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Transformation of follicular lymphoma in the era of immunochemotherapy: A population-based study from British Columbia.
Lymphoma and Plasma Cell Disorders
Session Type and Session Title:
General Poster Session, Lymphoma and Plasma Cell Disorders
J Clin Oncol 30, 2012 (suppl; abstr 8049)
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Several published series have established that the risk of transformation of follicular lymphoma (FL) to aggressive lymphoma is approximately 3% /year (15%-20% at 5 years). The addition of rituximab (R) to chemotherapy (immuno-chemotherapy) has significantly improved the outcome of patients with FL. The impact of immuno-chemotherapy on the risk of transformation remains unknown. We assessed whether the introduction of immuno-chemotherapy has altered this risk. Methods: We examined the Lymphoid Cancer Database of the British Columbia Cancer Agency for FL patients treated with immuno-chemotherapy. Inclusion criteria: FL grades 1-3A by WHO criteria; only patients requiring treatment at diagnosis were included. Exclusion criteria: FL grade 3B or composite histology (FL and DLBCL) at diagnosis; pts who received anthracycline-based chemotherapy; and HIV positivity. The diagnosis of transformation was confirmed by biopsy when possible (n=19; 79%) but patients who were considered to have transformed based on pre-defined clinical assessment (n=5; 21%) were also included in the analysis. Results: We identified 261 pts with FL grade 1-3A requiring treatment at diagnosis, who received immuno-chemotherapy; median f/u 47 months (0.2-116), median age, 61 y (34-86). Treatment: 243 (93%), R-CVP of which 145 (59%) also received maintenance R; 9 (4%), R-Fludarabine combination. 24 pts developed transformed aggressive lymphoma. The risk of transformation for the entire group was approximately 2% per year or 10% at 5 years. However, pts treated with maintenance R (n=151) had a lower risk of transformation compared to pts who only received R-chemo at induction (n= 110), 8% vs 20% at 5 years respectively, (P= 0.003). The post-transformation outcome remains poor with a median survival of 6 months. Conclusions: We and other groups have demonstrated that the risk of transformation from FL to aggressive lymphoma is approximately 15% to 20% by 5 years. Our study suggests that the introduction of immuno-chemotherapy has reduced this risk to less than 10%. This effect is particularly apparent when patients receive maintenance R. The outcome for patients who develop transformation remains poor.