Clinicopathological characteristics of rectal carcinoid patients undergoing surgical resection

Abstract

Abstract. The aim of this study was to clarify the clinical aspects, histopathological features and prognosis of patients with rectal carcinoids, focusing on properties associated with metastasis, in order to gain insights into appropriate management. A total of 20 patients (15 males, 5 females; mean age, 54.9 years; range, 23-71) who underwent surgery for rectal carcinoid tumors at the Department of Colorectal Surgery, Hyogo College of Medicine, between May 2000 and January 2011 were analyzed. Ki-67 immunostaining was performed in 13 cases with available tumor tissue specimens. Of the 20 patients, a radical operation including rectal resection with a lymphadenectomy was performed in 16. The mean tumor size was 11.9 mm (3-25 mm) and lymph node metastasis was confirmed in 9 cases, including 3 with lesions no greater than 7 mm in diameter. Overall, 16 (80%) of the tumors were localized in the submucosal layer and 4 (20%) involved the proper muscle layer. Ki-67 labeling index and lymphovascular invasion were shown to be associated with lymph node and/or distant metastasis by multiple logistic regression analysis, but were not statistically significant in ANOVA findings. Lymph node metastasis from rectal carcinoids, even those smaller than 10 mm in diameter, was not a rare event. More attention should be given to decision-making, including the possibility of endoscopic resection for the treatment of rectal carcinoid tumors regardless of size.

Excellent prognosis following endoscopic resection of patients with rectal neuroendocrine tumors despite the frequent presence of lymphovascular invasion

“…Many previous studies have reported the presence of lymphovascular invasion in rectal NETs as a strong risk factor for metastasis [9][10][11][12][13][14][15][16][17]. However, the fact that nearly a half of the small rectal NETs could be positive for lymphovascular invasion raises a question about the clinical significance of this histopathologic variable.…”

“…To date, in addition to tumor size and depth of invasion, several other risk factors for metastasis have also been reported, including the patient age, presence of lymphovascular invasion, tumor proliferative activity, presence of perineural invasion, and presence of atypical surface characteristics (depression and ulceration) [9][10][11][12][13][14][18][19][20][21][22]. Among these, lymphovascular invasion is the most wellestablished risk factor for metastasis of rectal NETs, and some studies suggest that the presence of lymphovascular invasion could be a risk factor for metastasis even in tumors smaller than 10 mm in size [9][10][11][12][13][14][15][16][17]20].…”

“…Based on the fact that rectal NETs that are small and confined to the submucosal layer rarely metastasize, these lesions are usually treated by local excision, including ER [2,3,[8][9][10][11][12][13][14]. However, small rectal NETs, including those less than 10 mm in size, can also metastasize [8][9][10][11][12][14][15][16][17]; therefore, identification of additional clinicopathological factors that could influence the risk of metastasis may help determine the most appropriate management. To date, in addition to tumor size and depth of invasion, several other risk factors for metastasis have also been reported, including the patient age, presence of lymphovascular invasion, tumor proliferative activity, presence of perineural invasion, and presence of atypical surface characteristics (depression and ulceration) [9][10][11][12][13][14][18][19][20][21][22].…”

Clinical impact of endoscopic ultrasonography for small rectal neuroendocrine tumors

“…Historically, endoscopic resection has been considered curative in cases of rectal NETs ≤10 mm in size (1,15). However, several studies and case reports have reported metastasis of small rectal NETs (16)(17)(18)(19). We performed EUS for all 76 lesions before endoscopic resection.…”

Asymptomatic primary rectal neuroendocrine carcinoma presented as a large pelvic mass

“…However, evidence of lymphovascular invasion and high Ki-67-ratio seem to be the most important risk factors 3. In this case, there is only one important risk factor, that is, high Ki-67-ratio.…”