Endoscopic treatment of submucosal invasive colorectal carcinoma with special reference to risk factors for lymph node metastasis

Investigating the Role of Tumor-Infiltrating Lymphocytes as Predictors of Lymph Node Metastasis in Deep Submucosal Invasive Colorectal Cancer: A Retrospective Cross-Sectional Study

The role of tumor-infiltrating T cells (TILs) in colorectal cancer (CRC) and their significance in early-stage CRC remain unknown. We investigated the role of TILs in early-stage CRC, particularly in deep submucosal invasive (T1b) CRC. Sixty patients with CRC (20 each with intramucosal [IM group], submucosal invasive [SM group], and advanced cancer [AD group]) were randomly selected. We examined changes in TILs with tumor invasion and the relationship between TILs and LN metastasis risk. Eighty-four patients with T1b CRC who underwent initial surgical resection with LN dissection or additional surgical resection with LN dissection after endoscopic resection were then selected. TIL phenotype and number were evaluated using triple immunofluorescence for CD4, CD8, and Foxp3. All subtypes were more numerous according to the degree of CRC invasion and more abundant at the invasive front of the tumor (IF) than in the center of the tumor (CT) in the SM and AD groups. The increased Foxp3 cells at the IF and high ratios of Foxp3/CD4 and Foxp3/CD8 positively correlated with LN metastasis. In conclusion, tumor invasion positively correlated with the number of TILs in CRC. The number and ratio of Foxp3 cells at the IF may predict LN metastasis in T1b CRC.

Artificial intelligence in intestinal polyp and colorectal cancer prediction

Artificial intelligence (AI) algorithms and their application to disease detection and decision support for healthcare professions have greatly evolved in the recent decade. AI has been widely applied and explored in gastroenterology for endoscopic analysis to diagnose intestinal cancers, premalignant polyps, gastrointestinal inflammatory lesions, and bleeding. Patients' responses to treatments and prognoses have both been predicted using AI by combining multiple algorithms. In this review, we explored the recent applications of AI algorithms in the identification and characterization of intestinal polyps and colorectal cancer predictions. AI-based prediction models have the potential to help medical practitioners diagnose, establish prognoses, and find accurate conclusions for the treatment of patients. With the understanding that rigorous validation of AI approaches using randomized controlled studies is solicited before widespread clinical use by health authorities, the article also discusses the limitations and challenges associated with deploying AI systems to diagnose intestinal malignancies and premalignant lesions.

Endoscopic Ultrasound Elastography as a Novel Diagnostic Method for the Assessment of Hardness and Depth of Invasion in Colorectal Neoplasms

INTRODUCTION

We aimed to compare the efficacy of endoscopic ultrasound elastography (EUS-EG) with that of magnifying chromoendoscopy (MCE) and endoscopic ultrasonography (EUS) for the diagnosis of the depth of invasion in colorectal neoplasms. This is an important clinical issue as the depth of invasion is associated with the risk of metastasis.

METHODS

Consecutive patients with suspected superficial colorectal neoplasms, evaluated by MCE, EUS, and EUS-EG, for whom endoscopic submucosal dissection was considered, were enrolled in 2018 (derivation study) and in 2019-2020 (validation study). The primary clinical endpoint was the diagnostic yield differentiating intramucosal and shallow submucosal neoplasms from deep submucosal (dSM) and advanced colorectal cancers. In addition, inter- and intra-observer agreements of the elastic score of colorectal neoplasm (ES-CRN) were evaluated by 2 expert and 2 non-expert endoscopists.

RESULTS

Thirty-one (33 lesions) and 50 (55 lesions) patients were enrolled in the derivation and validation studies, respectively. Sensitivity, specificity, positive, and negative predictive values, and accuracy of assessment of the depth of submucosal or deeper invasion in the derivation and validation groups were as follows: EUS-EG, 100/88.2/86.7/100/93.3% and 77.8/86.1/73.7/88.6/83.3%; MCE, 66.7/94.4/90.9/77.3/81.8% and 84.2/91.4/84.2/91.4/88.9%; and EUS, 93.3/77.8/77.8/93.3/84.8% and 89.5/65.7/58.6/92.0/74.1%, respectively. For the 2 expert endoscopists, interobserver agreement for the ES-CRN (first and second assessments) in the derivation group was 0.84 and 0.78, respectively; these values were 0.73 and 0.49, respectively, for the 2 non-expert endoscopists.

DISCUSSION/CONCLUSION

All 3 modalities presented similar diagnostic yield. Inter- and intra-observer agreements of the ES-CRN were substantial, even for non-expert endoscopists. Therefore, EUS-EG may be a useful modality in determining the depth of invasion in colorectal neoplasms.

[Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer]

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Role of tumor-associated macrophages at the invasive front in human colorectal cancer progression

Macrophages are an essential component of antitumor activity; however, the role of tumor‐associated macrophages (TAMs) in colorectal cancer (CRC) remains controversial. Here, we elucidated the role of TAMs in CRC progression, especially at the early stage. We assessed the TAM number, phenotype, and distribution in 53 patients with colorectal neoplasia, including intramucosal neoplasia, submucosal invasive colorectal cancer (SM‐CRC), and advanced cancer, using double immunofluorescence for CD68 and CD163. Next, we focused on the invasive front in SM‐CRC and association between TAMs and clinicopathological features including lymph node metastasis, which were evaluated in 87 SM‐CRC clinical specimens. The number of M2 macrophages increased with tumor progression and dynamic changes were observed with respect to the number and phenotype of TAMs at the invasive front, especially at the stage of submucosal invasion. A high M2 macrophage count at the invasive front was correlated with lymphovascular invasion, low histological differentiation, and lymph node metastasis; a low M1 macrophage count at the invasive front was correlated with lymph node metastasis. Furthermore, receiver operating characteristic curve analysis revealed that the M2/M1 ratio was a better predictor of the risk of lymph node metastasis than the pan‐, M1, or M2 macrophage counts at the invasive front. These results suggested that TAMs at the invasive front might play a role in CRC progression, especially at the early stages. Therefore, evaluating the TAM phenotype, number, and distribution may be a potential predictor of metastasis, including lymph node metastasis, and TAMs may be a potential CRC therapeutic target.

Clinical significance of immunohistochemical lymphovascular evaluation to determine additional surgery after endoscopic submucosal dissection for colorectal T1 carcinoma

PURPOSE

The Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines indicate lymphovascular invasion-evaluated by hematoxylin and eosin (HE) staining-as a surgical requirement after endoscopic submucosal dissection (ESD) in T1 colorectal carcinoma (CRC) patients; however, immunohistochemical evaluation may be superior. This study aimed to clarify the significance of immunohistochemical lymphovascular evaluation as an indicator for additional surgery of T1 CRC after ESD, and assessed the guidelines' adequacy, even when evaluating through immunostaining.

