Risk factors for lymph node metastasis in submucosal invasive colorectal cancer

Chinese national clinical practice guidelines on prevention, diagnosis and treatment of early colorectal cancer

BACKGROUND

The incidence and mortality of colorectal cancer (CRC) in China are increasing in recent years. The clarified pathogenesis and detectable precancerous lesions of CRC make it possible to prevent, screen, and diagnose CRC at an early stage. With the development of endoscopic and surgical techniques, the choice of treatment for early CRC is also worth further discussion, and accordingly, a standard follow-up program after treatment needs to be established.

METHODS

This clinical practice guideline (CPG) was developed following the recommended process of the World Health Organization, adopting Grading of Recommendations Assessment, Development and Evaluation (GRADE) in assessing evidence quality, and using the Evidence to Decision framework to formulate clinical recommendations, thereby minimizing bias and increasing transparency of the CPG development process. We used the Reporting Items for practice Guidelines in HealThcare (RIGHT) statement and Appraisal of Guidelines for Research and Evaluation II (AGREE II) as reporting and conduct guides to ensure the guideline's completeness and transparency.

RESULTS

This CPG comprises 46 recommendations concerning prevention, screening, diagnosis, treatment, and surveillance of CRC. In these recommendations, we have indicated protective and risk factors for CRC and made recommendations for chemoprevention. We proposed a suitable screening program for CRC based on the Chinese context. We also provided normative statements for the diagnosis, treatment, and surveillance of CRC based on existing clinical evidence and guidelines.

CONCLUSIONS

The 46 recommendations in this CPG are formed with consideration for stakeholders' values and preferences, feasibility, and acceptability. Recommendations are generalizable to resource-limited settings with similar CRC epidemiology pattern as China.

Diagnostic Accuracy of Highest-Grade or Predominant Histological Differentiation of T1 Colorectal Cancer in Predicting Lymph Node Metastasis: A Systematic Review and Meta-Analysis

INTRODUCTION

Treatment guidelines for colorectal cancer (CRC) suggest 2 classifications for histological differentiation-highest grade and predominant. However, the optimal predictor of lymph node metastasis (LNM) in T1 CRC remains unknown. This systematic review aimed to evaluate the impact of the use of highest-grade or predominant differentiation on LNM determination in T1 CRC.

METHODS

The study protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO, registration number: CRD42023416971) and was published in OSF ( https://osf.io/TMAUN/ ) on April 13, 2023. We searched 5 electronic databases for studies assessing the diagnostic accuracy of highest-grade or predominant differentiation to determine LNM in T1 CRC. The outcomes were sensitivity and specificity. We simulated 100 cases with T1 CRC, with an LNM incidence of 11.2%, to calculate the differences in false positives and negatives between the highest-grade and predominant differentiations using a bootstrap method.

RESULTS

In 42 studies involving 41,290 patients, the differentiation classification had a pooled sensitivity of 0.18 (95% confidence interval [CI] 0.13-0.24) and 0.06 (95% CI 0.04-0.09) ( P < 0.0001) and specificity of 0.95 (95% CI 0.93-0.96) and 0.98 (95% CI 0.97-0.99) ( P < 0.0001) for the highest-grade and predominant differentiations, respectively. In the simulation, the differences in false positives and negatives between the highest-grade and predominant differentiations were 3.0% (range 1.6-4.4) and -1.3% (range -2.0 to -0.7), respectively.

DISCUSSION

Highest-grade differentiation may reduce the risk of misclassifying cases with LNM as negative, whereas predominant differentiation may prevent unnecessary surgeries. Further studies should examine differentiation classification using other predictive factors.

Overexpression of circulating CD38+ NK cells in colorectal cancer was associated with lymph node metastasis and poor prognosis

Introduction

Lymph node metastasis (LNM) is a critical prognostic factor for colorectal cancer (CRC). Due to the potential influence of immune system on CRC progression, investigation into lymphocyte subsets as clinical markers has gained attention. The objective of this study was to assess the capability of lymphocyte subsets in evaluating the lymph node status and prognosis of CRC.

Methods

Lymphocyte subsets, including T cells (CD3+), natural killer cells (NK, CD3- CD56+), natural killer-like T cells (NK-like T, CD3+ CD56+), CD38+ NK cells (CD3- CD56+ CD38+) and CD38+ NK-like T cells (CD3+ CD56+ CD38+), were detected by flow cytometry. Univariate and multivariate analyses were used to assess the risk factors of LNM. The prognostic role of parameters was evaluated by survival analysis.

Results

The proportion of CD38+ NK cells within the NK cell population was significantly higher in LNM-positive patients (p <0.0001). However, no significant differences were observed in the proportions of other lymphocyte subsets. Poorer histologic grade (odds ratio [OR] =4.76, p =0.03), lymphovascular invasion (LVI) (OR =22.38, p <0.01), and CD38+ NK cells (high) (OR =4.54, p <0.01) were identified as independent risk factors for LNM. Furthermore, high proportion of CD38+ NK cells was associated with poor prognosis of CRC patients (HR=2.37, p =0.03).

Conclusions

It was demonstrated that the proportion of CD38+ NK cells was a marker overexpressed in LNM-positive patients compared with LNM-negative patients. Moreover, an elevated proportion of CD38+ NK cells is a risk factor for LNM and poor prognosis in CRC.

Early colorectal cancer diagnosed after endoscopic resection: Conservative treatment is safe in most of the cases. Proposal for a risk-based management

INTRODUCTION

Endoscopic resection offers advantages over surgical resection for early colorectal cancer (ECC). However, there might be a presumed risk of recurrence. We aimed to determine the risk of recurrence after endoscopic removal of ECC.

METHODS

A single-centre series of endoscopic resections for ECC. Patients were stratified according to four risk factors: positive resection margins, Haggitt 4, lymphatic/vascular invasion and tumour budding.

RESULTS

We included 127 patients. Haggitt classification was grade 4 in 54.0%. Positive margins were found in 43 (33.9%), 16 (12.6%) had lymphatic or vascular invasion, and 5 (4.0%) had high grade budding. In 82 (64.5%) endoscopic excision was the definitive treatment, 45 (35.4%) underwent surgery. Six patients (13.3%) had residual tumour on specimen and/or node metastases. Postoperative complications occurred in ten (22.2%). At a median follow-up of 63 months, none of the 82 patients treated with endoscopic resection alone had recurrence. After stratifying patients according to risk factors, those who had residual tumour also had ≥2 risk factors.

