Lymphopenia Predicts Survival in Peripheral T-Cell Lymphoma, Unspecified.

Abstract 1930

Poster Board I-953

Background: Lymphopenia is an independent prognostic factor for survival for different hematological malignancies like follicular lymphoma, Hodgkin lymphoma and diffuse large B-cell lymphoma. The role of lymphopenia at diagnosis on survival in peripheral T-cell lymphoma, unspecified (PTCLU) is not known. Methods: Eighty seven patients with a diagnosis of PTCLU were evaluated at the Edgardo Rebagliati Martins Hospital in Lima, Peru from October 1997 until April 2008. The primary objective of the study was to assess the role of lymphopenia at diagnosis in survival in cases with PTCLU. Lymphocyte count at diagnosis was obtained from the standard complete blood cell count (CBC). Lymphopenia was defined as a lymphocyte count of less than 1 × 10⁹/L. Kaplan-Meier survival estimates and the log-rank test were performed for univariate survival analyses and Cox proportion-hazard regression test was performed for the multivariate analysis. Results: Eighty four patients with a histological diagnosis of PTCLU were included in this study. The median follow-up was 13.4 months (range 1–68 months). The sample population included 54% males and 46% females with a median age of 57 years (range 18–87 years). The median number of lymphocytes at diagnosis was 1.3 × 10⁹/L (range 0.06–5.2 × 10⁹/L). Lymphopenia was present in 37% of cases. In the univariate analysis, lymphopenia was identified as a poor factor for survival (median OS 59 vs. 1 month; p<0.0001). In the multivariate analysis, lymphopenia was compared to the Prognostic Index for PTCLU (PIT) and it remained as an independent predictor for survival (Hazard Ratio 4.8, 95% confidence intervals 2.2–10.6; p<0.0001). Conclusion: This study demonstrates that lymphopenia is an independent prognostic factor for survival in patients with PTCLU, suggesting that the host immune system might play a preponderant role in survival in this group of patients.