A nomogram based on clinical factors to predict locally advanced stage of rectal cancer.

376 Background: Preoperative staging of rectal cancer is important for designing treatment strategy. The standard treatment for locally advanced rectal cancer is neoadjuvant radiochemotherapy followed by surgery. Magnetic resonance imaging (MRI) and transrectal ultrasonography are major staging approaches with a prediction accuracy of about 70-80% but not widely available in hospitals in China. We sought to define possible clinicopathological predictors and establish a simple nomogram as a reference tool for patients and clinicians to predict stage of rectal cancer and make decisions about neoadjuvant therapy. Methods: Preoperative staging of rectal cancer is important for designing treatment strategy. The standard treatment for locally advanced rectal cancer is neoadjuvant radiochemotherapy followed by surgery. Magnetic resonance imaging (MRI) and transrectal ultrasonography are major staging approaches with a prediction accuracy of about 70-80% but not widely available in hospitals in China. We sought to define possible clinicopathological predictors and establish a simple nomogram as a reference tool for patients and clinicians to predict stage of rectal cancer and make decisions about neoadjuvant therapy. Results: In the training set, 77.1% of patients had locally advanced stage by pathology. The multivariate analysis indicated that tumor size (Odds ratio (OR)=1.55, p< 0.001), differentiation (OR =0.38, p< 0.001), location (OR =1.06, p=0.038), serum CEA (OR =0.24, p< 0.001) and CA19-9 level (OR =0.13, p< 0.001) were associated with tumor stage. A nomogram consisting of these 5 factors was developed and predicted locally advanced stage with a concordance index of 0.756. The concordance index of this nomogram was 0.800 in the validation set. Conclusions: Large tumor size, far from anal verge, poor differentiation, elevated serum CEA and CA19-9 level were high-risk factors of locally advanced stage of rectal cancer. The nomogram based on these clinical factors can predicte locally advanced rectal cancer with a considerable accuracy and thus helpful for making neoadjuvant therapy recommendations.