Prognostic significance of neoadjuvant rectal score in locally advanced rectal cancer after neoadjuvant chemoradiotherapy and construction of a prediction model

摘要

Aim To evaluate the prognostic significance of neoadjuvant rectal (NAR) score after neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer (LARC), and to develop a nomogram predicting disease‐free survival (DFS). Method A total of 522 LARC patients undergoing nCRT and surgery were included. NAR scores were calculated using the equation [5pN?3(cT?pT)?+?12]^2/9.61, and classified as low (8), intermediate (8‐16), and high (16). Clinicopathological and survival outcomes were compared. Cox regression analysis was performed to identify risk factors of DFS. A predicting nomogram was developed and validated internally. Results For NAR score classification, 193 (37.0%) were low, 183 (35.0%) were intermediate, and 146 (28.0%) were high. Higher NAR score was associated with fewer pCR, lower tumor regression grade (TRG), and higher ypTNM stage. A total of 5‐year DFS for low, intermediate, and high NAR groups was 85.6%, 71.9%, and 47.2%, respectively ( P? ?0.001). NAR score (HR?=?2.488, P ?=?0.002), TRG (HR?=?2.811, P ?=?0.047), CRM involvement (HR?=?2.703, P ?=?0.002), and IMA nodal metastasis (HR?=?2.441, P ?=?0.001) were independent prognostic factors of DFS. A predicting nomogram was developed with C‐index of 0.701. Conclusion NAR score could help in predicting DFS after nCRT. A nomogram was developed to identify subpopulations with aggressive tumors during clinical decision‐making.