High pre-treatment neutrophil-to-lymphocyte ratio in patients with dermatomyositis/polymyositis predicts an increased risk of cancer.

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.