Prognostic Index for Acute- and Lymphoma-Type Adult T-Cell Leukemia/Lymphoma

Abstract

Purpose: The prognosis of acute- and lymphoma-type adult T-cell leukemia/lymphoma (ATL) is poor, but there is marked diversity in survival outcomes. The aim of this study was to develop a prognostic index (PI) for acute- and lymphoma-type ATL (ATL-PI). Patients and Methods: In a retrospective review, data from 807 patients newly diagnosed with acute- and lymphoma-type ATL between January 2000 and May 2009 were evaluated. We randomly divided subjects into training (n = 404) and validation (n = 403) samples, and developed a PI using a multivariable fractional polynomial model. Results: Median overall survival time (MST) for the 807 patients was 7.7 months. The Ann Arbor stage (I and II v III and IV), performance status (0 to 1 v 2 to 4), and three continuous variables (age, serum albumin, and soluble interleukin-2 receptor [sIL-2R]) were identified as independent prognostic factors in the training sample. Using these variables, a prognostic model was devised to identify different levels of risk. In the validation sample, MSTs were 3.6, 7.3, and 16.2 months for patients at high, intermediate, and low risk, respectively (P < .001; χ² = 89.7, 2 df; log-rank test). We also simplified the original ATL-PI according to dichotomizing age at 70 years, serum albumin at 3.5 g/dL, and sIL-2R at 20,000 U/mL and developed an easily calculable PI with prognostic discrimination power (P < .001; χ² = 74.2, 2 df; log-rank test). Conclusion: The ATL-PI is a promising new tool for identifying patients with acute- and lymphoma-type ATL at different risks.