Logistic Regression Analysis Of Factors Related To Preoperative Concurrent Chemoradiotherapy Resistance In Locally Advanced Rectal Cancer

Abstract

Preoperative concurrent chemoradiotherapy (CCRT), as an important part of the comprehensive treatment of locally advanced rectal cancer (LARC), has been widely applied in clinic practice with an effective rate of approximately 40-80%. However, there are still many patients cannot benefit from this treatment. If these patients receive preoperative CCRT, not only cannot improve the efficacy, but also may affect the prognosis due to the adverse effects of radiation and the postponement of operation time. The aim of this study is to investigate the influencing factors of preoperative CCRT resistance in LARC patients. A total of 79 patients were included in this prospective study. Fifteen factors that might affect the resistance to CCRT were included in this logistic regression analysis, these factors include the general clinical data of patients, the expression status of tumor stem cell marker CD44v6 and the volumetric imaging parameters of primary tumor lesions. The resistance status to preoperative CCRT was positively correlated with the real tumor volume (RTV), the total surface area of tumor (TSA), and CD44v6 expression, whereas negatively correlated with the tumor compactness (TC). According to the results of logistic regression analysis, we established two regression models for predicting the resistance and drew two nomograms for clinicians to predict the probability of preoperative CCRT resistance. The Area Under Curve (AUC) of the two models and those significant measurement data (RTV, TC, TSA) were 0.900, 0.858, 0.771, 0.754, 0.859, the sensitivity were 95.8%, 79.17%, 62.50%, 95.83%, 62.5%, the specificity were 70.9%, 74.55%, 83.64%,47.27%, 96.36%, the positive predictive values were 58.96%, 57.58%, 62.51%,44.23%, 88.23%, the negative predictive values were 97.48%, 89.13%, 83.64%, 96.29%, and 85.48%, respectively. The logistic regression models and nomograms we obtained are methods for prediction of patients' suitability for preoperative CCRT. The application of this method would reduce the risk probability of those patients, who are not sensitive to CCRT, from suffering the radiation complications as well as longer waiting periods for surgery and would also provide evidence for individualized treatment options for LARC patients.