METHODS

Patients with T1 CRC who underwent ESD were enrolled across three institutions between January 2012 and December 2017. Immunohistochemical lymphovascular evaluation was performed. Clinicopathological features, pathological evaluations, and surgery indications were recorded. Univariate and multivariate logistic regression identified risk factors for lymph node (LN) metastasis of T1 CRC after ESD.

RESULTS

Among 370 patients with T1 CRC, recurrence, 5-year overall survival, and 5-year disease specific survival rates were 1.6%, 94.6%, and 99.5%, respectively. Six patients (1.6%) experienced recurrence, five of whom underwent additional surgery. Those with no risk factors did not exhibit recurrence. A total of 215 (58.1%) patients underwent additional surgery after ESD, 21 (9.7%) of whom exhibited LN metastasis. Among 16 patients who underwent additional surgery due to lymphovascular invasion, three (18.8%) had LN metastasis. Multivariate logistic regression analysis identified lymphatic invasion as a significant risk factor for LN metastasis (odds ratio 3.9, 95% confidence interval 1.0-14.6, P = 0.0421).

CONCLUSIONS

The JSCCR guidelines have clinical validity, and immunohistochemical lymphatic evaluation findings potentially predict LN metastasis for T1 CRC after ESD.

Clinical practice guideline for endoscopic resection of early gastrointestinal cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by <i>en bloc</i> fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Additional Surgical Resection After Endoscopic Resection for Patients With High-risk T1 Colorectal Cancer

BACKGROUND/AIM

The purpose of this study was to reveal the safety and efficacy of additional surgical resection (ASR) for high-risk T1 colorectal cancer (CRC) after endoscopic resection (ER).

PATIENTS AND METHODS

We retrospectively analyzed 191 patients with high-risk T1 CRC after ER.

RESULTS

The ASR was performed in 176 (92.1%) patients and 15 (7.9%) rejected ASR. All patients that underwent ASR experienced R0 resection; laparoscopic surgery was performed in 159 (90.3%) patients. Clavien-Dindo complications ≥grade II occurred in 33 patients (18.8%). Anastomotic leakage (8.5%) and ileus (5.7%) were the most frequent complications. The anus function was preserved in all patients. Metastatic lymph node was detected in 21 (11.9%) patients. There were no deaths or relapses in patients with ASR. One patient without ASR (6.7%) had a lymph node recurrence.

CONCLUSION

ASR was safe and effective and is recommended for high-risk T1 CRC patients after ER. A satisfactory long-term outcome can be achieved.

Long-term prognosis after treatment for T1 carcinoma of laterally spreading tumors: a multicenter retrospective study

PURPOSE

Long-term prognosis of T1 laterally spreading tumors (LSTs) after treatment have not been clarified. This study compared clinicopathological characteristics and long-term prognosis of T1 LSTs.

METHODS

We retrospectively assessed 169 patients with 169 T1 LSTs between January 1992 and December 2008 by ten hospitals. Patients who did not meet the Japanese Society for Cancer of the Colon and Rectum (JSCCR) 2016 guidelines for the treatment of colorectal carcinoma (CRC) criteria were defined as non-endoscopically curable. The number of non-endoscopically curable patients with LST-granular/ nodular mixed (LST-G-M) was 61, that with LST-non-granular/ flat elevated (LST-NG-FE) was 23, and that with LST-non-granular/ pseudo depressed (LST-NG-PD) was 23. Clinicopathological variables and long-term prognosis were analyzed.

RESULTS

For overall patients, tumor size, number of non-endoscopically curable cases, and rate of submucosal invasion depth ≥ 1000 μm for the LST-G-M group were significantly higher than those in the other groups. For non-endoscopically curable patients, the tumor size for those with LST-G-M was significantly larger than those in the other groups. The rate of submucosal invasion width ≥ 4000 μm and type B/C muscularis mucosae with LST-G-M was higher than that with LST-NG-FE. All recurrences occurred in non-endoscopically curable patients with LST-G-M. Five-year overall and disease-free survivals for non-endoscopically curable patients with LST-G-M were significantly shorter than those for patients with non-endoscopically curable LST-NG-FE and PD.

CONCLUSIONS

Our data supported adequacy of the JSCCR guidelines for the treatment of CRC criteria for endoscopically curable patients after T1 LSTs treatment. Patients with T1 LST-G-M should be followed up more carefully.

Are we doing too much?: local excision before radical surgery in early rectal cancer

PURPOSE

In early rectal cancer cases, the use of local excision is increasing. The general indication for local excision is based on the preoperative stage, but there is often a discrepancy between pre and postoperative stages. We sought to determine the indications for local excision in T1 rectal adenocarcinoma patients by comparing the preoperative clinical and postoperative pathological stages. A second aim was to compare the oncologic outcomes between local excision and radical resection.

METHODS

Between 2004 and 2014, 152 T1 rectal adenocarcinoma patients were enrolled. We divided the subjects into two groups, local excision and radical resection, depending on the modality of treatment the patients initially received. The group of patients who underwent radical resection was subsequently subdivided into "excisable" and "non-excisable" groups based on the postoperative pathology.

RESULTS

Of 152 patients, 28 patients (18.4%) underwent local excision, while 124 patients (81.6%) underwent radical resection. Of 124 patients, in clinically suspected T2 or less and N0 (93) cases, 50 patients (53.8%) needed treatment beyond local excision, and local excision was sufficient for 43 patients (46.2%). The 3-year overall survival (p = 0.393) and 3-year disease-free survival (p = 0.076) between the local excision and radical resection groups showed no significant difference.

CONCLUSIONS

The clinical T stage was overestimated in more than half of the cases. Therefore, if cT1/2 tumors with cN0 are suspected preoperatively, local excision is initially recommended and will allow for determination of underlying pathology. The clinician can then decide whether to monitor or intervene with radical resection.

Long-term outcomes after treatment for T1 colorectal carcinoma: a multicenter retrospective cohort study of Hiroshima GI Endoscopy Research Group

BACKGROUND

We aimed to clarify the long-term outcomes of patients with T1 colorectal carcinoma (CRC) after endoscopic resection (ER) and surgical resection.

METHODS

We examined T1 CRC patients treated during 1992-2008 and who had ≥5 years of follow-up. Patients who did not meet the curative criteria after ER according to the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines were defined as "non-endoscopically curable" and classified into three groups: ER alone (Group A: 121 patients), additional surgery after ER (Group B: 238 patients), and surgical resection alone (Group C: 342 patients). Long-term outcomes and predictors of recurrence were analyzed.

