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

Risk of recurrence in high-risk T1 colon cancer following endoscopic and surgical resection: registry-based cohort study

BACKGROUND

Endoscopic resection of T1 colon cancer (CC) is currently limited by guidelines related to risk of lymph node metastases. However, clinical outcome following endoscopic and surgical resection is poorly investigated.

METHOD

A retrospective multicentre national cohort study was conducted on prospectively collected data from the Swedish colorectal cancer registry on all non-pedunculated T1 CC patients undergoing surgical and endoscopic resection between 2009 and 2021. Patients were categorized on the basis of deep submucosal invasion (Sm2-3), lymphovascular invasion (LVI), poor tumour differentiation, and R1/Rx into low- and high-risk cases. The primary outcomes of interest were recurrence rates and disease-free interval (DFI, defined as time from treatment to date of recurrence) according to resection methods and risk factors (sex, age at diagnosis, histologic grade, LVI, perineural invasion, mucinous subtype, submucosal invasion, tumour location, resection margin and nodal positivity in the surgical group).

RESULTS

In total, 1805 patients undergoing endoscopic (488) and surgical (1317) resection with 60.0 months median follow-up were included. Recurrence occurred in 18 (3.7%) endoscopically and 48 (3.6%) surgically resected patients. Adjuvant treatment was administered in 7.4% and 0.2% of the cases respectively in the surgical and endoscopically treated patients. Five-year DFI was 95.6% after endoscopic and 96.2% after surgical resection, with no significant difference when adjusting for confounding factors (HR 1.03, 95% c.i. 0.56 to 1.91, P = 0.920). There were no statistically significant differences in recurrence comparing endoscopic (1.7%) versus surgical (3.6%) low-risk and endoscopic (5.4%) versus surgical (3.8%) high-risk cases. LVI was the only significant risk factor for recurrence in multivariate Cox regression (HR 3.73, 95% c.i. 1.76 to 7.92, P < 0.001).

CONCLUSIONS

This study shows no difference in recurrence after endoscopic and surgical resection in high-risk T1 CC. Although it was not possible to match groups according to treatment, the multivariate analysis showed that lymphovascular invasion was the only independent risk factor for recurrence.

A new clinical model for predicting lymph node metastasis in T1 colorectal cancer

PURPOSE

Lymph node metastasis (LNM) is a crucial factor that determines the prognosis of T1 colorectal cancer (CRC) patients. We aimed to develop a practical prediction model for LNM in T1 CRC.

METHODS

We conducted a retrospective analysis of data from 825 patients with T1 CRC who underwent radical resection at a single center in China. All enrolled patients were randomly divided into a training set and a validation set at a ratio of 7:3 using R software. Risk factors for LNM were identified through multivariate logistic regression analyses. Subsequently, a prediction model was developed using the selected variables.

RESULTS

The lymph node metastasis (LNM) rate was 10.1% in the training cohort and 9.3% in the validation cohort. In the training set, risk factors for LNM in T1 CRC were identified, including depressed endoscopic gross appearance, sex, submucosal invasion combined with tumor grade (DSI-TG), lymphovascular invasion (LVI), and tumor budding. LVI emerged as the most potent predictor for LNM. The prediction model based on these factors exhibited good discrimination ability in the validation sets (AUC: 79.3%). Compared to current guidelines, the model could potentially reduce over-surgery by 48.9%. Interestingly, we observed that sex had a differential impact on LNM between early-onset and late-onset CRC patients.

CONCLUSIONS

We developed a clinical prediction model for LNM in T1 CRC using five factors that are easily accessible in clinical practice. The model has better predictive performance and practicality than the current guidelines and can assist clinicians in making treatment decisions for T1 CRC patients.

Differentiation grade as a risk factor for lymph node metastasis in T1 colorectal cancer

Objectives

Japanese guidelines include high-grade (poorly differentiated) tumors as a risk factor for lymph node metastasis (LNM) in T1 colorectal cancer (CRC). However, whether the grading is based on the least or most predominant component when the lesion consists of two or more levels of differentiation varies among institutions. This study aimed to investigate which method is optimal for assessing the risk of LNM in T1 CRC.

Methods

We retrospectively evaluated 971 consecutive patients with T1 CRC who underwent initial or additional surgical resection from 2001 to 2021 at our institution. Tumor grading was divided into low-grade (well- to moderately differentiated) and high-grade based on the least or predominant differentiation analyses. We investigated the correlations between LNM and these two grading analyses.

Results

LNM was present in 9.8% of patients. High-grade tumors, as determined by least differentiation analysis, accounted for 17.0%, compared to 0.8% identified by predominant differentiation analysis. A significant association with LNM was noted for the least differentiation method (p < 0.05), while no such association was found for predominant differentiation (p = 0.18). In multivariate logistic regression, grading based on least differentiation was an independent predictor of LNM (p = 0.04, odds ratio 1.68, 95% confidence interval 1.00-2.83). Sensitivity and specificity for detecting LNM were 27.4% and 84.1% for least differentiation, and 2.1% and 99.3% for predominant differentiation, respectively.

Conclusions

Tumor grading via least differentiation analysis proved to be a more reliable measure for assessing LNM risk in T1 CRC compared to grading by predominant differentiation.

Challenges in Implementing Endoscopic Resection for T2 Colorectal Cancer

The current standard treatment for muscularis propria-invasive (T2) colorectal cancer is surgical colectomy with lymph node dissection. With the advent of new endoscopic resection techniques, such as endoscopic full-thickness resection or endoscopic intermuscular dissection, T2 colorectal cancer, with metastasis to 20%-25% of the dissected lymph nodes, may be the next candidate for endoscopic resection following submucosal-invasive (T1) colorectal cancer. We present a novel endoscopic treatment strategy for T2 colorectal cancer and suggest further study to establish evidence on oncologic and endoscopic technical safety for its clinical implementation.

How Does Omitting Additional Surgery After Local Excision Affect the Prognostic Outcome of Patients With High-risk T1 Colorectal Cancer?

OBJECTIVE

To investigate how omitting additional surgery after local excision (LE) affects patient outcomes in high-risk T1 colorectal cancer (CRC).

BACKGROUND

It is debatable whether additional surgery should be performed for all patients with high-risk T1 CRC regardless of the tolerability of invasive procedures.

METHODS

Patients who had received LE for T1 CRC at the Japanese Society for Cancer of the Colon and Rectum institutions between 2009 and 2016 were analyzed. Those who had received additional surgical resection and those who did not were matched one-on-one by the propensity score-matching method. A total of 401 propensity score-matched pairs were extracted from 1975 patients at 27 Japanese Society for Cancer of the Colon and Rectum institutions and were compared.

RESULTS

Regional lymph node metastasis was observed in 31 (7.7%) patients in the LE + surgery group. Comparatively, the incidence of oncologic adverse events was low in the LE-alone group, such as the 5-year cumulative risk of local recurrence (4.1%) or overall recurrence (5.5%). In addition, the difference in the 5-year cancer-specific survival between the LE + surgery and LE-alone groups was only 1.8% (99.7% and 97.9%, respectively), whereas the 5-year overall survival was significantly lower in the LE-alone group than in the LE + surgery group [88.5% vs 94.5%, respectively ( P = 0.002)].

