ABCL-242 Definition of Bulky Disease in Early-Stage Diffuse Large B-Cell Lymphoma on Longitudinal and Axial Planes

Abstract

In early-stage diffuse large B-cell lymphoma (DLBCL), tumor bulkiness and stage-adjusted International Prognostic Index (sa-IPI) are the main determinants of treatment and prognosis. Bulky disease is variably defined from 5 to 10 cm. The aim of our study is to investigate the prognostic significance of bulky disease measured on longitudinal and axial planes on computed tomography (CT) imaging. Medical records of patients diagnosed with early-stage DLBCL and treated in King Hussein Cancer Center were reviewed. Maximal longitudinal and axial planes on initial CT scans were reviewed by two radiologists; sa-IPI was calculated as previously described. Correlation between tumor dimensions and relapse-free survival (RFS) and overall survival (OS) was done using the Pearson correlation test. Survival analyses were performed using the Kaplan-Meier method. A total of 127 patients were included with a median age of 47 years. Fifty-one (40.2%) patients were having extranodal involvement, and sa-IPI was 0-1 in 73 (57.4%). Eighty-two (64.6%) patients were treated with combined modality treatment (RCHOP followed by radiotherapy), and the remaining were treated with RCHOP only. A cut-off of 5 cm correlated with RFS in both the longitudinal and axial dimensions and was used to define bulky disease. Seventy-eight (61.5%) patients with bulky disease in either dimension had 3-year RFS of 76.4% versus 95.4% for patients with non-bulky disease (P=0.0045) and 3-year OS of 71.8% versus 93.2% (P=0.0043), respectively. On multivariate analysis, bulky disease (P=0.028) and sa-IPI >1 (P=0.044) were significantly associated with RFS, whereas OS significantly correlated with sa-IPI >1 (P=0.014). In patients with bulky disease, the use of combined modality treatment resulted in better RFS (62.9% vs. 83.3%, P=0.0157) and OS (81.6% vs. 52.1%, P=0.0042). Tumor bulk of more than 5 cm in the longitudinal or axial dimensions on CT scan should be considered in treatment decisions of patients with early-stage DLBCL, including the use of consolidative radiotherapy. More studies are needed to define the best treatment approach in such patients.