CONCLUSIONS

Endoscopic follow up might be a valid option for patients with ECC. A risk-adjusted management seems prudent.

Early colorectal cancer diagnosed after endoscopic resection: Conservative treatment is safe in most of the cases. Proposal for a risk-based management

INTRODUCTION

Endoscopic resection offers advantages over surgical resection for early colorectal cancer (ECC). However, there might be a presumed risk of recurrence. We aimed to determine the risk of recurrence after endoscopic removal of ECC.

METHODS

A single-centre series of endoscopic resections for ECC. Patients were stratified according to four risk factors: positive resection margins, Haggitt 4, lymphatic/vascular invasion and tumour budding.

RESULTS

We included 127 patients. Haggitt classification was grade 4 in 54.0%. Positive margins were found in 43 (33.9%), 16 (12.6%) had lymphatic or vascular invasion, and 5 (4.0%) had high grade budding. In 82 (64.5%) endoscopic excision was the definitive treatment, 45 (35.4%) underwent surgery. Six patients (13.3%) had residual tumour on specimen and/or node metastases. Postoperative complications occurred in ten (22.2%). At a median follow-up of 63 months, none of the 82 patients treated with endoscopic resection alone had recurrence. After stratifying patients according to risk factors, those who had residual tumour also had ≥2 risk factors.

CONCLUSIONS

Endoscopic follow up might be a valid option for patients with ECC. A risk-adjusted management seems prudent.

Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

Efficacy of PET/CT in diagnosis of regional lymph node metastases in patients with colorectal cancer: retrospective cohort study

Background

Endoscopic and transanal local resection without lymph node dissection are treatment options for patients with a low risk of lymph node metastasis; however, some patients might have undiagnosed lymph node metastases before surgery. This retrospective study aimed to evaluate the efficacy of preoperative PET/CT for diagnosing regional lymph node metastasis.

Methods

Patients who underwent curative resection with lymph node dissection for colorectal cancer at Osaka University between January 2012 and December 2015 were included. The cut-off values appropriate for diagnosing lymph node metastasis were calculated by way of a receiver operating characteristic (ROC) curves from maximum standard unit value (SUVmax) of main tumour, and lymph node short axis, and SUVmax of lymph node. The cut-off values of primary tumour SUVmax: 7, short-axis diameter of the lymph node at 7 mm, and lymph node SUVmax at 1.5 were set.

Result

A total of 541 patients were included. Regional lymph node metastases were confirmed in resected specimens from 187 patients (35 per cent). With a primary tumour SUVmax of 7 used as a cut-off value, the sensitivity and specificity of regional lymph node metastasis were 70.1 per cent and 45.5 per cent respectively. With a cut-off short-axis diameter of the regional lymph node of 7 mm, the sensitivity and specificity of regional lymph node metastasis were 75.2 per cent and 82.6 per cent respectively, and with a cut-off regional lymph node SUVmax of 1.5, the sensitivity and specificity of regional lymph node metastasis were 78.6 per cent and 96.8 per cent respectively. When the diagnostic criteria were defined by a lymph node short-axis diameter of 7 mm or SUVmax of 1.5, the sensitivity and specificity were 87.4 per cent and 81.8 per cent respectively.

Conclusion

Preoperative PET/CT is a useful modality for evaluating regional lymph node metastasis in patients with colorectal cancer.

Deep Submucosal Invasion Is Not an Independent Risk Factor for Lymph Node Metastasis in T1 Colorectal Cancer: A Meta-Analysis

BACKGROUND & AIMS

Deep submucosal invasion (DSI) is considered a key risk factor for lymph node metastasis (LNM) and important criterion to recommend surgery in T1 colorectal cancer. However, metastatic risk for DSI is shown to be low in the absence of other histologic risk factors. This meta-analysis determines the independent risk of DSI for LNM.

METHODS

Suitable studies were included to establish LNM risk for DSI in univariable analysis. To assess DSI as independent risk factor, studies were eligible if risk factors (eg, DSI, poor differentiation, lymphovascular invasion, and high-grade tumor budding) were simultaneously included in multivariable analysis or LNM rate of DSI was described in absence of poor differentiation, lymphovascular invasion, and high-grade tumor budding. Odds ratios (OR) and 95% CIs were calculated.

RESULTS

Sixty-seven studies (21,238 patients) were included. Overall LNM rate was 11.2% and significantly higher for DSI-positive cancers (OR, 2.58; 95% CI, 2.10-3.18). Eight studies (3621 patients) were included in multivariable meta-analysis and did not weigh DSI as a significant predictor for LNM (OR, 1.73; 95% CI, 0.96-3.12). As opposed to a significant association between LNM and poor differentiation (OR, 2.14; 95% CI, 1.39-3.28), high-grade tumor budding (OR, 2.83; 95% CI, 2.06-3.88), and lymphovascular invasion (OR, 3.16; 95% CI, 1.88-5.33). Eight studies (1146 patients) analyzed DSI as solitary risk factor; absolute risk of LNM was 2.6% and pooled incidence rate was 2.83 (95% CI, 1.66-4.78).

CONCLUSIONS

DSI is not a strong independent predictor for LNM and should be reconsidered as a sole indicator for oncologic surgery. The expanding armamentarium for local excision as first-line treatment prompts serious consideration in amenable cases to tailor T1 colorectal cancer management.

Endoscopic diagnosis and treatment of early colorectal cancer

Early colorectal cancer refers to cancer in the colorectum that is confined to the mucosa or submucosa and does not invade the muscularis propria, irrespective of lymph node or distant metastasis. As the number of persons undergoing screening colonoscopy increases, the proportion of patients diagnosed with precancerous colorectal lesions and early colorectal cancer also increases. In the last decade, innovative optical technologies for endoscopic diagnosis have been introduced and endoscopic treatment techniques such as endoscopic submucosal dissection have provided major breakthroughs in the management of early colorectal cancer. With these remarkable developments, endoscopic treatment has established itself as an alternative to surgical resection in the treatment of early colorectal cancer. This review will discuss the endoscopic diagnosis and treatment of early colorectal cancer. Furthermore, the unmet needs in this field and the latest research addressing those issues will be summarized.

Proper surgical extent for clinical Stage I right colon cancer

Purpose:

Pre-operative evaluation identifying clinical-stage affects the decision regarding the extent of surgical resection in right colon cancer. This study was designed to predict a proper surgical resection through the prognosis of clinical Stage I right colon cancer.