RESULTS

Of the 882 patients with T1 CRC, 701 were non-endoscopically curable. Among these patients, recurrence and 5-year overall survival (OS) rates were 0.6 and 91.1%, respectively. In Groups A, B, and C, recurrence rates were 5.0, 5.5, and 3.8%, OS rates were 79.3, 92.4, and 91.5% (p < 0.01), and 5-year disease-free survival (DFS) rates were 98.1, 97.9, and 98.5%, respectively. Thirty-two patients experienced local recurrence or distant/lymph node metastasis (Group A: 6; Group B: 13; Group C: 13) and 14 patients died of primary CRC (Group A: 3; Group B: 7; Group C: 4). Age ≥65 years, protruded gross type, positive lymphatic invasion, and high budding grade were significant predictors of recurrence in non-endoscopically curable patients.

CONCLUSIONS

Our findings supported the JSCCR criteria for endoscopically curable T1 CRC. ER for T1 CRC did not worsen the clinical outcomes of patients who required additional surgical resection.

Distinct histopathological characteristics in colorectal submucosal invasive carcinoma arising in sessile serrated adenoma/polyp and conventional tubular adenoma

The histopathological characteristics of colorectal submucosal invasive carcinoma arising in sessile serrated adenoma/polyp (SSA/P), a rare malignant tumour, have not yet been fully elucidated. To investigate the features of such, we retrospectively analysed 40 submucosal invasive carcinomas with SSA/P (CA-SSA/P) and compared them to 129 cases of submucosal invasive carcinoma with conventional tubular adenoma (CA-AD). We additionally performed hMLH1 immunostaining. CA-SSA/Ps were significantly smaller than CA-ADs (P < 0.001). Histologically, well to moderately differentiated adenocarcinoma was predominant in both CA-SSA/Ps and CA-ADs. No significant differences in depth of invasion were found between the two groups. However, lymphatic invasion was more often found in CA-SSA/Ps (30%) than in CA-ADs (13%; P = 0.028), as was lymph node metastasis (CA-SSA/Ps, 28%; CA-ADs, 7%; P = 0.011). Furthermore, mucinous component and serrated architecture were significantly more frequent in CA-SSA/Ps (30 and 63%) than in CA-ADs (5 and 18%; P < 0.001, respectively). Tumour-infiltrating lymphocytes and Crohn-like inflammatory reaction were also more frequently found in CA-SSA/Ps (70 and 30%) than in CA-ADs (31 and 9%; P ≤ 0.001, respectively), whereas the opposite was true of desmoplastic reaction (CA-SSA/Ps, 35%; CA-ADs, 67%; P < 0.001). Loss of hMLH1 expression was more frequent in CA-SSA/P cases (93%) than in CA-AD cases (5%; P < 0.001). In conclusion, CA-SSA/P lesions exhibit a higher potential for lymphatic invasion and lymph node metastasis and have distinct histopathological features, including mucinous component, serrated architecture, tumour-infiltrating lymphocytes, Crohn-like inflammatory reaction, and absence of desmoplastic reaction, compared to their conventional counterparts.

Colorectal endoscopic submucosal dissection: patient selection and special considerations

Endoscopic submucosal dissection (ESD) enables en bloc resection of large complex colorectal superficial neoplastic lesions, resulting in very low rates of local recurrence, high-quality pathologic specimens for accurate histopathologic diagnosis and potentially curative treatment of early adenocarcinoma without resorting to major surgical resection. The safety and efficacy of the technique, which was pioneered in the upper gastrointestinal tract, has been established by the consistently impressive outcomes from expert centers in Japan and some other eastern countries. However, ESD is challenging to perform in the colorectum and there is a significant risk of complications, particularly in the early stages of the learning curve. Early studies from western centers raised concerns about the high complication rates, and the impressive results from Japanese centers were not replicated. As a result, many western endoscopists are skeptical about the role of ESD and few centers have incorporated the technique into their practice. Nevertheless, although the distribution of expertise, referral centers and modes of practice may differ in Japan and western countries, ESD has an important role and can be safely and effectively incorporated into western practice. Key to achieving this is meticulous lesion assessment and selection, appropriate referral to centers with the necessary expertise and experience and application of the appropriate technique individualized to the patient. This review discusses the advantages, risks and benefits of ESD to treat colorectal lesions and the importance of preprocedure lesion assessment and in vivo diagnosis and outlines a pragmatic rationale for appropriate lesion selection as well as the patient, technical and institutional factors that should be considered.

Is the assessment of submucosal invasion still useful in the management of early rectal cancer? A study of 91 consecutive patients

AIM

The only studies on the prognosis of T1 tumours are old and investigate colic and rectal cancers. Very few studies use Kikuchi's classification (of dividing submucosa into three strata) to evaluate the depth of the submucosal invasion. This study aimed to assess the pathological risk factors for lymph node metastasis (LNM), and the pathological and oncological results of patients with early rectal cancer (ERC, pT1 tumour).

METHOD

Between 2000 and 2014, 91 consecutive patients undergoing surgery [primary total mesorectal excision (TME) or local excision (LE) alone, or LE followed by TME] for ERC were included.

RESULTS

Eighteen patients underwent LE, 22 underwent LE followed by TME and 51 underwent primary total TME. After TME (n = 73), 16 (23%) patients had LNM. The LNM rate was 15% for Sm1 tumours, 14% for Sm2 tumours and 30% for Sm3 tumours. In multivariate analysis, lymphovascular invasion (P = 0.027) and high tumour budding (P = 0.037) were the only independent factors predictive of LNM. The depth of submucosal invasion was not associated with an increased risk of LNM. After a mean follow up of 56 ± 46 months, 5-year overall survival, specific survival and disease-free survival were, respectively, 82%, 93% and 75%. No significant difference of survival was found according to the depth of submucosal invasion or to the surgical management.

CONCLUSION

Histological features seem to be stronger risk factors for LNM than depth of submucosal invasion. Considering the LNM rate, TME should be discussed after LE in terms of one of these pathological criteria.

Colonic Polyps: Treatment

Colonic polyps are considered to be precursors of colon cancer based on several different molecular pathway models and should be resected with a principle of complete excisional biopsy. Several techniques are available for excisional biopsy, ranging from endoscopic techniques such as snare polypectomy, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD) to surgical colonic resection and colonic endolaparoscopic surgery (CELS). This article focuses on these modalities with contemporary recommendations for choice of modality based on the size and features of the polyp encountered upon endoscopy. In addition, the morphologically apparent risk factors for polyps harboring invasive malignancy are discussed along with implications for management. Current literature on the comparative risks and benefits of EMR, ESD, CELS, and surgical resection is reviewed, as well as recommendations regarding cancer risk and subsequent surveillance.