CONCLUSIONS

Those who had decided to omit additional surgery at the dedicated center for CRC treatment presented a small number of oncologic events and a satisfactory cancer-specific survival, which may suggest an important role of risk assessment regarding nononcologic adverse events to achieve a best practice for each individual with high-risk T1 tumors.

Management after non-curative endoscopic resection of T1 rectal cancer

Since the introduction of population-based screening, increasing numbers of T1 rectal cancers are detected and removed by local endoscopic resection. Patients can be cured with endoscopic resection alone, but there is a possibility of residual tumor cells remaining after the initial resection. These can be located intraluminally at the resection site or extraluminally in the form of (lymph node) metastases. To decrease the risk of residual cells progressing towards more advanced disease, additional treatment is usually needed. However, with the currently available risk stratification models, it remains challenging to determine who should and should not be further treated after non-curative endoscopic resection. In this review, the different management strategies for patients with non-curatively treated T1 rectal cancers are discussed, along with the available evidence for each strategy and relevant considerations for clinical decision making. Furthermore, we provide practical guidance on the management and surveillance following non-curative endoscopic resection of T1 rectal cancer.

Risk Factors for Lymph Node Metastasis and Recurrence in T1 Colorectal Cancer: Analysis of 801 Patients in a Single Institute

OBJECTIVE

To identify risk factors for lymph node metastasis and postoperative recurrence of pT1 colorectal cancer by clinicopathological study of surgically resected cases.

METHODS

In 801 patients with pT1 colorectal cancer who underwent surgical resection with lymph node dissection between April 2007 and January 2021, we evaluated clinicopathological factors (age, gender, BMI, serum CEA level, tumor localization, additional resection after endoscopic treatment, operation time, blood loss, histological type, tumor size, vascular invasion, and central lymph node dissection). We performed univariate and multivariate analyses to examine risk factors for lymph node metastasis. We also examined risk factors for recurrence in 583 patients up to December 2017.

RESULTS

Lymph node metastasis was observed in 100/801 patients (12.5%). Multivariate analysis of lymph node metastasis showed that patients with positive lymphatic invasion (odds ratio 2.57, 95% CI 1.62-4.04, P < .0001), positive venous invasion (odds ratio 2.31, 95% CI 1.48-3.61, P = .0002), and histologically poorly differentiated type (odds ratio 4.54, 95% CI 1.35-15.2, P = .014) were identified as risk factors. Postoperative recurrence was observed in 18/580 patients (3.1%). Risk factors for postoperative recurrence were also examined, including preoperative endoscopic treatment (odds ratio 3.59, 95% CI 1.18-10.9, P = .024), positive venous invasion (odds ratio 3.63, 95% CI 1.22-10.8, P = .021), positive lymph node metastasis (odds ratio 4.91, 95% CI 1.10-21.8, P = .037) were extracted as risk factors.

DISCUSSION

In this study, venous invasion, lymphatic invasion, and histologically poorly differentiated type were identified as risk factors for lymph node metastasis in T1 colorectal cancer, and positive venous invasion, positive lymph node metastasis, and preoperative endoscopic treatment were identified as risk factors for recurrence. We hope that large prospective study will lead to the development of a more specific treatment strategy, including endoscopic treatment and additional surgical resection.

Longitudinal analysis of long-term outcomes of colorectal cancer after laparotomy and laparoscopic surgery: The Shizuoka study

BACKGROUND

Long-term cancer prognosis after initial surgical procedures is an unlikely endpoint for clinical trials. Medical claim databases may aid in addressing this issue regardless of limited information on disease and patient background. However, the long-term prognosis (especially regarding long-term care needs) following surgical procedures remains unclear. This study aimed to assess whether long-term outcomes, such as the exacerbation of long-term care needs and mortality, differ with surgical methods.

METHODS

Using a longitudinal study with linkage between medical claim and long-term care database, patients with primary colorectal cancer who underwent initial colonoscopies were identified through anonymized data in Japan (Shizuoka Kokuho Database, 2012-2018). Odds ratios (ORs) for long-term outcomes (long-term care needs and all-cause mortality during a 6.5-year follow-up period) were analyzed using logistic regression to compare laparoscopy and endoscopic surgery to laparotomy.

RESULTS

Overall, 3,744 primary colorectal cancer cases (822 laparotomies, 705 laparoscopies, and 2,217 endoscopic surgeries) were included. Compared to the laparotomy group, the crude OR for exacerbation of long-term care needs in the laparoscopic surgery group was 0.376 (95% confidence interval, 0.227, 0.624), while the OR for all-cause mortality was 0.22 (0.329, 0.532).

CONCLUSION

This is the first study to analyze long-term prognosis after surgery for patients with colorectal cancer to combine medical and long-term needs data. As the national health insurance claim database rarely includes information on cancer stage and comorbidities, better prognosis on endoscopic surgery may need careful interpretation. Therefore, laparoscopy has superior outcomes in terms of long-term care needs and mortality compared to those of laparotomy.

pT1 colorectal cancer: A treatment dilemma

The implementation of population screening programs for colorectal cancer (CRC) has led to a considerable increase in the prevalence pT1-CRC originating on polyps amenable by local treatments. However, a high proportion of patients are referred for unnecessary oncological surgeries without a clear benefit in terms of survival. Selecting the appropriate endoscopic resection technique in the moment of diagnosis becomes crucial to provide the best treatment alternative to each individual polyp and patient. For this, it is imperative to increase the optical diagnostic skill for differentiating pT1-CRCs and decide the appropriate initial therapy. En bloc resection is crucial to obtain an adequate histological specimen that might allow organ preserving therapeutic management. In this review, we address key challenges in T1 CRC management, explore the efficacy and safety of the available diagnostic and therapeutic approaches, and shed light on upcoming advances in the field.

Computer-aided diagnosis of early-stage colorectal cancer using nonmagnified endoscopic white-light images (with videos)

BACKGROUND AND AIMS

Differentiation of colorectal cancers (CRCs) with deep submucosal invasion (T1b) from CRCs with superficial invasion (T1a) or no invasion (Tis) is not straightforward. This study aimed to develop a computer-aided diagnosis (CADx) system to establish the diagnosis of early-stage cancers using nonmagnified endoscopic white-light images alone.

METHODS

From 5108 images, 1513 lesions (Tis, 1074; T1a, 145; T1b, 294) were collected from 1470 patients at 10 academic hospitals and assigned to training and testing datasets (3:1). The ResNet-50 network was used as the backbone to extract features from images. Oversampling and focal loss were used to compensate class imbalance of the invasive stage. Diagnostic performance was assessed using the testing dataset including 403 CRCs with 1392 images. Two experts and 2 trainees read the identical testing dataset.

