CLINICAL USEFULNESS OF HIGH‐FREQUENCY ULTRASOUND PROBES FOR NEW INVASION DEPTH DIAGNOSIS IN SUBMUCOSAL COLORECTAL CARCINOMA

Recently it has become very important to diagnose more precisely the invasion depth of submucosal carcinoma prior to endoscopic mucosal resection (EMR) whether selecting lesion is with or without indications for EMR. This study aimed to evaluate the usefulness of high‐frequency ultrasound probes (HFUP) for preoperative diagnosis of vertical invasion depth < 1000 µm or not in superficial and sessile type submucosal colorectal carcinomas. Twenty‐seven cases of superficial and sessile type submucosal colorectal carcinoma were examined with high‐frequency ultrasound probes (HFUP; 15 or 20 MHz radial‐scan ultrasound probes; Olympus Optical, Tokyo, Japan and Fujinon Omiya, Saitama, Japan) at Hiroshima University Hospital and analyzed. Diagnostic accuracy was confirmed by comparing the ultrasonic with the pathologic vertical invasion depth of specimens resected either by EMR or surgical resection. Histologic depth of submucosal invasion was defined as the distance from muscularis mucosae measured microscopically with a micrometer. When muscularis mucosae in the tumor could not be detected, we measured the invasion depth from the surface of the carcinoma to the apex of the deepest invasive portion. As a result, invasion depth between ultrasonic image and histologic findings showed a significantly close correlation. HFUP diagnosis was demonstrated as useful in determining the distance of vertical invasion and for planning a therapeutic strategy against submucosal colorectal carcinomas.     

Correlations between lymph node metastasis and depth of submucosal invasion in submucosal invasive colorectal carcinoma: a Japanese collaborative study

Background Depth of submucosal invasion (SM depth) in submucosal invasive colorectal carcinoma (SICC) is considered an important predictive factor for lymph node metastasis. However, no nationwide reports have clarified the relationship between SM depth and rate of lymph node metastasis. Our aim was to investigate the correlations between lymph node metastasis and SM depth in SICC.Methods SM depth was measured for 865 SICCs that were surgically resected at six institutions throughout Japan. For pedunculated SICC, the level 2 line according to Haggitts classification was used as baseline and the SM depth was measured from this baseline to the deepest portion in the submucosa. When the deepest portion of invasion was limited to above the baseline, the case was defined as a head invasion. For nonpedunculated SICC, when the muscularis mucosae could be identified, the muscularis mucosae was used as baseline and the vertical distance from this line to the deepest portion of invasion represented SM depth. When the muscularis mucosae could not be identified due to carcinomatous invasion, the superficial aspect of the SICC was used as baseline, and the vertical distance from this line to the deepest portion was determined.Results For pedunculated SICC, rate of lymph node metastasis was 0% in head invasion cases and stalk invasion cases with SM depth <3000µm if lymphatic invasion was negative. For nonpedunculated SICC, rate of lymph node metastasis was also 0% if SM depth was <1000µm.Conclusions These results clarified rates of lymph node metastasis in SICC according to SM depth, and may contribute to defining therapeutic strategies for SICC.     

Importance of histological evaluation in endoscopic resection of early colorectal cancer

The diagnostic criteria for colonic intraepithelial tumors vary from country to country.While intramucosal adenocarcinoma is recognized in Japan,in Western countries adenocarcinoma is diagnosed only if the tumor invades to the submucosa and accesses the muscularis mucosae.However,endoscopic therapy,including endoscopic mucosal resection(EMR)and endoscopic submucosal dissection(ESD),is used worldwide to treat adenoma and early colorectal cancer.Precise histopathological evaluation is important for the curativeness of these therapies as inappropriate endoscopic therapy causes local recurrence of the tumor that may develop into fatal metastasis.Therefore,colorectal ESD and EMR are not indicated for cancers with massive submucosal invasion.However,diagnosis of cancer with massive submucosal invasion by endoscopy is limited,even when magnifying endoscopy for pit pattern and narrow band imaging and flexible spectral imaging color of enhancement are performed.Therefore,occasional cancers with massive submucosal invasion will be treated by ESD and EMR.Precise histopathological evaluation of these lesions should be performed in order to determine the necessity of additional therapy,including surgical resection.     

