Prognostic Value of the Neutrophil-to-Lymphocyte Ratio before and after Radiotherapy for Anaplastic Thyroid Carcinoma

SIMPLE SUMMARY: Systemic hematologic markers such as the neutrophil–lymphocyte ratio (NLR) are attracting attention in a simple blood test predicting survival and treatment outcomes in various solid cancers. In our study including 40 patients with anaplastic thyroid cancer (ATC) who underwent radiotherapy, we found that high NLR before and after radiotherapy was associated with poor survival. This study result means that host immunity has an important role in patients with ATC, which can be important information for designing future investigations on the impact of immune system modulating therapy in ATC. ABSTRACT: The neutrophil–lymphocyte ratio (NLR) is a marker of systemic inflammation, and its elevation has recently been associated with poor survival in many solid cancers. Leukocyte elevation and lymphocyte reduction are associated with a poor response to radiotherapy (RT). This study aimed to assess the prognostic value of NLR before and after RT for anaplastic thyroid carcinoma (ATC). This retrospective study analyzed 40 patients with ATC who received RT with available complete blood cell count data from November 1995 through May 2020 at Samsung Medical Center (Seoul, Korea). Patients were classified into two groups according to the NLR before and after RT. The median overall survival (OS) was 8.9 months (range, 3.5–18.2) in the low NLR group (<3.47) and 5.2 months (range, 2.7–7.5) months in the high NLR group (≥3.47). The association between NLR and OS was also observed in multivariable Cox regression analysis (hazard ratio, 3.18; 95% confidence interval, 1.15–8.85; p = 0.026). The OS curves differed significantly according to post-RT NLR (p = 0.036). A high NLR before and after RT may be significantly associated with poor OS in patients with ATC who receive RT.