RESULTS

At a 90% cutoff for the per-lesion score, CADx showed the highest specificity of 94.4% (95% confidence interval [CI], 91.3-96.6), with 59.8% (95% CI, 48.3-70.4) sensitivity and 87.3% (95% CI, 83.7-90.4) accuracy. The area under the characteristic curve was 85.1% (95% CI, 79.9-90.4) for CADx, 88.2% (95% CI, 83.7-92.8) for expert 1, 85.9% (95% CI, 80.9-90.9) for expert 2, 77.0% (95% CI, 71.5-82.4) for trainee 1 (vs CADx; P = .0076), and 66.2% (95% CI, 60.6-71.9) for trainee 2 (P < .0001). The function was also confirmed on 9 short videos.

CONCLUSIONS

A CADx system developed with endoscopic white-light images showed excellent per-lesion specificity and accuracy for T1b lesion diagnosis, equivalent to experts and superior to trainees. (Clinical trial registration number: UMIN000037053.).

Identification of a CEACAM5 targeted nanobody for positron emission tomography imaging and near-infrared fluorescence imaging of colorectal cancer

PURPOSE

Here, we aim to identify a CEACAM5-targeted nanobody and demonstrate its application in positron emission tomography (PET) imaging and near-infrared (NIR) fluorescence imaging in colorectal cancer (CRC).

METHODS

Immunohistochemistry was applied to verify CEACAM5 expression in CRC and metastatic lymph nodes (mLNs). CEACAM5-targeted nanobodies were obtained by immunization of human CEACAM5 protein in a dromedary, followed by several rounds of phage screenings. Immunofluorescence staining and flow cytometry was carried out to determine the binding affinity of the nanobodies. The nanobodies were radiolabeled by coupling 18F-SFB for PET imaging of CRC subcutaneous xenografts and lymph node metastasis (LNM). IRDye800CW (IR800) were conjugated to form NIR probes for NIR imaging in CRC subcutaneous models.

RESULTS

CEACAM5 was overexpressed in either human CRC tissues or mLNs. A CEACAM5 targeted nanobody, Nb41 was successfully generated, with excellent in vitro binding properties. Incorporation of albumin binding domain (ABD) did not affect the affinity of Nb41. In vivo imaging showed that both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed obvious accumulation in the tumor. Due to the longer retention in the blood, 18F-FB-Nb41-ABD enrichment in tumors was significantly delayed but higher compared to 18F-FB-Nb41. Both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed prominent LNM enrichment. Similarly, the IR800-conjugated nanobodies Nb41-IR800 and Nb41-ABD-IR800 exhibited superior imaging effects in subcutaneous models, while Nb41-ABD-IR800 exhibited higher fluorescence intensity in the tumor accompanied with a remarkedly delay compared to Nb41-IR800.

CONCLUSION

Collectively, we presented the identification and in vivo validation of a CEACAM5-targeted nanobody and a fused nanobody with an ABD, which enabled to the non-invasive visualization of malignancy of CRC using PET imaging and NIR imaging in subcutaneous models as well as LNM models.

Long-term outcomes of local resection versus surgical resection for high-risk T1 colorectal cancer: a systematic review and meta-analysis

BACKGROUND AND AIMS

Patients with T1 colorectal cancer (CRC) are at high risk for lymph node metastasis and recurrence after local resection (LR) and need surgical resection (SR) for additional lymph node dissection to improve prognosis. However, the net benefits of SR and LR are still unquantified.

METHODS

We conducted a systematic search for studies in which survival analysis among high-risk T1 CRC patients undergoing LR and SR was performed. Overall survival (OS), recurrence-free survival (RFS), and disease-specific survival (DSS) data were extracted. Hazard ratios (HRs) and fitted survival curves for OS, RFS, and DSS were used to estimate the long-term clinical outcomes of patients in the 2 groups.

RESULTS

This meta-analysis included 12 studies. Compared with those in the SR group, patients in the LR group had higher risks of death (HR, 2.06; 95% confidence interval [CI], 1.59-2.65), recurrence (HR, 3.51; 95% CI, 2.51-4.93), and cancer-related mortality (HR, 2.31; 95% CI, 1.17-4.54) in the long term. Fitted survival curves for the LR and SR groups revealed the 5-year, 10-year, and 20-year rates for OS (86.3% and 94.5%, 72.9% and 84.4%, and 61.8% and 71.1%), RFS (89.9% and 96.9%, 83.3% and 93.9%, and 29.6% and 90.8%), and DSS (96.7% and 98.3%, 86.9% and 97.1%, and 86.9% and 96.4%). Log-rank tests showed significant differences among all outcomes except 5-year DSS.

CONCLUSIONS

For high-risk T1 CRC patients, the net benefit of DSS appears to be significant when the observation period exceeds 10 years. A long-term net benefit may exist but may not be applicable to all patients, especially high-risk patients with comorbidities. Therefore, LR may be a reasonable alternative for individualized treatment for some high-risk T1 CRC patients.

Endoscopic submucosal dissection for tumors involving the ileocecal valve with extension into the terminal ileum: a multicenter study from the Hiroshima GI Endoscopy Research Group

BACKGROUND

The efficacy and safety of endoscopic submucosal dissection (ESD) for tumors extending into the terminal ileum remain obscure. We aimed to evaluate the outcomes of ESD for tumors involving the ileocecal valve (ICV) with extension into the terminal ileum.

METHODS

Sixty-eight patients (40 men; mean age, 67 years) with 68 tumors involving the ICV that were resected by ESD between December 2013 and December 2018 were included and classified into Group A (21 tumors with extension into the terminal ileum) and Group B (47 tumors without extension). ESD outcomes were compared between groups.

RESULTS

The clinical features of the patients and tumors were not significantly different between the groups. There were no significant differences in en bloc resection rate (95% and 94%, respectively; p = 0.79), R0 resection rate (90% and 89%, respectively; p = 0.89), procedure time (95 ± 54 min and 94 ± 69 min, respectively; p = 0.64), postoperative bleeding rate (5% and 3%, respectively; p = 0.79), intraoperative perforation rate (0% and 4%, respectively; p = 0.34), delayed perforation rate (0% and 0%, respectively), or postoperative symptomatic stenosis rate (0% and 0%, respectively) between Groups A and B. No specific factors related to the outcomes of ESD were found by subgroup analysis according to the dominance and degree of circumference of the ICV. Local recurrence was observed in 1 patient in Group A who was retreated using ESD.

CONCLUSIONS

ESD for tumors involving the ICV with extension into the terminal ileum is safe and effective.

Prognostic Factors for Lymph Node Metastases in pT1 Colorectal Cancer Differ According to Tumor Morphology: A Nationwide Cohort Study

OBJECTIVE

To investigate whether there is a differential impact of histopathological risk factors for lymph node metastases (LNM) in pedunculated and nonpedunculated pT1 colorectal cancers (CRC).

BACKGROUND

Tumor budding, lymphovascular invasion (LVI), and venous invasion (VI) are recognized risk factors for LNM in pT1 CRC. Whether the importance of these factors varies according to tumor morphology is unknown.