Clinicopathological features of nonpolypoid colorectal tumors as viewed from the patients' background

Background This study was performed to characterize the clinicopathological features of colorectal tumors with flat-, depressed-, or protruded-type morphology (hereafter referred to simply as flat, depressed, or protruded lesions). Methods There are two major types of colorectal tumor: polypoid (protruded) and nonpolypoid (flat and depressed). A total of 130 lesions from 130 patients with colorectal submucosal invasive cancer were classified into three groups according to their macromorphology seen during endoscopy: flat (laterally spreading) and depressed nonpolypoid tumors and protruded polypoid tumors. The following factors in the patients' background were evaluated: indication for colonoscopy, age, and family history of colorectal cancer in first-degree relatives (i.e., parents, siblings, children). We also compared the following characteristics of the tumors: size, location, depth of submucosal invasion, vascular invasion, and frequency of synchronous and metachronous tumor lesions. Results The incidence of abnormal findings on follow-up studies after polypectomy as an indication for colonoscopy was significantly higher among patients with flat lesions (4/24, 16.7%) and depressed lesions (3/22, 13.6%) than among those with protruded lesions (1/84, 1.2%) (P < 0.01, P < 0.01). Patients with flat lesions (65.8 ± 7.6 years old) were significantly older than those with protruded lesions (P < 0.05). The patients with flat tumors had a significantly higher rate of a family history of colorectal cancer (6/24, 25.0%) than patients with protruded or depressed lesions (P < 0.01, P < 0.05). The protruded lesions were significantly larger than the depressed lesions (size 13.3 ± 6.7 mm) (P < 0.05), and the flat lesions (24.1 ± 10.1 mm) were significantly larger than either the protruded or depressed lesions (P < 0.01, P < 0.01). Seventy-five percent (18/24) of the flat lesions were located in the right colon, and this proportion was significantly higher than that among the protruded or depressed lesions (P < 0.01, P < 0.01). The mean ± SD depth of submucosal invasion was 1218 ± 1034 μm in the flat lesions, 2392 ± 1869 μm in the depressed lesions, and 2761 ± 1929 μm in the protruded lesions, representing a significant difference (P < 0.05, P < 0.0001). Of the 24 patients with flat lesions, 9 (37.5%) showed vascular invasion; this proportion was significantly lower than that among patients with the depressed or protruded lesions (P < 0.01, P < 0.01). Patients with depressed lesions tended to have higher incidence of synchronous and metachronous malignant polyps than those with protruded or flat lesions. Conclusion It is important to examine the morphology of colorectal tumors when diagnosing them and planning the treatment strategy, including follow-up, after resection of nonpolypoid tumors. It is useful to know the patient's family history so nonpolypoid tumors can be accurately diagnosed.     

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.     

Predictive Histopathologic Factors for Lymph Node Metastasis in Patients With Nonpedunculated Submucosal Invasive Colorectal Carcinoma