Patients and Methods:

We included patients who were diagnosed with clinical and pathological Stage I right-sided colon cancer, including appendiceal, caecal, ascending, hepatic flexure and proximal transverse colon cancer, between August 2010 and December 2016 in two tertiary teaching hospitals. Patients who underwent open surgeries were excluded because laparoscopic surgery is the initial approach for colorectal cancer in our institutions.

Results:

Eighty patients with clinical Stage I and 104 patients with pathological Stage I were included in the study. The biopsy reports showed that the tumour size was larger in the clinical Stage I group than in the pathological Stage I group (3.4 vs. 2.3 cm, P < 0.001). Further, the clinical Stage I group had some pathological Stage III cases (positive lymph nodes, P = 0.023). The clinical Stage I group had a higher rate of distant metastases (P = 0.046) and a lower rate of overall (P = 0.031) and cancer-specific survival (P = 0.021) than the pathological Stage I group. Compared to pathological Stage II included in the period, some of the survival curves were located below the pathological Stage II, but there was no statistical difference.

Conclusion:

The study results show that even clinical Stage I cases, radical resection should be considered in accordance with T3 and T4 tumours.

Classic and Novel Histopathologic Risk Factors for Lymph Node Metastasis in T1 Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Treatment of endoscopically resected T1 colorectal cancers is based on the risk of lymph node metastasis. Risk is based on histopathologic features, although there is lack of consensus as to what constitutes high-risk features.

OBJECTIVE

The purpose of this study was to conduct a systematic review and meta-analysis of histopathologic risk factors for lymph node metastasis.

DATA SOURCES

A search of MEDLINE, Embase, Scopus, and Cochrane controlled register of trials for risk factors for lymph node metastasis was performed from inception until August 2018.

STUDY SELECTION

Included patients must have had an oncologic resection to confirm lymph node status and reported at least 1 histopathologic risk factor.

INTERVENTION

Rates of lymph node positivity were compared between patients with and without risk factors.

MAIN OUTCOME MEASURES

We report the results of the meta-analysis as ORs.

RESULTS

Of 8592 citations, 60 met inclusion criteria. Pooled analyses found that lymphovascular invasion, vascular invasion, neural invasion, and poorly differentiated histology were significantly associated with lymph node metastasis, as were depths of 1000 µm (OR = 2.76), 1500 µm (OR = 4.37), 2000 µm (OR = 2.37), submucosal level 3 depth (OR = 3.08), and submucosal level 2/3 (OR = 3.08) depth. Depth of 3000 µm, Haggitt level 4, and widths of 3000 µm and 4000 µm were not significantly associated with lymph node metastasis. Tumor budding (OR = 4.99) and poorly differentiated clusters (OR = 14.61) were also significantly associated with lymph node metastasis.

LIMITATIONS

Included studies reported risk factors independently, making it impossible to examine the additive metastasis risk in patients with numerous risk factors.

CONCLUSIONS

We identified 1500 μm as the depth most significantly associated with lymph node metastasis. Novel factors tumor budding and poorly differentiated clusters were also significantly associated with lymph node metastasis. These findings should help inform guidelines regarding risk stratification of T1 tumors and prompt additional investigation into the exact contribution of poorly differentiated clusters to lymph node metastasis.

Histopathological risk factors for lymph node metastases in T1 colorectal cancer: meta-analysis

BACKGROUND

National screening programmes increase the proportion of T1 colorectal cancers. Local excision may be possible, but the risk of lymph node metastases (LNMs) could jeopardize long-term outcomes. The aim of the present study was to review the association between histopathological findings and LNMs in T1 colorectal cancer.

METHODS

A systematic literature search was conducted using PubMed,Embase, and Cochrane online databases. Studies investigating the association between one or more histopathological factors and LNMs in patients who underwent resection for T1 colorectal cancer were included.

RESULTS

Sixteen observational studies were included in the meta-analysis, including a total of 10 181 patients, of whom 1 307 had LNMs. Lymphovascular invasion (odds ratio (OR) 7.42; P < 0.001), tumour budding (OR 4.00; P < 0.001), depth of submucosal invasion, whether measured as at least 1000 µm (OR 3.53; P < 0.001) or Sm2-3 (OR 2.12; P = 0.020), high tumour grade (OR 3.75; P < 0.001), polypoid growth pattern (OR 1.59; P = 0.040), and rectal location of tumour (OR 1.36; P = 0.003) were associated with LNMs.

CONCLUSION

Distinct histopathological factors associated with nodal metastases in T1 colorectal cancer can aid selection of patients for local excision or major excisional surgery.

[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.

Local excision for T1 rectal tumours: are we getting better?

AIM

The objective was to assess the effect of three different surgical treatments for T1 rectal tumours, radical resection (RR), open local excision (open LE) and laparoscopic local excision (laparoscopic LE), on overall survival (OS).

METHODS

Adults from the National Cancer Database (2008-2016) with a diagnosis of T1 rectal cancer were stratified by treatment type (LE vs RR). We assumed that laparoscopic LE equates to transanal minimally invasive surgery (TAMIS) or transanal endoscopic microsurgery. The primary outcome was 5-year OS. Subgroup analyses of the LE group stratified by time period [2008-2010 (before TAMIS) vs 2011-2016 (after TAMIS)] and approach (laparoscopic vs open) were performed.

RESULTS

Among 10 053 patients, 6623 (65.88%) underwent LE (74.33% laparoscopic LE vs 25.67% open LE) and 3430 (34.12%) RR. The use of LE increased from 52.69% in 2008 to 69.47% in 2016, whereas RR decreased (P < 0.001). In unadjusted analysis, there was no significant difference in 5-year OS between the LE and RR groups (P = 0.639) and between the two LE time periods (P = 0.509), which was consistent with the adjusted analysis (LE vs RR, hazard ratio 1.05, 95% CI 0.92-1.20, P = 0.468; 2008-2010 LE vs 2011-2016 LE, hazard ratio 1.09, 95% CI 0.92-1.29, P = 0.321). Laparoscopic LE was associated with improved OS in the unadjusted analysis only (P = 0.006), compared to the open LE group (hazard ratio 0.94, 95% CI 0.78-1.12, P = 0.495).

CONCLUSIONS

This study supports the use of a LE approach for T1 rectal tumours as a strategy to reduce surgical morbidity without compromising survival.

