Histological transformation (HT) and response to therapy are significantly associated with survival, and HT should be a standard variable in clinical trials for assessing outcomes among patients with follicular lymphoma (FL), according to research published in the British Journal of Haematology.1

For this study, researchers enrolled and tracked 1734 patients with grade 1 to 3A FL to investigate the cumulative incidence of HT (CI-HT), risk factors associated with HT, and the role of treatment and response on survival following transformation (SFT).

Patients received varying first-line therapies, and the High Follicular Lymphoma International Prognostic Index (FLIPI) and Revised International Prognostic index (R-IPI) were used to predict prognosis. Complete response (CR) or uncertain CR (uCR) was observed in 75% of patients, partial response (PR) was observed in 18%, and 6% of patients were refractory, progressed, or died.

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The 10-year overall survival (OS) was 72% (95% CI, 69%-75%). At a median follow-up of 6.2 years, 106 patients developed HT; the median time to transformation was 2.5 years after initial diagnosis.

The CI-HT at 5 years and 10 years were 5% and 8%, respectively. Patients with low-, intermediate-, and high-risk FLIPI assessments had CI-HT of 7%, 9%, and 14%, respectively (P < .001). Non-responsiveness to first-line therapy (hazard ratio [HR], 2.9%; 95% CI, 1.3-6.8) was also associated with HT.

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The 5-year SFT was 26% in the 106 patients that developed HT. Variables significantly associated with SFT were response to HT first-line therapy (HR, 5.3; 95% CI, 2.4-12.0), autologous stem cell transplantation (HR, 3.9; 95% CI, 1.5-10.1), and R-IPI score (HR, 2.2; 95% CI, 1.1-4.2). 


  1. Alonso-Alvarez S, Magnano L, Alcoceba M, et al. Risk of, and survival following, histological transformation in follicular lymphoma in the rituximab era. A retrospective multicentre study by the Spanish GELTAMO group. Brit J Haematol. doi: 10.111/bjh.14831 [Epub ahead of print]