RESUMO
BACKGROUND: Therapy-related leukemia is a term that describes the occurrence of leukemia following exposure to hematotoxins and radiation to emphasize the difference from leukemia that arises de novo. Many agents and host factors contribute to this entity of leukemias. Therapy-related acute myeloid leukemia has an extensive literature review in contrast to therapy-related chronic myeloid leukemia (t-CML). Radioactive iodine (RAI), an established agent in the management of differentiated thyroid carcinomas, has raised concern due to its possible carcinogenic effects. SUMMARY: In this article, we reviewed all the reports from the 1960s to date related to t-CML following RAI on Google Scholar and PubMed. We have identified 14 reports and found that most reports were for men under the age of 60 years with primary papillary thyroid carcinoma and mixed follicular-papillary thyroid carcinoma who developed t-CML mainly between 4 and 7 years after exposure to varying doses of I131. However, the mean dose was 287.78 millicuries (mCi). It was reported that a statistically significant increase in leukemia following RAI therapy (relative risk of 2.5 for I131 vs. no I131). Also, there was a linear relationship between the cumulative dose of I131 and the risk of leukemia. Doses higher than 100 mCi were associated with a greater risk of developing secondary leukemia, and most of the leukemias developed within the initial 10 years of exposure. The precise mechanism through which RAI provokes leukemia is largely unclear. A few mechanisms have been proposed. KEY MESSAGES: Although the risk for t-CML appears to be low based on current reports and does not represent a contraindication to RAI therapy, it should not be disregarded. We suggest including it in the risk-benefit discussion before initiating this therapy. Long-term follow-up for patients is advisable for those who received doses over 100 mCi with a complete blood count, possibly yearly, for the first 10 years. The new onset of significant leukocytosis post RAI exposure should raise the suspicion for t-CML. Further studies are needed to establish or refute a causal relationship.
Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva , Neoplasias da Glândula Tireoide , Masculino , Humanos , Pessoa de Meia-Idade , Neoplasias da Glândula Tireoide/etiologia , Neoplasias da Glândula Tireoide/radioterapia , Radioisótopos do Iodo/efeitos adversos , Câncer Papilífero da Tireoide/induzido quimicamente , Câncer Papilífero da Tireoide/complicações , Câncer Papilífero da Tireoide/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/etiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/radioterapia , Medição de RiscoRESUMO
Chronic myeloid leukemia (CML) is a myeloproliferative disorder diagnosed by demonstrating the Philadelphia chromosome (Ph) or the BCR-ABL fusion gene. Tyrosine kinase inhibitors (TKIs) are the standard of therapy. There are increasing reports of hepatitis B virus reactivation (HBVr) in patients on this treatment. We report a case of a 46-year-old male patient diagnosed to have CML in the chronic phase and resolved hepatitis B infection. He was treated with imatinib as upfront therapy for CML and with lamivudine as prophylaxis against HBVr. The patient tolerated both treatments well with no adverse effects. The aim is to address the deficiencies in the literature in regard to managing these patients, prevention, and follow-up.