The Ratio of Hemoglobin to Red Cell Distribution Width Predicts Pathological Complete Response with Rectal Cancer Treated by Neoadjuvant Chemoradiotherapy

Abstract

C oncurrent neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) is a standard of care treatment for locally advanced rectal cancer (LARC). [1,2] The use of nCRT in LARC is associated with improved rates of local control and tumor regression as well as an improved toxicity profile. [3] About 20% of patients achieve pathological complete response (pCR) after nCRT. [4,5] Patients who respond to nCRT have demonstrated improved outcomes, including disease-free survival (DFS) and overall survival (OS). [6][7][8] Identification of pCR after nCRT remains a major challenge. [9] Predicting the complete response in patients undergoing neoadjuvant treatment for rectal cancer may allow clinicians to develop risk-adapted treatment strategies. Unfortunately, there are no effective biomarkers for predicting response to nCRT.Objectives: Concurrent neoadjuvant chemoradiotherapy followed by total mesorectal excision is the standard treatment for locally advanced rectal cancer (LARC). Approximately 20% of patients achieved pathological complete response (pCR) after neoadjuvant treatment. This study aimed to evaluate the relationship between the ratio of hemoglobin to red cell distribution (HRR) width and response to neoadjuvant chemoradiotherapy for rectal cancer. Methods: We retrospectively analyzed patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy followed by surgery between July 2014 and March 2020. The effects of hematological parameters on the response to neoadjuvant chemoradiotherapy were analyzed. Results: A total of 49 patients were eligible for analysis. Red blood cell distribution width (p=0.04), lower systemic immune-inflammation index (p=0.03), and a higher pre-chemoradiotherapy ratio of hemoglobin to red cell distribution width (p=0.03) were associated with a pathological complete response. The multivariate analysis showed that pretreatment ratio of hemoglobin to red cell distribution width >0.88 significantly predicted a complete pathological response, and it was an independent predictor of complete histological response (p=0.009, OR:8, %95 CI: (1,6). Conclusion:The ratio of hemoglobin to red cell distribution width can be used to predict complete pathological response in rectal cancer patients receiving neoadjuvant treatment.