Purpose: To report five cases of acute monocytic or myelomonocytic leukemia after chemotherapy with 4-epidoxorubicin for breast cancer and to evaluate the risk of leukemia after the use of this drug.
Patients and methods: One hundred fifty-seven patients with advanced breast cancer were randomized to either 4-epi-doxorubicin plus cisplatin or 4-epi-doxorubicin alone. An additional 203 patients were treated prospectively with 4-epi-doxorubicin alone. All were observed closely for leukemic complications.
Results: Three patients from the randomized study developed leukemia; all were in the subgroup of 74 patients who received 4-epi-doxorubicin plus cisplatin, whereas no leukemia was observed among the remaining 83 patients in the randomized study or among the additional 203 patients who were treated prospectively with 4-epi-doxorubicin alone (P = .023, log-rank test). In the subgroup of 74 patients who were treated with 4-epi-doxorubicin plus cisplatin, the cumulative risk of leukemia was 16.0% +/- 9.9% (mean +/- SE) 33 months after the start of therapy; the relative risk was 668 (95% confidence interval [Cl], 138 to 1,953). Two other cases of acute monocytic and myelomonocytic leukemia were observed after 4-epi-doxorubicin plus alkylating agents were administered for breast cancer. Three of five cases of leukemia presented balanced translocations to chromosome band 11q23 and two, loss of a whole chromosome no. 7 or its long arm.
Conclusions: 4-epi-doxorubicin is leukemogenic, and the leukemias are often acute monocytic or myelomonocytic with balanced chromosome translocations to band 11q23, such as in the leukemias after therapy with the epipodophyllotoxins. Furthermore, our results suggest a synergistic effect in leukemogenesis between 4-epi-doxorubicin targeting DNA-topoisomerase II and directly genotoxic drugs such as cisplatin or alkylating agents.