Subclassification of diffuse large B-cell lymphomas according to the Kiel classification: distinction of centroblastic and immunoblastic lymphomas is a significant prognostic risk factor.

Abstract

Among high-grade malignant non-Hodgkin's lymphomas the updated Kiel classification identifies three major B-cell entities: centroblastic (CB), B-immunoblastic (B-IB), and B-large cell anaplastic (Ki-1+) (now termed anaplastic large cell [CD30+], [B-ALC]). The clinical prognostic relevance of this distinction was evaluated in a randomized prospective treatment trial (COP-BLAM/IMVP-16 regimen randomly combined +/- radiotherapy in complete responders) conducted in adult (age 15 to 75) patients with Ann Arbor stage II-IV disease (n = 219) diagnosed by optimal histomorphology (Giemsa staining) and by immunohistochemistry. Overall survival was significantly better in CB lymphoma as compared to B-IB (P = .0002) or B-ALC (P = .046). Relapse-free survival was worse for B-IB (P = .0003) as compared to CB lymphomas. The prognostic differences between CB and B-IB were confirmed by multivariate analyses including the risk factors of the International Index. Overall survival was significantly determined by performance status (P = .0003), serum-LDH (P = .036), and B-IB histology subtype (P = .036). Relapse-free survival was influenced by age (P = .007) and histological subtype (P = .007). Thus, the diagnosis of the CB and B-IB lymphomas by the histological criteria of the Kiel classification was identified as an independent prognostic factor in diffuse large B-cell lymphomas.