热点聚焦--中低位直肠癌侧方淋巴结转移风险评估与综合治疗策略的制定

Evaluation of lateral lymph node metastasis in mid-low rectal cancer and planning of multi-disciplinary treatment

侧方型局部复发已成为中低位直肠癌新辅助放化疗后最主要的复发方式,初诊时存在肿大可疑的侧方淋巴结是导致侧方型复发的主要因素。越来越多的证据支持新辅助放化疗联合侧方淋巴结清扫的治疗策略。侧方淋巴结转移尚缺乏有效的诊断指标,目前疑诊侧方淋巴结转移主要依据是淋巴结短径大小(5~8 mm),结合淋巴结影像学特征、肿瘤分化程度、环周切缘、肠壁外脉管受侵及淋巴结对放化疗的反应性等因素有助于更准确选择侧方淋巴结清扫的适应人群。设计侧方淋巴结可疑转移患者的综合治疗策略时,应兼顾局部复发及全身转移的风险。对高复发风险人群宜采取全程新辅助放化疗策略。同步增量放疗的应用可能成为未来加强局部控制的模式之一,但对治疗失败患者,其对侧方淋巴结清扫术实施的安全性影响尚缺乏研究。合并小的侧方淋巴结患者及放化疗后淋巴结消失的患者,行TME术后应密切关注淋巴结大小变化,早期发现复发,早期手术。依据侧方淋巴结转移的风险分层,应采取不同的综合治疗策略,以最大限度改善患者的生存及生活质量。

After the implementation of neoadjuvant chemoradiotherapy and total mesorectal excision,lateral local recurrence becomes the major type of local recurrence after surgery in rectal cancer.Most lateral recurrence develops from enlarged lateral lymph nodes on an initial imaging study.Evidence is accumulating to support the combined use of neoadjuvant chemoradiotherapy and lateral lymph node dissection.The accuracy of diagnosing lateral lymph node metastasis remains poor.The size of lateral lymph nodes is still the most commonly used variable with the most consistent accuracy and the cut-off value ranging from 5 to 8 mm on short axis.The morphological features,differentiation of the primary tumor,circumferential margin,extramural venous invasion,and response to chemoradiotherapy are among other risk factors to predict lateral lymph node metastasis.Planning multiple disciplinary treatment strategies for patients with suspected nodes must consider both the risk of local recurrence and distant metastasis.Total neoadjuvant chemoradiotherapy is the most promising regimen for patients with a high risk of recurrence.Simultaneous Integrated Boost Intensity-Modulated Radiation Therapy seemingly improves the local control of positive lateral nodes.However,its impact on the safety of surgery in patients with no response to the treatment or regrowth of lateral nodes remains unclear.For patients with smaller nodes below the cut-off value or shrunken nodes after treatment,a close follow-up strategy must be performed to detect the recurrence early and perform a salvage surgery.For patients with stratified lateral lymph node metastasis risks,plans containing different multiple disciplinary treatments must be carefully designed for long-term survival and better quality of life.