中低位直肠癌新辅助放疗后系膜内淋巴结隐匿转移的临床病理学研究

Occult lymph node metastasis in the middle and lower third rectal cancer after neoadjuvant radiotherapy

目的探讨新辅助放疗后中低位直肠癌系膜内淋巴结隐匿转移及其与临床病理因素的关系。方法74例中低位直肠癌患者接受了新辅助放疗及全直肠系膜切除手术（TME），术后应用脂肪清除技术获取全部淋巴结．将苏木精-伊红染色无淋巴结转移的标本进一步行抗CK抗体免疫组织化学（免疫组化）染色，检测淋巴结内肿瘤隐匿转移情况，并分析隐匿转移与临床病理因素之间的关系。结果74例标本共检出1883枚淋巴结．每例（25．4±1．3）枚。淋巴结常规病检发现172枚有转移（35例，占47.3％），其直径（4．9＋2．6）mm，显著大于无转移淋巴结的直径（2．7±1．4）mm（P〈0．01）。对常规病检无转移的1711枚淋巴结进一步行抗CK抗体免疫组化检测．发现其中40枚（2．3％）有隐匿转移（24例，占32．4％），隐匿转移淋巴结直径（3．2±1．2）mm，显著小于常规病理有转移的淋巴结（P〈0．01）。常规病检淋巴结无转移的39例患者有淋巴结隐匿转移者9例（23．1％），明显低于常规病检淋巴结有转移者的淋巴结隐匿转移率（15／35，42．8％，P〈0．01）。ypN0期患者淋巴结隐匿转移与否对预后的影响差异无统计学意义（P=0．157）。结论对常规病检淋巴结无转移的直肠癌患者．存在淋巴结隐匿转移不应改变其N分期：不应将淋巴结隐匿转移单独作为TNM分期中对淋巴结转移情况的判断指标。

Objective To investigate the occult lymph node metastasis in the middle and lower third rectal cancer after neoadjuvant radiotherapy. Methods From June 2003 to December 2006, 74 rectal cancer patients received neoadjuvant radiotherapy（30 Gy/10 f/2 w, CACA-CRC-001 ） and underwent total mesorectal excision （TME） two weeks later. Fat clearance technique was used in all the samples. Occult lymph node metastasis was detected in the mesoreetum using the anti-CK antibody. Results In total 1883 retrieved lymph nodes, 172 metastasis lymph nodes were harvested by HE examination with the mean diameter [（4.9±2.6） mml being larger than that （2.7±1.4） mm of the 1711 negative nodes（P〈0.01 ）. In HE negative nodes, occult metastasis was found in 40 lymph nodes （2.33%） from 24 patients. Most of these nodes were less than 5 mm（90.0%） with a mean diameter of （3.2± 1.2） mm, smaller than those of HE-positive metastasis nodes （P〈0.01）. Occult metastasis was found in 23.1% （9/39） of HE-negative patients. Occult metastasis incidence was higher in patients with HE- positive nodes（42.8%, P〈0.01 ）. No correlation of lymph node occult metastasis with tumor differentiation, age, or surgical procedures was found. There was no significant difference in recurrence-free survival between ypN0 patients with and without occult metastasis（P=0.157）. Conclusion It is not necessary to include occult lymph node metastasis in the TNM staging in patients with ypN0 rectal cancer.