Clinicopathological prognostic indicators in 107 patients with diffuse large B‐cell lymphoma transformed from follicular lymphoma

Follicular lymphoma ( FL ) frequently transforms into diffuse large B‐cell lymphoma ( DLBCL ). To clarify the associated clinicopathological prognostic parameters, we examined the correlation of 11 histopathological parameters with progression‐free survival ( PFS ) and overall survival ( OS ) in 107 consecutive patients who had DLBCL with pre‐existing (asynchronous) or synchronous FL . The patients comprised 58 men and 49 women with a median age of 56 years. For DLBCL , the complete response rate was 81%, overall response rate was 88%, and 5‐year PFS and OS rates were 55% and 79%, respectively. Immunohistochemical analysis of the DLBCL component revealed the following positivity rates: CD 10, 64%; Bcl‐2, 83%; Bcl‐6, 88%; MUM1 , 42%; GCB , 82%; cM yc index ≥80%, 17%; and Ki‐67 index ≥90%, 19%. IGH/BCL2 fusion was positive in 57% of DLBCL cases. In univariate analyses, asynchronous FL and DLBCL (24%, P  = 0.021), 100% proportion of DLBCL (29%, P  = 0.004), Bcl‐2 positivity ( P  = 0.04), and high Ki‐67 index ( P  = 0.003) were significantly correlated with shorter PFS . Asynchronous FL and DLBCL ( P  = 0.003), 100% proportion of DLBCL ( P  = 0.001), and high Ki‐67 index ( P  = 0.004) were significantly correlated with shorter OS . In a multivariate analysis, asynchronous FL and DLBCL ( P  = 0.035) and 100% proportion of DLBCL ( P  = 0.016) were significantly correlated with shorter OS . Thus, asynchronism and 100% proportion of DLBCL , that is, FL relapsed as pure DLBCL , or FL and DLBCL at different sites, were significant predictors of unfavorable outcome of patients with DLBCL transformed from FL .