Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Predicting Complete Pathological Response in Rectal Cancer Patients Receiving Neoadjuvant Chemoradiotherapy.

BACKGROUND Pathologic response after neoadjuvant therapy has been shown to improve outcomes in rectal cancer. Inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR), have been studied to predict pathologic response and survival. This study aimed to evaluate the association between NLR and pathological response as well as outcome in patients with rectal cancer who underwent neoadjuvant chemoradiotherapy (nCRT). MATERIAL AND METHODS We retrospectively analyzed 187 patients with rectal cancer treated with nCRT followed by surgery between 2016 and 2020. The NLR was calculated using archival complete blood count records. Postoperative pathology reports were recorded. The NLR cut-off was determined by receiver operating characteristic curve. Kaplan-Meier survival curves and univariate and multivariate Cox regression analyses were used to analyze the relationship between NLR and clinicopathologic data to predict survival and prognosis. RESULTS An NLR >3.63 at diagnosis was the optimal cut-off value for predicting progression. Near-complete response rates were higher in patients with NLR <3.63 (38%) than in those with NLR >3.63 (18%) (P=0.035). The NLR <3.63 group had a significantly higher 5-year progression-free survival rate compared to the NLR >3.63 group (63.6% vs 40.1%, respectively; P=0.007). The NLR <3.63 group also had a higher 5-year overall survival (OS) rate than the NLR >3.63 group (72.3% vs 63.1%, respectively), but the difference was not statistically significant (P=0.077). CONCLUSIONS Our study showed a higher near-complete response rate in rectal cancer patients with NLR <3.63 receiving nCRT. This finding supports that a low preoperative NLR is a good prognostic factor in indicating pathological response.