Endoscopic mucosal resection of flat and depressed types of early colorectal cancer

Colorectal endoscopic submucosal dissection: Systematic review of mid-term clinical outcomes

With a drive towards minimally invasive surgery, endoscopic submucosal dissection (ESD) is now gaining popularity. In a number of East Asian countries, ESD is now the treatment of choice for early non-metastatic gastric cancer, but the outcomes of ESD for colorectal lesions are unclear. The present review summarizes the mid-term outcomes of colorectal ESD including complication and recurrence rates. A systematic literature search was done in May 2014, identifying 20 publications reporting the outcomes of colorectal ESD which were included in this review. En-bloc resection rates, complete (R0) resection rates, endoscopic clearance rates, complication and recurrences rates were analyzed. Statistical pooling was done to calculate weighted means using random effects modeling. Twenty studies reporting the outcomes of 3060 colorectal ESD procedures were reported. Overall weighted en-bloc resection rate was 89% (95% CI: 83-94%), R0 resection rate 76% (95% CI: 69-83%), endoscopic clearance rate 94% (95% CI: 90-97%) and recurrence rate 1% (95% CI: 0.5-2%). Studies that followed up patients for over 1 year were found to have an en-bloc resection rate of 91% (95% CI: 86-96%), R0 resection rate of 81% (95% CI: 75-88%), endoscopic clearance rate 93% (95% CI: 90-97%) and recurrence rate of 0.8% (95% CI: 0.4-1%). Colorectal ESD can be carried out effectively and safely with a 1% recurrence rate. Further studies with longer follow-up periods are required to determine whether colorectal ESD is a viable alternative to conventional surgical therapy.

Meta-analysis comparing differing methods of endoscopic therapy for colorectal lesions

AIM: To compare the outcomes of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) of colorectal lesions.

METHODS: An electronic systematic literature search of four computerized databases was performed in July 2014 identifying studies reporting the outcomes of colorectal ESD and EMR. The primary outcome measures were en-bloc resection rate, endoscopic clearance rate and lesion recurrence rate of the patients followed up. The secondary outcome was the complication rate (including bleeding, perforation and surgery post EMR or ESD rate). Statistical pooling and random effects modelling of the studies calculating risk difference, heterogeneity and assessment of bias and quality were performed.

RESULTS: Six observational studies reporting the outcomes of 1324 procedures were included. The en-bloc resection rate was 50% higher in the ESD group than in the EMR group (95%CI: 0.17-0.83, P < 0.0001, I² = 99.7%). Endoscopic clearance rates were also significantly higher in the ESD group (95%CI: -0.06-0.02, P < 0.0001, I² = 92.5%). The perforation rate was 7% higher in the ESD group than the EMR group (95%CI: 0.05-0.09, P > 0.05, I² = 41.1%) and the rate of recurrence was 50% higher in the EMR group than in the ESD group (95%CI: 0.20-0.79, P < 0.001, I² = 99.5%). Heterogeneity remained consistent when subgroup analysis of high quality studies was performed (with the exception of piecemeal resection rate), and overall effect sizes remained unchanged for all outcomes.

CONCLUSION: ESD demonstrates higher en-bloc resection rates and lower recurrence rates compared to colorectal EMR. Differences in outcomes may benefit from increased assessment through well-designed comparative studies.

Endoscopic submucosal dissection and its potential role in the management of early colorectal neoplasia in UK

In Europe, colorectal cancer is the most common newly diagnosed cancer and the second most common cause of cancer deaths, accounting for approximately 436 000 incident cases and 212 000 deaths in 2008. National screening programmes will increase the number of early (pT1) cancers detected. pT1 cancers are those showing invasion through the muscularis mucosae into the submucosa but not into the muscularis propria. Microstaging of pT1 cancer is crucial in predicting those cases less likely to cause nodal disease and that will be cured with endoscopic resection alone. The submucosal extent and other histological features predict the risk of nodal disease, and for this reason, en bloc resection is highly desirable. Endoscopic submucosal dissection enables en bloc resection of mucosal and submucosal disease and could reduce the need for surgery in some cases by definitive initial resection.

A long-term follow-up study on the prognosis of endoscopic submucosal dissection for colorectal laterally spreading tumors

BACKGROUND AND AIMS

Colorectal laterally spreading tumors (LSTs) are divided into homogeneous (LST-G-H), nodular mixed (LST-G-M), flat elevated (LST-NG-F), and pseudodepressed (LST-NG-PD) subtypes. We hypothesized that based on the rates of advanced histology, the recurrence rates of the LST-NG-PD and LST-G-M groups may be higher than those of the other subgroups.

METHODS

Endoscopic submucosal dissection (ESD) was performed in 156 patients with a total of 177 LSTs. The clinicopathological features and long-term prognosis of ESD according to specific subtype were investigated.

RESULTS

LSTs were most commonly found in the rectum, and the highest percentage of rectal lesions was observed in the LST-G-M group (71.1% vs overall 55.4%, P = .032). The LST-G-M lesions were larger (60 ± 22 mm vs 40 ± 33 mm, P = .034) than the LST-G-H lesions. The LST-G-M group also demonstrated more high-grade intraepithelial neoplasias (32.2% vs 10.8%, P = .003) and submucosal carcinomas (13.6% vs 1.5%, P = .010) compared with the LST-G-H group. The LST-NG-PD group exhibited the highest incidence of submucosally invasive cancer (16.7%). The overall perforation rate was 2.3%. The perforation rate in the LST-NG group was higher than that in the LST-G group (5.7% vs 0.8%, P = .047). All recurrences (7.7%) were found by colonoscopy without any detection of cancers, and no difference was found among the subtypes.

CONCLUSIONS

No significant differences were observed among subgroups with 44.4 ± 16.3 months of follow-up. Considering that all recurrences were discovered by colonoscopy and most could be cured by repeated ESD, the LSTs of all subgroups require more intensive follow-up compared with smaller adenomatous lesions.

Management of colorectal T1 carcinoma treated by endoscopic resection

As a result of recent advances in endoscopic therapeutic technology, the number of endoscopic resections carried out in the treatment of early colorectal carcinomas with little risk of lymph node metastasis has increased. There are no reports of lymph node metastasis in intramucosal (Tis) carcinomas, whereas lymph node metastasis occurs in 6.8-17.8% of submucosal (T1) carcinomas. Three clinical guidelines have been published in Japan and the management strategy for early colorectal tumors has been demonstrated. According to the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines for the Treatment of Colorectal Cancer, additional surgery should be done in cases of endoscopically resected T1 carcinoma with a histologically diagnosed positive vertical margin. Additional surgery may also be considered when one of the following histological findings is detected: (i) SM invasion depth ≥1000 µm; (ii) histological type por., sig., or muc.; (iii) grade 2-3 tumor budding; and (iv) positive vascular permeation. A resected lesion that is histologically diagnosed as a T1 carcinoma without any of the above-mentioned findings can be followed up without additional surgery. As for the prognosis of endoscopically resected T1 carcinomas, the relapse ratio of approximately 3.4% (44/1312) is relatively low. However, relapse is associated with a poor prognosis, with 72 cancer-related deaths reported out of 134 relapsed cases (54%). A more detailed stratification of the lymph node metastasis risk after endoscopic resection for T1 carcinomas and the prognosis of relapsed cases will be elucidated through prospective studies. Thereafter, the appropriate indications and safe and secure endoscopic resection for T1 carcinomas will be established.