Retrospective analysis of LNM risk factors and the effect of chemotherapy in early colorectal cancer: A Chinese multicenter study

Background

Estimating the risk of lymph node metastasis (LNM) is crucial for determining subsequent treatments following curative resection of early colorectal cancer (ECC). This multicenter study analyzed the risk factors of LNM and the effectiveness of postoperative chemotherapy in patients with ECC.

Methods

We retrospectively analyzed the data of 473 patients with ECC who underwent general surgery in five hospitals between January 2007 and October 2018. The correlations between LNM and sex, age, tumor size, tumor location, endoscopic morphology, pathology, depth of invasion and tumor budding (TB) were directly estimated based on postoperative pathological analysis. We also observed the overall survival (OS) and recurrence in ECC patients with and without LNM after matching according to baseline measures.

Results

In total, 473 ECC patients were observed, 288 patients were enrolled, and 17 patients had LNM (5.90%). The univariate analysis revealed that tumor size, pathology, and lymphovascular invasion were associated with LNM in ECC (P = 0.026, 0.000, and 0.000, respectively), and the multivariate logistic regression confirmed that tumor size, pathology, and lymphovascular invasion were risk factors for LNM (P = 0.021, 0.023, and 0.001, respectively). There were no significant differences in OS and recurrence between the ECC patients with and without LNM after matching based on baseline measures (P = 0.158 and 0.346, respectively), and no significant difference was observed between chemotherapy and no chemotherapy in ECC patients without LNM after surgery (P = 0.729 and 0.052).

Conclusion

Tumor size, pathology, and lymphovascular invasion are risk factors for predicting LNM in ECC patients. Adjuvant chemotherapy could improve OS and recurrence in patients with LNM but not always in ECC patients without LNM.

A Focused Review on Advances in Risk Stratification of Malignant Polyps

Colorectal cancer is the third most common cancer in both men and women in the United States, with most cases arising from precursor adenomatous polyps. Colorectal malignant polyps are defined as cancerous polyps that consist of tumor cells invading through the muscularis mucosae into the underlying submucosa (pT1 tumor). It has been reported that approximately 0.5-8.3% of colorectal polyps are malignant polyps, and the potential for lymph node metastasis in these polyps ranges from 8.5% to 16.1%. Due to their clinical significance, recognition of malignant polyps is critical for clinical teams to make treatment decisions and establish appropriate surveillance schedules after local excision of the polyps. There is a rapidly developing interest in malignant polyps within the literature as a result of an increasing number of identifiable adverse histologic features and recent advancements in endoscopic treatment techniques. The purpose of this paper is to have a focused review of the recent histopathologic literature of malignant polyps.

Long-Term Outcomes of T1 Colorectal Cancer after Endoscopic Resection

BACKGROUND AND AIMS

Endoscopic resection (ER) for submucosal invasive colorectal cancer (T1 CRC) can be grouped as curative ER (C-ER) and non-curative ER (NC-ER). Little is known about the long-term outcomes of patients in these two groups. Therefore, we have evaluated the long-term outcomes in endoscopically resected T1 CRC patients in C-ER and NC-ER groups.

METHODS

We conducted a retrospective study on 220 patients with T1 CRC treated with ER from January 2007 to December 2017. First, we investigated the long-term outcomes (5-year overall survival [OS] and recurrence-free survival [RFS]) in the C-ER group (n = 49). In the NC-ER group (n = 171), we compared long-term outcomes between patients who underwent additional surgical resection (ASR) (n = 117) and those who did not (surveillance-only, n = 54).

RESULTS

T1 CRC patients in the C-ER and NC-ER groups had a median follow-up of 44 (interquartile range 32-69) months. There was no risk of tumor recurrence and cancer-related deaths in patients with C-ER. In the NC-ER group, the 5-year OS rates were 75.3% and 92.6% in the surveillance-only and ASR subgroups, respectively. The hazard ratio (HR) for ASR in NC-ER vs. surveillance-only in NC-ER was statistically insignificant. However, RFS rates were significantly different between the ASR (97.2%) and surveillance-only (84.0%) subgroups. Multivariate analysis indicated a submucosal invasion depth (SID) of >2500 µm and margin positivity to be associated with recurrence.

CONCLUSIONS

The surveillance-only approach can be considered as an alternative surgical option for T1 CRCs in selected patients undergoing NC-ER.

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.

Is radical surgery for clinical stage I right-sided colon cancer relevant? A retrospective review

Purpose

Radical lymph node dissection for right-sided colon cancer is technically challenging. No clear guideline is available for surgical resection of clinical stage I right-sided colon cancer. This study was designed to review the pathologic stage of clinical stage I right-sided colon cancer and determine the relevant extent of surgical resection.

Methods

Patients were treated for clinical stage I right-sided colon cancers (cecal, ascending, hepatic flexure, and proximal transverse colon) between July 2006 and December 2014 at a tertiary teaching hospital. Open surgery was not included because laparoscopic surgery is an initial major procedure in the institution.

Results

During the study period, 80 patients diagnosed with clinical stage I right-sided colon cancer were classified into 2 groups according to the pathology: stage 0/I and II/III. Tumor sizes were larger in the stage II/III group (P = 0.003). The stage II/III group had higher rates of vascular (P = 0.023) and lymphatic invasion (P = 0.023) and lower rates of well differentiation (P = 0.022). During follow-up, 1 case of local and 4 cases of systemic recurrences were found. Multivariate analysis to confirm odds ratios affecting change from clinical stage I to pathological stage II/III showed that tumor size (P = 0.010) and the number of retrieved lymph nodes (P = 0.046) were risk factors.

Conclusion

For right-sided colon cancer, even with clinical stage I included, radical lymph node dissection should be performed for exact staging with sufficient number of lymph nodes. This will help determine appropriate adjuvant treatment, especially in large tumor sizes.

Long-term Transanal Excision Outcomes in Patients With T1 Rectal Cancer: Comparative Analysis of Radical Resection

PURPOSE

Transanal excision (TAE) is an alternative surgical procedure for early rectal cancer. This study compared long-term TAE outcomes, in terms of survival and local recurrence (LR), with total mesorectal excision (TME) in patients with pathologically confirmed T1 rectal cancer.

METHODS

T1 rectal adenocarcinoma patients who underwent surgery from 1990 to 2011 were retrospectively reviewed. Patients that were suspected to have preoperative lymph node metastasis were excluded. Demographics, recurrence, and survival were analyzed based on TAE and TME surgery.

