Background and Aims:According to the Chinese Guidelines for the Diagnosis and Treatment of Colorectal Cancer(2023 Edition),patients with early-stage colorectal cancer who present with high-risk factors require additional radical surgery following endoscopic resection.However,due to the relatively low rate of lymph node metastasis in early colorectal cancer,some patients may not benefit from such supplemental surgery.Therefore,accurately identifying patients who are truly likely to benefit and refining the indications for supplemental surgery are pressing clinical challenges.This study was conducted to investigate the risk factors and distribution patterns of lymph node metastasis following additional radical surgery through retrospectively analyzing a large single-center cohort,thereby providing evidence-based support for clinical decision-making.Methods:Clinicopathologic data were retrospectively reviewed for patients with early-stage colorectal cancer who underwent additional radical surgery at Fudan University Shanghai Cancer Center between 2008 and 2023.Binary Logistic regression and multivariate analyses were performed to identify risk factors associated with lymph node metastasis,and the distribution characteristics of metastatic lymph nodes were further examined.Results:A total of 417 patients were included in the study,with lymph node metastasis confirmed in 36 cases(8.63％)postoperatively.Over time,the number of patients undergoing supplemental surgery increased,while the proportion of cases with residual cancer decreased.Among 243 patients included in the risk factor analysis,univariate analysis indicated that submucosal invasion depth of SM2 or greater,poor tumor differentiation,positive vascular invasion,and tumor location were high-risk factors for lymph node metastasis.Multivariate analysis identified invasion depth(P=0.039)and tumor location(P=0.014)as independent risk factors.Among the metastatic cases,58.3％involved a single lymph node;63.9％of metastases were limited to the first station,and 36.1％extended to the second station,with no metastasis found at the third station.Only four patients had preoperative imaging suggestive of lymph node enlargement.Conclusion:Although the number of supplemental surgeries following endoscopic resection of early-stage colorectal cancer has increased significantly,the actual rate of lymph node metastasis remains low,suggesting a potential risk of overtreatment.Submucosal invasion depth ≥SM2 and tumor location are independent risk factors for metastasis.D2 lymph node dissection is deemed necessary,while the diagnostic value of imaging remains limited.Clinical decisions should prioritize precision and individualized treatment planning.

In recent years,the surgical treatment model for rectal cancer has undergone profound changes.The therapeutic goal has gradually shifted from single tumor radical resection to balancing functional preservation,and the therapeutic concept has transformed from merely emphasizing surgical techniques to attaching importance to comprehensive treatment.Especially in the treatment of low rectal cancer,the neoadjuvant therapy model has been continuously optimized.For patients with good tumor regression after neoadjuvant therapy,"watch and wait"and transanal local excision have become important optional strategies.This not only avoids some severe surgery-related complications but also maximizes the preservation of patients'organ functions,bringing a qualitative leap in their quality of life.This treatment strategy is gradually expanding from locally advanced low rectal cancer to relatively early-stage low rectal cancer.In terms of surgical techniques,based on the traditional intermediate approach of"first plane,then vessels",the concept of a"vessel-centered"approach is proposed.By managing vessels first and then expanding the plane,it enables thorough dissection of lymph nodes at the root of the inferior mesenteric artery while preserving the left colic artery.With the aid of dual-fluorescence intraoperative navigation technology[indocyanine green(ICG)fluorescence and intraoperative real-time imaging system(IRIS)ureter fluorescence imaging],real-time visualization of lymph nodes and ureters is achieved,ensuring the completeness of lymph node dissection and helping to reduce the risk of ureteral injury.The angulation-free double anastomosis technique used during surgery effectively reduces the incidence of anastomotic leakage and improves surgical safety.For patients with high-risk factors for anastomotic leakage,intestinal stent bypass is expected to replace the traditional prophylactic end ileostomy,thus avoiding complications associated with prophylactic end ileostomy and the trauma caused by secondary stoma closure.In general,the development trend of surgical treatment for rectal cancer is to minimize patient trauma,preserve organ functions,and improve quality of life under the premise of ensuring oncological efficacy,promoting the development of surgical techniques towards standardization and precision to maximize patients'perioperative safety.