Management of colorectal T1 carcinoma treated by endoscopic resection from the Western perspective

Detection of early colorectal cancer is expected to rise in light of national colorectal cancer screening programs. This The present review article delineates current endoscopic risk assessments, differentiating invasive from non-invasive neoplasia, for high likelihood of lymph node metastasis in early colorectal cancer, also termed high-risk early colorectal cancer, and endoscopic and surgical resection methods from a Western hemisphere perspective.

Endoscopic Full-thickness Resection (EFTR) for Gastrointestinal Subepithelial Tumors

There has been booming interest in the endoscopic full-thickness resection (EFTR) technique since it was first described. With the advent of improved and more secure endoscopic closure techniques and devices, such as endoscopic suturing devices, endoscopists are empowered to perform more aggressive procedures than ever. This article focuses on the procedural technique and clinical outcomes of EFTR for gastrointestinal subepithelial tumors.

Key factors in achieving successful endoscopic dissection of rectal tumors: early results of 33 consecutive rectal endoscopic submucosal dissections in Polish academic center

INTRODUCTION

The aim of the study was to investigate outcomes of rectal endoscopic dissection (ESDs) performed in a single academic institution in Poland.

METHODS AND PATIENTS

Thirty-three consecutive cases of rectal ESDs were performed between June 2013 and April 2014. Effectiveness of dissection, complications, and the tumor recurrence after 3 months of treatment were than retrospectively investigated.

RESULTS

The average size of the dissected tumor was 4.025 cm. Overall en-block resection rate was 70%. Follow-up examinations after 3 months so far were conducted in 15 patients. There was no local recurrence. In univariate analysis, the en-bloc resection rate was significantly higher in smaller lesions (P<0.001) and in patients undergone ESD in second half period of service duration.

CONCLUSIONS

ESD of the rectal tumors is a valuable alternative treatment method for adenomas and T1 SM1 rectal cancers. The risk of serious complications and local recurrence is low.

Predictors for regional lymph node metastasis in T1 rectal cancer: a population-based SEER analysis

BACKGROUND

Local resection of early-stage rectal cancer significantly reduces perioperative morbidity compared with radical resection. Identifying patients at risk of regional lymph node metastasis (LNM) is crucial for long-term survival after local resection.

METHODS

Patients after oncological resection of T1 rectal cancer were identified in the Surveillance, Epidemiology, and End Results register 2004-2012. Potential predictors of LNM and its impact on cancer-specific survival were assessed in logistic and Cox regression with and without multivariable adjustment.

RESULTS

In total, 1593 patients with radical resection of T1 rectal cancer and a minimum of 12 retrieved regional lymph nodes were identified. The overall LNM rate was 16.3 % (N = 260). A low risk of LNM was observed for small tumor size (P = 0.002), low tumor grade (P = 0.002) and higher age (P = 0.012) in multivariable analysis. The odds ratio for a tumor size exceeding 1.5 cm was 1.49 [95 % confidence interval (CI) 1.06-2.13], for G2 and G3/G4 carcinomas 1.69 (95 % CI 1.07-2.82) and 2.72 (95 % CI 1.50-5.03), and for 65- to 79-year-old and over 80-year-old patients 0.65 (95 % CI 0.43-0.96) and 0.39 (95 % CI 0.18-0.77), respectively. Five-year cancer-specific survival for patients with LNM was 90.0 % (95 % CI 85.3-95.0 %) and for patients without LNM 97.1 % (95 % CI 95.9-98.2 %, hazard ratio = 3.21, 95 % CI 1.82-5.69, P < 0.001).

CONCLUSIONS

In this population-based analysis, favorable cancer-specific survival rates were observed in nodal-negative and nodal-positive T1 rectal cancer patients after primary radical resection. The predictive value of tumor size, grading and age for LNM should be considered in medical decision making about local resection.

Blue laser imaging endoscopy system for the early detection and characterization of colorectal lesions: a guide for the endoscopist

Blue laser imaging is a new system for image-enhanced endoscopy using laser light. Blue laser imaging utilizes two monochromatic lasers (410 and 450 nm) instead of xenon light. A 410 nm laser visualizes vascular microarchitecture, similar to narrow band imaging, and a 450 nm laser provides white light by excitation. According to three recently published reports, the diagnostic ability of polyp characterization using blue laser imaging compares favorably with narrow band imaging. No published data are available to date regarding polyp detection with blue laser imaging. However, blue laser imaging has the possibility to increase the detection of colorectal polyps by depicting brighter and clearer endoscopic images, even at a distant view, compared with first-generation image-enhanced endoscopy. A clinical trial to compare the detection between blue laser imaging and xenon light is warranted.

Practical problems of measuring depth of submucosal invasion in T1 colorectal carcinomas

PURPOSE

Submucosal invasion depth (SID) in colorectal carcinoma (CRC) is an important factor in estimating risk of lymph node metastasis, but can be difficult to measure, leading to inadequate or over-extensive treatment. Here, we aimed to clarify the practical aspects of measuring SID in T1 CRC.

METHODS

We investigated 568 T1 CRCs that were resected surgically at our hospital from April 2001 to December 2013, and relationships between SID and clinicopathological factors, including the means of measurement, lesion morphology, and lymph node metastasis.

RESULTS

Of these 568 lesions, the SID was ≥1000 μm in 508 lesions. SIDs for lesions measured from the surface layer were all ≥1000 μm. Although lesions with SIDs ≥1000 μm were associated with significantly higher levels of unfavorable histologic types and lymphovascular infiltration than shallower lesions, a depth of ≥1000 μm was not a significant risk factor for lymph node metastasis (LNM) (6.7 vs. 9.8 %; P = 0.64), and no lesions for which the sole pathological factor was SID ≥1000 μm had lymph node metastasis. Protruded lesions showed deeper SIDs than other types.

CONCLUSIONS

Although we found several problems of measuring SID in this study, we also found, surprisingly, that SID is not a risk factor for lymph node metastasis, and its measurement is not needed to estimate the risk of lymph node metastasis.

Comparing endoscopic mucosal resection with endoscopic submucosal dissection: the different endoscopic techniques for colorectal tumors

BACKGROUND

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are used for the removal of colorectal tumors. There are no current guidelines or consensus on the optimal treatment strategy for these lesions. A meta-analysis was conducted to compare the effectiveness and safety of ESD and EMR for colorectal tumors.

METHODS

For the years 1966 until October 2014, Medline, PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials were searched for articles comparing the effectiveness and safety of ESD and EMR. STATA 11.0 and RevMan 5.0 were used for meta-analysis and publication bias.

RESULTS

Seventeen articles were included in this meta-analysis. ESD was more effective than EMR in endoscopic complete resection rate (odds ratio [OR] = 2.81; 95% confidence interval [CI], 1.39-5.70; Z = 2.86; P = 0.004) and pathologic complete resection rate (OR = 2.81; 95% CI, 1.39-5.70; Z = 2.86; P = 0.004). ESD resulted in a higher perforation rate (OR = 5.27; 95% CI, 2.75-10.08; Z = 5.01; P < 0.00001) and a lower recurrence rate (OR = 0.14; 95% CI, 0.06-0.30; Z = 5.04; P < 0.00001). The tumor size was larger in the ESD group (OR = 3.09; 95% CI, 1.54-4.63; Z = 3.92; P < 0.0001), and the procedure time was longer in the ESD group (OR = 21.39; 95% CI, 10.33-32.46; Z = 3.79; P = 0.0002). But bleeding rate did not differ significantly (OR = 1.34; 95% CI, 0.81-2.20; Z = 1.14; P = 0.25). There was no publication bias analyzed by Begg test and Egger test.