METHODS

Patients undergoing resection with lymphadenectomy for pT1 CRC in Denmark from January 2016 to January 2019 were identified in the Danish Colorectal Cancer Database and clinicopathological data was reviewed. Prognostic factors for LNM were investigated using multivariable analyses on the cohort as a whole as well as when stratifying according to tumor morphology (pedunculated vs. nonpedunculated).

RESULTS

A total of 1167 eligible patients were identified, of whom 170 had LNM (14.6%). Independent prognostic factors for LNM included LVI [odds ratio (OR)=4.26, P <0.001], VI (OR=3.42, P <0.001), tumor budding (OR=2.12, P =0.002), high tumor grade (OR=2.76, P =0.020), and age per additional year (OR=0.96, P <0.001). On subgroup analyses, LVI and VI remained independently prognostic for LNM regardless of tumor morphology. However, tumor budding was only prognostic for LNM in pedunculated tumors (OR=4.19, P <0.001), whereas age was only prognostic in nonpedunculated tumors (OR=0.61, P =0.003).

CONCLUSIONS

While LVI and LI were found to be prognostic of LNM in all pT1 CRC, the prognostic value of tumor budding differs between pedunculated and nonpedunculated tumors. Thus, tumor morphology should be taken into account when considering completion surgery in patients undergoing local excision.

Long-Term Outcomes of Endoscopic Submucosal Dissection for Colorectal Epithelial Neoplasms: A Systematic Review

In this review, we summarize up-to-date reports with five-year observation after colorectal endoscopic submucosal dissection (ESD). Five-year cause-specific survival rates ranged from 98.6 to 100%. The local recurrence rates ranged from 1.1 to 2.2% in complete resection and 7.5 to 25.0% in incomplete resection. Incomplete resection was a risk factor for local recurrence. In non-curative ESD, five-year cause-specific survival rates ranged from 93.8 to 100% with additional surgery, and 92.7 to 99.1% without surgery. The choice of additional surgery should be based on the individual patient's age, concomitant diseases, wishes, life expectancy, and the risk of lymph node metastasis. The metachronous cancer rates ranged from 0.22 to 1.1%. Both local recurrence and metachronous tumors should be checked with a follow-up colonoscopy after ESD.

Novel endoscopic ultrasonography classification for assured vertical resection margin (≥500 μm) in colorectal endoscopic submucosal dissection

BACKGROUND AND AIM

The risk of local recurrence might be low in pT1 colorectal carcinoma with a tumor vertical margin (VM) ≥500 μm. We investigated the relationship between endoscopic ultrasonography (EUS) findings and VM in cases with colorectal endoscopic submucosal dissection (ESD) categorized as Type 2B according to the Japan NBI Expert Team (JNET) classification.

METHODS

We analyzed 179 JNET Type 2B colorectal tumors resected by ESD at Hiroshima University Hospital from January 2010 to May 2021. The distance from the tumor invasive front to the muscle layer on EUS was defined as the tumor-free distance (EUS-TFD) and classified as Type I (EUS-TFD ≥1 mm) and II (<1 mm). We investigated the relationship between EUS-TFD and VM and analyzed the predictive factors for VM ≥500 μm.

RESULTS

EUS-TFD Type I was diagnosed in 133 (74.3%) lesions: VM ≥500 μm (114, 85.7%); VM <500 μm (19, 14.3%); and VM positive (VM1) (0, 0%). Type II was diagnosed in 46 (25.7%) lesions: VM ≥500 μm (14, 30.5%); VM <500 μm (22, 47.8%); and VM1 (10, 21.7%). In the EUS-TFD Type I cases, 84.5% and 87.8% were protruded and superficial types; whereas for Type II cases, these were 38.9% and 25%, respectively. EUS-TFD classification (Type I), scope operability (good), submucosal invasion depth (<2000 μm), histology at the deepest invasive portion (favorable), and degree of fibrosis (F0/F1) were significant predictors of VM ≥500 μm.

CONCLUSIONS

In JNET Type 2B lesions, EUS-TFD classification is a novel diagnostic indicator to predict VM ≥500 μm in ESD preoperatively.

Subpopulation analysis of survival in high-risk T1 colorectal cancer: surgery versus endoscopic resection only

BACKGROUND AND AIMS

This study aimed to assess the long-term survival of patients with T1 colorectal cancer (CRC) after local or surgical resection considering the type and number of risk factors for lymph node metastasis.

METHODS

This study included patients with high-risk T1 CRC who underwent therapeutic resection at the National Cancer Center, Korea between January 2001 and December 2014. Risk factors included positive resection margin, high-grade histology, deep submucosal invasion, vascular invasion, budding, and no background adenoma (BGA). We statistically divided the population into favorable or unfavorable subpopulations. The favorable subpopulation included the following 5 combinations of risk factors: positive margin only or unconditional for margin status, deep submucosal invasion only, budding only, no BGA only, and budding + no BGA. We analyzed the survival rate according to the resection type (local or surgical) in the total cohort and in each subpopulation.

RESULTS

Eighty-one and 466 patients underwent local and surgical resections, respectively. The distant recurrence-free survival (DRFS) and overall survival (OS) rates were significantly high in the surgical group (hazard ratio [HR], .20; 95% confidence interval [CI], .06-.61; P = .0045 and HR, .41; 95% CI, .25-.70; P = .0010, respectively). In the favorable subpopulation, both DRFS and OS rates were not significantly different between the surgical and local groups (HR, .26; 95% CI, .02-4.19; P = .3431 and HR, .58; 95% CI, .27-1.23; P = .1534, respectively).

CONCLUSIONS

Intensive surveillance without additional surgery may be another option in selected cases after of high-risk T1 CRC endoscopic resection.

Risk of recurrence after endoscopic resection of nonpedunculated T1 colorectal cancer

BACKGROUND

The long-term outcome after local excision of T1 colorectal cancer (CRC) remains unknown. The aim of this study was to examine clinical and histopathological risk factors for recurrence in patients with T1 CRC undergoing endoscopic resection.

METHODS

This was a retrospective registry-based population study on prospectively collected data of all patients with nonpedunculated T1 CRC undergoing only local excision (no salvage surgery) in Sweden between 2009 and 2018. Potential risk factors for recurrence, including age, sex, tumor location, resection margins, lymphovascular, perineural, and submucosal invasion, grade of differentiation, and mucinous subtype, were analyzed using univariate and multivariate cox regression.

RESULTS

Median follow-up time was 60 months, and 28 /602 patients (4.7 %) had a recurrence (13 local and 18 distant). Recurrence rate stratified by submucosal invasion was: Sm1 3.5 % (14 /397), Sm2 6.0 % (8 /133), and Sm3 8.3 % (6 /72), with no significant differences. Resection margins, lymphovascular and perineural invasion, grade of differentiation, mucinous subtype, and age were not significant risk factors for recurrence. In contrast, rectal location was found to be a significant risk factor for tumor recurrence in multivariate analysis (hazard ratio 3.08, P = 0.006). The 3- and 5-year disease-free survival was 96.2 % and 91.1 %, respectively, in T1 CRC patients undergoing endoscopic resection.

