Masau Sekiguchi1,2, Shigeki Sekine3, Taku Sakamoto4, Yosuke Otake4, Takeshi Nakajima4, Takahisa Matsuda4, Hirokazu Taniguchi5, Ryoji Kushima5, Yuichiro Ohe6, Yutaka Saito4. 1. Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan. masekigu@ncc.go.jp. 2. Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan. masekigu@ncc.go.jp. 3. Pathology and Clinical Laboratory Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. ssekine@ncc.go.jp. 4. Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan. 5. Pathology and Clinical Laboratory Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. 6. Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan.
Abstract
BACKGROUND: Endoscopic resection (ER) has been increasingly used for the treatment of rectal neuroendocrine tumors (NETs); however, only limited data are available on its long-term outcomes. This study analyzed the long-term outcomes of rectal NETs treated by ER and characterized potential risk factors for metastasis in these cases, with emphasis on lymphovascular invasion. METHODS: We retrospectively analyzed the clinicopathological features and outcomes of 86 patients with 90 rectal NETs who had been treated by ER. Lymphovascular invasion was reevaluated using elastic-staining and double-staining immunohistochemistry. RESULTS: En bloc resection with tumor-free margins was achieved in 87 lesions (96.7%). The median tumor size was 5 mm (range 2-13), and all the lesions were confined to the submucosal layer. The Ki-67 index was less than 3% in all the lesions, which were therefore classified as NET G1. Elastic-staining and double-staining immunohistochemistry revealed the presence of lymphatic and venous invasion in 23 (25.6%) and 35 lesions (36.7%), respectively. Collectively, lymphatic and/or vascular invasion was identified in 42 lesions (46.7%). All cases were followed up without additional surgery, and no metastasis or recurrence was detected during the median follow-up period of 67.5 months. CONCLUSIONS: This study showed an excellent long-term prognosis following ER of patients with rectal NETs, confirming that ER is a valid treatment option for small rectal NETs. The present study also revealed highly prevalent lymphovascular invasion even in minute rectal NETs; this observation raises a question regarding its significance as a risk factor for metastasis.
BACKGROUND: Endoscopic resection (ER) has been increasingly used for the treatment of rectal neuroendocrine tumors (NETs); however, only limited data are available on its long-term outcomes. This study analyzed the long-term outcomes of rectal NETs treated by ER and characterized potential risk factors for metastasis in these cases, with emphasis on lymphovascular invasion. METHODS: We retrospectively analyzed the clinicopathological features and outcomes of 86 patients with 90 rectal NETs who had been treated by ER. Lymphovascular invasion was reevaluated using elastic-staining and double-staining immunohistochemistry. RESULTS: En bloc resection with tumor-free margins was achieved in 87 lesions (96.7%). The median tumor size was 5 mm (range 2-13), and all the lesions were confined to the submucosal layer. The Ki-67 index was less than 3% in all the lesions, which were therefore classified as NET G1. Elastic-staining and double-staining immunohistochemistry revealed the presence of lymphatic and venous invasion in 23 (25.6%) and 35 lesions (36.7%), respectively. Collectively, lymphatic and/or vascular invasion was identified in 42 lesions (46.7%). All cases were followed up without additional surgery, and no metastasis or recurrence was detected during the median follow-up period of 67.5 months. CONCLUSIONS: This study showed an excellent long-term prognosis following ER of patients with rectal NETs, confirming that ER is a valid treatment option for small rectal NETs. The present study also revealed highly prevalent lymphovascular invasion even in minute rectal NETs; this observation raises a question regarding its significance as a risk factor for metastasis.
Authors: Lowell B Anthony; Jonathan R Strosberg; David S Klimstra; William J Maples; Thomas M O'Dorisio; Richard R P Warner; Gregory A Wiseman; Al B Benson; Rodney F Pommier Journal: Pancreas Date: 2010-08 Impact factor: 3.327
Authors: James C Yao; Manal Hassan; Alexandria Phan; Cecile Dagohoy; Colleen Leary; Jeannette E Mares; Eddie K Abdalla; Jason B Fleming; Jean-Nicolas Vauthey; Asif Rashid; Douglas B Evans Journal: J Clin Oncol Date: 2008-06-20 Impact factor: 44.544
Authors: K-N Shim; S-K Yang; S-J Myung; H-S Chang; S-A Jung; J W Choe; Y J Lee; J S Byeon; J H Lee; H-Y Jung; W-S Hong; J-H Kim; Y I Min; J C Kim; J-S Kim Journal: Endoscopy Date: 2004-04 Impact factor: 10.093