Kojima Motohiro, Ikeda Koji, Saito Norio, Sakuyama Naoki, Koushi Kenichi, Kawano Shingo, Watanabe Toshiaki, Sugihara Kenichi, Ito Masaaki, Ochiai Atsushi
Division of Pathology, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center , Kashiwa , Japan.
Division of Surgical Oncology, National Cancer Center Hospital East, Kashiwa, Japan; Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan.
Front Oncol. 2016 Jul 18;6:173. doi: 10.3389/fonc.2016.00173. eCollection 2016.
A new histological classification of neuroendocrine tumors (NETs) was established in WHO 2010. ENET and NCCN proposed treatment algorithms for colorectal NET. Retrospective study of NET of the large intestine (colorectal and appendiceal NET) was performed among institutions allied with the Japanese Society for Cancer of the Colon and Rectum, and 760 neuroendocrine tumors from 2001 to 2011 were re-assessed using WHO 2010 criteria to elucidate the clinicopathological features of NET in the large intestine. Next, the clinicopathological relationship with lymph node metastasis was analyzed to predict lymph node metastasis in locally resected rectal NET. The primary site was rectum in 718/760 cases (94.5%), colon in 30/760 cases (3.9%), and appendix in 12/760 cases (1.6%). Patients were predominantly men (61.6%) with a mean age of 58.7 years. Tumor size was <10 mm in 65.4% of cases. Proportions of NET G1, G2, G3, and mixed adeno-neuroendocrine carcinoma (MANEC) were 88.4, 6.3, 3.9, and 1.3%, respectively. Of the 760 tumors, 468 were locally resected, and 292 were surgically resected with lymph node dissection. Rectal NET showed a higher proportion of NET G1, and colonic and appendiceal NET was more commonly G3 and MANEC. Of the 292 surgically resected cases, 233 NET G1 and G2 located in the rectum were used for the prediction of lymph node metastasis. Lymphatic and blood vessel invasion were independent predictive factors of lymph node metastasis. NET G2 cases showed more frequent lymph node metastasis than that seen in NET G1 cases, but this was not an independent predictor of lymph node metastasis. Of the 98 surgically resected cases <10 mm in size, we found 9 cases with lymph node metastasis (9.2%). All cases were NET G1, and eight of the nine cases were positive either for lymphatic invasion or blood vessel invasion. Using the WHO classification, we found NET in the large intestine showed a tumor-site-dependent variety of histological and clinicopathological features. Risk of lymph node metastasis in rectal NET was confirmed even in lesions smaller than 10 mm. Concordant assessment of vascular invasion will be required to estimate lymph node metastasis in small lesions.
2010年世界卫生组织（WHO）建立了神经内分泌肿瘤（NETs）的新组织学分类。欧洲神经内分泌肿瘤学会（ENET）和美国国立综合癌症网络（NCCN）提出了结直肠NET的治疗算法。在日本结直肠癌学会下属机构中对大肠NET（结直肠和阑尾NET）进行了回顾性研究，并使用WHO 2010标准对2001年至2011年的760例神经内分泌肿瘤进行了重新评估，以阐明大肠NET的临床病理特征。接下来，分析与淋巴结转移的临床病理关系，以预测局部切除的直肠NET中的淋巴结转移情况。原发部位在718/760例（94.5%）为直肠，30/760例（3.9%）为结肠，12/760例（1.6%）为阑尾。患者以男性为主（61.6%），平均年龄58.7岁。65.4%的病例肿瘤大小<10mm。NET G1、G2、G3和混合性腺神经内分泌癌（MANEC）的比例分别为88.4%、6.3%、3.9%和1.3%。在760例肿瘤中，468例为局部切除，292例为行淋巴结清扫的手术切除。直肠NET中NET G1的比例较高，结肠和阑尾NET更常见的是G3和MANEC。在292例行手术切除的病例中，233例位于直肠的NET G1和G2用于预测淋巴结转移。淋巴管和血管侵犯是淋巴结转移的独立预测因素。NET G2病例的淋巴结转移比NET G1病例更频繁，但这不是淋巴结转移的独立预测因素。在98例手术切除的肿瘤大小<10mm的病例中，发现9例有淋巴结转移（9.2%）。所有病例均为NET G1，9例中的8例淋巴管侵犯或血管侵犯呈阳性。使用WHO分类，我们发现大肠NET显示出与肿瘤部位相关的多种组织学和临床病理特征。即使在小于10mm的病变中，直肠NET的淋巴结转移风险也得到了证实。对于小病变，需要对血管侵犯进行一致评估以估计淋巴结转移情况。
