Beneficiaries of radical surgery among clinical complete responders to neoadjuvant chemoradiotherapy in rectal cancer.

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.