Prognostic Impact Of Peripheral Blood Flow Cytometry At Staging In Patients With Aggressive Peripheral T Cell Lymphoma

Peripheral T-Cell Lymphomas (PTCL) are a rare subgroup of lymphomas, comprising approximately 10-15% of all non-Hodgkin’s lymphomas. Traditional prognostic measures rely heavily on disease stage, and with the advent of targeted treatment, further stratification criteria is necessary to guide treatment. Peripheral blood analysis by flow cytometry is readily available and has not been extensively investigated as a prognostic tool, and the impact from burden of blood involvement has not been assessed. Here we present a single center retrospective analysis of the prognostic impact of flow cytometry obtained at diagnosis in 102 patients with aggressive T cell lymphomas. Positive flow cytometry (n=44) was determined by the presence of atypical populations of T-cells based on multiparameter flow cytometry. A positive flow cytometry was highly correlated with bone marrow involvement (78.8% vs 21.2%, p= 0.007). The patients with a negative flow cytometry had a significantly longer median PFS compared to those with a positive flow (15.8 months versus 6.2 months, p=0.007). When stratified by the percent of abnormal cells (negative flow grouped with less than 10% atypical cells) overall survival was significantly longer (p=0.008) for the negative group. We conclude that positive flow cytometry may be a surrogate for bone marrow involvement and may be used as a novel prognostic factor in PTCL