Tyrosine kinase inhibitors (TKI) have completely changed the outcome of chronic myeloid leukemia (CML) patients from an incurable disease to a chronic disease. The occurrence of a second malignancy (SM) in CML patients may significantly affect their prognosis. We aimed to study the incidence of second malignancies among our CML patients compared to the general population and their outcome.
The hospital records of CML patients diagnosed between 2003 and 2012 were retrospectively analyzed for the occurrence of second malignancies, incidence in comaprison to the general population, time to occurrence of SM after diagnosis of CML and survival compared to other CML patients.
A total of 1568 patients with CML were treated at our center between 2003 and 2012. SM was detected in 11 (0.7%) patients on TKI therapy. The median intervals from the diagnosis of CML and from the start of TKI therapy to the diagnosis of SM were 16 months (range 5 - 146) and 14 months (range 1 - 97) respectively. The second malignancies diagnosed were three cases of carcinoma tongue and one each of squamous cell carcinoma esophagus, prostatic adenocarcinoma, carcinoma rectum, carcinoma cervix, carcinoma stomach, carcinoma anus, renal cell carcinoma and Hodgkin lymphoma. The age-standardized incidence rate of all malignancies in India was 94 / 100,000 as per GLOBOCAN 2012 while the incidence rate of SM in CML patients from our center treated with TKI was 700/ 100,000. The observed to expected ratio of malignancies in the CML patients was 3.8, p < 0.0001. The median overall survival (OS) of patients who developed SM (53 months) was shorter than the OS of those who did not have SM (median OS not reached, log rank test p < 0.0001.
The incidence of SM in CML patients is higher compared to that of the general population. Prospective population-based studies in CML patients are needed to determine if SM in CML patients is inherently related to the disease or its therapy.
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All authors have declared no conflicts of interest.