Long-term outcomes after treatment for pedunculated-type T1 colorectal carcinoma: a multicenter retrospective cohort study

BACKGROUND

The risk for lymph node metastasis and the prognostic significance of pedunculated-type T1 colorectal carcinomas (CRCs) require further study. We aimed to assess the validity of the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines based on long-term outcomes of pedunculated-type T1 CRCs.

METHODS

In this multicenter retrospective cohort study, we examined 176 patients who underwent resection endoscopically or surgically at 14 institutions between January 1990 and December 2010. Patients meeting the JSCCR curative criteria were defined as "endoscopically curable (e-curable)" and those who did not were "non-e-curable". We evaluated the prognosis of 116 patients (58 e-curable, 58 non-e-curable) who were observed for >5 years after treatment.

RESULTS

Overall incidence of lymph node metastasis was 5 % (4/81; 95 % confidence interval 1.4-12 %: three cases of submucosal invasion depth ≥1000 μm [stalk invasion] and lymphatic invasion, one case of head invasion and budding grade 2/3). There was no local or metastatic recurrence in the e-curable patients, but six of them died of another cause (observation period, 80 months). There was no local recurrence in the non-e-curable patients; however, distant metastasis was observed in one patient. Death due to the primary disease was not observed in non-e-curable patients, but six of them died of another cause (observation period, 72 months).

CONCLUSIONS

Our data support the validity of the JSCCR curative criteria for pedunculated-type T1 CRCs. Endoscopic resection cannot be considered curative for pedunculated-type T1 CRC with head invasion alone.

Impact of tumor location on lymph node metastasis in T1 colorectal cancer

PURPOSE

Data evaluating the risk of lymph node metastasis depending upon the location of the primary tumor are limited in patients with T1 colorectal cancer. We aimed to evaluate the impact of tumor location on lymph node metastasis in T1 colorectal cancer.

METHODS

Patients who underwent an oncologic resection with curative intent for T1 adenocarcinoma of the colon and rectum between January 1997 and October 2014 were assessed. Exclusion criteria were distant organ metastases, previous or concurrent cancer, past history of surgical or medical cancer treatment, preoperative chemoradiation, and patients with inflammatory bowel disease or polyposis syndromes.

RESULTS

Out of 232 (56 % male) patients fulfilling the study criteria, 24 (10 %) had lymph node metastasis. Age (65 vs 61 years, p = 0.1), gender (55 vs 63 % male, p = 0.5), tumor size (2 vs 2 cm, p = 0.49), and lymphovascular invasion (5 vs 8 %, p = 0.46) were not associated with lymph node metastasis. While there was no statistical significance (p = 0.2), lymph node positivity was higher in rectal cancer (14 %, n = 11/79) compared to colon cancer (9 %, n = 13/153).

CONCLUSIONS

Although it was not statistically significant, lymph node positivity varies based on tumor location of T1 colorectal adenocarcinoma regardless of fundamental tumor characteristics including size, differentiation, and lymphovascular invasion.

Prognostic significance of VEGF-C immunohistochemical expression in colorectal cancer: A meta-analysis

BACKGROUND

We sought to comprehensively summarize available evidence for the use of VEGF-C protein to evaluate the clinicopathological and prognostic role of VEGF-C in colorectal cancer.

METHODS

Electronic databases from inception to February 2016 were used to search without language restrictions for original articles. A meta-analysis was undertaken to assess the relationship between VEGF-C expression and overall survival (OS) in colorectal cancer.

RESULTS

Twenty-seven studies were included in the final meta-analysis. We aggregated 13 trials (n=1.428 patients) that evaluated the correlation between OS and VEGF-C overexpression. Statistics were performed for OS (HR=1.95; 95%CI=1.31-2.92, P=0.007). When the studies were stratified by the pathological variables, including T stage (n=383 patients; OR=1.79; 95%CI=1.14-2.81), lymph node metastasis (n=3212 patients; OR=4.21; 95%CI=3.49-5.08), M stage (n=1106 patients; OR=4.46; 95%CI=2.96-6.70), vascular invasion(n=1471 patients; OR=2.18; 95%CI=1.65-2.88), lymph invasion (n=831 patients; OR=3.95; 95%CI=2.80-5.56), histo-differentiation (n=1695 patients; OR=1.34; 95%CI=1.00-1.79) and Duke's stage(n=778 patients; OR=4.90; 95%CI=3.55-6.75), TNM stage (n=808 patients; OR=1.73; 95%CI=1.18-2.54) provided critical and comprehensive prognostic information.

CONCLUSION

Our results demonstrated that VEGF-C overexpression was associated with OS in colorectal cancer.

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.

Long-term outcomes after treatment for T1 colorectal carcinoma

PURPOSE

Long-term outcomes of patients with T1 colorectal carcinoma (CRC) treated by endoscopic resection (ER) or surgical resection are unclear in relation to the curative criteria in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines. The aim of this study was to retrospectively compare the long-term outcomes among patients with T1 CRC in relation to the treatment methods.

METHODS

We examined 322 T1 CRC cases treated between January 1992 and August 2008 at Hiroshima University Hospital. Patients who did not meet the curative criteria in the JSCCR guidelines were defined as "non-endoscopically curable" and classified into three groups: underwent ER alone (group A: 45 patients), underwent additional surgery after ER (group B: 106 patients), and underwent surgical resection alone (group C: 92 patients).

RESULTS

Of the 322 T1 CRC patients, 79 were categorized as endoscopically curable and 243 as non-endoscopically curable. Among the endoscopically curable T1 CRC patients, recurrence and 5-year OS rates were 0 and 94.2%, respectively. In groups A, B, and C, recurrence rates were 4.4, 6.6, and 4.3%, and OS rates were 85.6, 95.1, and 96.3%, respectively (p < 0.05). Local recurrence or distant/lymph node metastasis was observed in 13 patients (group A: 2; group B: 7; group C: 4). Death due to primary CRC occurred in six patients (group B: 4; group C: 2).

CONCLUSION

Long-term outcomes support the curative criteria according to the JSCCR guidelines. ER for T1 CRC did not worsen clinical outcomes in cases that required additional surgical resection.

Endoscopic submucosal dissection as total excisional biopsy for clinical T1 colorectal carcinoma

BACKGROUND/AIMS

Only the depth of submucosal invasion can be estimated prior to determining the indications for endoscopic submucosal dissection (ESD) as a curative treatment for colorectal carcinoma (CRC). Here we evaluated the outcomes of ESD for clinical T1 CRCs.

