Prognostic implications of histologic grade and intensity of Bcl-2 expression in follicular lymphomas undergoing rituximab-containing therapy

SummaryThis study aimed to determine the correlations of 7 histopathologic prognostic indicators of follicular lymphoma (follicular lymphoma grade, CD10 expression, Bcl-2 expression, IGH/BCL2 fusion, diffuse area, fibrosis, and marginal zone differentiation) with progression-free survival, overall survival, and follicular lymphoma histologic grade in 255 follicular lymphoma patients who were treated with rituximab-containing therapy. The complete response, overall response, 6-year progression-free survival, and 6-year overall survival rates were 83%, 96%, 56%, and 97%, respectively. Patients with follicular lymphoma grades 3a and 3b showed 100% 6-year and 10-year overall survival, and progression-free survival did not significantly differ between patients with follicular lymphoma grade 3 and those with follicular lymphoma grades 1 and 2. The absence or presence of Bcl-2 expression and intensity of Bcl-2 expression were not significant prognostic indicators of progression-free survival and overall survival. Likewise, the presence of IGH/BCL2 fusion, diffuse area, fibrosis, and marginal zone differentiation were not significantly correlated with progression-free survival and overall survival. Follicular lymphoma grade 3 was correlated with nodal disease and negative or lower intensity of Bcl-2 expression, but not with age, stage, or IGH/BCL2 status. In the prerituximab era, grade 3 disease was reported to be associated with a poor prognosis; however, the opposite was true for patients treated with rituximab-containing therapy, regardless of their age or disease stage. Bcl-2 expression and marginal zone differentiation were not prognostic indicators in follicular lymphoma patients treated with rituximab-containing therapy.