Increased risk of second malignancies in chronic lymphocytic leukaemia patients as compared with follicular lymphoma patients: a Canadian population-based study.

BACKGROUND: Chronic lymphocytic leukaemia (CLL) patients have an increased risk of other malignancies. This may be due to surveillance bias, treatment or immunosuppression. METHODS: Cohort study of 612 consecutively diagnosed CLL patients in a Canadian province, with comparisons to follicular lymphoma (FL) patients. RESULTS: Treated CLL patients had a 1.7-fold increased risk of second cancers compared with untreated CLL patients. As compared with untreated FL patients, untreated CLL patients had a two-fold increased incidence of second malignancies. CONCLUSION: Chronic lymphocytic leukaemia patients have an inherent predisposition to second cancers and the incidence is further increased by treatment.