Background: The revised World Health Organization (WHO) classification maintains a histological grading system (grades 1-3) for follicular lymphoma (FL) and subdivides grade 3 into 3A (FL3A) and 3B (FL3B) subtypes. Optimal therapy of FL grade 3 and its potential curability with anthracycline-based chemotherapy remain uncertain.
Patients and methods: We carried out a retrospective population-based analysis evaluating the clinical characteristics and outcome of FL3A and FL3B as strictly defined by WHO diagnostic criteria. Using the BC Cancer Agency Lymphoid Cancer Database, 161 patients with FL grade 3 were identified and, following detailed pathology review, composed of 139 with FL3A and 22 with FL3B.
Results: Patients with FL3B had a higher overall International Prognostic Index (IPI) score than FL3A patients (P = 0.03), though no significant difference in individual IPI risk factor frequencies was noted. More patients with FL3B received front-line anthracycline-containing chemotherapy (82% versus 36%, P ≤ 0.001). With median follow-up of 45 months, no difference in disease-specific survival (P = 0.74) or overall survival (OS) (P = 0.87) was found between FL3A and FL3B and no survival curve plateau was observed. Analysis limited to FL3A patients showed no OS advantage with front-line anthracycline use (P = 0.33).
Conclusion: Using strict diagnostic criteria, there appears to be no difference in outcome between patients with FL3A and FL3B and no evidence of curability with anthracycline-based therapy.