Risk of secondary haematological malignancies in patients with follicular lymphoma: an analysis of 1028 patients treated in the rituximab era.

Follicular lymphoma (FL) is the most common indolent lymphoma. Currently there are many comparable treatment options available for FL. When selecting the most optimal therapy it is important to consider possible late effects of the treatment as well as survival. Secondary haematological malignancy (SHM) is a severe late effect of treatments, but the incidence of SHMs is still largely unknown. The goal of the present study was to determine the incidence of SHMs and how therapeutic decisions interfere with this risk. The study included 1028 FL patients with a median follow-up time of 5 center dot 6 years. The 5-year risk of SHM was 1 center dot 1% and the risk was associated with multiple lines of treatment (P = 0 center dot 016). The 5-year risk of SHM was 0 center dot 5% after the first-line treatment and 1 center dot 6% after the second-line. The standardized incidence ratio (SIR) was 6 center dot 2 (95% confidence interval 3 center dot 4-10 center dot 5) for SHM overall. This retrospective study found that the risk of SHM was low after first-line treatment in FL patients from the rituximab era. However, the risk of SHM increases with multiple lines of treatment. Therapeutic approaches should aim to achieve as long a remission as possible with first-line treatment, thereby postponing the added risk of SHM.