PURPOSE Risk factors for lymph node metastasis in patients with nonpedunculated submucosal invasive colorectal carcinoma remain to be characterized. This study examines the relationship between lymph node metastasis and clinicopathologic factors in nonpedunculated submucosal invasive colorectal carcinoma.METHODS The study cohort comprised 155 patients who had undergone surgical treatment for nonpedunculated submucosal invasive colorectal carcinoma. The clinicopathologic factors investigated included gender, age, tumor location, macroscopic type, tumor size, histologic type and grade, intramucosal growth pattern, lymphatic invasion, venous invasion, degree of focal dedifferentiation at the submucosal invasive front, status of the remaining muscularis mucosa, and the depth and width of submucosal invasion.RESULTS Lymph node metastases were found in 19 patients (12.3 percent). Univariate analysis showed that lymphatic invasion, focal dedifferentiation at the submucosal invasive front, status of the remaining muscularis mucosa, and depth of submucosal invasion all had a significant influence on lymph node metastasis. Multivariate analysis showed lymphatic invasion (P = 0.014) and high-grade focal dedifferentiation at the submucosal invasive front (P = 0.049) to be independent factors predicting lymph node metastasis. No lymph node metastasis was found in tumors with a depth of submucosal invasion of <1.3 mm.CONCLUSIONS Lymphatic invasion and high-grade focal dedifferentiation at the submucosal invasive front are important predictors of lymph node metastasis in patients with nonpedunculated submucosal invasive colorectal carcinoma. Depth of submucosal invasion can be used as an identifying marker for patients who do not require subsequent surgery after endoscopic resection.Supported in part by a grant-in-aid for cancer research from the Ministry of Health and Welfare of Japan.     

Colorectal endoscopic submucosal dissection: present status and future perspective,including its differentiation from endoscopic mucosal resection

Endoscopic submucosal dissection (ESD) allows en bloc resection of a lesion, irrespective of the size of the lesion. ESD has been established as a standard method for the endoscopic ablation of malignant tumors in the upper gastrointestinal (GI) tract in Japan. Although the use of ESD for colorectal lesions has been studied via clinical research, ESD is not yet established as a standard therapeutic method for colorectal lesions because colorectal carcinoma has unique pathological, organ specific characteristics that differ radically from those of the esophagus and stomach, and scope handling and control is more difficult in the colorectum than in the upper GI tract. Depending on the efficacy of endoscopic mucosal resection (EMR) and the clinicopathological characteristics of the colorectal tumor, the proposed indications for colorectal ESD are as follows: (1) lesions difficult to remove en bloc with a snare EMR, such as nongranular laterally spreading tumors (particularly the pseudo depressed type), lesions showing a type VI: pit pattern, and large lesions of the protruded type suspected to be carcinoma; (2) lesions with fibrosis due to biopsy or peristasis; (3) sporadic localized lesions in chronic inflammation such as ulcerative colitis; and (4) local residual carcinoma after EMR. Colorectal ESD is currently in the development stage, and a standard protocol will be available in the near future. We hope that colorectal tumors will be efficiently treated by a treatment method appropriately selected from among EMR, ESD, and surgical resection after precise preoperative diagnosis based on techniques such as magnifying colonoscopy.     

Warning for unprincipled colorectal endoscopic submucosal dissection: Accurate diagnosis and reasonable treatment strategy

Piecemeal endoscopic mucosal resection (EMR) is generally indicated for laterally spreading tumors (LST) >2 cm in diameter. However, the segmentation of adenomatous parts does not affect the histopathological diagnosis and completeness of cure. Thus, possible indications for piecemeal EMR are both adenomatous homogenous‐type granular‐type LST (LST‐G) and LST‐G as carcinoma in adenoma without segmentalizing the carcinomatous part. Diagnosis of the pit pattern using magnifying endoscopy is essential for determining the correct treatment and setting segmentation borders. In contrast, endoscopic submucosal dissection (ESD) is indicated for lesions requiring endoscopic en bloc excision, as it is difficult to use the snare technique for en bloc excisions such as in non‐granular‐type LST (LST‐NG), especially for the pseudodepressed type, tumors with a type V_I pit pattern, shallow invasive submucosal carcinoma, largedepressed tumors and large elevated lesions, which are often malignant (e.g. nodular mixed‐type LST‐G). Other lesions, such as intramucosal tumor accompanied by submucosal fibrosis, induced by biopsy or peristalsis of the lesion; sporadic localized tumors that occur due to chronic inflammation, including ulcerative colitis; and local residual early carcinoma after endoscopic treatment, are also indications for ESD. In clinical practice, an efficient endoscopic treatment with segregation of ESD from piecemeal EMR should be carried out after a comprehensive evaluation of the completeness of cure, safety, clinical simplicity, and cost–benefit, based on an accurate preoperative diagnosis.     

