CML as Part of Dual Malignancies-A Retrospective Analysis: Possible Mechanisms and Review of Literature

Introduction of imatinib has changed the outlook of chronic myeloid leukaemia (CML) patients with overall survival approaching general population. Long term survival in CML patients has provided an opportunity to better study natural history and long term complications of disease as well as the treatment modalities. To study the occurrence and association of other malignancies with their outcomes in patients with CML. This is a single centre retrospective study. All CML patients case records registered with haematology clinic of a tertiary care centre in North India from 2001 to 2014 were perused and evaluated for dual malignancies. Those patients with dual malignancies were personally examined and interviewed if alive. Out of 1677 patients, 15 cases had co-existent malignancies. Four of fifteen cases of dual malignancies had CML as secondary cancer. Three had synchronous and rest 12 patients had metachronous malignancies. Only one patient was in accelerated phase, rest all were in chronic phase. Median age of the dual malignancy cases was 50 years (25-66 years), much younger than reported in west. The initial dose of imatinib was 400 mg OD in all except one. We did not find any causal association between CML or imatinib therapy with development of secondary tumours. Interestingly in this series, incidence of CML as secondary or synchronous malignancy was higher than earlier published studies.