RESULTS

Of 268 individuals, 61 patients (26%) underwent TAE, which was characterized by proximity to the anus, submucosal invasion depth, and lesion infiltration, compared with TME patients (P < 0.001-0.033). During a median follow-up of 10.4 years, 12 patients had systemic and/or LR. Ten-year cancer-specific survival in the TAE and TME groups was not significantly different (98% vs. 100%). However, the 10-year LR rate in the TAE group was greater than that of TME group (10% vs. 0%, P < 0.001). Although 5 of the 6 TAE patients with LR underwent salvage surgery, one of the patients eventually died. The TAE surgical procedure (hazard ratio, 19.066; P = 0.007) was the only independent risk factor for LR.

CONCLUSION

Although long-term survival after TAE was comparable to that after TME, TAE had a greater recurrence risk than TME. Thus, TAE should only be considered as an alternative surgical option for early rectal cancer in selected patients.

Histopathological factors help to predict lymph node metastases more efficiently than extra-nodal recurrences in submucosa invading pT1 colorectal cancer

The therapeutic management of patients with endoscopic resection of colorectal cancer invading the submucosa (i.e. pT1 CRC) depends on the balance between the risk of cancer relapse and the risk of surgery-related morbidity and mortality. The aim of our study was to report on the histopathological risk factors predicting lymph node metastases and recurrences in an exhaustive case series comprising every pT1 CRC (of adenocarcinoma subtype only) diagnosed in Finistère (France) during 5-years. For 312 patients with at least 46 months follow-up included in the digestive cancers registry database, histopathological factors required for risk stratification in pT1 CRC were reviewed. Patients were treated by endoscopic resection only (51 cases), surgery only (138 cases), endoscopic resection followed by surgery (102 cases) or transanal resection (21 cases). Lymph node metastases were diagnosed in 19 patients whereas 15 patients had an extra-nodal recurrence (7 local recurrences only, 4 distant metastases only and 4 combining local and distant recurrences). Four patients with distant metastases died of their cancer. Poor tumor differentiation, vascular invasion and high grade tumor budding on HES slides were notably identified as strong risk-factors of lymph node metastases but the prediction of extra-nodal recurrences (local, distant and sometimes fatal) was less obvious, albeit it was more frequent in patients treated by transanal resection than with other treatment strategies. Beyond good performances in predicting lymph node metastases and guiding therapeutic decision in patients with pT1 CRC, our study points that extra-nodal recurrence of cancer is more difficult to predict and requires further investigations.

Long-term oncological outcomes of local excision versus radical resection for early colorectal cancer in young patients without preoperative chemoradiotherapy: a population-based propensity matching study

The incidence and mortality of colorectal carcinoma are rising in young adults. This population-based propensity matching study aimed to compare long-term oncological outcomes of local excision with radical resection for early localized colorectal cancer (CRC) in young patients without preoperative chemoradiotherapy. Patients under 45 years old with T1 colon or rectal adenocarcinoma who underwent local excision or radical resection were included from the Surveillance, Epidemiology, and End Results (SEER) database between 1998 and 2014. Survival curves were plotted using the Kaplan-Meier method. Cancer-specific survival (CSS) was compared using adjusted hazard ratios (HRs) between local excision and radical resection. After propensity score matching procedure, total of 1719 patients were included in the analysis, among which 573 treated with local excision and 1146 treated with radical resection. The median follow-up was 80 months (interquartile range(IQR): 37-132), with 1074 patients followed for ≥5 years and 508 patients followed for ≥10 years. Five-year CSS of local excision versus radical resection was 93.4% versus 96.7% for colon cancer and 96.6% versus 98.4% for rectal cancer. Ten-year CSS of local excision versus radical resection was 91.4% versus 94.0% for colon cancer and 92.8% versus 96.7% for rectal cancer. On multivariable analysis, compared with radical resection, local excision was not associated with inferior CSS for colon (HR 1.74, 95% CI: 0.92-3.29, P = 0.090) and rectal cancer (HR 2.16, 95% CI: 0.99-4.71, P = 0.052). There is no evidence of differential long-term oncological outcomes between local excision and radical resection. These findings supported clinical application of local excision for early colon and rectal cancer in young adults.

Increased Rate of Incidental Colorectal Malignant Polyps: A Single-Center Experience

Background and Aims

To investigate the incidence and treatment of colorectal malignant polyps before and after colorectal cancer screening initiation in March 2014 in a single Danish center.

Materials and Methods

71 patients with colorectal malignant polyps in a single center from 2012 to 2015 were reported retrospectively.

Results

There was a significant increase (P < 0.01) in the incidence of colorectal malignant polyps from 2012 to 2013 and 2014 to 2015 (8 versus 63) relative to the increase in colonoscopies with polypectomy (1029 versus 2706). It coincides with the initiation of screening in March 2014. A positive, nonradical, or undeterminable resection margin was found in 57% (36/63), and this was the primary indication for surgery. Additional surgery was done in 49% of the cases (31/63) with 27 bowel resections and 4 transanal endoscopic microsurgery (TEM) procedures. Nineteen percent (5/27) had either residual cancer cells at the polypectomy site or lymph node metastasis in the resection specimens.

Conclusion

Colorectal malignant polyps have become more frequent after the initiation of screening. The primary, and operator-dependent, indicator for surgery is the positive, nonradical, or undeterminable resection margin, and 1 in 5 operated has remaining cancer in the resection specimens.

Endoscopic resection of high-risk T1 colorectal carcinoma prior to surgical resection has no adverse effect on long-term outcomes

OBJECTIVE

It is difficult to predict the presence of histological risk factors for lymph node metastasis (LNM) before endoscopic treatment of T1 colorectal cancer (CRC). Therefore, endoscopic therapy is propagated to obtain adequate histological staging. We examined whether secondary surgery following endoscopic resection of high-risk T1 CRC does not have a negative effect on patients' outcomes compared with primary surgery.

DESIGN

Patients with T1 CRC with one or more histological risk factors for LNM (high risk) and treated with primary or secondary surgery between 2000 and 2014 in 13 hospitals were identified in the Netherlands Cancer Registry. Additional data were collected from hospital records, endoscopy, radiology and pathology reports. A propensity score analysis was performed using inverse probability weighting (IPW) to correct for confounding by indication.

