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A prognostic index for chronic- and smoldering-type adult T-cell leukemia-lymphoma

Hiroo Katsuya, Mototsugu Shimokawa, Kenji Ishitsuka, Kazuhiro Kawai, Masahiro Amano, Atae Utsunomiya, Ryosuke Hino, Shuichi Hanada, Tatsuro Jo, Kunihiro Tsukasaki, Yukiyoshi Moriuchi, Eisaburo Sueoka, Shinichiro Yoshida, Hitoshi Suzushima, Masaharu Miyahara, Kiyoshi Yamashita, Tetsuya Eto, Junji Suzumiya and Kazuo Tamura

Key points

  • The soluble interleukin-2 receptor was identified as an only independent prognostic factor for chronic and smoldering ATL in this study.

  • The prognostic index using the values of sIL-2R (iATL-PI) is a promising tool for the risk-adapted therapeutic intervention.

Abstract

Adult T-cell leukemia-lymphoma (ATL) has been divided into 4 clinical subtypes: acute, lymphoma, chronic, and smoldering. The aim of this study is to develop a novel prognostic index (PI) for chronic and smoldering ATL. We conducted a nationwide retrospective survey on ATL patients, and 248 fully eligible individuals were used in this analysis. In the univariate analysis, gender, performance status, log10[soluble interleukin-2 receptor (sIL-2R)], neutrophils count, and lymphadenopathy showed P values less than .05 in training samples. A multivariate analysis was performed on these factors, and only log10(sIL-2R) was identified as an independent prognostic factor in training samples. Using a regression coefficient of this variable, a prognostic model was formulated to identify different levels of risk: indolent ATL-PI (iATL-PI) = 1.51 x log10[sIL-2R(U/ml)]. The values calculated by iATL-PI were divided into 3 groups using a quartile point. In the validation sample, median survival times (MSTs) were 1.6, 5.5 years, and not reached for patients in the high, intermediate, and low risk groups, respectively (P < .0001). To make the scoring system clinically practicable, we simplified iATL-PI according to trichotomizing sIL-2R at 1,000 and 6,000 U/mL using a quartile point. Patients with more than 6,000 U/mL of sIL-2R were categorized into the high risk, less than and equal to 1,000 U/mL into the low risk, and the others into the intermediate risk group, and MSTs were 1.6 years, not reached, and 5.5 years, respectively (P < .0001). iATL-PI has potential as a novel tool for a risk-adapted therapeutic approach.

  • Submitted January 3, 2017.
  • Accepted May 8, 2017.