CONCLUSIONS

The study indicates that ESD is the better treatment for colorectal tumors for its higher complete resection rate despite the longer procedure time and higher perforation rate.

Management of Malignant Adenomas

Most polyps that originate in the colon and rectum are benign. A small subset of polyps will contain a malignancy. Although most malignant adenomas are managed with colonic resection a number can be approached with endoscopic, minimally invasive, and observational techniques. This article reviews the histologic characteristics and adverse risk factors that would portend a poor oncologic outcome and therefore suggest formal colonic resection. Modern endoscopic techniques such as endoscopic mucosal resection and endoscopic submucosal resection are discussed.

Radiation promotes colorectal cancer initiation and progression by inducing senescence-associated inflammatory responses

Proton radiotherapy is becoming more common since protons induce more precise DNA damage at the tumor site with reduced side effects to adjacent normal tissues. However, the long-term biological effects of proton irradiation in cancer initiation compared to conventional photon irradiation are poorly characterized. In this study, using a human familial adenomatous polyposis syndrome susceptible mouse model, we show that whole body irradiation with protons are more effective in inducing senescence-associated inflammatory responses (SIR) which are involved in colon cancer initiation and progression. After proton irradiation, a subset of SIR genes (Troy, Sox17, Opg, Faim2, Lpo, Tlr2 and Ptges) and a gene known to be involved in invasiveness (Plat), along with the senescence associated gene (P19Arf) are markedly increased. Following these changes loss of Casein kinase Iα (CKIα) and induction of chronic DNA damage and TP53 mutations are increased compared to x-ray irradiation. Proton irradiation also increases the number of colonic polyps, carcinomas and invasive adenocarcinomas. Pretreatment with the non-steroidal anti-inflammatory drug, CDDO-EA, reduces proton irradiation associated SIR and tumorigenesis. Thus, exposure to proton irradiation elicits significant changes in colorectal cancer initiation and progression that can be mitigated using CDDO-EA.

Learning curve analysis of colorectal endoscopic submucosal dissection (ESD) for laterally spreading tumors by endoscopists experienced in gastric ESD

BACKGROUND

Endoscopic submucosal dissection (ESD) for various colorectal neoplasms is more technically difficult than gastric ESD. We evaluated treatment outcomes and the learning curve for colorectal ESD of laterally spreading tumors (LSTs) based on the experience of a single endoscopist.

METHODS

We included 93 colorectal ESD procedures for colorectal LST that were performed between March 2009 and June 2012 by a single experienced endoscopist who previously performed hundreds of cases of gastric ESD. The cases were grouped chronologically into three periods by multi-dimensional analyses. For procedure time, the learning curve was analyzed using the moving average method, and for complication, the learning curve was analyzed using cumulative sum (cusum) method.

RESULTS

The median procedure time for 93 colorectal ESD was 45 min, and the rates of en bloc resection and R0 resection were 89.25 and 83.87 %. When results were compared among three periods in order to determine the learning curve, the procedure time and en bloc resection rates were not significantly different. However, the procedure proficiency (about 0.16 cm(2)/min) was significantly faster during the second period, after about 25 cases of colorectal ESD. In the third period (about 50 cases), the number and rate of en bloc resection (over 90 %) reached the same as that of en bloc R0 resection. When comparing outcomes based on LST subtype, the procedure proficiency of LST-granular type (LST-G) was significantly faster than that of LST-non granular type (LST-NG) (LST-NG, 0.072 cm(2)/min; LST-G, 0.157 cm(2)/min; p = 0.01).

CONCLUSION

Endoscopists fully experienced in gastric ESD need a relatively short learning period for colorectal ESD in terms of procedure time and complication. However, approximately 50 cases might be needed to acquire an adequate skill of colorectal ESD for LST in an experienced gastric ESD endoscopist. Colorectal ESD for LST-NG seems to have higher technical difficulty and a longer learning curve than LST-G.

Current concepts of colorectal cancer resection pathology

The discussion of pathology results is one of the important items in the multidisciplinary meeting. These results describe not only the adequacy of earlier treatments (neoadjuvant therapy, surgery), but guide subsequent treatment decisions by providing staging information and additional prognostic and predictive factors. In the era of next-generation sequencing, every so often the emphasis is put on the molecular background of tumours, but the information that can be retrieved from the resection specimen remains essential for optimal patient care. In the current review the different surgical approaches will be described, together with the relevant macroscopic evaluations. Microscopic features will be addressed, giving an overview that is aimed at optimal information exchange in the multidisciplinary meeting. Finally, special requirements for reporting local excisions and specimen after neoadjuvant therapy will be discussed.

Long-Term Outcomes of Endoscopic Versus Surgical Resection of Superficial Submucosal Colorectal Cancer

BACKGROUND

The long-term outcomes of endoscopic resection of superficial submucosal colorectal cancer (CRC) had not been adequately compared with those of surgical resection.

AIMS

We aimed to compare the long-term clinical outcomes of endoscopic resection of superficial submucosal CRC to those of surgical resection.

METHODS

Submucosal CRC patients with a tumor depth of sm1 or less than 1 mm from the muscularis mucosa were enrolled. Patients with unfavorable histology, such as poorly differentiated cancer or lymphovascular invasion, were excluded. Recurrence-free survival and overall survival were investigated in 87 patients who underwent endoscopic resection and in 171 patients who underwent surgical resection.

RESULTS

The mean ages of the endoscopic and surgical resection groups were 59.7 and 59.8 years, respectively. Hospital stay was shorter in the endoscopic resection group (1.7 ± 1.6 vs. 8.6 ± 3.8 days; p < 0.001). The 3- and 5-year recurrence-free survival rates were 98.7 and 96.7 % in the endoscopic resection group and 98.7 and 97.5 % in the surgical resection group, respectively (p = 0.837). The 3- and 5-year overall survival rates were 100.0 and 95.2 % in the endoscopic resection group and 98.7 and 92.8 % in the surgical resection group, respectively (p = 0.928). Recurred cases showed an unfavorable histology that was overlooked at the time of initial resection.

CONCLUSIONS

Long-term outcomes after endoscopic resection of superficial submucosal CRC are comparable to those after surgical resection. Thorough initial histopathological evaluations are needed to guarantee the correct indication for endoscopic resection of submucosal CRC.

The Ueno method for substaging pT1 colorectal adenocarcinoma by depth and width measurement: an interobserver study

AIM

Early pT1 polyp colorectal cancers (CRCs) present challenges for accurate pathology substaging. Haggitt and Kikuchi stages depend on polyp morphology and are often difficult to apply due to suboptimal orientation or fragmentation, or absence of the muscularis propria in polypectomy or submucosal resection specimens. European guidelines for quality assurance suggest using Ueno's more objective approach, using depth and width measurements beyond muscularis mucosae. We have investigated interobserver variation using Ueno's approach.

METHOD

Ten consecutive pT1 polyp CRCs were identified and the slides assessed by six gastrointestinal pathologists for depth and width of invasion. A further 60 polyps were studied by a group of specialist and general pathologists. Agreement was assessed by analysis of variance. A polyp CRC is classified as high risk if it has a depth ≥ 2000 μm or a width ≥ 4000 μm and low risk with a depth < 2000 μm or a width < 4000 μm. Concordance for the dichotomized values was assessed using the kappa statistic.

