MA20.06 Neutrophil to Lymphocyte Ratio Is an Independent Prognostic Predictor in Thymoma

Abstract

Thymoma is the most common primary neoplasm of the anterior mediastinum in adults and conventional prognostic factors include Masaoka Stage, WHO histology and completeness of resection. Little is known of preoperative peripheral neutrophil-to-lymphocyte ratio (NLR) as an independent additional discriminator of prognosis. We performed an international multicentre retrospective cohort study (UK Health Research Reference 19/HRA/0440 and EU internal approval reference xxxxxx). We included patients who underwent complete resection for thymoma and data was acquired through patient medical records with follow up data obtained through national database and hospital records. NLR calculated on pre-operation bloods results. From July 1987 to December 2017, 433 patients underwent surgery for thymoma. The majority were male 228(53%) with a mean age (SD) of 55(15) years. The surgical approach was sternotomy in 335 patients (77%), thoracotomy in 23(5%) and VATS in 75(17%). The WHO classification was type A 63(15%), AB 126(29%), B1 98(23%), B2 55(13%) and B3 86(20%) patients. The Masaoka-Koga stage was I in 135(33%) II in 194(47%), III in 54 (13%) and IV in 31(7%) patients. Median (IQR) follow-up time was 86 (30 to 152) months with a 5 and 10-year survival of 88% and 79% respectively. The median NLR was 2.1 (1.5 to 3.1), when split into three groups (NLR < 1.4, NLR between 1.4 and 2.3 and NLR > 2.3), higher NLR was associated with poorer survival (log rank P<0.001) that persisted on Cox regression after adjustment for WHO grade and Masaoka stage with a HR of 1.69 (95% CI 1.20 to 2.39; P=0.002). Pre-operative NLR is a simple, low cost biomarker that can stratify risk of death independent to WHO grade and Masaoka stage in patients undergoing surgery for thymoma.