[Clinical factors of pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer]

Objective: To explore the feasibility of clinical factors to predict the pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer. Methods: A retrospective analysis was performed on clinical factors of 162 patients with rectal cancer, who underwent neoadjuvant chemoradiotherapy in the General Hospital of People's Liberation Army from January 2011 to December 2018.According to the postoperative pathological results, the patients were divided into pathological complete response (pCR) group and non-pathological complete response group (non-pCR group) to check the predictive clinical factors for pCR. Results: Twenty-eight cases achieved pCR after neoadjuvant chemoradiation (17.3%, 28/162). Univariate analysis showed that patients with higher differentiation (P=0.024), tumor occupation of the bowel lumen≤1/2 (P=0.006), earlier clinical T stage (P=0.013), earlier clinical N stage (P=0.009), the time interval between neoadjuvant chemoradiotherapy and surgery>49 days (P=0.006), and maximum tumor diameter≤5 cm (P=0.019) were more likely to obtain pCR, and the differences werestatistically significant. Multivariate analysis showed that tumor occupation of the bowel lumen≤1/2 (P=0.01), maximum tumor diameter≤5 cm (P=0.035), and the interval>49 days (P=0.009) were independent factors in predicting pCR after neoadjuvant therapy. Conclusion: Tumor occupation of the bowel lumen, maximum tumor diameter, and the time interval between neoadjuvant chemoradiotherapy and surgery can predict the pCR in rectal cancer.