RESULTS

The intraclass correlation coefficient (ICC) for depth was 0.83 and for width 0.56 in the 10-polyp group. The ICC for the 60-polyp CRCs was 0.67 for depth and 0.37 for width. In both groups, when polyp CRCs are divided into high- and low-risk categories based on depth, there was substantial and moderate agreement (κ = 0.80 and 0.47) but only fair agreement when based on width (κ = 0.34 and 0.35).

CONCLUSION

Ueno's method has the advantage of being independent of polyp morphology. Our study shows better concordance for depth measurement and reproducibility in nonfragmented specimens, with poorer agreement when based on width.

Gene expression profiling of laterally spreading tumors

BACKGROUND

Laterally spreading tumors (LSTs) are generally defined as lesions >10 mm in diameter, are characterized by lateral expansion along the luminal wall with a low vertical axis. In contrast to other forms of tumor, LSTs are generally considered to have a superficial growth pattern and the potential for malignancy. We focused on this morphological character of LSTs, and analyzed the gene expression profile of LSTs.

METHODS

The expression of 168 genes in 41 colorectal tumor samples (17 LST-adenoma, 12 LST-carcinoma, 12 Ip [pedunculated type of the Paris classification)-adenoma, all of which were 10 mm or more in diameter] was analyzed by PCR array. Based on the results, we investigated the expression levels of genes up-regulated in LST-adenoma, compared to Ip-adenoma, by hierarchical and K-means clustering. To confirm the results of the array analysis, using an additional 60 samples (38 LST-adenoma, 22 Ip-adenoma), we determined the localization of the gene product by immunohistochemical staining.

RESULT

The expression of 129 genes differed in colorectal tumors from normal mucosa by PCR array analysis. As a result of K-means clustering, the expression levels of five genes, AKT1, BCL2L1, ERBB2, MTA2 and TNFRSF25, were found to be significantly up-regulated (p < 0.05) in LST-adenoma, compared to Ip-adenoma. Immunohistochemical analysis showed that the BCL2L1 protein was significantly and meaningfully up-regulated in LST-adenoma compared to Ip-adenoma (p = 0.010). With respect to apoptosis status in LST-Adenoma, it assumes that BCL2L1 is anti-apoptotic protein, the samples such as BCL2L1 positive and TUNEL negative, or BCL2L1 negative and TUNEL positive are consistent with the assumption. 63.2 % LST-adenoma samples were consistent with the assumption.

CONCLUSIONS

LSTs have an unusual profile of gene expression compared to other tumors and BCL2L1 might be concerned in the organization of LSTs.

A clinical model for predicting lymph node metastasis in submucosal invasive (T1) colorectal cancer

BACKGROUND

No single histopathological feature of submucosal invasive colorectal cancer (T1-CRC) can reliably predict the risk for lymph node metastasis (LNM).

AIM

The purpose of the study was to develop a prediction model of LNM in T1-CRC.

METHODS

Ninety-seven surgically resected T1-CRC at our institution were retrospectively evaluated. Morphology, localization, grading, mode of growth, presence of background adenoma, lymphoid infiltration, angiolymphatic invasion, budding, and depth of invasion were assessed. Mortality and morbidity related to surgery were also evaluated. Benefit-risk balance was assessed according to the presence of severe complications and to the presence of LNM.

RESULTS

Fourteen cases had LNM (14%). Eight patients (8%) presented severe surgical complications and there were two deaths (2 %). Infiltrative growth pattern (OR 31.91, 95% CI 2.37-428.36; p = 0.009) and the absence of lymphoid infiltrate (OR 28.75; 95% CI 2.13-388.37; p = 0.011) were the only variables independently associated with LNM in the multivariate analysis. Both variables were included in the prediction model together with sessile morphology (OR 4.88; 95% CI 0.81-29.3; p = 0.083) and poorly differentiated carcinoma (OR 11.77; 95% CI 0.77-179.83; p = 0.076). A 0-100 score was developed (infiltrative growth pattern: no = 0, yes = 33; lymphoid infiltrate: no = 29, yes = 0; sessile morphology: no = 0, yes = 15; poorly differentiated: no = 0, yes = 23). Cutoff point to indicate additional surgery was set in 35 points (i.e., 10% risk LNM). Discrimination of the prediction model was excellent (AUC 0.90; 95% CI 0.81-0.99).

CONCLUSION

Combined evaluation of infiltrative growth pattern, lymphoid infiltration, poorly differentiated carcinoma, and sessile appearance showed good performance for discriminating T1-CRC patients with LNM. The benefit-risk balance was in favor of surgery when at least two of these criteria were present.

Relationship between indeterminate or positive lateral margin and local recurrence after endoscopic resection of colorectal polyps

BACKGROUND AND STUDY AIMS

Although endoscopic resection is widely used for the treatment of superficial colorectal neoplasms, the rate of local recurrence of lesions with a positive or indeterminate lateral margin on histologic evaluation is unclear. We aimed to demonstrate the relationship between lateral margin status and local recurrence after the endoscopic resection of intramucosal colorectal neoplasms.

PATIENTS AND METHODS

We retrospectively collected the clinical and pathologic data for 844 endoscopically resected colorectal intramucosal neoplasms with a size of 10 mm or larger. We investigated the relationship between the local recurrence rate and the lateral margin status (categorized as LM0 [negative], LM1 [positive], or LMX [indeterminate]).

RESULTS

In total, 389 lesions were evaluated as LM0 and showed no local recurrence. Of the 455 lesions evaluated as LMX or LM1, 30 showed local recurrence within a median period of 6.3 months (range, 1.7 - 48.1) from the initial endoscopic resection. The local recurrence rate of the en bloc-LMX group (2.2 %) was significantly lower than that of the piecemeal-LMX group (15.2 %). Of the 30 cases of recurrence, 28 were successfully treated with a second endoscopic resection. Of the two lesions that showed further recurrence, one was treated with a third endoscopic resection, whereas the other - which was a piecemeal-LMX lesion - was eventually diagnosed as invasive cancer and treated with surgery.

CONCLUSIONS

The local recurrence rate was lower in the en bloc-LMX group than in the piecemeal-LMX group. Thus, we believe that en bloc-LMX lesions that are completely and confidently resected endoscopically can be treated as en bloc-LM0 lesions.

A three-tier classification system based on the depth of submucosal invasion and budding/sprouting can improve the treatment strategy for T1 colorectal cancer: a retrospective multicenter study

More than 85% of patients with T1 colorectal cancer have no lymph node metastasis and can be cured by endoscopic resection. To avoid unnecessary surgery after complete endoscopic resection, accurate histologic methods for evaluating resected specimens are needed to discriminate those at high risk for lymph node metastasis. A retrospective multi-institutional, cross-sectional study of 806 T1 colorectal cancer patients was conducted. A budding/sprouting score was incorporated for predicting lymph node metastasis in addition to other parameters, including the depth of submucosal invasion, histologic grade, and lymphovascular invasion. Lymph node metastasis was detected in 97 patients. Independent predictors of lymph node metastasis by multivariate analysis were depth of submucosal invasion ≥1000 μm (odds ratio (95% confidence interval)=5.56 (2.14-19.10)) and high-grade budding/sprouting (3.14 (1.91-5.21)). Among lesions with a depth of submucosal invasion ≥1000 μm, lymph node metastasis was detected in 59 (29%) of 207 patients with high-grade budding/sprouting, and in 34 (9%) of 396 with low-grade budding/sprouting. Lymph node metastasis was detected in only 4 (2%) of 203 lesions with a depth of submucosal invasion <1000 μm. Of these four tumors, three invaded lymphatic and/or venous vessels. Thus, the risk for lymph node metastasis can be classified into three groups: high risk with a depth of submucosal invasion ≥1000 μm and high-grade budding/sprouting, intermediate-risk with a depth of submucosal invasion ≥1000 μm and low-grade budding/sprouting, and low-risk with a depth of submucosal invasion <1000 μm. These findings revealed that a depth of submucosal invasion ≥1000 μm and high-grade budding/sprouting are powerful predictive parameters for lymph node metastasis in T1 colorectal cancer. This three-tier risk classification system will facilitate the decision for additional major surgery for T1 colorectal cancer patients after successful endoscopic treatment.

