Development and validation of neoadjuvant rectal score-based signature nomograms to predict overall survival and disease-free survival in locally advanced rectal cancer: a retrospective, double center, cohort study.

ABSTRACT

AIM: To evaluate the prognostic significance of the NAR score and develop nomograms for locally advanced rectal cancer (LARC) treated after neoadjuvant chemo-radiotherapy (nCRT) combined with total meso-rectal excision (TME) surgery to predict prognostic. METHODS: Retrospective collection among LARC patients treated at Fujian Medical University Union Hospital (training cohort) and Fujian Medical University Affiliated Zhangzhou Hospital (external validation cohort) between Jan 10, 2011 and Dec 28, 2021. The NAR score was calculated by formula [5pN-3(cT-pT) + 12]^2/9.61. NAR score low (< 8), intermediate (8-16), and high (> 16). RESULTS: 1665 patients in the training cohort and 256 patients in the external validation cohorts were enrolled. Lower NAR score was significantly associated with better cumulative incidence of OS, DFS, local recurrence (LR), and distant metastasis (DM) (all P < 0.001). Multivariate Cox regression analysis indicates that NAR score, distance to the anal verge, no.253 LN metastasis, post-CRT carbohydrate antigen 19-9, tumor regression grade, and surgery method are independent predictors of OS and DFS (all P < 0.001). Among these independent factors, the NAR score had the highest area under the curve (AUC) and the nomograms to predict OS and DFS were generated. The AUCs for the accuracy of the prediction OS were 1 year = 0.742, 3 years = 0.749, 5 years = 0.713; prediction DFS were 1 year = 0.727, 3 years = 0.739, 5 years = 0.718, the models have good accuracy. CONCLUSIONS: The NAR score can effectively classify patients with LARC into groups with varying outcomes of OS, DFS, LR, and DM. Moreover, the novel nomograms comprising the NAR score were developed and validated to help predict OS and DFS.