Factors influencing outcome in advanced stage, low-grade follicular lymphoma treated at MD Anderson Cancer Center in the rituximab era

Background: The optimal initial therapy of follicular lymphoma (FL) remains unclear. The aims of this study were to compare primary treatment strategies and assess the impact of maintenance rituximab and patterns of treatment failure.

Patients and methods: We retrospectively analyzed patients with treatment-naive advanced stage, grade 1-2 FL treated at our center from 2004 to 2014. We included 356 patients treated on clinical trials or standard of care with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP, n = 119); R-CHOP with maintenance (R-CHOP + M, n = 65); bendamustine/rituximab (BR, n = 45); BR with maintenance (BR + M, n = 35); R(2) (n = 94). We compared baseline characteristics, progression-free survival (PFS), overall survival (OS) and analyzed prognostic factors using univariate and multivariate analysis adjusted for treatment.

Results: After a median follow-up of 4 years (range 0.2-15.0), the 3-year PFS was 60% [95% confidence interval (CI) 51% to 69%] for R-CHOP, 72% (59% to 82%) for R-CHOP + M, 63% (42% to 78%) for BR, 97% (80% to 100%) for BR + M and 87% (78% to 93%) for R(2). Patients treated with R-chemotherapy had more high-risk features than patients treated with R(2) but, by adjusted multivariate analysis, treatment with R(2) [hazard ratio (HR) 0.39 (0.17-0.89), P = 0.02] was associated with a superior PFS. Eastern Cooperative Oncology Group Performance status of one or more predicted inferior OS. Among patients treated with R-chemotherapy, maintenance was associated with the superior PFS [HR 0.38 (95% CI 0.21-0.68)]. By adjusted multivariate analysis, disease progression within 2 years [HR 5.1 (95% CI 1.57-16.83)] and histologic transformation (HT) [HR 11.05 (95% CI 2.84-42.93)] increased risk of death.

Conclusion: Induction therapy with R(2) may result in disease control which is comparable with R-chemotherapy. Early disease progression and HT are predictive of inferior survival.