JGES guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Colorectal endoscopic submucosal dissection (ESD) has become common in recent years. Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also many types of precarcinomatous adenomas. It is important to establish practical guidelines in which the preoperative diagnosis of colorectal neoplasia and the selection of endoscopic treatment procedures are properly outlined, and to ensure that the actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with the guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society has recently compiled a set of colorectal ESD/endoscopic mucosal resection (EMR) guidelines using evidence-based methods. The guidelines focus on the diagnostic and therapeutic strategies and caveat before, during, and after ESD/EMR and, in this regard, exclude the specific procedures, types and proper use of instruments, devices, and drugs. Although eight areas, ranging from indication to pathology, were originally planned for inclusion in these guidelines, evidence was scarce in each area. Therefore, grades of recommendation were determined largely through expert consensus in these areas.

Area of submucosal invasion and width of invasion predicts lymph node metastasis in pT1 colorectal cancers

BACKGROUND

The prediction of lymph node metastasis by current histopathological methods is imprecise.

OBJECTIVE

The aim of this study was to evaluate currently used and possible new high-risk features associated with lymph node metastasis to identify the markers of lymph node metastasis.

DESIGN/PATIENT/SETTING

Two hundred seven pT1 cancers were identified through the Northern and Yorkshire Cancer Registry and Information Services database and digitally scanned. Phenotypic and quantitative features of the pT1 cancers were evaluated. Lymph node metastasis and high-risk feature status were obtained through pathology reports of resections, and high-risk phenotypic features were identified.

RESULTS

Lymph node metastasis was noted in 19 patients (9.2%). pT1 cancers with lymph node metastasis had a significantly wider area of invasion (p = 0.001) and greater area of submucosal invasion (p < 0.001) compared with pT1 cancers without lymph node metastasis. Qualitative features such as grade of differentiation and vascular and lymphatic invasion were significant predictors of lymph node metastasis (p < 0.0001, p = 0.039, and p = 0.018). Modified receiver-operating characteristics curves generated cutoff values of 11.5 mm for the width of invasion and 35 mm(2) for the area of submucosal invasion. When tested separately with other qualitative factors on multivariate analysis, both width greater than 11.5 mm (OR, 12.12; 95% CI, 2.19-67.23; p = 0.004) and area of submucosal invasion greater than 35 mm(2) (OR, 22.44; 95% CI, 2.7-186.63; p = 0.004) was predictive of lymph node metastasis.

LIMITATIONS

This is a retrospective study and is limited by its small sample size.

CONCLUSION

This study has shown that the width and area of submucosal invasion are potential predictors of lymph node metastasis and superior to the depth of invasion. Together with the other qualitative phenotypic features, these quantitative factors could be used to decide the most appropriate treatment for pT1 cancers.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines 2014 for treatment of colorectal cancer

Colorectal cancer is a major cause of death in Japan, where it accounts for the largest number of deaths from malignant neoplasms among women and the third largest number among men. Many new methods of treatment have been developed during recent decades. The Japanese Society for Cancer of the Colon and Rectum Guidelines 2014 for treatment of colorectal cancer (JSCCR Guidelines 2014) have been prepared as standard treatment strategies for colorectal cancer, to eliminate treatment disparities among institutions, to eliminate unnecessary treatment and insufficient treatment, and to deepen mutual understanding among health-care professionals and patients by making these guidelines available to the general public. These guidelines have been prepared as a result of consensuses reached by the JSCCR Guideline Committee on the basis of careful review of evidence retrieved by literature searches and taking into consideration the medical health insurance system and actual clinical practice in Japan. They can, therefore, be used as a guide for treating colorectal cancer in clinical practice. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. As a result of the discussions of the Guideline Committee, controversial issues were selected as clinical questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories, on the basis of consensus reached by Guideline Committee members. Here we present the English version of the JSCCR Guidelines 2014.

Evidence-based clinical practice guidelines for management of colorectal polyps

BACKGROUND

Recently in Japan, the morbidity of colorectal polyp has been increasing. As a result, a large number of cases of colorectal polyps that are diagnosed and treated using colonoscopy has now increased, and clinical guidelines are needed for endoscopic management and surveillance after treatment.

METHODS

Three committees [the professional committee for making clinical questions (CQs) and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators] were organized. Ten specialists for colorectal polyp management extracted the specific clinical statements from articles published between 1983 and September 2011 obtained from PubMed and a secondary database, and developed the CQs and statements. Basically, statements were made according to the GRADE system. The expert panel individually rated the clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than seven on a nine-point scale from the panel was regarded as valid.

RESULTS

The professional committee created 91CQs and statements for the current concept and diagnosis/treatment of various colorectal polyps including epidemiology, screening, pathophysiology, definition and classification, diagnosis, treatment/management, practical treatment, complications and surveillance after treatment, and other colorectal lesions (submucosal tumors, nonneoplastic polyps, polyposis, hereditary tumors, ulcerative colitis-associated tumor/carcinoma).

CONCLUSIONS

After evaluation by the moderators, evidence-based clinical guidelines for management of colorectal polyps have been proposed for 2014.

Safe and efficient colorectal endoscopic submucosal dissection in European settings: is successful implementation of the procedure possible?

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD) is gaining worldwide recognition as valuable alternative to treat early colorectal neoplasia. Although the method is perceived as technically difficult and carries a higher risk of complications than conventional endoscopy, the oncological results are very promising. Herein we aim to present the treatment outcomes of ESD for lesions in the colon and rectum at the beginning of our learning curve.

METHODS

Seventy consecutive cases of colorectal ESD carried out in our center between June 2013 and May 2014 were analyzed. Effectiveness of dissection, complications and tumor recurrence after 3 months of treatment were investigated.

RESULTS

Of the 70 ESD procedures, 39 were in the rectum, 10 in the sigmoid, eight in the descending colon, six in the ascending colon and seven in the cecum. Average size of removed tumors was 38.1 mm. In 50 cases, en-block resection was achieved. In this group, 97% cases were R0 resection. Perforation occurred in four cases (5.7%) of which three were managed with endoclips. In four cases, significant bleeding occurred. In a follow-up examination, two of 41 patients (4.9%) had recurrent adenoma that was successfully endoscopically removed.

CONCLUSIONS

The results confirm that ESD is an effective and safe modality for treatment of colorectal epithelial neoplasia in the colon and rectum even at the beginning of the learning curve. After proper training, results in Europe and Japan may be comparable.

