Subclassification of diffuse large B-cell lymphomas according to the REAL classification: Distinction of immunoblastic and non-immunoblastic subtypes / 대한내과학회지

BACKGROUND: Diffuse large B-cell lymphoma (DLBL) category in the REAL classification includes histologically heterogeneous subtypes in Working Formulation or Kiel classification. Some investigators insist that the prognosis of B-cell immunoblastic lymphoma (IBL) is worse than other types of DLBL. This study was performed to determine the clinical significance of histological subclassification of DLBL. METHODS: All non-Hodgkin's lymphomas diagnosed at 3 hospitals in Korea between 1989 and 1995 were reclassified according to the REAL classification. Medical records of 404 patients with DLBL were reviewed. Their pathologies were categorized into IBL or non-IBL according to Working Formulation. We compared clinical characteristics and treatment outcomes of IBL with those of non-IBL. RESULTS: Of 404 DLBL patients, 341 cases (84%) were classified as non-IBL and 63 cases (16%) as IBL. Male patients were more common in IBL than in non-IBL (76% vs. 62%). IBL presented more often with advanced stage (III or IV) and B-symptoms than non-IBL (57% vs. 42%, 40% vs. 27%, respectively). In other clinical characteristics, no significant differences were found between the two groups. Complete response rates were 59% in IBL and 68% in non-IBL (p=0.137). With a median follow-up of 52 months (range 1-108 months), the median progression-free survival was 11 (95% confidence interval [95% CI] 8-14) months for IBL and 41 (95% CI 18-64) months for non-IBL (p=0.004). The median overall survival was 21 (95% CI 13-29) months for IBL and 72 months for non-IBL (p=0.002). A multivariate analysis for progression-free survival and overall survival showed that histological subtype (non-IBL vs. IBL) was a significant prognostic factor independent of International Prognostic Index (p=0.013 for progression-free survival, p=0.003 for overall survival). CONCLSUION: DLBL includes heterogeneous subtypes with different prognosis. Subclassification of DLBL into IBL and non-IBL has prognostic significance. IBL needs to be separated from other types of DLBL.

Clinicopathologic Charcteristics of Korean Non - Hodgkin's Lymphomas Based on REAL Classification / 대한암학회지

PURPOSE: Non-Hodgkins lymphoma (NHL) is recognized as not a single disease but a group of diseases heterogeneous in biology and clinical characteristics. Recently, a new pathologic classification system, the REAL classification, has been introduced into the clinic. Although REAL classification has tried to define the subtypes biologically more correctly, its clinical usefulness has not been established yet. A retrospective study was performed to define the clinical characteristics of Korean NHLs according to the REAL classification and to determine its clinical usefulness. MATERIALS AND METHODS: Pathologies of NHLs managed at 3 major hospitals in Korea between 1989 and 1995 were reviewed with immunophenotyping to determine the pathologic subtypes according to REAL classification. Clinical characteristics at the presentation and treatment outcomes of the eligible patients were analyzed. To determine the differences from the NHLs in the western countries, data of Non-Hodgkins Lymphoma Classification Project (NHLCP) were also compared. RESULTS: Total 802 cases were eligible for this study. Although it was similar to NHLCP study that B-cell subtypes were the majority and diffuse large B-cell lymphoma was the most common subtype, the proportion of T-cell subtypes were much higher in our patient population than in the western population. It was because peripheral T-cell lymphomas, angiocentric lymphoma in particular, were more common and follicular lymphomas were less common in our patients. Eleven common pathologic subtypes could be classified into 3 prognostic groups. Marginal zone B-cell lymphoma and lymphoplasmacytoid lymphoma of which 5-year overall survival rate (5-yOSR) were > 80% were classified in the good prognostic group. Precursor T-lymphoblastic lymphoma was classified in the poor prognostic group because its 5-yOSR was less than 30%. The other 9 subtypes were classified in the intermediate prognostic group with S-yOSR of 30-79%. CONCLUSION: The clinical. character' tics and prognoses of Korean NHLs could be defined according to REAL classification. These information would be helpful for the clinicians in formulating treatment strategies of Korean NHLs according to REAL classification.