大肠癌粘膜下浸润类型与癌转移及凝集素受体表达关系的研究

本文观察了76例大肠癌粘膜下浸润方式，表明间隙浸润型和淋巴小结浸润型者分别占42．1％和11．8％，血管浸润或淋巴管润型分别占21．1％和25．8％。组织病理学分析表明，大肠癌的分布部位和分化程度与粘膜下浸润类型无关，但血管或淋巴管浸润者，其癌细胞浸润深度和转移癌的发生明显比间隙或淋巴小结浸润型为高。应用荆豆凝集素（UEA－Ⅰ）免疫组化技术要使血管内皮层着染，因而可容易辨认血管浸润的癌细胞团。对癌细胞UEA－Ⅰ和PNA受体表达的分析表明，粘膜下各浸润型大肠癌，其凝集素受体表达阳性率及PNA阳性细胞量和染色强度，类型，无明显差别，但UEA－Ⅰ的表达在血管或淋巴浸润型者呈减少趋势，提示用内镜活检粘膜标本综合评价肿瘤病变预估病变进展有参考意义。     

Rapid growth of residual colonic tumor after incomplete mucosal resection

We report an 89-year-old man with colon cancer that developed rapidly after an incomplete endoscopic mucosal resection (EMR), and discuss the adverse effect of this maneuver on the tumor biology. A sessile polyp, 15 mm in size, was detected at the hepatic flexure. EMR was performed immediately. Histologi-cal examination showed well differentiated adenocarcinoma with an adenomatous component invading the submucosal layer. There was vascular invasion (positive on elastica van Gieson staining) and the surgical margin was positive for cancer. A right hemicolectomy was performed. The surgical specimen showed the residual tumor, 22 mm in diameter. The relevant histopathological findings of the surgical specimen were: well differentiated adenocarcinoma, with partly mucinous carcinoma and a tubular adenomatous component, depth muscularis propria (mp), lymph node (LN) (0/9). Most of the submucosally invasive cancer was resected by the initial EMR, but the small residual tumor showed rapid growth within only 3 months after the EMR. It was assumed that the residual tumor cells had acquired more malignant characteristics after EMR. In regard to EMR we propose that: (1) except for patients who are at high risk for a major operation, EMR should be avoided for carcinoma with massive submucosal invasion, (2) colonic resection should be performed immediately when histology shows a positive surgical margin for carcinoma, and (3) patients operated after an incomplete EMR should be watched very carefully for the detection of recurrence. (Received: June 26, 1998; accepted: Oct. 23, 1998)     

平坦型大肠肿瘤内镜下浸润深度的判断与治疗方式的选择

目的探讨内镜在平坦型大肠肿瘤浸润深度判断及治疗方式选择中的作用。方法222例大肠平坦型病变根据腺管开口类型及空气介导变形试验和抬举试验判断肿瘤浸润深度,空气介导变形试验和抬举试验均为阳性选择内镜下治疗,否则行手术治疗。经内镜或外科手术切除的标本均完整送检,按WHO的病理学标准做出组织病理学诊断。计算空气介导变形试验和抬举试验判断肿瘤浸润深度的敏感度、特异度、阳性预测值、阴性预测值和准确度。结果空气介导变形试验和抬举试验阳性者212例,其中192例行内镜黏膜切除术（EMR）,15例行内镜下黏膜分片切除术（EPMR）,2例行EPMR＋外科手术治疗,3例行手术治疗。空气介导变形试验和（或）抬举试验阴性者10例,4例行手术治疗。空气介导变形试验和抬举试验判断肿瘤浸润深度的敏感度为97．2％,特异度为44．4％,阳性预测值为97．6％,阴性预测值为40．0％。结论空气介导变形试验和抬举试验可大致判断平坦型大肠肿瘤浸润深度,指导即时的治疗方式选择,有利于防止过度治疗或治疗不足。     