Efficacy and adverse events of EMR and endoscopic submucosal dissection for the treatment of colon neoplasms: a meta-analysis of studies comparing EMR and endoscopic submucosal dissection

BACKGROUND

EMR and endoscopic submucosal dissection (ESD) are used frequently to remove colon neoplasms. However, the predominance of these procedures has not yet been thoroughly explored.

OBJECTIVE

To compare the efficacy and adverse events related to EMR with those related to ESD for colon neoplasms.

DESIGN

A meta-analysis of 8 studies published between 2005 and 2013.

SETTING

Multicenter review.

PATIENTS

Patients from 8 studies yielding 2299 lesions.

INTERVENTIONS

EMR or ESD.

MAIN OUTCOME MEASUREMENTS

En bloc resection, curative resection, recurrence, and adverse events.

RESULTS

The pooled odds ratios (OR) (OR [95% confidence interval]) for the tumor size, length of the procedure, en bloc resection, curative resection, recurrence, additional surgery, delayed bleeding, and perforation by ESD versus EMR were 7.38 (6.42-8.34), 58.07 (36.27-79.88), 6.84 (3.30-14.18), 4.26 (3.77-6.57), 0.08 (0.04-0.17), 2.16 (1.16-4.03), 0.85 (0.45-1.60), and 4.96 (2.79-8.85), respectively.

LIMITATIONS

This analysis included only nonrandomized studies.

CONCLUSION

The size of the tumor and rate of en bloc resection and curative resection were higher, and the rate of recurrence was lower in the ESD group versus the EMR group. However, in the ESD group, the procedure was longer, and the rate of additional surgery and perforation was higher, suggesting that the indications for ESD should therefore be rigorously determined in order to avoid such problems.

Endoscopic mucosal resection with circumferential incision for the treatment of large sessile polyps and laterally spreading tumors of the colorectum

Background/Aims

Endoscopic mucosal resection (EMR) is the standard treatment for colorectal polyps such as adenomas and early cancers with no risk of lymph node metastasis. However, endoscopic resection of large colorectal polyps (≥20 mm diameter) is difficult to perform. We evaluated the clinical outcomes of EMR with circumferential incision (EMR-CI) for the resection of large sessile polyps (Is) and laterally spreading tumors (LSTs) in the colorectum.

Methods

Between February 2009 and March 2011, we resected 80 large colorectal polyps by EMR-CI. We retrospectively investigated the en bloc resection rate, histologic complete resection rate, recurrence rate, and complications.

Results

The median polyp size was approximately 25 mm (range, 20 to 50), and the morphologic types included Is (13 cases), LST-granular (37 cases), and LST-nongranular (30 cases). The en bloc and complete histologic resection rates were 66.3% and 45.0%, respectively. The recurrence rate was 0% (median follow-up duration, 23 months), and perforation occurred in five cases (6.3%).

Conclusions

EMR-CI is an effective treatment modality for 20 to 30 mm-sized colorectal polyps, and may be considered as a second line therapeutic option if ESD is difficult.

Endoscopic Band Ligation For Treatment of a Colonic Polyp Extending Into the Colonic Diverticulum

A 66-year-old male was referred for the treatment of a polyp extending into a diverticulum. Endoscopic band ligation (EBL) was used to resolve the diverticulum. The banded diverticulum resolved and scar formation was observed 2 months after EBL. Residual small polypoid lesions were resected using endoscopic mucosal resection (EMR), and no complications occurred after treatment.

Towards safer and appropriate application of endoscopic submucosal dissection for T1 colorectal carcinoma as total excisional biopsy: future perspectives

According to the Japanese Society for Cancer of the Colon and Rectum Guidelines 2014 for the Treatment of Colorectal Cancer, cases with T1 colorectal carcinoma should be considered for additional colectomy with lymph node dissection when histologically complete en bloc resection is endoscopically carried out and when one of the four risk factors listed below is present. These four risk factors are: (i) submucosal (SM) invasion depth ≥1000 μm; (ii) positive vascular invasion; (iii) poorly differentiated adenocarcinoma, signet ring cell carcinoma, or mucinous carcinoma; and (iv) grade 2/3 budding at the deepest part of SM invasion. However, the probability of lymph node metastasis is extremely low if none of these risk factors are present, with the exception of SM invasion depth ≥1000 μm. Consequently, it is assumed that there will be an increasing number of cases where no additional surgery is done, or cases of moderate invasive carcinoma in which endoscopic treatment is carried out to achieve an excisional biopsy, for which complete resection is applicable. In these cases, the preoperative diagnosis, resection techniques such as endoscopic submucosal dissection, features of resected specimens, and the accuracy of pathological diagnosis are all extremely important.

Risk assessment in early colorectal cancer: histological and molecular markers

The pathological examination of early colorectal cancer specimens, in particular 'malignant polyps', provides important prognostic information. The depth of invasion into the submucosal layer assessed according to the Haggitt (for pedunculated lesions) or Kikuchi (for nonpolypoid lesions) classification systems or by direct measurement has been associated with the risk of lymph node metastasis. Angioinvasion, in particular lymphatic invasion, budding, tumor differentiation or grade, and resection margin status have been identified as further risk factors. The combination of these parameters allows the stratification of affected individuals into low- and high-risk categories, which is pivotal for clinical management. For low-risk cancers, defined as a completely excised Haggitt level 1-3/Kikuchi sm1 tumor with no evidence of poor differentiation or angioinvasion, local excision is generally regarded as adequate treatment. Oncological surgical resection is, however, indicated for high-risk cancers, which show at least one of the following features: Haggitt level 4/Kikuchi sm3 invasion, the presence of lymphatic (or vascular) invasion, poor differentiation, or positive resection margin. The inclusion of molecular markers such as tumor suppressor genes and their products, markers involved in tumor vascularization, and markers related to tumor cell adhesion and invasion may help to refine risk stratification, but data on molecular markers are still limited in this regard.

Endoscopic mucosal resection for middle and large colorectal polyps with a double-loop snare

BACKGROUND/AIMS

This study aimed to analyze the endoscopic mucosal resection (EMR) with a novel uniquely shaped, double-loop snare (Dualoop, Medico's Hirata Inc., Tokyo, Japan) for colorectal polyps.

METHODS

This was a clinical trial conducted in two referral centers, Kyoto Prefectural University of Medicine and National Cancer Center Hospital in Japan. First, the firmness of various snares including 'Dualoop' was experimentally analyzed with a pressure gauge. Five hundred and eighty nine consecutive polyps that underwent EMR with 'Dualoop' were compared to 339 polyps with the standard round snare. Lesion characteristics, en bloc resection, and complications were analyzed.

RESULTS

'Dualoop' had the most firmness among the various snares. The average tumor size was 9.3 mm (5-30), and en bloc resection was achieved in 95.4%. The rate of en bloc resection for middle polyps 15-19 mm in diameter was significantly higher with the 'Dualoop' than that with the round snare (97.9 vs. 80.0%, p < 0.05). The rate of en bloc resection was 64.7% for large polyps ≥20 mm in diameter using 'Dualoop'. Higher age, larger tumor size, and superficial polyps were associated with the failure of en bloc resection.

CONCLUSION

EMR with 'Dualoop' was effective for resecting both middle and large polyps en-bloc.

