Chronic lymphocytic leukemia and secondary hematological malignancies: A nation‐wide cancer registry study

OBJECTIVE: Chronic lymphocytic leukemia (CLL) treatment has changed dramatically, and landscape of second hematologic malignancies (SHM) evolves in the new era of targeted therapy. No data were available about the real-world burden of SHM. METHODS: All 2631 patients with CLL in the Cancer registry of Norway registered 2003-2012 were included. RESULTS: After median follow-up of 6.6 years, 103 patients (4%) developed SHM. Diffuse large B-cell lymphoma (DLBCL) was most common (n = 65; 63%). Median survival was 9.3 years (95% CI; 8.9-9.8) in non-SHM patients and 1.7 years in DLBCL, 0.8 years in Hodgkin lymphoma (n = 12), and 2.8 years in myeloid neoplasia (n = 15; 95% CI: 0.3-2.6, 0.6-2.9, and 0.4-5.3, respectively; P < .001). Outcomes were poorest for SHM patients treated for CLL (HR 2.76, 95% CI 1.4-5.5, P = 0.003). A higher proportion of men and younger age were found in SHM patients (median age 66 vs 72 years in non-SHM; P < .001; men 68% vs 57%, P = .03). Myeloid neoplasia was rare (incidence rate 1/1000 person-years; 95% CI: 0.6-1.5) and tended to occur later than DLBCL in patients treated for CLL (median time from CLL to SHM 62 vs 45 months; P = .09). CONCLUSIONS: SHM and especially myeloid malignancies were rare in chemoimmunotherapy era.