Short- and Long-term Outcomes of Laparoscopic Total Mesenteric Excision for Neuroendocrine Tumors of the Rectum

Abstract

BACKGROUND: To our knowledge, no studies to date have assessed the short- and long-term outcomes of laparoscopic total mesenteric excision in patients with neuroendocrine tumors of the rectum. OBJECTIVE: The purpose of this study was to investigate the short- and long-term outcomes of patients who underwent laparoscopic rectal resection plus total mesenteric excision for rectal neuroendocrine tumors at our institution. DESIGN: This was a single center, retrospective study. SETTINGS: The study was conducted at a tertiary care facility. PATIENTS: Eight-two patients with neuroendocrine tumors who underwent rectal resection with total mesenteric excision, 77 laparoscopically, between June 2005 and August 2015 were included. INTERVENTIONS: Laparoscopic rectal resection and total mesenteric excision were the study interventions. MAIN OUTCOME MEASURES: Demographic characteristics and surgical and postoperative outcomes were measured. RESULTS: Median tumor size was 8.8 mm (range, 3.0–35.0 mm); 63.6% of tumors were located in the lower rectum, with the median distance from the tumor to the anal verge being 50.0 mm (range, 20.0–130.0 mm). Anal preservation was achieved in all of the patients. Anastomotic leakage occurred in 5 patients (6.5%), but there were no deaths. Seventy-one patients (92.2%) had tumor invasion confined to the submucosa. Lymph node metastasis was present in 29 patients (37.7%), including 26 (33.8%) with perirectal and 5 (6.5%) with lateral lymph node metastasis. The median follow-up period in 59 patients was 42 months (range, 11–113 months), and the 3-year overall survival rate was 97.8%. LIMITATIONS: The study was limited by its single-center, retrospective analysis. CONCLUSIONS: Laparoscopic rectal resection with total mesenteric excision is safe in patients with rectal neuroendocrine tumors, with good short- and long-term outcomes. Because rectal neuroendocrine tumors are smaller and show superficial invasion, the rate of anal preservation may be high.

Difficulty of predicting lymph node metastasis on CT in patients with rectal neuroendocrine tumors

“…This has also been reported and recognized as a pathological manifestation of mild-to-moderate nuclear atypia and localized disease, mostly with very small rates of metastasis to regional lymph nodes (LNs) or distant organs [2]. However, because of similar cancer-specific survival rates of rectal NET with regional or distant metastasis of rectal adenocarcinoma [3–5] according to some recent reports of long-term follow-up data, rectal NET is now considered a malignant disease [1,6]. As difficulty with chemotherapy has been reported [7–9], not only local resection but surgical resection with LN dissection around the rectum if LNs metastases are suspected must be used to achieve cure.…”

Rectal neuroendocrine tumor developing lateral lymph node metastasis after curative resection: a case report

“…1 Colonoscopy of the primary site shows a 14-mm submucosal tumor with central depression located at the anterior wall of the distal rectum endoscopic resection or dissection [13]. However, 7-18.6% of lymph node metastases come from tumors < 10 mm in size [7,14,15]. Given that most of these tumors harbor lymphovascular invasion, Matsuhashi et al emphasized the importance of evaluating lymphovascular invasion of the resected specimen [16].…”

“…In Japan, lateral lymph node dissection is recommended for rectal cancer with muscularis propria invasion that is located distal to the peritoneal reflection [18]. Takatsu et al reported a single-center, retrospective study of the short-and longterm outcomes of curative surgery of 82 patients with rectal NET [7]. In their study, 5 of 6 patients who underwent lateral lymph node dissection had lymph node metastasis.…”

“…Fahy et al stratified patients at risk by using parameters such as tumor size, mitotic rate, lymphovascular invasion, and depth of invasion of the obtained tissue specimen [5]. From previous reports, 5.9-6.5% of patients with rectal NETs were confirmed to have lateral lymph node metastasis after rectal resection [6,7]. However, the recurrence of lateral lymph node metastasis is very rare, and to the best of our knowledge, there are no case reports in English of lateral lymph node recurrence after curative resection of a rectal NET.…”

A small, well-differentiated rectal neuroendocrine tumor with multiple lymph node metastases: A case report

“…The majority of rectal NETs are small and superficial, with indolent characteristics ( 8 ). Traditionally, tumor size and depth of invasion are considered important risk factors for metastasis.…”