The impact of radiation induced lymphopenia in the prognosis of head and neck cancer: A systematic review and meta-analysis

Abstract

ObjectivesRadiotherapy is a key part of head and neck cancer (HNC) treatment. Radiation induced lymphopenia (RIL) is a severe complication of radiotherapy. The aim of this study was to evaluate the prognostic role of RIL in HNC patients. MethodWe conducted a PRISMA guideline based systematic review and meta-analysis. The studies were identified on the PubMed, Embase and Cochrane Library from 2007 to October 2021. The quality of each study was assessed by Newcastle-Ottawa Quality Assessment Form for Cohort Studies (NOS). ResultsThere were 8 studies with 2,733 samples finally included in current study. The meta-analysis showed that the odds ratio of developing grade 3–4 RIL was 13.49 (95%CI = 7.03–25.89, I2 = 94%). The incidence rate of grade 3–4 RIL ranged from 73%-88%. Multivariate meta-analysis found that the RIL significantly decreased the overall survival (HR = 2.94, 95%CI = 1.83–4.74, I2 = 0%) and distant metastasis free survival of HNC (HR = 3.79, 95%CI = 2.06–6.97, I2 = 0%). After sensitivity analysis and excluding a potential study that caused heterogeneity, the new pooled multivariate meta-analysis showed RIL was a risk factor to the progression free survival of HNC patients (HR = 3.16, 95%CI = 1.77–5.63, I2 = 0%). ConclusionThis is the first meta-analysis which showed severe RIL decreased the overall survival and promoted the progression of HNC patients. Future large-scale prospective studies are required to evaluate the association between severe RIL and the prognosis of HNC.