CONCLUSION

Tumor recurrence was rare (4.7 %) in this large population-based study on recurrence after local excision of nonpedunculated T1 CRC. Rectal location was an independent risk factor for recurrence, suggesting the need for strict surveillance after endoscopic resection of early rectal cancer.

Current problems and perspectives of pathological risk factors for lymph node metastasis in T1 colorectal cancer: Systematic review

With the prevalence of endoscopic submucosal dissection and endoscopic full thickness resection, which enable complete resection of T1 colorectal cancer with a negative margin, the treatment strategy following endoscopic resection has become more important. The necessity of secondary surgical resection is determined on the basis of the risk of lymph node metastasis according to the histopathological findings of resected specimens because ~10% of T1 colorectal cancer cases have lymph node metastasis. The current Japanese treatment guidelines state four risk factors for lymph node metastasis: lymphovascular invasion, histological differentiation, depth of submucosal invasion, and tumor budding. These guidelines have succeeded in stratifying the low-risk group for lymph node metastasis, in which endoscopic resection alone is acceptable for cure. On the other hand, there are some problems: there is variation in diagnosis methods and low interobserver agreement for each pathological factor and 90% of surgical resections are unnecessary, with lymph node metastasis negativity. To ensure patients with T1 colorectal cancer receive more appropriate treatment, these problems should be addressed. In this systematic review, we gave some suggestions to these practical issues of four pathological factors as predictors.

Impact of ≥ 0.1-mm free resection margins on local intramural residual cancer after local excision of T1 colorectal cancer

Background and study aims  A free resection margin (FRM) > 1 mm after local excision of a T1 colorectal cancer (CRC) is known to be associated with a low risk of local intramural residual cancer (LIRC). The risk is unclear, however, for FRMs between 0.1 to 1 mm. This study evaluated the risk of LIRC after local excision of T1 CRC with FRMs between 0.1 and 1 mm in the absence of lymphovascular invasion (LVI), poor differentiation and high-grade tumor budding (Bd2-3). Patients and methods  Data from all consecutive patients with local excision of T1 CRC between 2014 and 2017 were collected from 11 hospitals. Patients with a FRM ≥ 0.1 mm without LVI and poor differentiation were included. The main outcome was risk of LIRC (composite of residual cancer in the local excision scar in adjuvant resection specimens or local recurrence during follow-up). Tumor budding was also assessed for cases with a FRM between 0.1 and 1mm. Results  A total of 171 patients with a FRM between 0.1 and 1 mm and 351 patients with a FRM > 1 mm were included. LIRC occurred in five patients (2.9 %; 95 % confidence interval [CI] 1.0-6.7 %) and two patients (0.6 %; 95 % CI 0.1-2.1 %), respectively. Assessment of tumor budding showed Bd2-3 in 80 % of cases with LIRC and in 16 % of control cases. Accordingly, in patients with a FRM between 0.1 and 1 mm without Bd2-3, LIRC was detected in one patient (0.8%; 95 % CI 0.1-4.4 %). Conclusions  In this study, risks of LIRC were comparable for FRMs between 0.1 and 1 mm and > 1 mm in the absence of other histological risk factors.

Comparison of Prognosis and Lymph Node Metastasis in T1-Stage Colonic and Rectal Carcinoma: A Retrospective Study

Background

Limited evidence and contradictory results have been reported regarding the impact of tumor site on lymph node metastasis (LNM) and prognosis in T1 stage adenocarcinoma (AC). We aimed to compare two anatomic locations in terms of LNM and prognosis using a comprehensive statistical analysis of a large population.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database and our center (First Affiliated Hospital of Nanchang University) were used to extract patient information. Univariate and multivariate logistic or Cox regression and propensity score matching were used to explore the association between LNM/survival and tumor site.

Results

Information for 12,404 patients, including 9655 colonic AC and 2749 rectal AC patients, was extracted from the SEER database. The 516 AC patients included 184 colonic and 332 rectal AC patients from our center. Multivariate logistic regression analysis revealed a correlation between LNM and tumor site (colon vs rectum, odds ratio [OR] =1.52, 95% CI, 1.349–1.714, P<0.001). Additionally, we found that younger age, T1b stage, poor differentiation, and lymphatic invasion were risk factors for LNM. After adjusting for confounding factors by PSM, we found that the location of the rectum remained a higher risk factor for LNM. However, we found that patients diagnosed with rectal AC had a prognosis similar to that of patients diagnosed with colonic AC, which was demonstrated by the analysis of SEER data and data from our center.

Conclusion

T1-stage rectal AC may have a higher risk of LNM than colonic AC, while rectal AC has a prognosis similar to that of colonic AC.

Full-Thickness Scar Resection After R1/Rx Excised T1 Colorectal Cancers as an Alternative to Completion Surgery

INTRODUCTION

Local full-thickness resections of the scar (FTRS) after local excision of a T1 colorectal cancer (CRC) with uncertain resection margins is proposed as an alternative strategy to completion surgery (CS), provided that no local intramural residual cancer (LIRC) is found. However, a comparison on long-term oncological outcome between both strategies is missing.

METHODS

A large cohort of patients with consecutive T1 CRC between 2000 and 2017 was used. Patients were selected if they underwent a macroscopically complete local excision of a T1 CRC but positive or unassessable (R1/Rx) resection margins at histology and without lymphovascular invasion or poor differentiation. Patients treated with CS or FTRS were compared on the presence of CRC recurrence, a 5-year overall survival, disease-free survival, and metastasis-free survival.

RESULTS

Of 3,697 patients with a T1 CRC, 434 met the inclusion criteria (mean age 66 years, 61% men). Three hundred thirty-four patients underwent CS, and 100 patients underwent FTRS. The median follow-up period was 64 months. CRC recurrence was seen in 7 patients who underwent CS (2.2%, 95% CI 0.9%-4.6%) and in 8 patients who underwent FTRS (9.0%, 95% CI 3.9%-17.7%). Disease-free survival was lower in FTRS strategy (96.8% vs 89.9%, P = 0.019), but 5 of the 8 FTRS recurrences could be treated with salvage surgery. The metastasis-free survival (CS 96.8% vs FTRS 92.1%, P = 0.10) and overall survival (CS 95.6% vs FTRS 94.4%, P = 0.55) did not differ significantly between both strategies.

DISCUSSION

FTRS after local excision of a T1 CRC with R1/Rx resection margins as a sole risk factor, followed by surveillance and salvage surgery in case of CRC recurrence, could be a valid alternative strategy to CS.

Risk and Time Pattern of Recurrences After Local Endoscopic Resection of T1 Colorectal Cancer: A Meta-analysis

BACKGROUND & AIMS

Growing numbers of patients with T1 CRC are being treated with local endoscopic resection only and as a result, the need for optimization of surveillance strategies for these patients also increases. We aimed to estimate the cumulative incidence and time pattern of CRC recurrences for endoscopically treated patients with T1 CRC.

