改良脂肪清除术对直肠癌患者直肠系膜内淋巴结转移的诊断作用

Effects of modified fat clearance technique in the diagnosis of metastatic lymph nodes in the mesorectum of patients with rectal cancer

目的运用改良脂肪清除术处理直肠癌标本，并探讨直肠癌标本直肠系膜内淋巴结的数量、分布及转移规律。方法选取2003年至2008年就诊于北京大学临床肿瘤学院的60例未经过新辅助治疗的中低位直肠癌患者设为研究组，行全直肠系膜切除术（TME）后，应用改良脂肪清除技术对标本进行处理。同期对照组50例患者于TME术后取直肠癌标本并采用福尔马林浸泡法固定24h，常规手工检出系膜淋巴结。研究组直肠系膜被分割为前、后、左、右4个象限，每个象限被进一步分割为上、中、下3段。两组淋巴结检出率及淋巴结转移率比较采用t检验和Χ^2检验。结果（1）研究组共检出1436枚系膜淋巴结（平均23．9枚／例），对照组共检出525枚（平均10．5枚／例），两组比较差异有统计学意义（t=-12．153，P〈0．05）。研究组共检出直径≤5mm的小淋巴结985枚。（2）前方、后方及侧方直肠系膜分别检出淋巴结125、696、615枚。沿标本长轴方向，上、中、下段直肠系膜分别检出淋巴结395、534、507枚。上段直肠系膜淋巴结转移率为18．5％（37／200），显著低于中、下段直肠系膜淋巴结转移率的43．5％（87／200）和38．0％（76／200）（妒=9．414，6．406，P〈0．05）。全组中有33例共检出200枚转移淋巴结，其中48．0％（96／200）为直径45mm的小淋巴结。20％患者冈检出了转移的小淋巴结而发生N分期的改变。结论改良脂肪清除术可有效提高直肠系膜淋巴结特别是直径≤5mm的小淋巴结检出率，有利于更准确的分期。直肠癌向中、下方系膜发生播散的趋势较强。控制直肠癌患者局部复发的关键是确保足够长的远端直肠系膜被切除。

Objective To investigate the number, distribution and metastatic rule of lymph nodes in the mesoreetum of rectal cancer specimen after processing the rectal cancer specimen with modified fat clearance technique. Methods Sixty patients with mid-low rectal cancer who had been admitted to Peking University School of Oncology from 2003 to 2008 were assigned to test group. All the 60 patients who denied neo-adjuvant therapy were treated with total mesorectal excision, and the rectums resected were processed with the modified fat clearance technique. Rectums from another 50 patients with mid-low rectal cancer in control group were fixed in formalin solution for 24 hours. The mesorectum was divided into anterior, posterior, left and right quadrants, and each quadrant was further divided into upper, middle and lower parts. The numbers of lymph nodes harvested and metastatic rate of lymph nodes between the 2 groups were analyzed by t test and chi-square test. Results （ 1 ） The numbers of lymph nodes harvested in the test and control groups were 1436 and 525, with statistical difference between the 2 groups （t =- 12. 153, P 〈 0.05 ）. The number of small lymph nodes （diameter≤5 mm） harvested in test group was 985. （2） The numbers of lymph nodes harvested in the anterior, posterior and bilateral mesoreetum were 125,696 and 615, respectively. The numbers of lymph nodes harvested in the upper, middle and lower part of the mesorectum were 395, 534 and 507, respectively. The metastatic rate of lymph nodes in the upper part of the mesoreetum was 18.5% （37/200）, which was significantly lower than in the middle [43.5% （87/200）1and lower [ 38.0% （76/200） ] part of the mesorectum （ Χ^2 = 9. 414, 6. 406, P 〈 0.05 ）. Two hundred metastatic lymph nodes in 33 patients were harvested, 48.0% （96/200） of whieh with a diameter of ≤5 mm. Twenty percent patients had their TNM stage changed after the retrieval of metastatic small lymph nodes. Conclusions Modified fat clearance teehnique significantly improves the retrieval of lymph nodes, and more small lymph nodes retrieved can increase the accuracy of staging. Rectal cancer cells have strong tendeney to disseminate to the distal mesorectum. Adequate excision of the distal mesorectum is key in controlling the local recurrence.