内镜治疗早期肠道肿瘤相关问题探讨

内镜黏膜下剥离术(ESD)与内镜黏膜切除术(EMR)是消化道内镜手术中的两种重要手术方式,目前基于两者又出现了改良的新术式：ESD-S(ESD with snare,ESD联合圈套器法)与EMR-P术(EMR with precutting,预环切EMR法)。这四种手术方式在治疗结直肠肿瘤中具有各自不同的优缺点,如较高的完全切除率,较低的并发症风险等。综合近几年国际发表的临床试验,笔者认为：对于直径小于20 mm的结直肠肿瘤,可根据肿瘤的情况,选择ESD术、ESD-S术,EMR-P术或者EMR术。对于直径大于20 mm的肿瘤,ESD术与ESD-S术由于其较低的复发率与较高的完全切除率,可以作为处理此类肿瘤的首选。如上述两种术式风险较高,可以采用EMR-P进行处理。EMR术由于完全切除率较低,复发率偏高,而大于20 mm肿瘤恶变风险较高,不适合用于这类肿瘤的切除。     

Endoscopic removal of primary B‐cell mucosa‐associated lymphoid tissue lymphoma of the cecum

A 61‐year‐old woman with a history of positive fecal occult blood test was referred for further evaluation. She was symptom‐free and had no family history of colorectal cancer. Colonoscopy revealed a semipedunculated polyp with a surface of normal appearance. Although a biopsy specimen revealed inflammatory cells including numerous small lymphocytes in the mucosa, a definitive diagnosis was not made. Four weeks later, endoscopic removal using the submucosal injection method was performed for diagnosis as well as treatment. The tumor measured 14 × 13 × 6 mm. The pathological diagnosis was low‐grade B‐cell mucosa‐associated lymphoid tissue (MALT) lymphoma, and the depth of invasion was estimated as the submucosal layer. The case described here suggests that MALT lymphoma should be added to the differential diagnosis of colorectal submucosal tumors, and some cases of them might be resected endoscopically using the submucosal injection method.     

Malignant polyp

Malignant polyps are now being encountered more frequently because of increased colorectal cancer screening. Endoscopy offers a minimally invasive option for treating some malignant polyps thus reducing surgical morbidity and mortality. This chapter reviews the endoscopic assessment of colorectal polypoid lesions and risk stratification using gross polyp morphology (Paris classification), lesion surface appearance (Kudo pit pattern and mucosal microvessel appearance, via high-magnification chromoendoscopy and narrow-band imaging), and by the lesion's lifting characteristics (“nonlifting sign”). In combination, these features allow an assessment of the potential for malignancy as well as the likely depth of submucosal invasion, so as to guide appropriate management. We also consider possible adjunct assessment modalities, such as endoscopic ultrasound, and discuss postpolypectomy histologic classification, including Haggitt staging for pedunculated lesions and Kikuchi staging for sessile lesions or laterally spreading tumors. Finally, we describe endoscopic resection techniques for removal of malignant polyps, including endoscopic mucosal resection and endoscopic submucosal dissection, and compare these with surgical management options.     

Endoscopic ultrasonography for diagnosis of submucosal invasion in early gastric cancer

