Real world data on histological transformation in patients with follicular lymphoma: incidence, clinico-pathological risk factors and outcome in a nationwide Danish cohort

Abstract

We investigated incidence, risk factors and outcome for follicular lymphoma (FL) patients with histologic transformation (HT) found at primary diagnosis (discordant/composite, dc-tFL) or sequentially (s-tFL). Between 2000 and 2015, 2773 patients were identified. The majority of patients (2252, 81%) did not experience HT (nt-FL), while 224 (8%) had dc-tFL and 297 (11%) s-tFL. The risk of HT was 2.2% per year and 9.6% at 5 years. Age ≥60, a high FLIPI risk score and LDH-elevation were associated with increased risk of HT. Calculated from primary diagnosis and compared with nt-FL, 5-year overall survival (OS) was inferior in both s-tFL and dc-tFL (nt-FL: 82%, s-tFL: 68%, dc-tFL: 68%; p = .001), whereas 5-year progression-free survival (PFS) was worse only in s-tFL (s-tFL: 18%, dc-tFL: 58%, nt-FL: 60%). Calculated from time of HT, s-tFL had inferior outcome compared to dc-tFL for both OS (s-tFL: 47%, dc-tFL: 68%, p = .001) and PFS (s-tFL: 35%, dc-tFL: 58%, p = .001).

Keywords:

• Rituximab era
• follicular lymphoma
• transformation

Acknowledgements

The authors thank all doctors and Hematological departments who have contributed to collection of data to the Danish Lymphoma Registry (LYFO).

Author contributions

C.M., M.L. and F.D.A. were responsible for study conception and design. All authors contributed to the collection and assembly of data. C.M. and T.L.P revised all pathology reports. C.M., M.L. and F.D.A. planned and performed data analysis. All authors interpreted data. C.M., M.L. and F.D.A. drafted the manuscript. All authors took part in revision and final approval of the manuscript.

Disclosure statement

The authors declare no conflicts of interest pertinent to the topic of this manuscript.

Additional information

Funding

This work was supported by Region Midtjyllands Forskningsfond, Aarhus University Research Foundation, donation from Peter and Alice Madsen Foundation, The Merchant Einer Willumsen Memorial Foundation and the Karen Elise Jensen Foundation.