Taku Sakamoto

Long-term Outcomes After Resection for Submucosal Invasive Colorectal Cancers

BACKGROUND & AIMS Little is known about the long-term outcomes of patients with submucosal invasive colorectal cancer who undergo endoscopic or surgical resection. We performed a retrospective analysis of long-term outcomes of patients treated for submucosal colon and rectal cancer. METHODS We collected data on 549 patients with submucosal colon cancer and 209 patients with submucosal rectal cancer who underwent endoscopic or surgical resection at 6 institutions over a median follow-up period of 60.5 months. Patients were classified into one of 3 groups: low-risk patients undergoing only endoscopic resection (group A), high-risk patients undergoing only endoscopic resection (group B), and high-risk patients undergoing surgical resection that included lymph node dissection (group C). We assessed recurrence rates, 5-year disease-free survival, and 5-year overall survival. Cox regression analysis was used to compare recurrences. RESULTS The rates of recurrence, disease-free survival, and overall survival in group A for submucosal colon and rectal cancer were 0% versus 6.3% (P < .05), 96% versus 90%, and 96% versus 89%, respectively. For group B, these values were 1.4% versus 16.2% (P < .01), 96% versus 77% (P < .01), and 98% versus 96%, respectively; local recurrence was observed in 5 patients (one with submucosal colon cancer and 4 with submucosal rectal cancer). Tumor location was the only factor that contributed significantly to disease recurrence and death (hazard ratio, 6.73; P = .045). For group C, these values were 1.9% versus 4.5%, 97% versus 95%, and 99% versus 97%, respectively. CONCLUSIONS The risk for local recurrence was significantly higher in high-risk patients with submucosal rectal cancer than in patients with submucosal colon cancer when treated with only endoscopic resection. The addition of surgery is therefore recommended for patients with submucosal rectal cancer with pathologic features indicating a high risk of tumor progression; University Hospital Medical Network Clinical Trials Registry, Number: UMIN 000008635.

Learning curve associated with colorectal endoscopic submucosal dissection for endoscopists experienced in gastric endoscopic submucosal dissection.

BACKGROUND: Colorectal endoscopic submucosal dissection requires a high level of skill and experience in therapeutic endoscopy because of the high risk of complications such as perforation and bleeding. Greater understanding of the procedural learning curve is required to standardize training and to achieve wider acceptance of this procedure. OBJECTIVE: The aims of this study were to evaluate the clinical outcomes of colorectal endoscopic submucosal dissection and to clarify its learning curve for endoscopists. DESIGN: We retrospectively reviewed the clinical outcomes for consecutive patients with colorectal neoplasms who underwent endoscopic submucosal dissection by 2 trainees under the guidance of experienced specialists. SETTING: The study was performed at the National Cancer Center Hospital, Tokyo, Japan. PATIENTS: Colorectal endoscopic submucosal dissections were performed for 101 consecutive patients with 102 colorectal neoplasms between April 2008 and December 2010. MAIN OUTCOME MEASURES: Procedure time, en bloc resection rate, completion rate, and complications were retrospectively compared between 4 training periods in which each trainee performed 10 endoscopic submucosal dissections per period and a final training period in which the trainees performed 10 to 12 endoscopic submucosal dissections to analyze the skill improvement with time. RESULTS: The procedure time and en bloc resection rate were not significantly different among the training periods. However, the completion rates in the fourth (100%) and fifth (95.5%) training periods (≥31 cases/trainee) were significantly higher (P < .001) than those in the first (45%), second (70%), and third (80%) training periods (1–30 cases/trainee). Two cases of perforation occurred during the study. LIMITATIONS: Limitations include the single-center design. Training programs and instruments vary with institution, which could affect the learning curve. CONCLUSIONS: Trainee endoscopists are able to perform colorectal endoscopic submucosal dissection without serious complications under the guidance of experienced specialists. They can perform it safely and independently after preparatory training and experience with ≥30 cases.

Endoscopic submucosal dissection (ESD) for colorectal tumors.

Background:  Endoscopic submucosal dissection (ESD) is accepted as a minimally invasive treatment for early gastric cancer, however, it is not widely used in the colorectum because of its technical difficulty.

Narrow-band imaging (NBI) magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team.

