Introduction. Imatinib mesylate (IM) remains a treatment of choice for chronic myeloid leukemia (CML) showing a remarkable efficacy and providing a perspective for a long disease-free survival. Due to the long-term administration of IM, the questions about the possible impact on the development of secondary malignancies (SM) are raised.
Objective. To investigate the frequency and clinical outcome of secondary malignancies during IM therapy for CML.
Material and Methods. The records of 221 CML patients treated with IM between 2003-2013 in single institution were reviewed. The Chi-squared test was used for statistic analysis.
Results. Secondary malignancies developed in eight out of the 221 patients (3.6%) receiving IM for a median of 61 months (range, 10-137 months). Female/male ratio was 5/3. Two patients were diagnosed with their CML at accelerated phase whereas 6 had chronic phase. The median age at IM initiation was 58 years (range, 31-72 years). Five of these 8 SM patients received IM after other treatments failure: interferon α (n=5), hydroxyurea (n=4) and cytarabine (n=1). Three patients received IM as a frontline therapy. All patients were on IM at 400mg daily at SM occurrence. The therapy for SM included surgery (n=3); chemotherapy only (n=3); and chemotherapy followed by radiotherapy (n=1). One patient did not receive treatment due to disseminated disease. At the time of SM development all patients were in hematologic and cytogenetic remission (CCR) of their CML and all patients continued their IM while receiving treatment for their SM. Among 8 patients with SM, five patients are alive and remain in CCR on IM whereas 3 patients died due to SM. The observed incidence of SM was found to be comparable with that expected in the age-adjusted population (chi-squared=0.4; p=0.52).
Conclusions. The association between IM therapy for CML and SM development has not been found.