METHODS

Of 660 patients who underwent ESD for CRC at the Hiroshima University Hospital between June 2003 and December 2013, we examined the outcomes of 37 (6%; 26 men, 11 women; mean age ± SD, 68 ± 12 years) who underwent ESD as total excisional biopsy for various reasons, in spite of an endoscopic diagnosis of T1 CRC.

RESULTS

The mean lesion size was 25 ± 14 mm; 14 lesions were protruding and 23 were superficial. The en bloc resection rate was 100% (37/37). The histological en bloc resection rate was 92% (34/37). ESD resulted in a positive vertical margin in 3 cases. Deep submucosal invasion was seen in 3 cases, 2 of which had severe submucosal fibrosis. Although severe submucosal fibrosis was not found in other cases, pathologic examination of the deepest invasive portion of the tumor revealed poorly differentiated adenocarcinoma. The rates of post-ESD bleeding and perforation were 8% (3/37) and 5% (2/37), respectively. All patients recovered under conservative therapy. No cases of recurrence were noted in patients without additional surgical resection when the lesions satisfied the curative conditions listed in the 2014 Japanese Society for Cancer of the Colon and Rectum guidelines.

CONCLUSION

En bloc resection by ESD as total excisional biopsy for clinical T1 CRC is a highly effective treatment and establishes a precise histological diagnosis.

Systematic review and meta-analysis of histopathological predictive factors for lymph node metastasis in T1 colorectal cancer

BACKGROUND

In this study we examined whether histopathological findings, specifically lymphatic vessel invasion identified by an anti-human podoplanin antibody, and several other factors are associated with lymph node metastasis in T1 colorectal cancer.

METHODS

We searched PubMed and Cochrane Library, and also handsearched relevant journals, for reports written in English and published between 1998 and 2012, utilizing combination headings, such as 'colorectal cancer,' 'lymph node metastasis,' and 'risk factors.' For the report to be included in our study, the following criteria had to be met: (1) data on the frequency of lymph node metastasis in T1 colorectal cancer in relation to histopathological factors were reported; (2) patients had undergone bowel resection and had histologically diagnosed T1 colorectal cancer; (3) lymphatic vessel invasion was identified by immunohistochemistry with an anti-human podoplanin antibody rather than by hematoxylin and eosin staining; (4) univariate and multivariate analyses were conducted. Studies investigating molecular markers were excluded. The independent predictive factors were confirmed in at least one study included in the meta-analysis in the present systematic review. Microsoft Excel 2013 for Windows was used for the statistical analysis.

RESULTS

Initially, 369 publications were identified in the database searches and handsearches, of which five ultimately met all of the inclusion criteria and selected for this systematic review. The meta-analysis revealed that only two factors were significantly associated with T1 colorectal cancer lymph node metastasis: (1) lymphatic vessel invasion identified by an anti-human podoplanin antibody [Mantel-Haenszel odds ratio (OR) 5.19; (95% confidence interval (CI) 3.31-8.15; P = 0.01]; (2) tumor budding (OR 7.45; 95 % CI 4.27-13.02; P = 0.0077).

CONCLUSION

Our meta-analysis revealed that lymphatic vessel invasion identified by an anti-human podoplanin antibody and tumor budding were significantly associated with T1 colorectal cancer lymph node metastasis.

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.

Meta-analysis of predictive clinicopathologic factors for lymph node metastasis in patients with early colorectal carcinoma

The objective of this study was to conduct a meta-analysis to determine risk factors that may facilitate patient selection for radical resections or additional resections after a polypectomy. Eligible articles were identified by searches of PUBMED, Cochrane Library and Korean Medical Database using the terms (early colorectal carcinoma [ECC], lymph node metastasis [LNM], colectomy, endoscopic resection). Thirteen cohort studies of 7,066 ECC patients who only underwent radical surgery have been analysed. There was a significant risk of LNM when they had submucosal invasion (≥ SM2 or ≥ 1,000 µm) (odds Ratio [OR], 3.00; 95% confidence interval [CI], 1.36-6.62, P = 0.007). Moreover, it has been found that vascular invasion (OR, 2.70; 95% CI, 1.95-3.74; P < 0.001), lymphatic invasion (OR, 6.91; 95% CI, 5.40-8.85; P < 0.001), poorly differentiated carcinomas (OR, 8.27; 95% CI, 4.67-14.66; P < 0.001) and tumor budding (OR, 4.59; 95% CI, 3.44-6.13; P < 0.001) were significantly associated with LNM. Furthermore, another analysis was carried out on eight cohort studies of 310 patients who underwent additional surgeries after an endoscopic resection. The major factors identified in these studies include lymphovascular invasion on polypectomy specimens (OR, 5.47; 95% CI, 2.46-12.17; P < 0.001) and poorly or moderately differentiated carcinomas (OR, 4.07; 95% CI, 1.08-15.33; P = 0.04). For ECC patients with ≥ SM2 or ≥ 1,000 µm submucosal invasion, vascular invasion, lymphatic invasion, poorly differentiated carcinomas or tumor budding, it is deemed that a more extensive resection accompanied by a lymph node dissection is necessary. Even if the lesion is completely removed by an endoscopic resection, an additional surgical resection should be considered in patients with poorly or moderately differentiated carcinomas or lymphovascular invasion.

Effectiveness of adjuvant radiotherapy after local excision of rectal cancer with deep submucosal invasion: a single-hospital, case-control analysis

BACKGROUND

The role of postoperative radiation therapy (RT) after local excision (LE) of deep submucosal invasive rectal cancer remains unclear. We evaluated the efficacy of adjuvant RT after LE of early rectal cancer with deep submucosal invasion.

METHODS

We screened 227 patients who underwent transanal excision or endoscopic removal of deep submucosal invasive rectal cancer between 1992 and 2012, of which 66 did not undergo radical surgery owing to the patient's preference or poor medical conditions. Of these, 35 (53 %) underwent LE alone (LE group) and 31 (47 %) received adjuvant RT after LE (LE + RT group). Nine patients in the RT group received concurrent adjuvant chemotherapy with 5-fluorouracil. Two independent pathologists reviewed histological data.

RESULTS

The mean age of patients in the LE + RT and LE groups was 59.5 ± 9.6 and 55.3 ± 11.2 years, respectively. The mean follow-up duration was 78.7 ± 66.7 months in the LE + RT group and 70.5 ± 45.7 months in the LE group. Cancer eventually recurred in six patients (9.1 %; two in the LE + RT group and four in the LE group). In five of these patients, recurrence occurred within 4 years after the initial treatment. The other patient, who was in the LE group, exhibited multiple lymph node metastases at the 116-month follow-up. Kaplan-Meier estimates of recurrence-free survival at 5 years after treatment were 96.8 % in the LE + RT group and 97 % in the LE group (P = 0.657).

