenous leukemia are often related to deletions of monosomies of chromosomes 5 and 7 amd a relatively long latency of 4-6 years.
Related to alkylating agents typically develop 5-7 years after initial cancer treatment.
Frequently associated with myelodysplastic syndromes and have poor prognoses.
Associated with topoisomerase II agents usually not associated with myelodysplastic syndrome and frequently associated with 11q23 cytogenetic abnormality.
Studies show that patients with breast cancer 0.5% develop AML/Myelodysplastic syndrome after treatment with doxorubicin and cyclophosphamide.
The risk of secondary leukemia is associated with the type of cytotoxic agents, cumulative dose, intensity of such agents and cumulative ionizing radiation doses.