METHODS

Using a systematic literature search in PubMed, EMBASE, Web of Science and Cochrane Library (from inception till 15 May 2020), we identified and extracted data from studies describing the cumulative incidence of local or distant CRC recurrence for patients with T1 CRC treated with local endoscopic resection only. Pooled estimates were calculated using mixed-effect logistic regression models.

RESULTS

Seventy-one studies with 5167 unique, endoscopically treated patients with T1 CRC were included. The pooled cumulative incidence of any CRC recurrence was 3.3% (209 events; 95% CI, 2.6%-4.3%; I² = 54.9%), with local and distant recurrences being found at comparable rates (pooled incidences 1.9% and 1.6%, respectively). CRC-related mortality was observed in 42 out of 2519 patients (35 studies; pooled incidence 1.7%, 95% CI, 1.2%-2.2%; I² = 0%), and the CRC-related mortality rate among patients with recurrence was 40.8% (42/103 patients). The vast majority of recurrences (95.6%) occurred within 72 months of follow-up. Pooled incidences of any CRC recurrence were 7.0% for high-risk T1 CRCs (28 studies; 95% CI, 4.9%-9.9%; I² = 48.1%) and 0.7% (36 studies; 95% CI, 0.4%-1.2%; I² = 0%) for low-risk T1 CRCs.

CONCLUSIONS

Our meta-analysis provides quantitative outcome measures which are relevant to guidelines on surveillance after local endoscopic resection of T1 CRC.

Vertical tumor margin of endoscopic resection for T1 colorectal carcinoma affects the prognosis of patients undergoing additional surgery

BACKGROUND

Vertical tumor margin-negative T1 colorectal carcinoma (CRC) is an absolute curative condition following complete endoscopic resection (ER). However, the influence on prognosis in relation to vertical tumor margin is unclear. Therefore, we evaluated the influence of the distance from vertical tumor margin to resected specimen edge (vertical margin distance) of ER for T1b (submucosal invasion depth > 1000 μm) CRC on the prognosis of patients undergoing additional surgery after ER.

METHODS

In total, 215 consecutive patients with T1b CRC who underwent additional surgery after ER at Hiroshima University Hospital between February 1992 and June 2019 were enrolled. We assessed 191 patients without lymph node metastases at the additional surgery. The specimens resected by ER were classified into three groups based on the vertical margin distance: patients with a vertical margin distance of ≥ 500 μm (Group A); patients with a vertical margin distance of < 500 μm (Group B); and patients with a positive vertical tumor margin (Group C). Subsequently, we evaluated the prognosis of the patients in relation to the clinicopathological characteristics among the three groups.

RESULTS

There were no significant differences in clinicopathological characteristics among the three groups. Group A had a significantly higher recurrence-free 5-year survival rate than Groups B and C (100%, 84.5%, and 81.8%, respectively). Similarly, Group A had a significantly higher disease-specific 5-year survival rate than Group C (100% vs. 95.5%).

CONCLUSIONS

Complete en bloc resection with sufficient submucosal layer from the invasive front (vertical margin distance > 500 μm) by ER for T1 CRC reduces the risk of metastatic recurrence after additional surgery.

Deep learning can predict lymph node status directly from histology in colorectal cancer

BACKGROUND

Lymph node status is a prognostic marker and strongly influences therapeutic decisions in colorectal cancer (CRC).

OBJECTIVES

The objective of the study is to investigate whether image features extracted by a deep learning model from routine histological slides and/or clinical data can be used to predict CRC lymph node metastasis (LNM).

METHODS

Using histological whole slide images (WSIs) of primary tumours of 2431 patients in the DACHS cohort, we trained a convolutional neural network to predict LNM. In parallel, we used clinical data derived from the same cases in logistic regression analyses. Subsequently, the slide-based artificial intelligence predictor (SBAIP) score was included in the regression. WSIs and data from 582 patients of the TCGA cohort were used as the external test set.

RESULTS

On the internal test set, the SBAIP achieved an area under receiver operating characteristic (AUROC) of 71.0%, the clinical classifier achieved an AUROC of 67.0% and a combination of the two classifiers yielded an improvement to 74.1%. Whereas the clinical classifier's performance remained stable on the TCGA set, performance of the SBAIP dropped to an AUROC of 61.2%. Performance of the clinical classifier depended strongly on the T stage.

CONCLUSION

Deep learning-based image analysis may help predict LNM of patients with CRC using routine histological slides. Combination with clinical data such as T stage might be useful. Strategies to increase performance of the SBAIP on external images should be investigated.

Curative value of underwater endoscopic mucosal resection for submucosally invasive colorectal cancer

BACKGROUND AND AIM

Occasionally, colorectal tumors without characteristics of deep submucosal invasion are found to be invasive upon pathological evaluation after endoscopic resection (ER). Because the resection depth for underwater endoscopic mucosal resection (UEMR) has not been clarified, we evaluated the feasibility of UEMR for pathologically invasive colorectal cancer (pT1-CRC).

METHODS

We retrospectively investigated data on the backgrounds and outcomes of patients with pT1-CRC who underwent UEMR between January 2014 and June 2019 at our institute. As a reference standard, the backgrounds and outcomes of pT1-CRCs that had undergone conventional EMR (CEMR) were also investigated.

RESULTS

Thirty-one patients (median age, 68 years [range, 32-88 years]; 22 men [71%]) were treated with UEMR. Median lesion size was 17 mm (range, 6-50 mm). The endoscopic complete resection rate was 100%. The overall en bloc resection rate was 77%, and the VM0, HM0, and R0 resection rates were 81%, 58%, and 55%, respectively. In cases of pT1a (invasion <1000 μm)-CRC (n = 14), the en bloc, VM0, and R0 resection rates were 92%, 100%, and 71%, respectively. Seventeen patients (five with risk factors for lymph node metastasis and 12 without) were followed up, and no local recurrence and distant metastasis were observed during the follow-up period (median follow-up period, 18 months [range, 6-62 months]) after UEMR. The outcomes of UEMR seemed to be comparable with those of CEMR (n = 32).

CONCLUSIONS

The VM0 rate of UEMR for pT1-CRC, especially for pT1a-CRC, without characteristics of deep submucosal invasion seems feasible.

Comparison of long-term recurrence-free survival between primary surgery and endoscopic resection followed by secondary surgery in T1 colorectal cancer

BACKGROUND AND AIMS

We aimed to investigate whether endoscopic resection of T1 colorectal cancer (CRC) before surgery (secondary surgery) unfavorably affects long-term recurrence-free survival (RFS) compared with surgery without prior endoscopic resection (primary surgery).

METHODS

We reviewed the medical records of patients who underwent radical surgery for T1 CRC with high-risk histologic features at a tertiary referral hospital in Korea between 2011 and 2016. The primary outcome was RFS. We performed 2 types of propensity score (PS) analyses to control for confounders.

