The Clinicopathological Profile of Diffuse Large B-cell Lymphoma at Kenyatta National Hospital

Abstract

Background: High grade Lymphoma such as diffuse large cell lymphoma (DLBCL) is a major cause of morbidity and mortality in developing countries. DLBCL is increasingly understood to be a heterogeneous disease with genetic, biologic, and clinical variants that have an important impact on clinical outcomes. There are three subtypes of DLBCL: Germinal Centre B-cell like DLBCL, Activated B-cell like DLBCL and Primary Mediastinal DLBCL. Whereas the association between the various subtypes and outcome is known, there is paucity of local data that examines the clinicopathological profile of DLBCL especially in an HIV endemic region. These data could provide more information on the association between DLBCL subtypes and in-depth understanding of the biology of DLBCL in the HIV setting. Objectives: The aim of this study was to determine the clinicopathological profile of DLBCL classify DLBCL diagnosed at the Kenyatta National Hospital based on the Hans' algorithm and to correlate with the demographic and clinical characteristics of the patients. Study design: This was a descriptive cross-sectional study Study area: Kenyatta National Teaching and referral hospital Materials and methods: Eighty-two patients diagnosed with diffuse large B cell lymphoma were consecutively recruited from among patients with non-Hodgkin’s Lymphomas managed at the Kenyatta National Hospital. The paraffin embedded tissue blocks were retrieved from the archives at the various Pathology laboratories after relevant ethical and administrative approvals. Haematoxylin and eosin slides were prepared and reviewed to confirm the previous diagnosis and to classify the tumors. Immunohistochemical expression for various lymphoma markers were assessed and scored. Findings were correlated with relevant demographic, pathologic and clinical data. Data management and analysis: Data was collected via written paper forms. After verification, data was then entered into a Microsoft Excel worksheet, and thereafter imported into the statistical analysis software for data management and analysis. Continuous data such as age was presented using means and respective standard deviations (SD) while categorical variables such as gender, treatment outcome were presented as percentages. Bivariate comparisons such as comparisons of by Germinal center DLBCL vs. Non-Germinal center DLBCL and Gender (Male vs. Female) was done using chi square or fishers’ exact tests for categorical variables and t-test for continuous variables as appropriate. Univariable Logistic regression analysis to assess for demographic and clinical factors associated with Germinal center DLBCL was done reporting the odds ratios (OR) and 95% Confidence Intervals. Stata version 15.1 (Stata Corp, College Station, Texas) was used for all statistical analyses. All statistical tests were evaluated at the 5% level (p<0.05) for statistical significance. Results: Clinicopathological and immunophenotypic characteristics of 82 patients with diffuse large B‐cell lymphoma (DLBCL) were examined. The mean age was 43.9 years (SD= 13.7) while the Median age was 43 (17-71years). The M: F was 1.4:1. Based on immunophenotyping with anti‐CD10, bcl‐6, and MUM1 antibodies, the cases were categorized as GCB (CD10+ or CD10–, bcl‐6+, MUM1+) or non‐GCB phenotype. Forty-Five (54.9%) of the patients had GCB type while Thirty-Seven (45.1%) were of non-GCB origin. Age and ECOG performance status were the only clinical characteristics significantly associated with cell of origin. Older age was significantly associated with development of GCB subtype of DLBCL OR 1.45(1.03-2.04) p=0.032 and on univariate analysis and OR 1.67(1.07-2.52) P=0.023 on multivariate analysis. Conclusions and recommendation: These results imply that cell of origin determination using immunohistochemistry on paraffin embedded tissue blocks has yielded important information that may predict the outcome of patients with non-Hodgkin B cell lymphomas in KNH. Generally, the patients studied had a poor CR rate (37%). Several factors including lack of timely chemotherapy seem to be responsible for this. Evaluation of prognostic or predictive biomarkers in the management of DLBCL, such as the COO, within prospective clinical trials will be important in the future.