8049 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.
PF486 THE IMPACT OF PRIOR MALIGNANCIES ON THE DEVELOPMENT OF SECOND MALIGNANCIES AND SURVIVAL IN PATIENTS WITH FOLLICULAR LYMPHOMA: A NATIONWIDE POPULATION-BASED STUDY IN THE NETHERLANDS