RESULTS

602 patients were eligible for analysis (263 primary; 339 secondary surgery). Overall, 34 recurrences were observed (5.6%). After adjusting with IPW, no differences were observed between primary and secondary surgery for the presence of LNM (OR 0.97; 95% CI 0.49 to 1.93; p=0.940) and recurrence during follow-up (HR 0.97; 95% CI 0.41 to 2.34; p=0.954). Further adjusting for lymphovascular invasion, depth of invasion and number of retrieved lymph nodes did not alter this outcome.

CONCLUSIONS

Our data do not support an increased risk of LNM or recurrence after secondary surgery compared with primary surgery. Therefore, an attempt for an en-bloc resection of a possible T1 CRC without evident signs of deep invasion seems justified in order to prevent surgery of low-risk T1 CRC in a significant proportion of patients.

Tumor budding as a risk factor for nodal metastasis in pT1 colorectal cancers: a meta-analysis

Worldwide, colorectal cancer (CRC) screening programs have significantly increased the detection of submucosal (pT1) adenocarcinoma. Completion surgery may be indicated after endoscopic excision of these potentially metastasizing early cancers. However, the postsurgical prevalence of nodal implants does not exceed 15%, leading to questions concerning the clinical appropriateness of any post-endoscopy surgery. Eastern scientific societies (Japanese Society for Cancer of the Colon-Rectum, in particular) include tumor budding (TB), defined as the presence of isolated single cancer cells or clusters of fewer than 5 cancer cells at the tumor invasive front, among the variables that must be included in histologic reports. In Western countries, however, no authoritative endorsements recommend the inclusion of TB in the histology report because of the heterogeneity of definitions and measurement methods as well as its apparent poor reproducibility. To assess the prognostic value of TB in pT1 CRCs, this meta-analysis evaluated 41 studies involving a total of 10137 patients. We observed a strong association between the presence of TB and risk of nodal metastasis in pT1 CRC. In comparing TB-positive (684/2401; 28.5%) versus TB-negative (557/7736; 7.2%) patients, the prevalence of nodal disease resulted in an odds ratio value of 6.44 (95% confidence interval, 5.26-7.87; P<.0001; I2 = 30%). This increased risk of regional nodal metastasis was further confirmed after accounting for potential confounders. These results support the priority of histologically reporting TB in any endoscopically removed pT1 CRC to direct more appropriate patient management.

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.

Transanal endoscopic microsurgery and transanal minimally invasive surgery: is one technique superior?

BACKGROUND

Transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS) have been shown to improve the quality of transanal resections, allowing for improved visibility and access to the proximal rectum. This study compares the short-term outcomes between TEM and TAMIS among experienced colorectal surgeons.

METHOD

A retrospective review was conducted for TEM and TAMIS performed from 2012 to 2015 by local colorectal surgeons. Baseline patient demographics, operative variables, pathology results, and short-term outcomes were assessed.

RESULTS

Sixty-nine patients were identified (40 TEM and 29 TAMIS). Patient demographics, tumor characteristics, operative variables, margin status, and postoperative complications were similar for both. Volume of resection was higher for TAMIS (P < .001). Lymph node retrieval was achieved in 17.2% of TAMIS cases compared with 0% of TEM (P = .01).

CONCLUSIONS

TAMIS appears to have equivalent indications and outcomes compared with TEM. TAMIS is associated with larger specimens and more frequent presence of mesorectal lymph nodes.

Update on Difficult Polypectomy Techniques

Endoscopists often encounter colon polyps that are technically difficult to resect. These lesions traditionally were managed surgically, with significant potential morbidity and mortality. Recent advances in endoscopic techniques and instruments have allowed endoscopists to safely and effectively remove colorectal lesions with high technical and clinical success and potentially avoid invasive surgery. Endoscopic mucosal resection (EMR) has gained acceptance as the first-line therapy for large colorectal lesions. Endoscopic submucosal dissection (ESD) has been reported to be associated with higher rate of en bloc resection and less risk of short-time recurrence, but with an increased risk of adverse events. Therefore, the role of colorectal ESD should be restricted to lesions with high-risk morphologic features of submucosal invasion. In this article, we review the recent literature on the endoscopic management of difficult colorectal neoplasms.

Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis

BACKGROUND AND AIM

Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection.

METHODS

Initial or additional surgery with nodal dissection was performed in 653 T1 carcinoma cases. Clinicopathological factors were retrospectively analyzed with respect to nodal metastasis. The status of the muscularis mucosae (MM grade) was defined as grade 1 (maintenance) or grade 2 (fragmentation or disappearance). The lesions were then stratified based on the risk of nodal metastasis.

RESULTS

Muscularis mucosae grade was associated with nodal metastasis (P = 0.026), and no patients with MM grade 1 lesions had nodal metastasis. Significant risk factors for nodal metastasis in patients with MM grade 2 lesions were attribution of women (P = 0.006), lymphovascular infiltration (P < 0.001), tumor budding (P = 0.045), and poorly differentiated adenocarcinoma or mucinous carcinoma (P = 0.007). Nodal metastasis occurred in 1.06% of lesions without any of these pathological factors, but in 10.3% and 20.1% of lesions with at least one factor in male and female patients, respectively. There was good inter-observer agreement for MM grade evaluation, with a kappa value of 0.67.

CONCLUSIONS

Stratification using MM grade, pathological factors, and patient sex provided more appropriate indication for additional surgery with lymph node dissection after endoscopic treatment for T1 colorectal carcinomas.

Perineural Invasion is a Strong Prognostic Factor in Colorectal Cancer: A Systematic Review

Perineural invasion (PNI) is a possible route for metastatic spread in various cancer types, including colorectal cancer (CRC). PNI is linked to poor prognosis, but systematic analyses are lacking. This study systematically reviews the frequency and impact of PNI in CRC. A literature search was performed using PubMed database from inception to January 1, 2014. Data were analyzed using Review Manager 5.3. A quality assessment was performed on the basis of modified REMARK criteria. Endpoints were local recurrence (LR), 5-year disease-free survival (5yDFS), 5-year cancer-specific survival (5yCSS), and 5-year overall survival (5yOS). Meta-analysis was performed in terms of risk ratios (RR) and hazard ratios (HR) with 95% confidence interval (95% CI). In this meta-analysis, 58 articles with 22,900 patients were included. PNI was present in 18.2% of tumors. PNI is correlated with increased LR (RR 3.22, 95% CI, 2.33-4.44) and decreased 5yDFS (RR 2.35, 95% CI, 1.66-3.31), 5yCSS (RR 3.61, 95% CI, 2.76-4.72), and 5yOS (RR 2.09, 95% CI, 1.68-2.61). In multivariate analysis PNI remains an independent prognostic factor for 5yDFS, 5yCSS, and 5yOS (HR 2.35, 95% CI, 1.97-3.08; HR 1.91, 95% CI, 1.50-2.42; and HR 1.85, 95% CI, 1.63-2.12, respectively). We confirmed the strong impact of PNI for LR and survival in CRC. The prognostic value of PNI is similar to that of well-established prognostic factors as depth of invasion, differentiation grade, lymph node metastases, and lymphatic and extramural vascular invasion. Therefore, PNI should be one of the factors in the standardized reporting of CRC and might be considered a high-risk feature.