RESULTS

Of 852 patients, 388 underwent primary surgery and 464 secondary surgery. During the median follow-up period of 57.0 months (range, 41.0-63.0), cancer recurred in 18 patients (2.1%). The 5-year RFS rates did not differ between the primary and secondary surgery groups (97.0 vs 98.5%, P = .194). Further analyses of RFS rates according to nodal stages and number of high-risk histologic features showed no difference between groups. Moreover, RFS rates were not different between the groups after PS matching. In multivariable Cox proportional regression analysis, baseline serum carcinoembryonic antigen level was an independent risk factor for cancer recurrence (hazard ratio, 1.464; 95% confidence interval, 1.242-1.725; P < .001) but prior endoscopic resection of T1 CRC was not (P = .201). Both PS analyses consistently showed no increase in cancer recurrence risk in the secondary surgery group.

CONCLUSIONS

Our data showed no additional cancer recurrence risk by endoscopic resection before surgery of T1 CRC with high-risk histologic features.

A Liquid Biopsy Assay for Noninvasive Identification of Lymph Node Metastases in T1 Colorectal Cancer

BACKGROUND & AIMS

We recently reported use of tissue-based transcriptomic biomarkers (microRNA [miRNA] or messenger RNA [mRNA]) for identification of lymph node metastasis (LNM) in patients with invasive submucosal colorectal cancers (T1 CRC). In this study, we translated our tissue-based biomarkers into a blood-based liquid biopsy assay for noninvasive detection of LNM in patients with high-risk T1 CRC.

METHODS

We analyzed 330 specimens from patients with high-risk T1 CRC, which included 188 serum samples from 2 clinical cohorts-a training cohort (N = 46) and a validation cohort (N = 142)-and matched formalin-fixed paraffin-embedded samples (N = 142). We performed quantitative reverse-transcription polymerase chain reaction, followed by logistic regression analysis, to develop an integrated transcriptomic panel and establish a risk-stratification model combined with clinical risk factors.

RESULTS

We used comprehensive expression profiling of a training cohort of LNM-positive and LMN-negative serum specimens to identify an optimized transcriptomic panel of 4 miRNAs (miR-181b, miR-193b, miR-195, and miR-411) and 5 mRNAs (AMT, forkhead box A1 [FOXA1], polymeric immunoglobulin receptor [PIGR], matrix metalloproteinase 1 [MMP1], and matrix metalloproteinase 9 [MMP9]), which robustly identified patients with LNM (area under the curve [AUC], 0.86; 95% confidence interval [CI], 0.72-0.94). We validated panel performance in an independent validation cohort (AUC, 0.82; 95% CI, 0.74-0.88). Our risk-stratification model was more accurate than the panel and an independent predictor for identification of LNM (AUC, 0.90; univariate: odds ratio [OR], 37.17; 95% CI, 4.48-308.35; P < .001; multivariate: OR, 17.28; 95% CI, 1.82-164.07; P = .013). The model limited potential overtreatment to only 18% of all patients, which is dramatically superior to pathologic features that are currently used (92%).

CONCLUSIONS

A novel risk-stratification model for noninvasive identification of T1 CRC has the potential to avoid unnecessary operations for patients classified as high-risk by conventional risk-classification criteria.

[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 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.

Endoscopic Resection Before Surgery Does Not Affect the Recurrence Rate in Patients With High-Risk T1 Colorectal Cancer

INTRODUCTION

Patients with high-risk T1 colorectal cancer (CRC) after endoscopic resection (ER) should undergo surgery in view of the risk of lymph node metastasis. Although additional surgery can potentially prevent recurrence, there is a paucity of data and longitudinal studies exploring this potential. Hence, this study aimed to evaluate the prolonged influence of ER before additional surgery on recurrence in T1 CRC.

METHODS

Between January 2004 and October 2015, 162 patients who underwent secondary surgery (SS) after ER ([ER + SS] group) and 392 consecutive patients with T1 CRC who underwent primary surgery at our institution were retrospectively analyzed. Recurrence was analyzed in these 2 groups. High-risk CRC patients were histologically defined according to the Japanese Society for Cancer of the Colon and Rectum guidelines (2016) for the treatment of CRC. Data were analyzed based on clinical and histological features, including lymph node metastasis, and the number of lymph nodes evaluated.

RESULTS

The recurrence rate was comparable between the ER + SS and primary surgery groups, with no significant difference (P = 0.625, log-rank test). There was no significant difference in the recurrence in patients receiving adjuvant chemotherapy in both groups (7.4% vs 10.4%, P = 0.27). The difference in the mean number of lymph nodes dissected between both groups was also not significant (24.3 vs 25.3, P = 0.43).

DISCUSSION

There was no significant difference in recurrence rates between patients undergoing ER before surgery and those undergoing primary surgery for high-risk T1 CRC. Hence, ER may be acceptable for high-risk T1 CRC.

Surgical resection after endoscopic resection in patients with T1 colorectal cancer: a meta-analysis

PURPOSE

Additional surgical resection (ASR) after endoscopic resection (ER) in patients with colorectal cancer (CRC) allows a complete staging and may decrease the recurrence rate, but no meta-analysis is available. This study aimed to compare the effectiveness of ER vs. ER + ASR as a treatment for patients with T1 (stage 1) CRC.

METHODS

We performed a systematic search from databases (PubMed, Embase, and Cochrane library) for cohort studies published up to November 2019. The outcomes were overall survival (OS), local recurrence, recurrence, disease-specific survival, recurrence-free survival, and metastasis.

RESULTS

Seven studies were included. There were 1205 patients in the ASR group and 993 patients in the ER group. Compared with ER, ASR was associated with better OS (OR = 0.31, 95% CI: 0.18-0.53, P < 0.001) and a borderline significant difference in lower local recurrence rates (OR = 0.29, 95% CI: 0.08-1.01, P = 0.052), but no differences were observed in recurrences, disease-specific survival, recurrence-free survival, and distant metastasis. A sensitivity analysis was performed; excluding each study sequentially from the pooled analysis did not affect the overall conclusion of the study.

CONCLUSION

Compared with ER, ASR after ER could improve the overall survival for patients with T1 CRC.

Diagnostic performance for T1 cancer in colorectal lesions ≥10 mm by optical characterization using magnifying narrow-band imaging combined with magnifying chromoendoscopy; implications for optimized stratification by Japan Narrow-band Imaging Expert Team classification

BACKGROUND

Magnifying narrow-band imaging (M-NBI) and magnifying chromoendoscopy (M-CE) enable accurate diagnosis of T1 colorectal cancer, but the diagnostic yields from combined M-NBI and CE have not been fully analyzed. We aimed to evaluate the diagnostic yield of combining Japan NBI Expert Team (JNET) classification using M-NBI and M-CE.

METHODS

Superficial colorectal lesions ≥10 mm removed at a Japanese tertiary cancer center between February 2016 and December 2018 were included. We analyzed the relationship between JNET classification, M-CE findings, and histological results based on prospectively collected endoscopic and pathologic data.

RESULTS

A total of 1573 lesions, including 56 superficial submucosal invasive cancers, 160 deep submucosal invasive cancers, and 81 advanced cancers (≥T2) were analyzed. The probability of deeply invasive cancer (95% confidence interval) was 1.8% (1.1-2.8), 30.1% (25.4-35.1), and 96.6% (91.5-99.1) in JNET Types 2A, 2B, and 3, respectively. The probability of deeply invasive cancer in JNET Type 2B lesions with non-V, VL, and VH pit pattern was 4.3%, 16.6%, 76.0%, respectively (P < 0.001).