Endoscopic ultrasonography (EUS) is considered to be useful for deciding the treatment course for early gastric cancer. To determine reliable indications suggesting submucosal tumor invasion, we retrospectively analyzed EUS images of the hyperechoic third layer, which corresponds to the submucosa. The subjects enrolled in this study were 75 patients, with 78 gastric cancers (diagnosed as mucosal cancer without ulcerous changes on endoscopy and as histologically differentiated adenocarcinoma on biopsy), who were also examined by EUS. We retrospectively classi-fied EUS features of the third layer (submucosa) into five groups: (1) irregular narrowing, (2) budding sign, (3) multiple echo-free spots, (4) unclear, and (5) no changes. In endoscopically diagnosed gastric mucosal cancer, 16 of the 78 lesions were associated with histologic submucosal invasion. EUS features that were associated with a high incidence of histological submucosal tumor invasion were irregular narrowing (submucosal invasion, 60.0%) and the budding sign (85.7%), and 90.9% of lesions with either of these features had submucosal invasion of tumors when tumorous changes in the third layer exceeded 1 mm in depth. Endosonographic irregular narrowing and a budding sign of more than 1 mm in depth in the third layer are useful for the diagnosis of submucosal invasion in gastric cancers that are diagnosed as mucosal cancers without ulcerous change on endoscopy. Received: March 29, 1999 / Accepted: November 26, 1999     

Matched case-control study comparing endoscopic submucosal dissection and endoscopic mucosal resection for colorectal tumors

Background and Aim: For large colorectal tumors, the en bloc resection rate achieved by endoscopic mucosal resection (EMR) is insufficient, and this leads to a high rate of local recurrence. As endoscopic submucosal dissection (ESD) has been reported to achieve a higher rate of en bloc resection and a lower rate of local recurrence in the short‐term, it is expected to overcome the limitations of EMR. We conducted a matched case‐control study between ESD and EMR to clarify the effectiveness of ESD for colorectal tumors. Methods: Between April 2005 and February 2009, a total of 28 colorectal tumors in 28 patients were resected by ESD and were followed up by colonoscopy at least once. As a control group, 56 EMR cases from our prospectively completed database were matched. En bloc resection, complication and recurrence rates were compared between the two groups. Results: The mean sizes of the lesions were 27.1 mm in the ESD group and 25.0 mm in the EMR group. The en bloc resection rate was significantly higher in the ESD group (92.9% vs 37.5% with ESD vs EMR), and the rate of perforation was also significantly higher (10.7% vs 0%). All cases of perforation were managed conservatively. No recurrence was observed in the ESD group, whereas local recurrences were detected in 12 EMR cases (21.4%). Eleven of the 12 recurrences (91.7%) were managed endoscopically, and one required surgical resection. Conclusions: Endoscopic submucosal dissection is a promising technique for the treatment of colorectal tumors, giving an excellent outcome in comparison with EMR.     

Correlation of lifting versus non-lifting and microscopic depth of invasion in early colorectal cancer.

BACKGROUND: The non-lifting sign is considered a contraindication to endoscopic resection. Our objective was to investigate whether lifting or nonlifting of a lesion is determined by the volume of normal submucosal tissue. METHODS: We measured the thickness of the submucosa and examined the relation between submucosal invasion and lesion elevation induced by submucosal injection in 60 patients with colorectal cancer with evidence of submucosal invasion. Extent of tumor elevation was classified into two groups: A, lifting; B, non-lifting. Submucosal invasion was classified as sm1, sm2, or sm3. The distance between the carcinoma and the line of resection and that between the carcinoma and the muscularis propria were measured. RESULTS: Of 31 sm1 lesions, 29 (93.5%) were group A. All 6 sm3 lesions were group B. All lesions in group A had a value for the distance between carcinoma and muscularis propria of more than 1000 microm. Group B lesions with sm3 invasion had distances of only 105 to 750 microm. CONCLUSION: Lesions classified as sm3 do not elevate in response to submucosal injection, and lesions that become elevated on injection can be resected endoscopically because they are sm1 or sm2 and have a thickness of normal submucosa of more than 1000 microm.     