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.

The Factors Effecting Lymphovascular Invasion in Adenocarcinoma of the Colon and Rectum

Adenocarcinomas of the colon and rectum are the most common gastrointestinal malignancy, and lymph node metastases are established as a prognostic factor. Lymphovascular invasion has been recognized as an indication of lymph node metastases. This prompted us to investigate the features of primary tumor that may serve as a risk factor for lymphovascular invasion in colorectal carcinoma. Clinical and pathologic tissue data of colorectal carcinoma treated in our hospital were retrieved from the computer files at Haydarpasa Numune Education and Research Hospital, from June 1998 to December 2010, retrospectively. We excluded all patients who have two-thirds distal rectal carcinoma to rule out neoadjuvant treatment bias. Tissues from the specimens were stained with standard hematoxylin and eosin. Clinical data including age and sex of patient, location and diameter of tumor, perineural invasion, peritumoral lymphocytic infiltration, tumor grade, lymphovascular invasion, Pathologic T level (pT), and lymph node metastasis were recorded. Lymphovascular invasion was present only in 43 patients out of 108. Only pT and lymph node metastases were found to be statistically significant related to lymphovascular invasion (p = 0.04 and p < 0.001). Perineural invasion, pT, and peritumoral lymphocytic infiltration are the factors with p < 0.2 in the univariate analysis that were investigated with multivariate analysis, but no factor was found as an independent prognostic factor for lymphovascular invasion. Lymphovascular invasion is significantly related to lymph node metastases. Only pT is found as a factor that increases the lymphovascular invasion.

Practice parameters for early colon cancer management: Italian Society of Colorectal Surgery (Società Italiana di Chirurgia Colo-Rettale; SICCR) guidelines

Early colon cancer (ECC) has been defined as a carcinoma with invasion limited to the submucosa regardless of lymph node status and according to the Royal College of Pathologists as TNM stage T1 NX M0. As the potential risk of lymph node metastasis ranges from 6 to 17% and the preoperative assessment of lymph node metastasis is not reliable, the management of ECC is still controversial, varying from endoscopic to radical resection. A meeting on recent advances on the management of colorectal polyps endorsed by the Italian Society of Colorectal Surgery (SICCR) took place in April 2014, in Genoa (Italy). Based on this material the SICCR decided to issue guidelines updating the evidence and to write a position statement paper in order to define the diagnostic and therapeutic strategy for ECC treatment in context of the Italian healthcare system.

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.

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.

Local excision for early stage rectal cancer in patients over age 65 years: 2000-2009

BACKGROUND

Local excision of rectal cancer is an attractive option because it avoids the morbidity of radical resection. Concerns have arisen during the past decade, however, regarding substandard oncologic results.

OBJECTIVE

Using the most recent Survey of Epidemiology and End Results-Medicare data, we examined the change in the use of local excision for rectal cancer from 2000 to 2009 and examined patient, surgeon, and hospital factors related to its use.

DESIGN

This study is a retrospective cohort study.

SETTINGS

This study was conducted at a tertiary care medical center using Survey of Epidemiology and End Results-Medicare data.

PATIENTS

Patients with pathologic Tis, T1, or T2 rectal cancer who were >65 years of age and underwent primary radical resection or local excision between 2000 and 2009 were included in this study.

MAIN OUTCOME MEASURES

The change in the use of local excision for rectal cancer from 2000 to 2009 was the main outcome measured.

RESULTS

A total of 8966 patients were identified. The use of local excision decreased significantly between 2000 and 2009. Women and patients who were older and had more comorbidities were significantly more likely to undergo local excision. Having a colorectal surgeon perform the surgery increased the odds of local excision by 1.5 times (p < 0.001). Similar trends were seen in patients operated on at the National Cancer Institute (OR, 1.7; p <0.001) and teaching hospitals (OR, 1.2; p = 0.003). Younger surgeons were more likely to perform local excisions. For surgeons graduating in 1980-1989 or 1990 and after, the odds of local excision were 1.40 (p = 0.001) and 2.1 (p <0.001) compared with surgeons graduating before 1970.

LIMITATIONS

The study was limited by the retrospective design, and the data were collected by multiple healthcare officials in their representative institutions.

CONCLUSIONS

In patient >65 years of age, the odds of undergoing local excision for early stage rectal cancer decreased significantly between 2000 and 2009, coincident with evidence of oncologic inferiority. However, there was still significant variation in its use. More studies are needed to better understand these variations in an attempt to bring more uniformity to the use of local excision in early stage rectal cancer.

Transanal endoscopic microsurgery: Current application and future prospects

Rectal neoplasms pose serious harm to human health. The options of surgical procedure for these patients have been limited because of the special features of anal and rectal anatomy and physiology. Tumors with a diameter less than 3 cm can be resected through the anus or soft microscope; however, those with a large diameter and wide base which are cancerous and relapse easily still need conventional laparotomy procedures. Transanal endoscopic microsurgery (TEM) was designed to avoid laparotomy for these patients. Using special instruments, TEM allows to totally resect tumors located 4-25 cm from the anus with safe margin and lower rate of complications. Because of minimal invasiveness, shorter operative time and lower rate of complications, TEM can be widely applied in rectal polyps and adenomas. Currently, there are still arguments about TEM usage in early-stage and advanced rectal cancer. This paper reviews the current situation of application and research of TEM, with emphasis put on its indications, clinical efficiency and future development.

Relationship between TopoⅡ protein expression and lymph node metastasis in rectal cancer

AIM: To detect topoisomerase Ⅱ (TopoⅡ) protein expression in colorectal cancer and to analyze its clinical significance.