CONCLUSION

RT after LE of early rectal cancer with deep submucosal invasion might not improve recurrence-free survival compared with LE alone.

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.

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.

Transanal endoscopic microsurgery: a review

Rectal adenomas and cancers occur frequently. Small adenomas can be removed colonoscopically, whereas larger polyps are removed via conventional transanal excision. Owing to technical difficulties, adenomas of the mid- and upper rectum require radical resection. Transanal endoscopic microsurgery (TEM) was first designed as an alternative treatment for these lesions. However, since its development TEM has been also used for a variety of rectal lesions, including carcinoids, rectal prolapse and diverticula, early stage carcinomas and palliative resection of rectal cancers. The objective of this review is to describe the current status of TEM in the treatment of rectal lesions. Since the 1980s, TEM has advanced substantially. With low recurrence rates, it is the method of choice for resection of endoscopically unresectable adenomas. Some studies have shown benefits to its use in treating early T1 rectal cancers compared with radical surgery in select patients. However, for more advanced rectal cancers TEM should be considered palliative or experimental. This technique has also been shown to be safe for the treatment of other uncommon rectal tumours, such as carcinoids. Transanal endoscopic microsurgery may allow for new strategies in the treatment of rectal pathology where technical limitations of transanal techniques have limited endoluminal surgical innovations.

When is local excision appropriate for "early" rectal cancer?

Local excision is increasingly performed for “early stage” rectal cancer in the US; however, local recurrence after local excision has become a controversial issue in Western countries. Local recurrence is considered to originate based on the type of tumor and procedure performed, and in surgical margin-positive cases. This review focuses on the inclusion criteria of “early” rectal cancers for local excision from the Western and Japanese points of view. “Early” rectal cancer is defined as T1 cancer in the rectum. Only the tumor grade and depth of invasion are the “high risk” factors which can be evaluated before treatment. T1 cancers with sm1 or submucosal invasion <1,000 μm are considered to be “low risk” tumors with less than 3.2 % nodal involvement, and are considered to be candidates for local excision as the sole curative surgery. Tumors with a poor tumor grade should be excluded from local excision. Digital examination, endoscopy or proctoscopy with biopsy, a barium enema study and endorectal ultrasonography are useful for identifying “low risk” or excluding “high risk” factors preoperatively for a comprehensive diagnosis. The selection of an initial local treatment modality is also considered to be important according to the analysis of the nodal involvement rate after initial local treatment and after radical surgery.

Risk factors for vertical incomplete resection in endoscopic submucosal dissection as total excisional biopsy for submucosal invasive colorectal carcinoma

PURPOSE

Endoscopic submucosal dissection (ESD) for colorectal tumor is a minimally invasive treatment. Histologic information obtained from the entire ESD specimen is important for therapy selection in submucosal invasive colorectal carcinoma (SMca). This study aimed to identify risk factors for vertical incomplete resection (vertical margin-positive [VM+]) when ESD was performed as total excisional biopsy for SMca.

METHODS

From June 2003 through December 2011, 78 SMca cases were resected by ESD at Hiroshima University Hospital. Patient and tumor characteristics, intraoperative variables, and histopathology were compared between the VM+ group and the vertical complete resection (vertical margin-negative) group. The ability of magnifying endoscopy (ME) and endoscopic ultrasonography (EUS) to predict VM+ was assessed.

RESULTS

ESD resulted in VM+ in eight cases (10.3 %), with a greater percentage invading to a depth of ≥2,000 vs. <2,000 μm (P = 0.047). Severe submucosal fibrosis was found in five of the eight cases (62.5 %, P = 0.017). Poor differentiation was seen at the deepest invasive portion in six cases (75.0 %), and two of six cases had an invasion depth <2,000 μm. Of 39 EUS cases, 36 not showing deep invasion close to the muscularis propria were completely resected by ESD.

CONCLUSIONS

Submucosal fibrosis and poor differentiation at the deepest invasive portion may be risk factors for VM+ in colorectal ESD for tumors with submucosal deep invasion. ME plus EUS is more likely to help determine whether ESD is indicated as complete total excisional biopsy for SMca.

Risk analysis of submucosal invasive rectal carcinomas for lymph node metastasis to expand indication criteria for endoscopic resection

In the 2010 guidelines for the treatment of colorectal cancer from the Japanese Society for Cancer of the Colon and Rectum (JSCCR), the criteria for identifying curable submucosal invasive colorectal carcinoma after endoscopic resection is as follows: differentiated adenocarcinoma, no vascular invasion, submucosal invasion depth <1000 μm and budding grade 1 (low grade). A total of 118 rectal submucosal carcinomas, treated by primary surgical resection or additional surgical resection with lymph node (LN) dissection, were analyzed. Relationships between clinicopathological findings and LN metastasis were evaluated. LN metastasis was found in 11.0% (13/118). There were no significant differences between clinicopathological findings and LN metastasis except for budding grade. Multivariate logistic regression analysis showed budding grade 2/3 (high grade) to be the independent risk factor for LN metastasis. When cases that met the curative condition of histological grade, tumor budding grade and vessel invasion together according to JSCCR 2010 criteria, the incidence of LN metastasis was only 2.2% (1/46, 95% confidence interval: 0.06-11.5%), regardless of the degree of submucosal invasion depth. In conclusion, even in cases of rectal carcinoma with submucosal deep invasion, the risk of LN metastasis is minimal under certain conditions.

Pathologic predictive factors for lymph node metastasis in submucosal invasive (T1) colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Colorectal adenocarcinoma with depth of invasion ≤1,000 μm from the muscularis mucosa and favorable histology is now considered for local resection. We aimed to examine the strength of evidence for this emerging practice.

METHODS

We searched Medline, Scopus, and Cochrane (1950-2011), then performed a meta-analysis on the risk of lymph node metastasis in nonpedunculated (sessile and nonpolypoid) T1 colorectal cancers. We included studies with nonpedunculated lesions, actual invasion depth, and pathologic factors of interest. Synchronous, polyposis or secondary cancers, and chemoradiation studies were excluded. Our primary outcome was the risk of LNM. We analyzed using Review Manager; we estimated heterogeneity using Cochran Q χ(2) test and I (2). We generated summary risk ratios using a random effects model, performed sensitivity analyses, and evaluated the quality of evidence using GRADEPro.

RESULTS

We identified 209 articles; 5 studies (n = 1213 patients) met the inclusion criteria. The risk of LNM in nonpedunculated ≤1,000 μm is 1.9 % (95 % confidence interval 0.5-4.8 %). The risk for all T1 is 13 % (95 % confidence interval 11.5-15.4 %). Characteristics protective against LNM were ≤1,000 μm invasion, well differentiation, absence of lymphatic and vascular invasion, and absence of tumor budding. We did not detect significant study heterogeneity. The quality of evidence was poor.