Many clinical studies on narrow‐band imaging (NBI) magnifying endoscopy classifications advocated so far in Japan (Sano, Hiroshima, Showa, and Jikei classifications) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions. However, discussions at professional meetings have raised issues such as: (i) the presence of multiple terms for the same or similar findings; (ii) the necessity of including surface patterns in magnifying endoscopic classifications; and (iii) differences in the NBI findings in elevated and superficial lesions. To resolve these problems, the Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011. Consensus was reached on this classification using the modified Delphi method, and this classification was proposed in June 2014. The JNET classification consists of four categories of vessel and surface pattern (i.e. Types 1, 2A, 2B, and 3). Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSP), low‐grade intramucosal neoplasia, high‐grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.

Treatment strategy for recurrent or residual colorectal tumors after endoscopic resection

BackgroundPiecemeal resection of colorectal neoplasms is associated with a higher risk of recurrent or residual tumors, but nearly all such cases can be cured by additional endoscopic resection (ER). Although the adoption of endoscopic submucosal dissection (ESD) for colorectal neoplasm is continuing, the safety of this treatment for recurrent or residual tumors has not been fully assessed. We evaluated salvage therapy for the treatment of recurrent or residual tumors, and propose an endoscopic treatment strategy for these tumors.MethodsThis retrospective study was conducted for 60 consecutive patients who had with locally recurrent or residual tumor after ER between January 2004 and October 2005. Endoscopic treatment strategy, treatment results, complications and clinical outcomes were recorded.ResultsAmong 69 lesions in 60 patients, 67 were treated endoscopically, whereas 2 required surgical treatment. Of these 67, 87% (58/67) were resected by endoscopic mucosal resection (EMR) and 13% (9/67) by ESD. En bloc resection rate was 39% (23/58) in the EMR group and 56% (5/9) in the ESD group. One limitation of this study is that it was a single-center retrospective analysis.ConclusionsESD is safe and effective for the treatment of recurrent or residual colorectal tumors. However, because of its technical difficulty, the en bloc resection rate is lower than that for the treatment of nonrecurrent lesions.

A large-scale multicenter study of long-term outcomes after endoscopic resection for submucosal invasive colorectal cancer

BACKGROUND AND STUDY AIMS Patients with submucosal invasive colorectal cancer (SM-CRC) treated with endoscopic resection who are at low risk of lymph node metastasis and local recurrence may be followed up with observation alone, while additional surgery is recommended for those with high risk features. However, the long-term outcomes that these strategies offer are still unclear. The objective of our study was to retrospectively evaluate the long-term outcomes of patients with SM-CRC managed with endoscopic resection. PATIENTS AND METHODS We retrospectively analyzed all patients with SM-CRC treated by endoscopic resection at six institutions between 2000 and 2007. SM-CRCs with (i) negative vertical margin, (ii) well or moderately differentiated adenocarcinoma, (iii) absence of lymphovascular invasion, and (iv) invasion depth < 1000 µm were classified as low risk. Patients with SM-CRCs without these characteristics were classified as high risk. Outcomes were assessed by 5-year recurrence-free survival (RFS) and recurrence rate. RESULTS During the study period, 428 patients with SM-CRC (low risk, 126; high risk, 302) who underwent endoscopic resection as their first treatment were enrolled (median follow-up 61 months). Among the 120 patients with low risk features treated by endoscopic resection alone, the 5-year RFS and recurrence rates were 98 % and 0.8 %, respectively. Of the 302 patients with high risk features, 196 underwent additional surgery and 106 were managed with endoscopic resection alone. For those who underwent additional surgery, the 5-year RFS and recurrence rates were 97 % and 3.6 %, respectively. Among the 106 patients managed with endoscopic resection alone, RFS and recurrence rates were 89 % (P < 0.05 vs. low risk patients treated by endoscopic resection alone) and 6.6 % (P < 0.05), respectively. CONCLUSIONS Endoscopic resection alone is adequate for the management of patients with SM-CRC and low risk features. However, in those patients with SM-CRC and high risk features, surgery should be considered in addition to endoscopic resection.