In recent years,the surgical treatment model for rectal cancer has undergone profound changes.The therapeutic goal has gradually shifted from single tumor radical resection to balancing functional preservation,and the therapeutic concept has transformed from merely emphasizing surgical techniques to attaching importance to comprehensive treatment.Especially in the treatment of low rectal cancer,the neoadjuvant therapy model has been continuously optimized.For patients with good tumor regression after neoadjuvant therapy,"watch and wait"and transanal local excision have become important optional strategies.This not only avoids some severe surgery-related complications but also maximizes the preservation of patients'organ functions,bringing a qualitative leap in their quality of life.This treatment strategy is gradually expanding from locally advanced low rectal cancer to relatively early-stage low rectal cancer.In terms of surgical techniques,based on the traditional intermediate approach of"first plane,then vessels",the concept of a"vessel-centered"approach is proposed.By managing vessels first and then expanding the plane,it enables thorough dissection of lymph nodes at the root of the inferior mesenteric artery while preserving the left colic artery.With the aid of dual-fluorescence intraoperative navigation technology[indocyanine green(ICG)fluorescence and intraoperative real-time imaging system(IRIS)ureter fluorescence imaging],real-time visualization of lymph nodes and ureters is achieved,ensuring the completeness of lymph node dissection and helping to reduce the risk of ureteral injury.The angulation-free double anastomosis technique used during surgery effectively reduces the incidence of anastomotic leakage and improves surgical safety.For patients with high-risk factors for anastomotic leakage,intestinal stent bypass is expected to replace the traditional prophylactic end ileostomy,thus avoiding complications associated with prophylactic end ileostomy and the trauma caused by secondary stoma closure.In general,the development trend of surgical treatment for rectal cancer is to minimize patient trauma,preserve organ functions,and improve quality of life under the premise of ensuring oncological efficacy,promoting the development of surgical techniques towards standardization and precision to maximize patients'perioperative safety.

Background and Aims:According to the Chinese Guidelines for the Diagnosis and Treatment of Colorectal Cancer(2023 Edition),patients with early-stage colorectal cancer who present with high-risk factors require additional radical surgery following endoscopic resection.However,due to the relatively low rate of lymph node metastasis in early colorectal cancer,some patients may not benefit from such supplemental surgery.Therefore,accurately identifying patients who are truly likely to benefit and refining the indications for supplemental surgery are pressing clinical challenges.This study was conducted to investigate the risk factors and distribution patterns of lymph node metastasis following additional radical surgery through retrospectively analyzing a large single-center cohort,thereby providing evidence-based support for clinical decision-making.Methods:Clinicopathologic data were retrospectively reviewed for patients with early-stage colorectal cancer who underwent additional radical surgery at Fudan University Shanghai Cancer Center between 2008 and 2023.Binary Logistic regression and multivariate analyses were performed to identify risk factors associated with lymph node metastasis,and the distribution characteristics of metastatic lymph nodes were further examined.Results:A total of 417 patients were included in the study,with lymph node metastasis confirmed in 36 cases(8.63％)postoperatively.Over time,the number of patients undergoing supplemental surgery increased,while the proportion of cases with residual cancer decreased.Among 243 patients included in the risk factor analysis,univariate analysis indicated that submucosal invasion depth of SM2 or greater,poor tumor differentiation,positive vascular invasion,and tumor location were high-risk factors for lymph node metastasis.Multivariate analysis identified invasion depth(P=0.039)and tumor location(P=0.014)as independent risk factors.Among the metastatic cases,58.3％involved a single lymph node;63.9％of metastases were limited to the first station,and 36.1％extended to the second station,with no metastasis found at the third station.Only four patients had preoperative imaging suggestive of lymph node enlargement.Conclusion:Although the number of supplemental surgeries following endoscopic resection of early-stage colorectal cancer has increased significantly,the actual rate of lymph node metastasis remains low,suggesting a potential risk of overtreatment.Submucosal invasion depth ≥SM2 and tumor location are independent risk factors for metastasis.D2 lymph node dissection is deemed necessary,while the diagnostic value of imaging remains limited.Clinical decisions should prioritize precision and individualized treatment planning.