METHODS: One hundred and twenty-six specimens were collected from patients with rectal cancer who were treated surgically from January 30, 2008 to January 29, 2012. The expression of TopoⅡ in the above specimens was detected by immunohistochemistry. The correlation between TopoⅡ expression and clinicopathologic parameters was then analyzed.

RESULTS: TopoⅡ was highly expressed in rectal cancer. TopoⅡ expression was positively correlated with rectal cancer pathological type (P = 0.007), cell differentiation (P = 0.004), depth of invasion (P = 0.042) and lymph node metastasis (P = 0.027), but not with sex, age, tumor location, histological type, or vascular thrombosis.

CONCLUSION: TopoⅡ is highly expressed in rectal cancer. TopoⅡ expression is closely associated with lymph node metastasis of rectal cancer, and can be used as a marker for lymph node metastasis of rectal 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.

Multivariate Logistic regression analysis of prognostic factors for stage Ⅲ rectal cancer

AIM: To analyze prognostic factors for stage Ⅲ rectal cancer by multivariate Logistic regression analysis.

METHODS: Clinical data for 198 patients with stage Ⅲ rectal cancer who underwent radical resection from June 2013 to June 2008 were analyzed retrospectively. Univariate and multivariate regression analyses were conducted to investigate the relationship of age, gender, gross type, TNM stage, lymph node metastasis, pathological type with prognosis. The patients were divided into two groups based on the extent of lymph node metastasis (33.9% as cutoff) to assess the relationship between lymph node metastasis and postoperative survival.

RESULTS: Univariate regression analysis indicated that age, TNM stage, pathological type and lymph node metastasis were factors significantly affecting prognosis of stage Ⅲ rectal cancer. Multivariate regression analysis indicated that the extent of lymph node metastasis, not age, sex, TNM stage, and pathological type, was an independent predictor of survival of patients with stage Ⅲ colorectal cancer.

CONCLUSION: Lymph node metastasis is an important predictor of prognosis of stage Ⅲ rectal cancer.

Is There an Indication for Surgical Resection in Colorectal Adenoma?

BACKGROUND

Due to the adenoma-carcinoma sequence, complete removal of colorectal polyps is essential.

METHOD

This article analyzes the role of surgery in the removal of colorectal adenoma.

RESULTS

Nowadays, most adenomas are removed properly by endoscopic methods. Also in the resection of giant polyps and recurrent adenoma endoscopic data is convincing. Therefore, surgical resection of colorectal adenomas is required in the case of endoscopic inaccessibility. Reasons for this may be the location of the polyp, incomplete endoscopic resection, or suspected malignancy. Endoscopic or limited surgical resection of malignant adenomas is acceptable only if 'low-risk' criteria are fulfilled. Otherwise oncologic radical resection is recommended. In general, radical resection is also necessary in the case of polyps that are not suitable for endoscopic removal, because here the rate of colorectal carcinoma is high.

CONCLUSION

If a surgical approach is necessary, minimally invasive surgery in the hands of an experienced laparoscopic surgeon is a suitable option. Adenomas in the lower two thirds of the rectum are suitable for transanal full-thickness resection. This is done by conventional resection or transanal endoscopic microsurgery. The histopathological preparation of these specimens provides diagnostic and therapeutic benefits, particularly compared to piecemeal resection of early carcinoma.

The detection and role of lymphatic and blood vessel invasion in predicting survival in patients with node negative operable primary colorectal cancer

Although vascular invasion in colorectal cancer has been recognised since 1938, detection methods and results remain inconsistent. Vascular invasion is currently an independent prognostic factor in colorectal cancer influencing disease progression and survival. The vascular system consists of three components, arterial, venous and lymphatic vessels, all of which can be invaded but accurate distinction between the components remains difficult with routine staining techniques. Even though higher detection rates with elastica staining, for large vessel invasion, and recent techniques for immunohistochemistry for small vessel invasion, have been reported, a standardised method of detection has not been agreed upon which is reflected in the variability of published results. As a result of the Bowel Cancer Screening Programme in the UK it will be necessary to attempt to identify and stratify patients better, to be able to handle the stage migration to early node negative colorectal cancer. At present up to a third of patients, with node-negative colorectal cancer on conventional histopathological analysis, ultimately die of recurrent disease. It is therefore important to develop and standardised methods to identify lymphatic and blood vessel invasion which will influence ultimate survival. The present review summarises the current status of detection methods for these components of vascular invasion.

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.

Survival outcome of local excision versus radical resection of colon or rectal carcinoma: a Surveillance, Epidemiology, and End Results (SEER) population-based study

OBJECTIVE

To compare cancer-specific results of local excision with major resection.

BACKGROUND

Technological advances have enabled endoscopic and local excision techniques to be applied in the treatment of early colorectal cancer in preference to radical surgery.

METHOD

Patients with stage 0 (carcinoma in situ) or stage I (T1/2N0M0) adenocarcinoma of the colon or rectum undergoing surgery between 1998 and 2009 were included from the SEER (Surveillance, Epidemiology, and End Results) database. Local excision (endoscopic or surgical) was compared with major surgical resection using adjusted hazard ratios (HRs) for 5-year cancer-specific survival (CSS).

RESULTS

This study included 7378 local excisions and 36,116 major resections. There were 3553 patients with carcinoma in situ and 39,941 with clinical stage I cancer. Local tumor excision for carcinoma in situ was associated with equivalent CSS compared to major resection (HRs = 1.06, P = 0.814, for colon and 0.78, P = 0.494, for rectum). Local excision of T1 and T2 colon cancer was associated with reduced CSS (HR = 1.31, P = 0.020, and 2.89, P < 0.001, respectively). Local excision of T1 rectal cancer did not affect CSS (HR = 1.16, P = 0.236), but it significantly reduced CSS for T2 cancer (HR = 1.71, P < 0.001). Subgroup analysis of T1 and T2 rectal cancer after neoadjuvant therapy and local excision showed oncological equivalence to major resection (HR = 1.12, P = 0.802, and 1.23, P = 0.802).

CONCLUSIONS

Local excision for early colorectal cancer was oncologically equivalent to major surgery for carcinoma in situ and T1 rectal cancer, but inferior for T1-2 colon and T2 rectal cancer. Exploratory data suggest local excision of T1-2 rectal cancer after neoadjuvant therapy may be safe.