Matsuhashi Nobuhisa, Takahashi Takao, Tomita Hiroyuki, Araki Hiroshi, Ibuka Takashi, Tanaka Kaori, Tanahashi Toshiyuki, Matsui Satoshi, Sasaki Yoshiyuki, Tanaka Yoshihiro, Okumura Naoki, Yamaguchi Kazuya, Osada Shinji, Yoshida Kazuhiro
Department of Surgical Oncology, Gifu University School of Medicine, Gifu 501-1194, Japan.
Department of Tumor Pathology, Gifu University School of Medicine, Gifu 501-1194, Japan.
Mol Clin Oncol. 2017 Sep;7(3):476-480. doi: 10.3892/mco.2017.1326. Epub 2017 Jul 18.
Rectal neuroendocrine tumor (NET) is a relatively rare lesion of the gastrointestinal tract, but the prospective examination with colonofiberoscopy or endoscopic ultrasound has increased the frequency of its detection. It is often difficult to determine the optimal treatment for NETs sized <20 mm in the clinical setting. Other clinicopathological variables are not considered in the current guidelines and staging systems. Although the effects of lymphovascular invasion are not covered by the World Health Organization (WHO) 2010 guidelines or tumor-node-metastasis (TNM) staging system, this may be promising for the establishment of improved guidelines and staging systems, particularly for early-stage colorectal carcinoids. The aim of the present study was to evaluate rectal NETs sized <20 mm in comparison with the WHO 2010 guidelines. Between January 2005 and December 2013, 40 consecutive patients [26 men and 14 women; median age, 59.3 years (range, 34-81 years)] who underwent endoscopic resection of rectal NETs, and 12 patients undergoing surgical resection of rectal NETs, were enrolled in this retrospective study. The median tumor size was 7.4 mm (range, 3-15 mm). The locations of the NET were the rectosigmoid colon (n=3), the upper rectum (n=13), and the lower rectum (n=25). The NETs were classified by size as 0-5 (n=7), 6-10 (n=29) and 11-15 mm (n=4). The surgical procedures performed included low anterior resection plus esophagectomy (n=1), laparoscopic low anterior resection (n=7) and laparoscopic intersphincteric resection (n=4). Only 1 patient had lymph node metastasis (tumor sized 6-10 mm, with lymphovascular invasion). NET recurrence was not detected in any of the patients. According to the WHO guidelines, the tumors were classified as grade (G)1 (n=8), G2 (n=3) and G1/G2 (n=1). The tumor in the patient with lymph node metastasis was G1. NETs sized <10 mm may be curatively treated by endoscopic resection. However, NETs with either lymphovascular invasion or sized >1 cm carry a risk for metastasis equivalent to that of adenocarcinomas. Therefore, it is mandatory to histologically examine lymphovascular invasion in specimens retrieved via endoscopic resection to determine the necessity for further radical surgery with regional lymph node dissection. The treatment of NETs sized <20 mm as presently defined in the WHO 2010 guidelines requires further evaluation.
直肠神经内分泌肿瘤（NET）是胃肠道相对少见的病变，但结肠镜检查或内镜超声的前瞻性检查提高了其检出率。在临床环境中，对于直径<20 mm的NET，通常难以确定最佳治疗方案。目前的指南和分期系统未考虑其他临床病理变量。尽管2010年世界卫生组织（WHO）指南或肿瘤-淋巴结-转移（TNM）分期系统未涵盖淋巴管侵犯的影响，但这可能有助于建立改进的指南和分期系统，特别是对于早期结直肠类癌。本研究的目的是根据WHO 2010指南评估直径<20 mm的直肠NET。2005年1月至2013年12月，40例连续接受直肠NET内镜切除的患者[26例男性和14例女性；中位年龄59.3岁（范围34 - 81岁）]以及12例接受直肠NET手术切除的患者纳入本回顾性研究。肿瘤中位大小为7.4 mm（范围3 - 15 mm）。NET的位置为直肠乙状结肠（n = 3）、直肠上段（n = 13）和直肠下段（n = 25）。NET按大小分类为0 - 5 mm（n = 7）、6 - 10 mm（n = 29）和11 - 15 mm（n = 4）。所进行的手术包括低位前切除术加食管切除术（n = 1）、腹腔镜低位前切除术（n = 7）和腹腔镜括约肌间切除术（n = 4）。仅1例患者有淋巴结转移（肿瘤大小6 - 10 mm，伴有淋巴管侵犯）。所有患者均未检测到NET复发。根据WHO指南，肿瘤分类为1级（G）1（n = 8）、G2（n = 3）和G1/G2（n = 1）。有淋巴结转移患者的肿瘤为G1级。直径<10 mm的NET可通过内镜切除治愈性治疗。然而，伴有淋巴管侵犯或直径>1 cm的NET发生转移的风险与腺癌相当。因此，必须对通过内镜切除获取的标本进行淋巴管侵犯的组织学检查，以确定是否有必要进一步行根治性手术并清扫区域淋巴结。WHO 2010指南目前定义的直径<20 mm的NET的治疗需要进一步评估。