A proportion of patients with locally advanced rectal cancer will achieve clinical complete response (cCR) or pathologic complete response (pCR) after neoadjuvant chemoradiotherapy. With the proposal of the concept of total neoadjuvant therapy (TNT), higher complete response rates will be observed. The management of patients with cCR has long been an issue of controversy and is attractive for clinical trials. A "watch and wait" strategy for patients with cCR has been put forward by some scholars. A non-operative approach can preserve the organfunction and avoid complications after radical surgery. The safety and feasibility of a "watch and wait" strategy have been established in several non-randomized controlled studies. There is no consensus on how to make an optimal decision for patients with cCR. For example, it is only observed in partial patients that cCR is consistent with pCR and the molecular biomarkers for predicting pCR are suboptimal. Besides, cCR is inconsistently defined and surveillance recommendations varies. Furthermore, there are insufficient high-level evidence for the "watch and wait" strategy. For patients with good response after chemoradiotherapy, local excision is an attractive alternative to total mesorectal excision, however with uncertain indications and challenged oncological safety. For patients with cCR, we implement the therapeutic principles of goal-orientation, layered treatment and the whole process management.

A proportion of patients with locally advanced rectal cancer will achieve clinical complete response (cCR) or pathologic complete response (pCR) after neoadjuvant chemoradiotherapy. With the proposal of the concept of total neoadjuvant therapy (TNT), higher complete response rates will be observed. The management of patients with cCR has long been an issue of controversy and is attractive for clinical trials. A "watch and wait" strategy for patients with cCR has been put forward by some scholars. A non?operative approach can preserve the organfunction and avoid complications after radical surgery. The safety and feasibility of a "watch and wait"strategy have been established in several non?randomized controlled studies. There is no consensus on how to make an optimal decision for patients with cCR. For example, it is only observed in partial patients that cCR is consistent with pCR and the molecular biomarkers for predicting pCR are suboptimal. Besides, cCR is inconsistently defined and surveillance recommendations varies. Furthermore, there are insufficient high ? level evidence for the "watch and wait"strategy. For patients with good response after chemoradiotherapy, local excision is an attractive alternative to total mesorectal excision, however with uncertain indications and challenged oncological safety. For patients with cCR, we implement the therapeutic principles of goal?orientation, layered treatment and the whole process management.

A proportion of patients with locally advanced rectal cancer will achieve clinical complete response (cCR) or pathologic complete response (pCR) after neoadjuvant chemoradiotherapy. With the proposal of the concept of total neoadjuvant therapy (TNT), higher complete response rates will be observed. The management of patients with cCR has long been an issue of controversy and is attractive for clinical trials. A "watch and wait" strategy for patients with cCR has been put forward by some scholars. A non?operative approach can preserve the organfunction and avoid complications after radical surgery. The safety and feasibility of a "watch and wait"strategy have been established in several non?randomized controlled studies. There is no consensus on how to make an optimal decision for patients with cCR. For example, it is only observed in partial patients that cCR is consistent with pCR and the molecular biomarkers for predicting pCR are suboptimal. Besides, cCR is inconsistently defined and surveillance recommendations varies. Furthermore, there are insufficient high ? level evidence for the "watch and wait"strategy. For patients with good response after chemoradiotherapy, local excision is an attractive alternative to total mesorectal excision, however with uncertain indications and challenged oncological safety. For patients with cCR, we implement the therapeutic principles of goal?orientation, layered treatment and the whole process management.