CONCLUSIONS

Well-differentiated nonpedunculated T1 colorectal cancer invasive into the submucosa ≤1,000 μm, without lymphovascular involvement or tumor budding, has the lowest risk of nodal metastasis. Importantly, the risk was not zero (1.9 %), and the qualitative formal analysis of data was not strong. As such, endoscopic resection alone may be adequate in select patients with submucosal invasive colorectal cancers, but more studies are needed. Overall, the quality of evidence was poor; data were from small retrospective studies from limited geographic regions.

Lymphatic invasion identified with D2-40 immunostaining as a risk factor of nodal metastasis in T1 colorectal cancer

BACKGROUND

The management of T1 colorectal cancer after local resection is controversial. Regional lymph node metastasis often occurs, requiring subsequent colonic resection. The aim of this study was to reevaluate the risk factors of nodal metastasis of T1 colorectal cancer, especially to examine lymphatic vessel invasion in serially prepared hematoxylin and eosin sections and D2-40 immunostained sections to determine which is a better indicator of lymph node metastasis of T1 colorectal cancer.

METHODS

The study investigated 120 patients who underwent bowel resection and were histologically diagnosed to have T1 colorectal cancer in Kanagawa Cancer Center Hospital from 1995 to 2005. Serially prepared paraffin sections were stained with hematoxylin and eosin, or immunostained with D2-40 antibody or von Willebrand factor, and reevaluated for lymphatic vessel invasion and other risk factors, including venous invasion, histological grade, depth of submucosal invasion, and budding.

RESULTS

Lymphatic invasion diagnosed with either hematoxylin and eosin staining (p = 0.022), or D2-40 immunostaining (p = 0.001), and budding (p = 0.013) were significant risk factors for lymph node metastasis in the univariate analysis. Venous involvement, histological grade, or depth of submucosal invasion was not significant. The multivariate logistic regression analysis for the three risk factors found lymphatic invasion diagnosed with D2-40 as an independent risk factor (odds ratio 6.048, p = 0.018, CI 1.360-26.89). The sensitivity, specificity, positive predictive value, and negative predictive value were 58 %, 88 %, 35 %, and 95 %, respectively.

CONCLUSIONS

Lymphatic vessel invasion diagnosed with D2-40 was a better indicator to evaluate the risk for lymph node metastasis by T1 colorectal cancer.

Comparison of diagnostic accuracies of various endoscopic examination techniques for evaluating the invasion depth of colorectal tumors

This study was designed to assess the clinical value of magnifying endoscopy combined with EUS for estimating the invasion depth of colorectal tumors. We studied 168 colorectal adenomas and carcinomas that were sequentially examined by conventional endoscopy followed by magnifying endoscopy and EUS in the same session to evaluate invasion depth. Endoscopic images obtained by each technique were reassessed by 3 endoscopists to determine whether endoscopic resection (adenoma, mucosal cancer, or submucosal cancer with slight invasion) or colectomy (submucosal cancer with massive invasion or advanced cancer) was indicated. The accuracy of differential diagnosis was compared among the examination techniques. The rate of correct differential diagnosis according to endoscopic examination technique was similar. The proportion of lesions that were difficult to diagnose was significantly higher for EUS (15.5%) than for conventional endoscopy and magnifying endoscopy. Among lesions that could be diagnosed, the rate of correct differential diagnosis was the highest for EUS (89.4%), but did not significantly differ among three endoscopic examination techniques. When it is difficult to evaluate the invasion depth of colorectal tumors on conventional endoscopy alone, the combined use of different examination techniques such as EUS may enhance diagnostic accuracy in some lesions.

Desmoplastic reaction in biopsy specimens of early colorectal cancer: a Japanese prospective multicenter study

We previously reported that detection of desmoplastic reaction (DR) in pretreatment biopsy specimens was useful for predicting the depth of submucosal invasion (SM depth) in nonpedunculated early colorectal cancers (ECRCs) in a retrospective study. Here, we performed a prospective multicenter study for verification of our previous findings. Subjects were diagnosed with ECRC by endoscopy, and with adenocarcinoma from the biopsy specimens. Eleven institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum participated in this collaborative study. A total of 112 patients with ECRC were enrolled. For nonpedunculated ECRCs, presence of DR was significantly correlated with SM depth. The sensitivity and specificity of detection of DR for prediction of pSM2 (tumor invasion ≥1000 µm) in nonpedunculated ECRCs were 68.6% and 92.0%, respectively. Evaluation of DR in pretreatment biopsy specimens may be useful for the clinicopathological diagnosis of colorectal carcinoma with massive invasion into the submucosal layer.

Risk factors for incomplete resection and complications in endoscopic mucosal resection for lateral spreading tumors

AIM

Lateral spreading tumors (LST) are relatively large flat lesions with diameters exceeding 10 mm in length. Endoscopic mucosal resection (EMR) is a commonly used technique for removing LST. We aimed to evaluate the risk factors for incomplete resection and complications of EMR for LST.

METHOD

Between January 2004 and December 2010, 497 patients who underwent EMR for LST were retrospectively reviewed. Risk factors for endoscopic and histopathological complete resection, complications, and clinical outcomes were investigated.

RESULTS

Risks for incomplete resection by piecemeal resection and en bloc resection of a lesion ≥ 30 mm were higher than for en bloc resection of a lesion <30 mm (OR=2.688, CI 1.036-6.993; OR=4.982, CI 1.894-13.101). Risks of post-EMR bleeding for piecemeal resection and en bloc resection for a lesion ≥ 40 mm were higher than for en bloc resection of a lesion <40 mm (OR=15.231, CI 1.816-127.744; OR=43.043, CI 4.306-430.314).

CONCLUSION

We found risk factors of EMR for LST and tentatively suggest a protocol for EMR adapted to the size of LST and resection methods. (i) Following piecemeal resection and en bloc resection for LST ≥ 40 mm, hospitalize patients for 36 h and note risk for incomplete resection and delayed bleeding. (ii) After en bloc resection for 40 mm>LST ≥ 30 mm, hospitalize patients for 12 h and note risk for incomplete resection. (iii) Following en bloc resection for LST<30 mm, hospitalize the patient for 12 h and expect complete resection.

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.

