Department of Dermatology, University Hospital, Tours
Clinical Data Centre, Department of Public Health, EA 1275
Department of Epidemiology, University of Tours, France
Department of Internal Medicine, University Hospital, Tours
Department of Rheumatology, University Hospital, Tours
Department of Neurology, University Hospital, Tours, France
UMR Inserm U1253, University of Tours, Tours, France
Background: Neutrophil-to-lymphocyte ratio (NLR) is increased and associated with overall survival (OS) in inflammatory diseases including dermatomyositis/polymyositis (DM/PM) and many cancers. The risk of cancer is increased with DM/PM especially in adults > 50 years old. Objectives: To determine whether high NLR is associated with an increased risk of cancer and OS in DM/PM patients. Materials and methods: A retrospective monocentric study was performed in a tertiary care referral centre between 2007 and 2018. Data on patient characteristics included pre-treatment NLR, visceral involvement, treatment, autoantibodies, creatine phosphokinase level, occurrence of cancer, and death. The cut-off value of NLR was determined by receiver operating characteristic curve analysis. Factors associated with risk of cancer and death were estimated by Cox proportional-hazards regression analysis. Results: In total, 75 patients had a diagnosis of DM/PM (median age: 60 [Q1-Q3: 41.3-70.2] years and median follow-up: 3.5 [Q1-Q3: 1-5.9] years) and 16 patients had cancer. NLR ≥5.5 was associated with occurrence of cancer based on univariate analysis (HR: 3.6; 95% CI: 1.2-10.6) and multivariate analysis (HR: 3.8; 95% CI: 1.2-12.1) adjusted for age (HR: 5.0; 95% CI: 1.1-22.7), as well as corticosteroid intake (p = 0.35) before initial NLR determination. Conclusions: This is the first study to demonstrate an association between high NLR and risk of cancer in patients with DM/PM. Moreover, analysis was performed with adjustment for potential confounding factors such as corticosteroid intake. High NLR at age ≥ 60 years should prompt investigation for cancer from diagnosis of DM/PM and during follow-up.