Indications for and Technical Aspects of Colorectal Endoscopic Submucosal Dissection

Due to the widespread acceptance of gastric and esophageal endoscopic submucosal dissections (ESDs), the number of medical facilities that perform colorectal ESDs has grown and the effectiveness of colorectal ESD has been increasingly reported in recent years. The clinical indications for colorectal ESD at the National Cancer Center Hospital, Tokyo, Japan include laterally spreading tumor (LST) nongranular type lesions >20 mm and LST granular type lesions >30 mm. In addition, 0-IIc lesions >20 mm, intramucosal tumors with nonlifting signs and large sessile lesions, all of which are difficult to resect en bloc by conventional endoscopic mucosal resection (EMR), represent potential candidates for colorectal ESD. Rectal carcinoid tumors less than 1 cm in diameter can be treated simply, safely, and effectively by endoscopic submucosal resection using a ligation device and are therefore not indications for ESD. The en bloc resection rate was 90%, and the curative resection rate was 87% for 806 ESDs. The median procedure time was 60 minutes, and the mean size for resected specimens was 40 mm (range, 15 to 150 mm). Perforations occurred in 23 (2.8%) cases, and postoperative bleeding occurred in 15 (1.9%) cases, but only two perforation cases required emergency surgery (0.25%). ESD was an effective procedure for treating colorectal tumors that are difficult to resect en bloc by conventional EMR. ESD resulted in a higher en bloc resection rate as well as decreased invasiveness in comparison to surgery. Based on the excellent clinical results of colorectal ESDs in Japan, the Japanese healthcare insurance system has approved colorectal ESD for coverage.

NBI magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team (JNET)

Many clinical studies on narrow‐band imaging (NBI) magnifying endoscopy classifications advocated so far in Japan (Sano, Hiroshima, Showa, and Jikei classifications) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions. However, discussions at professional meetings have raised issues such as: (i) the presence of multiple terms for the same or similar findings; (ii) the necessity of including surface patterns in magnifying endoscopic classifications; and (iii) differences in the NBI findings in elevated and superficial lesions. To resolve these problems, the Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011. Consensus was reached on this classification using the modified Delphi method, and this classification was proposed in June 2014. The JNET classification consists of four categories of vessel and surface pattern (i.e. Types 1, 2A, 2B, and 3). Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSP), low‐grade intramucosal neoplasia, high‐grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.

COMPARISON OF MAGNIFYING CHROMOENDOSCOPY AND NARROW-BAND IMAGING IN ESTIMATION OF EARLY COLORECTAL CANCER INVASION DEPTH : A PILOT STUDY

Background:  Several previous studies have identified narrow‐band imaging (NBI) with magnification as being useful in evaluating early colorectal cancer invasion depth, but comparative diagnostic accuracy of invasion depth between pit pattern analysis using magnifying chromoendoscopy and NBI remains unclear. The aim of this retrospective study was to compare NBI and pit pattern analysis using magnifying chromoendoscopy in estimating early colorectal cancer invasion depth and to assess interobserver agreement.

Efficacy of Endoscopic Mucosal Resection With Circumferential Incision for Patients With Large Colorectal Tumors

BACKGROUND & AIMS Treatment of large colorectal neoplasms (>20 mm in diameter) by conventional endoscopic mucosal resection (EMR) often results in piecemeal resection that requires further intervention. We evaluated the efficacy of EMR with circumferential incision (CEMR). METHODS From March 2008-July 2009, we resected 24 large colorectal neoplasms measuring 20-40 mm in diameter by using the CEMR technique. CEMR was performed by using a ball-tip bipolar needle knife with a snaring technique. After the injection of glycerol into the submucosal layer, a circumferential incision was made, and the neoplasm was resected by snaring. All lesions that showed a noninvasive pattern were diagnosed by magnifying chromoendoscopy as adenomas or intramucosal or submucosal superficial cancers. The number of en bloc resections and complications and the overall procedure time were determined. RESULTS The proportions of en bloc and 2-piece resections by CEMR were 67% (16/24) and 17% (4/24), respectively. The median (interquartile range) time for CEMR completion was 40 minutes (30-63 minutes). No postsurgery complications occurred in any patient. CONCLUSIONS CEMR might provide acceptable clinical outcomes for patients with large colorectal neoplasms. It results in a low incidence of incomplete treatments and low risk of complications.