Early progression of disease predicts shorter survival in MALT lymphoma patients receiving systemic treatment.

Abstract

Early progression of disease, within 2 years of diagnosis, is linked with poor overall survival in follicular lymphoma but its prognostic role in extranodal marginal zone B-cell lymphoma is less clear. We sought to identify prognostic factors associated with early progression of disease and to determine whether early progression is associated with inferior overall survival. We analyzed the impact of early progression of disease using the dataset of the International Extranodal Lymphoma Study Group-19 (IELSG-19) clinical trial (training set of 401 patients randomly assigned to chlorambucil or rituximab or chlorambucil plus rituximab). Reproducibility was examined in a validation set of 287 patients who received systemic treatment. We excluded from the analysis patients in both sets who, within 24 months of starting treatment, died without progression or were lost to follow-up without prior progression. Overall survival was calculated from progression in patients with early disease progression and from 24 months after the start of treatment in those whose disease did not progress early (reference group). Early disease progression occurred in 69 of the 384 (18%) evaluable patients of the IELSG-19 study. Patients with a high-risk Mucosa-Associated Lymphoid Tissue - International Prognostic Index score were more likely to have early disease progression (P=0.006). The 10-year overall survival rate was 64% in the group with early disease progression and 85% in the reference group (hazard ratio = 2.42; 95% confidence interval: 1.35-4.34; log-rank P=0.002). This prognostic impact was confirmed in the validation set, in which early progression was observed in 64 out of 224 (29%) evaluable patients with 10-year overall survival rates of 48% in the group with early disease progression and 71% in the reference group (hazard ratio = 2.15; 95% confidence interval: 1.19-3.90; log-rank P=0.009). In patients with extranodal marginal zone B-cell lymphoma who received front-line systemic treatment, early disease progression is associated with poorer survival and may represent a useful endpoint in future prospective clinical trials.