cT1N0M0肺腺癌肺内叶段淋巴结转移规律及对术式选择的影响

The regularity and clinical significance of intrapulmonary lobar and segmental lymph nodes metastasis in patients with cT1N0M0 stage lung adenocarcinoma

目的 探讨cT1N0M0肺腺癌肺内叶段淋巴结（lobar and segmental lymph nodes,LSNs）转移规律,为更加精确的判定N分期及制定肺段切除适应证提供依据.方法 设计前瞻性研究,入组自2014年3月至2015年12月就诊于中日友好医院胸外科,接受肺叶切除＋纵隔淋巴结清扫的cT1 N0M0肺腺癌病例103例.对肺叶切除标本进行LSNs分检,与对应的肺叶标本、其他各站淋巴结共同送病理检查.结合病变大小、影像学特征、血清CEA水平、病理亚型等进行统计分析.结果 103例肺腺癌患者经病理学检查确认pN0 82例,pN1 15例,pN1＋ N2 5例,跳跃性pN2 1例.pN1病例中14例（93.3％）检出12-14组淋巴结转移,5例（33.3％）仅有12-14组LSNs转移;pN2病例中4例（66.7％）检出12-14组淋巴结转移,1例（16.7％）仅检出13组和7组淋巴结转移.如未对LSNs进行分检,N分期假阴性率达6.1％ （5/82）;N1站淋巴结转移漏诊率高达33.3％ （6/20）.检出段区域内叶段淋巴结（aLSNs）,即病变所在段内或段周LSNs转移的病例,41.2％（7/17）检出段区域外叶段淋巴结（iLSNs）,即肺段切除无法清扫或不易解剖到的LSNs转移.按影像学特征分组,单纯GGN组与部分实性/实性结节组相比,iL-SNs转移率低,P=0.049.病理亚型为浸润性腺癌的病例组较浸润前或微浸润病变组iLSNs转移率高,P =0.055,差异无统计学意义.不同血清学CEA水平和不同肿瘤大小组间iLSNs转移率差异无统计学意义,P值分别为0.251和0.197.结论 分检肺内叶段淋巴结有助于精确化肿瘤N分期,减少淋巴结转移假阴性比率,为更准确评估预后、制定术后辅助治疗方案提供依据.肺段切除术中淋巴结采样范围应包括病变所在段内或段周LSNs.以纯GGN为影像学特征的cT1N0M0肺腺癌病例iLSNs转移率低,在满足其他条件的前提下,可能更适用肺段切除.

Objective To investigate the regularity of intrapulnonary lobar and segmental lymph nodes metastasis in patients with cT1N0M0 stage lung adenocarcinoma.To provide a basis for more accurate determination of N stage and indication for pulmonary segmental resection.Methods A prospective study was performed from March 2014 to December 2015.103 cases of cT1 N0M0 stage lung adenocarcinoma received lobectomy and mediastinal lymph node dissection in the thoracic surgery department of China-Japan Friendship Hospital.Intrapulmonary lobar and segmental lymph nodes were dissected and sorted carefully then sent to the pathological department with the corresponding lung specimen and other lymph nodes.Statistical analysis was carried out considering size of the lesion,imaging features,serum CEA levels,pathological subtypes and so on.Results In total 103 cases,pN0 was confirmed in 82 cases,pN1 in 15 cases,pN1 ＋ N2 in 5 cases,and skipping-pN2 in 1 case.14 cases（93.3%） in pN1 group were detected with station 12-14 lymph node metastasis,while only 5 cases （33.3%） were detected with station 12-14 LSNs metastasis.4 cases（66.7%） in pN2 group were detected with station 12-14 lymph node metastasis,while only 1 case（16.7%） with station 13 and station 7 lymph node metastasis.If LSNs were not detected,the false negative rate of N staging could be as high as 6.1% （5/82）,The rate of missed diagnosis of lymph node metastasis might be 30% （6/20） to N1 stations alone.41.2% （7/17）cases with metastasis to the adjacent LSNs had been proved with metastasis to the isolated LSNs.The metastasis rate of the isolated LSNs was significantly lower（P =0.049） in pure GGNs compared with those part-solid/solid nodules.Invasive adenocarcinoma had higher metastasis rate of isolated LSNs,compared with preinvasive lesions or minimally invasive adenocarcinomas,with no statistical difference between groups （P =0.055）.No significant difference in isolated LSNs metastasis rate was found between groups with different serum CEA levels（P =0.251） or tumor size（P =0.197）.Conclusion Dissection of intrapulmonary lobar and segmental lymph nodes might facilitate a more accurate N stage,reduce the false negative rate of lymph node metastasis,and provide basis for more accurate assessment of prognosis and postoperative adjuvant treatment.The sampling area of lymph nodes during segmental resection should include the adjacent LSNs of the target segment.The isolated LSNs metastasis rate of cT1N0M0 stage lung adenocarcinoma with pureGGN as imaging feature is relative low,which might be suitable for segmentectomy when meeting other criteria.