The prognostic value of the systemic immune-inflammation index (SII) and red cell distribution width (RDW) in cervical cancer patients treated with definitive radiotherapy.

Abstract

Background Malignant uterine cervical neoplasms continue to be the fourth leading cause of cancer-related mortality among women globally. There is a growing interest in the prognostic value of routinely performed pre-treatment blood test indices such as red cell distribution width (RDW) or systemic immune-inflammation index (SII), the latter combining neutrophils-to-lymphocyte ratio (NLR) and platelets-to-lymphocyte ratio (PLR). These indices were shown to be prognostic for survival in some malignancies. The purpose of the study was to evaluate the association between pre-treatment RDW and SII, and overall survival (OS) in patients treated with radiotherapy for primary localised cervical cancer. Methods This retrospective analysis included patients treated with definitive chemoradiation therapy (CRT) between 2011 and 2017 for histopathologically confirmed FIGO 2018 stage IB2-IVA cervical cancer. Statistical analysis was performed using the Kaplan-Meier method, two-sided log-rank tests, and Cox proportional hazards models, with the Akaike Information Criterion (AIC) serving as a prediction error estimator. Results The study group included 249 patients with a median age of 57.2 years and a median follow-up of 75.8 months. The majority were diagnosed with squamous cell carcinoma (237, 95.2%) and had FIGO stage III (211, 84.7%). Approximately half of the patients (116; 46.4%) had regional lymph node metastases. Patients with low RDW (≤13.4%) and low SII (≤986.01) had a significantly longer OS (p=0.001 and p=0.002). The RDW remained as an independent prognostic factor in the multivariable model (high vs low; HR=2.04; 95%CI: 1.32-3.16; p=0.001). Including RDW in the model decreased Akaike Information Criterion from 1028.25 to 1018.15. Conclusions RDW is a cheap and widely available index that is simultaneously an independent prognostic factor for survival and could be used to improve pre-treatment prognosis assessment in cervical cancer patients undergoing CRT. Available data encourages assessing RDW as a prognostic factor in prospective trials to aid identification of candidates for treatment escalation.