早期结直肠癌内镜切除后行补充根治性手术的淋巴结转移特点及危险因素分析

Characteristics and risk factors of lymph node metastasis in supplemental radical surgery following endoscopic resection for early-stage colorectal cancer

摘要:

背景与目的 根据《中国结直肠癌诊疗规范（2023版）》，对存在高危因素的早期结直肠癌患者，内镜切除后需行补充根治性手术。然而，鉴于早期结直肠癌的淋巴结转移率较低，部分患者可能并未从补充手术中获益。因此，精准筛选真正获益的患者，优化补充手术的适应证，是当前亟需解决的问题。本研究旨在通过单中心大样本的回顾性分析，探讨内镜切除后补充根治性手术中淋巴结转移的危险因素及其分布特征，为临床决策提供参考。方法 回顾性分析2008—2023年于复旦大学附属肿瘤医院内镜治疗后接受补充根治性手术的早期结直肠癌患者的临床及病理资料，采用二元Logistic回归及多因素分析补充外科术后淋巴结转移的危险因素，并对发生转移的淋巴结分布特点进行研究。结果 共纳入417例患者，其中36例（8.63%）术后证实存在淋巴结转移。随着时间推移，补充手术例数呈上升趋势，而术后癌残留比例逐渐下降。纳入243例患者进行危险因素分析，单因素分析提示黏膜下浸润深度SM2及以上、肿瘤分化差、脉管癌栓阳性及肿瘤位置为淋巴结转移的高危因素；多因素分析显示，浸润深度（P=0.039）及肿瘤位置（P=0.014）为独立危险因素。转移淋巴结中，58.3%为单枚转移，63.9%局限于第1站，36.1%涉及第2站，未见第3站转移。仅4例患者术前影像提示淋巴结肿大。结论 早期结直肠癌内镜切除后补充手术数量虽明显增加，但实际淋巴结转移比例较低，提示存在一定的过度治疗风险。黏膜下浸润深度≥SM2和肿瘤位置为独立危险因素，D₂淋巴结清扫为必要标准，影像学评估价值有限，临床决策需注重精准化与个体化。

Abstract:

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.