Abstract
This study aimed to identify patients who benefit from radical surgery among those with rectal cancer who achieved clinical complete response (cCR). Patients with locally advanced rectal cancer (LARC; stage II/III) who achieved cCR after neoadjuvant chemoradiotherapy (nCRT) were included (n = 212). Univariate/multivariate Cox analysis was performed to validate predictors for distant metastasis-free survival (DMFS). A decision tree was generated using recursive partitioning analysis (RPA) to categorize patients into different risk stratifications. Total mesorectal excision (TME) was compared with the watch-and-wait (W&W) strategy in each risk group. Two molecular predicators of CEA and CA19-9 were selected to establish the RPA-based risk stratification, categorizing LARC patients into low-risk (n = 139; CA19-9 < 35 U/mL and CEA < 5 ng/mL) and high-risk (n = 73; CA19-9 ≥ 35 U/mL or CEA ≥5 ng/mL) groups. Superior 5-y DMFS was observed in the low-risk group vs. the high-risk group (92.9% vs. 76.2%, P = .002). Low-risk LARC patients who underwent TME had significantly improved 5-y DMFS compared with their counterparts receiving the W&W strategy (95.9% vs. 84.3%; P = .028). No significant survival difference was observed in high-risk patients receiving the 2 treatment modalities (77.9% vs. 94.1%; P = .143). LARC patients with cCR who had both baseline CA19-9 < 35 U/mL and CEA < 5 ng/mL may benefit from radical surgery.