The Prognostic Value of the Neutrophil to Lymphocyte Ratio in 209 Patients with Peripheral T-Cell Lymphoma

Introduction: Peripheral T-cell lymphomas (PTCL) are rare hematologic malignancies with a poor prognosis when treated with current standard therapies. Several factors have been developed to prognosticate survival in PTCL patients; however, more refined, easy to use and reliable prognostic tools are needed. The neutrophil to lymphocyte ratio (NLR) has been reported prognostic in patients with diffuse large B-cell lymphoma (Troppan et al. BJC 2014). We have investigated the prognostic value of the NLR in the overall survival (OS) of patients with untreated PTCL.

Methods: We included patients with a pathological diagnosis of PTCL who were diagnosed and treated at our institution between 2001-2013. We excluded cases with primary cutaneous PTCL, CNS involvement, and patients with >50% incomplete data. IRB approval was obtained prior to research. Pathological samples were reviewed by expert hematopathologists to confirm a diagnosis of PTCL. Pertinent clinicopathological data such as age, sex, performance status, LDH levels, stage, bone marrow involvement, extranodal sites of disease, PTCL subtype, and absolute neutrophil and lymphocyte countswere collected through chart review, and are presented using descriptive statistics. The NLR was calculated by dividing the absolute neutrophil by the lymphocyte count, and dichotomized in NLR>=4 and NLR<4. The Prognostic Index for PTCL (PIT) was estimated using the clinical data above. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test. Multivariate analyses were performed using Cox proportional-hazard regression models.

Results: A total of 209 patients were included in our analysis from which 93 (44.5%) were PTCL, not otherwise specified (NOS), 83 (40%) were adult T-cell leukemia/lymphoma (ATLL), 22 (10.5%) were anaplastic large cell lymphoma (ALCL), 7 (3%) were extranodal NK/T-cell lymphoma (NKTCL), and 4 (2%) angioimmunoblastic T-cell lymphoma (AITL). The median age was 57 years (range 3-87 years) with equal distribution among men (52%) and women (48%). Poor performance status (ECOG >1) was seen in 85 (49%), elevated LDH levels in 116 (64%), >1 extranodal site in 31 (19%), bone marrow involvement in 64 (31%), and advanced stage (stage 3 and 4) in 151 (74%) of patients. Based on the NLR, 91 patients (59%) had NLR<4 and 62 (n=41%) had NLR>=4. Patients with NLR >=4 were more likely men (67% vs. 44%, p=0.005), and tended to present with elevated LDH (73% vs. 47%, p=0.002), advanced stage (87% vs. 61%, p=0.001) but lower bone marrow involvement (19% vs. 37%, p=0.02). There were no differences in age, performance status and number of extranodal sites. NLR>=4 was associated with a worse OS (HR 2.27, 95% CI 1.40-3.69; p=0.001). Specifically, NLR>=4 was associated with a worse OS in patients with non-ATLL PTCL (HR 2.99, 95% CI 1.67-5.37; p<0.001) but not in patients with ATLL (HR 1.16, 0.48-2.81; p=0.75). In the multivariate analysis, NLR>=4 was independently associated with worse OS when adjusting for the PIT score in non-ATLL PTCL patients (HR 2.12, 95% CI 1.06-4.26; p=0.03).

Conclusion: The NLR appears as a novel and easy to use prognostic factor for OS in patients with untreated non-ATLL PTCL, independent of the PIT score. The NLR did not seem to be prognostic in ATLL patients. Our findings support the need for validation of the NLR in larger retrospective or prospective studies in patients with PTCL.