BMI May Be a Prognostic Factor for Local Advanced Rectal Cancer Patients Treated with Long-Term Neoadjuvant Chemoradiotherapy

Hengchang Liu,1,* Ran Wei,1,* Chunxiang Li,2 Zhixun Zhao,1 Xu Guan,1 Ming Yang,1 Zheng Liu,1 Xishan Wang,1 Zheng Jiang1 1Department of Colorectal Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, People’s Republic of China; 2Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zheng Jiang; Xishan Wang Tel +86-010-88788798Email Jiangzheng@cicams.ac.cn; wangxishan@cicams.ac.cnObjective: This study aims to develop feasible nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of the local advanced rectal cancer (LARC) patients who were treated with neoadjuvant chemoradiotherapy (nCRT) and operation.Methods: A total of 243 LARC patients undergoing nCRT followed by total mesorectal excision (TME) were enrolled. Preoperative clinical features and postoperative pathological characteristics were collected. A Cox regression analysis was performed, and Cox-based nomograms were developed to predict the OS and CSS. We assessed the predictive performance of the nomogram with concordance index and calibration plots.Results: A total of 243 patients were included with a median follow-up period of 46 months (range from 9 to 86 months). Cox regression analysis showed that low BMI (BMI < 18.5, HR= 21.739, P < 0.05), high level of preoperative CA19-9 (HR = 3.369, P = 0.036), high ypStage (HR = 19.768, P < 0.001), positive neural invasion (HR = 4.218, P = 0.026) and no adjuvant chemotherapy (HR = 5.495, P < 0.001) were independent predictors of poor OS. Age ≥ 70 (HR = 2.284, P < 0.001), low BMI (BMI < 18.5, HR = 3.906, P < 0.05), positive preoperative CA19-9 (HR = 1.920, P = 0.012), high ypStage (HR = 5.147, P < 0.001) and positive neural invasion (HR = 2.873, P = 0.022) were independent predictors of poor CSS. The predictive nomograms were developed to predict the OS and CSS with a C-index of 0.837 and 0.760. Good statistical performance on internal validation was shown by calibration plots.Conclusion: In conclusion, this study demonstrated that BMI was an independent prognostic factor for OS and CSS in LARC patients treated with nCRT followed TME. A nomogram incorporating BMI, neural invasion, pre-CA19-9, ypStage, age, and adjuvant chemotherapy could be helpful to predict the OS and CSS.Keywords: local advanced rectal cancer, neoadjuvant chemoradiotherapy, nomogram, body mass index, prognosis, overall survival, cancer-specific survival