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

OBJECTIVE

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, < 0.05), high level of preoperative CA19-9 (HR = 3.369, = 0.036), high ypStage (HR = 19.768, < 0.001), positive neural invasion (HR = 4.218, = 0.026) and no adjuvant chemotherapy (HR = 5.495, < 0.001) were independent predictors of poor OS. Age ≥70 (HR = 2.284, <0.001), low BMI (BMI < 18.5, HR = 3.906, < 0.05), positive preoperative CA19-9 (HR = 1.920, = 0.012), high ypStage (HR = 5.147, <0.001) and positive neural invasion (HR = 2.873, = 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.