Management of malignant colon polyps: Current status and controversies

Colon cancer remains a significant clinical problem worldwide and in the United States it is the third most common cancer diagnosed in men and women. It is generally accepted that most malignant neoplasms of the colon arise from precursor adenomatous polyps. This stepwise progression of normal epithelium to carcinoma, often with intervening dysplasia, occurs as a result of multiple sequential, genetic mutations-some are inherited while others are acquired. Malignant polyps are defined by the presence of cancer cells invading through the muscularis mucosa into the underlying submucosa (T1). They can appear benign endoscopically but the presence of malignant invasion histologically poses a difficult and often controversial clinical scenario. Emphasis should be initially focused on the endoscopic assessment of these lesions. Suitable polyps should be resected en-bloc, if possible, to facilitate thorough evaluation by pathology. In these cases, proper attention must be given to the risks of residual cancer in the bowel wall or in the surrounding lymph nodes. If resection is not feasible endoscopically, then these patients should be referred for surgical resection. This review will discuss the important prognostic features of malignant polyps that will most profoundly affect this risk profile. Additionally, we will discuss effective strategies for their overall management.

Inter-observer agreement in the endoscopic classification of colorectal laterally spreading tumors: a multicenter study between experts and trainees

BACKGROUND AND AIM

The risk of cancer varies with the subtype of colorectal "laterally spreading tumors" (LSTs). However, visual interpretations vary among endoscopists. The aim of this study was to evaluate inter-observer agreement and accuracy in the endoscopic classification of LST subtypes among experts and trainees.

METHODS

In total, 40 LST images were collected and reviewed independently by 14 gastroenterology experts and 10 trainees. All investigators recorded their findings as one of the following four categories: homogeneous, nodular mixed, flat-elevated, and pseudo-depressed. Agreement was assessed in terms of the kappa (κ) statistic and AC1 estimate. Accuracy is reported as percentage agreement with the gold standard, based on the gross morphology of the resected specimens.

RESULTS

Of the possible 91 pair-wise κ estimates among experts, 41 (45.1%) were >0.75, indicating excellent agreement, while only 2 (4.44%) of the 45 pair-wise κ estimates among trainees were >0.75. Agreements for individual LST subtypes in the trainee group were significantly lower than those in the expert group. The κ and AC1 estimates showed similar values in individual subtypes of LSTs. The overall accuracy of LST was also significantly higher for the experts than the trainees (85.9 vs. 72.5%, P < 0.001). Notably, the flat-elevated subtype showed the lowest agreement and accuracy and was frequently misclassified as the pseudo-depressed subtype by both groups.

CONCLUSIONS

Inter-observer agreement and accuracy for LST subtype classification differ significantly between experts and trainees. Implementation of an adequate training system for beginners is necessary to better identify colorectal LSTs.

Clinicopathological differences of laterally spreading tumors arising in the colon and rectum

PURPOSE

Laterally spreading tumors (LST) have been recognized worldwide. The aim of our retrospective study was to evaluate the clinicopathological differences of LST arising in the colon and rectum.

METHODS

We investigated the clinical records of consecutive patients with LST that were endoscopically or surgically resected at our hospital between February 2006 and March 2011. LST were classified into three types: granular-homogenous (LST-GH), granular-nodular mixed (LST-GM), and nongranular (LST-NG) types. We also defined the hardly elevated flat lesion with a dilated pit pattern that occurs at the margins of LST as the "skirt." The clinicopathological characteristics of the LST arising in the colon and rectum, including the presence of the skirt, were compared.

RESULTS

A total of 496 colorectal LST in 435 patients were examined. LST-GM was predominant in the rectum, whereas LST-NG was predominant in the colon (p < 0.001). The mean tumor size was larger in the rectum (39.3 ± 17.9 mm) than the colon (25.8 ± 13.6 mm) (p < 0.001). Low-grade dysplasia frequency was lower in the rectum than the colon (4 vs. 37%, p < 0.001). The skirt was identified in 15 lesions (3.0%), with a higher incidence in the rectum than the colon (17 vs. 0.5%, p < 0.001). The skirt was found only in LST-GM.

CONCLUSIONS

A greater proportion of LST-GM, greater mean size, and lower incidence of low-grade dysplasia were found in rectal LST. The skirt was a novel and unique finding, primarily observed in rectal LST-GM cases.

Novel risk factors for lymph node metastasis in early invasive colorectal cancer: a multi-institution pathology review

BACKGROUND

Novel risk factors for lymph node metastasis (LNM) in T1 colorectal cancer (CRC) have been recently proposed, but most have not been implemented because of the lack of validation. Here we determined the value of poorly differentiated clusters (PDCs) in a multi-institutional cohort of T1 CRC cases.

METHODS

A pathology review involving 30 institutions was conducted for 3556 T1 CRCs. PDC was defined as malignant clusters comprising ≥5 cells and lacking a glandular formation. The ability to identify LNM risk was compared using Akaike's information criterion (AIC).

RESULTS

PDC was observed in 1401 tumors (39.4 %), including 94 (17.8 %) with <1000 µm submucosal invasion and 1307 (43.2 %) with ≥1000 µm submucosal invasion (P < 0.0001). The incidence of LNM was higher in PDC-positive tumors (17.4 %) than in PDC-negative tumors (6.9 %; P < 0.0001), and PDCs had an adverse impact on LNM irrespective of the degree of submucosal invasion. Grade 3, vascular invasion, budding, and submucosal invasion depth were also significant factors (all, P < 0.0001). AIC of risk factor to identify LNM risk was most favorable for vascular invasion (2273.4), followed by PDC (2357.4); submucosal invasion depth (2429.1) was the most unfavorable. Interinstitutional judgment disparities were smaller in PDC (kappa, 0.51) than vascular invasion (0.33) or tumor grade (0.48).

CONCLUSIONS

PDC is a promising new parameter with good ability to identify LNM risk. Use of its appropriate judgment criteria will enable us determine whether an observational policy can be safely applied following local tumor excision in T1 CRC cases.

Distinct molecular features of different macroscopic subtypes of colorectal neoplasms

BACKGROUND

Colorectal adenoma develops into cancer with the accumulation of genetic and epigenetic changes. We studied the underlying molecular and clinicopathological features to better understand the heterogeneity of colorectal neoplasms (CRNs).

METHODS

We evaluated both genetic (mutations of KRAS, BRAF, TP53, and PIK3CA, and microsatellite instability [MSI]) and epigenetic (methylation status of nine genes or sequences, including the CpG island methylator phenotype [CIMP] markers) alterations in 158 CRNs including 56 polypoid neoplasms (PNs), 25 granular type laterally spreading tumors (LST-Gs), 48 non-granular type LSTs (LST-NGs), 19 depressed neoplasms (DNs) and 10 small flat-elevated neoplasms (S-FNs) on the basis of macroscopic appearance.

RESULTS

S-FNs showed few molecular changes except SFRP1 methylation. Significant differences in the frequency of KRAS mutations were observed among subtypes (68% for LST-Gs, 36% for PNs, 16% for DNs and 6% for LST-NGs) (P<0.001). By contrast, the frequency of TP53 mutation was higher in DNs than PNs or LST-Gs (32% vs. 5% or 0%, respectively) (P<0.007). We also observed significant differences in the frequency of CIMP between LST-Gs and LST-NGs or PNs (32% vs. 6% or 5%, respectively) (P<0.005). Moreover, the methylation level of LINE-1 was significantly lower in DNs or LST-Gs than in PNs (58.3% or 60.5% vs. 63.2%, P<0.05). PIK3CA mutations were detected only in LSTs. Finally, multivariate analyses showed that macroscopic morphologies were significantly associated with an increased risk of molecular changes (PN or LST-G for KRAS mutation, odds ratio [OR] 9.11; LST-NG or DN for TP53 mutation, OR 5.30; LST-G for PIK3CA mutation, OR 26.53; LST-G or DN for LINE-1 hypomethylation, OR 3.41).

