Background: The natural history of follicular lymphoma is believed not to have changed over the last 30 years. Median survivals have ranged from 7 to 10 years, and the disease is considered incurable. However, multiple new treatment options have been developed in the last decade, and their impact on survival of follicular lymphoma remains unknown.
Patients and methods: In the current analysis, we identified all previously untreated, advanced-stage, follicular lymphoma patients treated with the following three sequential treatment approaches: cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy +/- nonspecific immunostimulants (Southwest Oncology Group [SWOG] 7426 and 7713: 1974 to 1983); prednisone, methotrexate, doxorubicin, cyclophosphamide, and etoposide (ProMACE) plus mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) +/- interferon (SWOG 8809: 1988 to 1994); and CHOP followed by monoclonal antibody (MoAb) therapy (SWOG 9800 and 9911: 1998 to 2000). We assessed the patients' progression-free survival (PFS) and overall survival (OS). The MoAb trials included CHOP followed by rituximab (SWOG 9800) and CHOP followed by (131)I-tositumomab (SWOG 9911).
Results: The PFS curves for the CHOP and ProMACE-MOPP studies are overlapping, with 4-year PFS estimates of 46% and 48%, respectively. However, the PFS rate of the CHOP + MoAb studies is significantly improved at 61% (P = .005). The OS curves show improvement with each succeeding study. The 4-year estimate of OS is 69% for the CHOP regimens, 79% for the ProMACE-MOPP study, and 91% for the CHOP + MoAb regimens (P < .001). These conclusions were retained after adjusting for differences in prognostic factors between the study groups.
Conclusion: The results of this study suggest that OS for patients with follicular lymphoma has improved over time and that the choice of initial therapy may matter.