Neutrophil-to-Lymphocyte Ratio (NLR) as a Poor Predictive Biomarker for Pathological Response to Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer: A Prospective Study

Background: The literature is inconsistent for the role of neutrophil-to-lymphocyte ratio (NLR) obtained before neoadjuvant therapy (pre-NLR) in predicting pathological response to neoadjuvant chemoradiation (neoCRT) in patients with locally advanced rectal cancer (LARC). In the present cohort study, we explored the predictive role of pre-NLR in this setting. Methods: We prospectively included patients with LARC who were candidates for neoCRT at the Shohada-e-Hafte Tir Hospital (Tehran, Iran) between Mar 2018 and Feb 2020. The pre-NLR was obtained through a peripheral blood smear before CRT. We used the AJCC system for evaluating tumor regression grade (TRG). The TRGs were categorized into: response-group 1 (TRG 0-1 vs. 2-3), response-group 2 (TRG 0 vs. 1-3), and response-group 3 (TRG 0-2 vs. 3). We applied receiver operating characteristic (ROC) analysis to assess the predictive value of pre-NLR. Results: Of the 86 screened patients with rectal cancer, 30   patients who fulfilled the inclusion criteria were included in the study. In total, 63.3% were responsive, and 23.3% had complete pathologic response. Pre-NLR could not predict the pathologic response in response-group 1 (area under the ROC curve [AUC]: 0.45, 95%CI 0.23-0.66) and response-group 2 (AUC: 0.36, 95%CI 0.13-0.59). Nevertheless, it had a poor predictive value in response-group 3 (AUC: 0.55, CI%95 0.33-0.75) with an optimal NLR cutoff value of 2.94. Conclusions: Pre-NLR could not predict the pathological response to neoCRT in our cohort of patients with LARC.