Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
Gut Liver. 2022 Mar 15;16(2):228-235. doi: 10.5009/gnl20364.
BACKGROUND/AIMS: Small rectal neuroendocrine tumors (NETs) are often managed with local resection (endoscopic or transanal excision) owing to their low risk of metastasis and recurrence. However, the clinical significance of lymphovascular invasion in resected specimens remains controversial. In this study, we aimed to analyze the frequency of and risk factors for lymph node metastasis proven by histopathologic examination after radical resection.
We retrospectively reviewed the records of 750 patients diagnosed with a rectal NET at four academic medical centers in South Korea between 2001 and 2019. The frequency of histopathologically proven lymph node metastasis and the associated risk factors were analyzed for small tumors (≤1.5 cm) with lymphovascular invasion.
Among 750 patients, 75 had a small tumor (≤1.5 cm) with lymphovascular invasion, of whom 31 patients underwent endoscopic resection only and 44 patients underwent additional radical surgery. Among the 41 patients who underwent surgery and had available data, the rate of regional lymph node metastasis was 48.8% (20/41). In multivariate analysis, the Ki-67 index (odds ratio, 6.279; 95% confidence interval, 1.212 to 32.528; p=0.029) was an independent risk factor for lymph node metastasis. During the mean follow-up period of 37.7 months, only one case of recurrence was detected in the surgery group. The overall survival was not significantly different between radical resection and local resection (p=0.332).
Rectal NETs with lymphovascular invasion showed a significantly high rate of regional lymph node metastasis despite their small size (≤1.5 cm).
背景/目的：由于转移和复发的风险较低，小直肠神经内分泌肿瘤（NET）通常采用局部切除（内镜或经肛门切除）进行治疗。然而，切除标本中淋巴管浸润的临床意义仍存在争议。本研究旨在分析经根治性切除术后病理检查证实有淋巴结转移的频率和危险因素。
我们回顾性分析了 2001 年至 2019 年间韩国四家学术医疗中心诊断为直肠 NET 的 750 例患者的记录。分析了伴有淋巴管浸润的小肿瘤（≤1.5cm）的经病理证实的淋巴结转移频率和相关危险因素。
在 750 例患者中，75 例有小肿瘤（≤1.5cm）伴淋巴管浸润，其中 31 例仅行内镜切除术，44 例行额外根治性手术。在接受手术且有可用数据的 41 例患者中，区域淋巴结转移率为 48.8%（20/41）。多因素分析显示，Ki-67 指数（比值比，6.279；95%置信区间，1.212 至 32.528；p=0.029）是淋巴结转移的独立危险因素。在平均 37.7 个月的随访期间，仅在手术组中发现 1 例复发。根治性切除与局部切除的总生存率无显著差异（p=0.332）。
尽管小直肠 NET（≤1.5cm）伴淋巴管浸润，但仍有明显的区域淋巴结转移率。