NBI and NBI Combined with Magnifying Colonoscopy

Although magnifying chromoendoscopy had been a reliable diagnostic tool, narrow-band imaging (NBI) has been developed in Japan since 1999 and has now replaced the major role of chromoendoscopy because of its convenience and simplicity. In this paper, we principally describe the efficacy of magnifying chromoendoscopy and magnifying colonoscopy with NBI for detection, histological prediction, estimation of the depth of early colorectal cancer, and future prospects. Although some meta-analyses have concluded that NBI is not superior to white light imaging for detection of adenomatous polyps in screening colonoscopy, NBI with magnification colonoscopy is useful for histological prediction, or for estimating the depth of invasion. To standardize these diagnostic strategies, we will focus on the NBI International Colorectal Endoscopic (NICE) classification proposed for use by endoscopists with or without a magnifying endoscope. However, more prospective research is needed to prove that this classification can be applied with satisfactory availability, feasibility, and reliability. In the future, NBI might contribute to the evaluation of real-time histological prediction during colonoscopy, which has substantial benefits for both reducing the risk of polypectomy and saving the cost of histological evaluation by resecting and discarding diminutive adenomatous polyps (resect and discard strategy).

Clinical significance of lymphatic and blood vessel invasion in oral tongue squamous cell carcinomas

Although vascular invasion (VI) is recognized as an important predictor of lymph node metastasis and a significant prognostic factor in head and neck squamous cell carcinoma (HNSCC), there is currently no common definition for the pathological evaluation of VI status. We reviewed the medical records of 63 consecutive resected primary oral tongue SCCs (OTSCCs) without preoperative treatment between June 1999 and April 2008, and evaluated VI status by investigating lymphatic vessel invasion (LVI) and blood vessel invasion (BVI) by using immunohistochemistry (IHC) with monoclonal antibody D2-40 (D2-40) and Elastica van Gieson (EVG) staining, respectively. Subsequently, we analyzed their correlations with cervical lymph node metastasis and prognosis. LVI was found in 16 of the 63 tumors (25.4%) and BVI was in 32 tumors (50.8%). Univariate analysis revealed that the presence of LVI is statistically correlated with lymph node metastasis. Moreover, multivariate logistic regression analysis revealed that LVI is an independent risk factor of nodal metastasis (odds ratio=4.262, 95% confidence interval=1.262-14.397, p=0.020). In contrast, Kaplan-Meier survival analysis revealed that patients with BVI had a significantly shorter disease-free survival (DFS) and overall survival (OS) rates than those without BVI (68.6% versus 90.3%, p=0.028 and 68.6% versus 93.5%, p=0.013, respectively). The present study clearly demonstrated that LVI at primary OTSCC had significant correlation with lymph node metastasis, and that BVI was significantly associated with recurrence and poor prognosis. Evaluation of VI status, as LVI and BVI status separately, using IHC with D2-40 and EVG staining may be useful in predicting lymph node metastasis and poor prognosis in OTSCCs.

Risk of lymph node metastasis in patients with pedunculated type early invasive colorectal cancer: a retrospective multicenter study

Depth of invasion in early invasive colorectal cancer is considered an important predictive factor for lymph node metastasis. However, no large-scale reports have established the relationship between invasion depth of pedunculated type early invasive colorectal cancers and risk of lymph node metastasis. The aim of this retrospective cohort study was to clarify the risk of lymph node metastasis in pedunculated type early invasive colorectal cancers in a large series. Patients with pedunculated type early invasive colorectal cancer who underwent endoscopic or surgical resection at seven referral hospitals in Japan were enrolled. Haggitt's line was used as baseline and the invasion depth was classified into two groups, head invasion and stalk invasion. The incidence of lymph node metastasis was investigated between patients with head and stalk invasion. We analyzed 384 pedunculated type early invasive colorectal cancers in 384 patients. There were 154, 156, and 74 endoscopic resection cases, endoscopic resection followed by surgical operation, and surgical resection cases, respectively. There were 240 head invasion and 144 stalk invasion lesions. Among the lesions treated surgically, the overall incidence of lymph node metastasis was 3.5% (8/230). The incidence of lymph node metastasis was 0.0% (0/101) in patients with head invasion, as compared with 6.2% (8/129) in patients with stalk invasion. Pedunculated type early invasive colorectal cancers pathologically diagnosed as head invasion can be managed by endoscopic treatment alone.

Small, Depressed-Type Early Colon Cancer Invading Shallow Submucosal Layer With Extensive Lymph Node Metastasis: A Case Report

Early colorectal cancers are defined as invasive tumors that are limited to the mucosal layer or submucosal layer (SM), regardless of the presence or absence of lymph node (LN) metastasis. The reported incidence of LN metastasis of SM1 colon cancers is 0 - 5.9%, but the incidence in SM2 and SM3 colon cancers could be as high as 11.3 - 25.0%, and risk factors for LN metastasis include depth of SM invasion, growth patterns (polypoid or non-polypoid), histological sub-classification (moderate or poor differentiation) and regional lymphatic and vascular invasion. Among colorectal cancers with non-polypoid growth, the malignant potential is higher for depressed, than polypoid types, even for small tumors. Herein, we describe a patient with small, depressed-type early colon cancer with extensive LN metastasis and superficial SM invasion (pSM 450 µm). Six courses of chemotherapy with mFOLFOX6 and bevacizumab reduced the size of the LN metastases, thus eliciting a partial response (PR) according to the response evaluation criteria in solid tumors (RECIST).

Characteristics of recurrence after curative resection for T1 colorectal cancer: Japanese multicenter study

BACKGROUND

Because the rate of recurrence after curative resection for T1 colorectal cancer is low, the characteristics of recurrence remain obscure. This multicenter study attempted to clarify the characteristics of recurrence after curative resection for T1 colorectal cancer.

METHODS

We analyzed the associations between recurrence and various clinicopathological features in 798 patients who had undergone curative resection alone for T1 colorectal cancer at 14 hospitals between 1991 and 1996.

RESULTS

The rate of lymph node metastasis (LNM) in patients with T1 colorectal cancer was 10.5% (84/798), and 18 (2.3%) of the 798 patients developed recurrence during the median follow-up of 7.8 years. The recurrence rates in patients with colon cancer with and without LNM were 3.6 and 1.3%, respectively (p = 0.19). These rates in patients with cancer of the rectum were 25.0 and 1.1% (p < 0.0001). Among various parameters, histological grade (p < 0.0001), location (p = 0.025), LNM (p < 0.0001), and venous invasion (p = 0.0013) were risk factors for recurrence. Among them, LNM (p = 0.0008) and histological grade (p = 0.041) were independent risk factors for recurrence after curative resection for T1 colorectal cancer. Time to recurrence was more likely to be shorter for patients with, than without nodal involvement. In patients with an unfavorable histological grade, all recurrences developed within 1 year.

CONCLUSIONS

The recurrence rate after curative resection for node-negative T1 colorectal cancer was very low. The effectiveness of surveillance to detect recurrence after curative resection for T1 colorectal cancer should be validated in further studies.