CONCLUSION

We demonstrated that CRNs could be classified into five macroscopic subtypes according to clinicopathological and molecular differences, suggesting that different mechanisms are involved in the pathogenesis of colorectal tumorigenesis.

Endoscopic resection as the first-line treatment for early colorectal cancer: comparison with surgery

INTRODUCTION

Endoscopic resection has emerged as an alternative therapeutic option for selected cases of early colorectal cancer. However, even now, few data are available on the comparative effectiveness of endoscopic versus surgical resection of early colorectal cancer. The aim of our study was to compare the clinical outcomes in patients with early colorectal cancer who underwent endoscopic resection and those who underwent surgical resection.

METHODS

292 early colorectal cancer lesions in 287 patients who were treated with either endoscopic resection or colorectal surgery (open or laparoscopic colorectal resection) between January 2005 and December 2010 were retrospectively analyzed. After excluding 54 deep submucosal lesions [and/or tumor budding (Grade 2 or 3)], a total of 168 lesions with mucosal/superficial submucosal invasion were treated by endoscopic resection, and 70 lesions with mucosal/superficial submucosal invasion were treated by colorectal surgery.

RESULTS

In the endoscopic resection group, the en bloc resection rate and the complete resection rate were 91.1 and 91.1%, respectively. In the colorectal surgery group, both the en bloc resection rate and the curative resection rate were 100%. However, using Log rank test in Kaplan-Meier curve, no significant difference in recurrence rate (including metachronous cancer) during the median follow-up period of 37 months (range, 6-98 months) was observed between the two groups (p = 0.647). In addition, a similar morbidity rate was observed for endoscopic resection compared with surgery (5.4 vs. 5.7%, p = 0.760). A significantly shorter hospital stay was observed in the endoscopic resection group than colorectal surgery group [median 2 days (range, 2-29) vs. median 10 days (range, 7-37), p < 0.001).

CONCLUSION

We suggest that endoscopic resection, being equally effective but less invasive than surgery, can be the first-line treatment for well selected early colorectal cancer.

Colorectal laterally spreading tumors show characteristic expression of cell polarity factors, including atypical protein kinase C λ/ι, E-cadherin, β-catenin and basement membrane component

Colorectal flat-type tumors include laterally spreading tumors (LSTs) and flat depressed-type tumors. The former of which shows a predominant lateral spreading growth rather than an invasive growth. The present study examined the morphological characteristics of LSTs, in comparison with polypoid- or flat depressed-type tumors, along with the expression of atypical protein kinase C (aPKC) λ/ι, a pivotal cell polarity regulator, and the hallmarks of cell polarity, as well as with type IV collagen, β-catenin and E-cadherin. In total, 37 flat-type (24 LSTs and 13 flat depressed-type tumors) and 20 polypoid-type colorectal tumors were examined. The LSTs were classified as 15 LST adenoma (LST-A) and nine LST cancer in adenoma (LST-CA). An immunohistochemical examination was performed on aPKC λ/ι, type IV collagen, β-catenin and E-cadherin. The LST-A and -CA showed a superficial replacing growth pattern, with expression of β-catenin and E-cadherin in the basolateral membrane and type IV collagen along the basement membrane. In addition, 86.6% of LST-A and 55.6% of LST-CA showed aPKC λ/ι expression of 1+ (weak to normal intensity staining in the cytoplasm compared with the normal epithelium). Furthermore, ~45% of the polypoid-type adenomas showed 2+ (moderate intensity staining in the cytoplasm and/or nucleus) and 66.7% of the polypoid-type cancer in adenoma were 3+ (strong intensity staining in the cytoplasm and nucleus). A statistically significant positive correlation was observed between the expression of aPKC λ/ι and β-catenin (r=0.842; P<0.001), or type IV collagen (r=0.823; P<0.001). The LSTs showed a unique growth pattern, different from the expanding growth pattern presented by a polypoid tumor and invasive cancer. The growth characteristics of LST appear to be caused by adequate coexpression of β-catenin, type IV collagen and aPKC λ/ι.

Prospective clinical trial of traction device-assisted endoscopic submucosal dissection of large superficial colorectal tumors using the S-O clip

BACKGROUND

Endoscopic submucosal dissection (ESD) allows en bloc resection of superficial colorectal tumors regardless of size. However, ESD is technically difficult, hazardous, and time consuming. New devices may help overcome these drawbacks. We focused on traction methods and designed a new traction device, the "S-O clip." Its main advantage is that it allows direct visualization of the cutting line during submucosal dissection. Moreover, it can be used at any location without withdrawing the endoscope. The purpose of this study was to evaluate the efficacy and safety of traction device-assisted ESD for large colorectal tumors using the S-O clip.

METHODS

Between August 2010 and December 2011, ESD was performed in 70 patients with a superficial colorectal tumor ≥20 mm in diameter in our department. Patients were randomized into two groups: 27 cases in the S-O clip-assisted ESD group and 23 cases in the conventional ESD group. Included in the analysis were patient's gender and age, tumor form, size, and location, rate of en bloc resection, procedure time, presence or absence of intraoperative perforation or delayed bleeding, and pathological findings. Subgroup analysis stratified by these factors and multivariate analyses were conducted.

RESULTS

In the S-O clip-assisted ESD group, all 27 tumors were resected en bloc without any complications. Although a micro perforation occurred in one patient in the conventional ESD group, further surgical treatment was not required. None of the other 22 cases in the conventional ESD group experienced complications. The mean procedure time for the S-O clip-assisted ESD group was significantly shorter than for the conventional ESD group (37.4 ± 32.6 vs. 67.1 ± 44.1 min, p = 0.03). No significant between-group differences were found for the other factors.

CONCLUSION

Our results demonstrated that S-O clip-assisted ESD is safe and fast for en bloc resection of large superficial colorectal tumors.

Poorly differentiated clusters (PDCs) as a novel histological predictor of nodal metastases in pT1 colorectal cancer

The practical use of histological factors such as submucosal (SM) invasion depth, poor differentiation, presence of lymphovascular invasion (LVI) and tumour budding to establish the risk of nodal dissemination in pT1 colorectal cancer (CRC) is limited by their low standardization and high inter-observer variability. It was recently suggested that the presence in CRC histological sections of poorly differentiated clusters (PDCs), defined as ≥5 cancer cells with no gland formation, may predict the metastatic potential of CRC. In addition, PDC assessment was shown to be more reproducible than the evaluation of the other aforementioned histological predictors. Hence, in this study, we investigated and compared the predictive value of PDC and other histological parameters on the risk of nodal involvement in pT1 CRC. The presence of PDC, SM invasion depth ≥1,000 μm and LVI was significantly associated with N+ status in pT1 CRC (P < 0.0001). Among these parameters, SM invasion depth had the highest sensitivity to identify N+ pT1 CRC but with the lowest specificity. When the analysis was restricted to CRCs with SM invasion depth ≥1,000 μm, the presence of PDC was the only independent risk factor for nodal metastases and allowed the identification of 87.5 % of N+ cancers. In conclusion, in this study, we demonstrate that the presence of PDC is associated with the metastatic potential of pT1 CRC. The combination of this parameter with SM invasion depth may allow identifying most of the pT1 CRC with nodal metastases.