Evaluation of microvessels in colorectal tumors by narrow band imaging magnification

BACKGROUND: Narrow band imaging (NBI) uses optical filters for sequential green and blue illumination and narrows the bandwidth of spectral transmittance. OBJECTIVE: We determined the clinical usefulness of NBI magnification for evaluation of microvascular architecture and qualitative diagnosis of colorectal tumors. DESIGN: This study was a retrospective study. SETTING: Department of Endoscopy, Hiroshima University, Hiroshima, Japan. PATIENTS AND MAIN OUTCOME MEASUREMENTS: A total of 189 colorectal lesions were analyzed. Each lesion was observed by NBI magnifying endoscopy and classified according to microvascular features (ie, thickness and irregularity). Microvessel thickness was classified as invisible, thin, or thick, and microvessel irregularity was classified as invisible, regular, mildly irregular, or severely irregular. NBI endoscopic images were compared with histologic findings. RESULTS: With respect to microvessel thickness, invisible microvessels were found significantly more often in hyperplasia lesions, and thick microvessels were found significantly more often in carcinoma with submucosal massive invasion (sm-m) (P < .01). With respect to microvessel irregularity, invisible microvessels were found significantly often in hyperplasia lesions, and severely irregular microvessels were found significantly often in sm-m lesions (P < .01). Accuracy of diagnosis of sm-m on the basis of thick and severely irregular lesions was 100%. CONCLUSION: Microvascular features determined by NBI magnification are associated with histologic grade and depth of submucosal invasion. These results indicate that NBI magnification is useful for the prediction of histologic diagnosis and selection of therapeutic strategies of colorectal tumors.     

Management of T1 colorectal carcinoma with special reference to criteria for curative endoscopic resection

Background and Aim: In guidelines 2010 for the treatment of colorectal cancer from the Japanese Society for Cancer of the Colon and Rectum (JSCCR), the criteria for identifying curable T1 colorectal carcinoma after endoscopic resection were well/moderately differentiated or papillary histologic grade, no vascular invasion, submucosal invasion depth less than 1000 µm and budding grade 1 (low grade). We aimed to expand these criteria. Methods: A total of 499 T1 colorectal carcinomas, resected endoscopically or surgically, were analyzed. Relationships between clinicopathologic findings and lymph node metastasis were evaluated. Results: Lymph node metastasis was found in 41 (8.22%) of the 499 cases. The incidence of lymph node metastasis was significantly higher in lesions featuring poorly differentiated/mucinous adenocarcinoma, submucosal invasion ≥ 1800 µm, vascular invasion, and high‐grade tumor budding than in other lesions. Multivariate logistic regression analysis showed all of these variables to be independent risk factors for lymph node metastasis. When cases that met three of the JSCCR 2010 criteria (i.e. all but invasion < 1000 µm) were considered together, the incidence of lymph node metastasis was only 1.2% (3/249, 95% confidence interval: 0.25–3.48%), and there were no cases of lymph node metastasis without submucosal invasion to a depth of ≥ 1800 µm. Conclusions: Even in cases of colorectal carcinoma with deep submucosal invasion, the risk of lymph node metastasis is minimal under certain conditions. Thus, even for such cases, endoscopic incisional biopsy can be suitable if complete en bloc resection is achieved.     

Indications and Techniques for Endoscopic Mucosal Resection in the Lesions of A Colorectal Tumor

We evaluated the possibility of an extended application of endoscopic treatment for submucosal‐invading colorectal cancers, and describe the method of endoscopic mucosal resection (EMR) using a one channel colonoscope. A total of 328 submucosal‐invading cancers were examined from July 1985 to September 2002. The patterns of infiltrating growth into the submucosal layer were further divided into two groups: expanding growth, and infiltrating growth. Lymph node metastasis occurred in sm2 and extension cancer in more advanced stages. The lowest measurement of submucosal invading cancer with lymph node metastasis was 1250 µm. As for patterns of invasion, the frequencies of lymph node metastasis in the groups of expanding growth and infiltrating growth were 0% (0/87) and 14.5% (16/110), respectively, (P = 0.0002, Fisher's direct method). Results showed that endoscopic treatment is suitable for sm1 extension without vessel invasion, but there is a possibility that some sm2 extension cancers can be cured radically when the pattern of submucosal invasion shows expanding growth with a distinct border.