CONCLUSIONS

Our study showed the stratification by M-NBI using JNET classification and the effect of additional M-CE for JNET Type 2B lesions.

Artificial Intelligence System to Determine Risk of T1 Colorectal Cancer Metastasis to Lymph Node

BACKGROUND & AIMS

In accordance with guidelines, most patients with T1 colorectal cancers (CRC) undergo surgical resection with lymph node dissection, despite the low incidence (∼10%) of metastasis to lymph nodes. To reduce unnecessary surgical resections, we used artificial intelligence to build a model to identify T1 colorectal tumors at risk for metastasis to lymph node and validated the model in a separate set of patients.

METHODS

We collected data from 3134 patients with T1 CRC treated at 6 hospitals in Japan from April 1997 through September 2017 (training cohort). We developed a machine-learning artificial neural network (ANN) using data on patients' age and sex, as well as tumor size, location, morphology, lymphatic and vascular invasion, and histologic grade. We then conducted the external validation on the ANN model using independent 939 patients at another hospital during the same period (validation cohort). We calculated areas under the receiver operator characteristics curves (AUCs) for the ability of the model and US guidelines to identify patients with lymph node metastases.

RESULTS

Lymph node metastases were found in 319 (10.2%) of 3134 patients in the training cohort and 79 (8.4%) of /939 patients in the validation cohort. In the validation cohort, the ANN model identified patients with lymph node metastases with an AUC of 0.83, whereas the guidelines identified patients with lymph node metastases with an AUC of 0.73 (P < .001). When the analysis was limited to patients with initial endoscopic resection (n = 517), the ANN model identified patients with lymph node metastases with an AUC of 0.84 and the guidelines identified these patients with an AUC of 0.77 (P = .005).

CONCLUSIONS

The ANN model outperformed guidelines in identifying patients with T1 CRCs who had lymph node metastases. This model might be used to determine which patients require additional surgery after endoscopic resection of T1 CRCs. UMIN Clinical Trials Registry no: UMIN000038609.

Long-term Outcomes of Primary Endoscopic Resection vs Surgery for T1 Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over the best therapeutic approach for T1 colorectal cancer. We performed a systematic review and meta-analysis of long-term outcomes of endoscopic resection (ER) vs those of primary or additional surgery.

METHODS

We performed a systematic review of the PubMed, Embase, and Cochrane databases through October 2019 for studies that reported outcomes (overall survival, disease-specific survival, recurrence-free survival at 5 years, recurrence, and metastasis) of ER vs surgery in patients with colorectal neoplasms. Hazard ratios (HR) were calculated based on time to events.

RESULTS

In total, 17 published studies with 19,979 patients were included. The median follow-up time among the studies was 36 months. The meta-analysis found no significant differences between primary ER and primary surgery in overall survival (79.6% vs 82.1%, HR, 1.10; 95% CI, 0.84-1.45), recurrence-free survival (96.0% vs 96.7%, HR, 1.28; 95% CI, 0.87-1.88), or disease-specific survival (94.8% vs 96.5%; HR, 1.09; 95% CI, 0.67-1.78). Additional surgery and primary surgery did not produce significant differences in recurrence-free survival (HR, 1.27; 95% CI, 0.85-1.89). A significantly lower proportion of patients who underwent primary ER had procedure-related adverse events (2.3%) than patients who underwent primary surgery (10.9%) (P < .001). Lymphovascular invasion and rectal cancer, but not depth of submucosal invasion, were independently associated with recurrence for all T1 colorectal cancers.

CONCLUSIONS

In a systematic review and meta-analysis, we found that ER should be considered as the first-line treatment for endoscopically resectable T1 colorectal cancers. In cases of noncurative resection, additional surgery can have comparable outcomes to primary 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.

Local recurrence after local excision of early rectal cancer: a meta-analysis of completion TME, adjuvant (chemo)radiation, or no additional treatment

BACKGROUND

The risks of local recurrence and treatment-related morbidity need to be balanced after local excision of early rectal cancer. The aim of this meta-analysis was to determine oncological outcomes after local excision of pT1-2 rectal cancer followed by no additional treatment (NAT), completion total mesorectal excision (cTME) or adjuvant (chemo)radiotherapy (aCRT).

METHODS

A systematic search was conducted in PubMed, Embase and the Cochrane Library. The primary outcome was local recurrence. Statistical analysis included calculation of the weighted average of proportions.

RESULTS

Some 73 studies comprising 4674 patients were included in the analysis. Sixty-two evaluated NAT, 13 cTME and 28 aCRT. The local recurrence rate for NAT among low-risk pT1 tumours was 6·7 (95 per cent c.i. 4·8 to 9·3) per cent. There were no local recurrences of low-risk pT1 tumours after cTME or aCRT. The local recurrence rate for high-risk pT1 tumours was 13·6 (8·0 to 22·0) per cent for local excision only, 4·1 (1·7 to 9·4) per cent for cTME and 3·9 (2·0 to 7·5) per cent for aCRT. Local recurrence rates for pT2 tumours were 28·9 (22·3 to 36·4) per cent with NAT, 4 (1 to 13) per cent after cTME and 14·7 (11·2 to 19·0) per cent after aCRT.

CONCLUSION

There is a substantial risk of local recurrence in patients who receive no additional treatment after local excision, especially those with high-risk pT1 and pT2 rectal cancer. The lowest recurrence risk is provided by cTME; aCRT has outcomes comparable to those of cTME for high-risk pT1 tumours, but shows a higher risk for pT2 tumours.

High practice variation in risk stratification, baseline oncological staging, and follow-up strategies for T1 colorectal cancers in the Netherlands

Background and study aims  Based on pathology, locally resected T1 colorectal cancer (T1-CRC) can be classified as having low- or high-risk for irradicality and/or lymph node metastasis, the latter requiring adjuvant surgery. Reporting and application of pathological high-risk criteria is likely variable, with inherited variation regarding baseline oncological staging, treatment and surveillance. Methods  We assessed practice variation using an online survey among gastroenterologists and surgeons participating in the Dutch T1-CRC Working Group. Results  Of the 130 invited physicians, 53 % participated. Regarding high-risk T1-CRC criteria, lymphangio-invasion is used by 100 %, positive or indeterminable margins by 93 %, poor differentiation by 90 %, tumor-free margin ≤ 1 mm by 78 %, tumor budding by 57 % and submucosal invasion > 1000 µm by 47 %. Fifty-two percent of the respondents do not perform baseline staging in locally resected low-risk T1-CRC. In case of unoperated high-risk patients, we recorded 61 different surveillance strategies in 63 participants, using 19 different combinations of diagnostic tests. Endoscopy is used in all schedules. Mean follow-up time is 36 months for endoscopy, 26 months for rectal MRI and 30 months for abdominal CT (all varying 3-60 months). Conclusion  We found variable use of pathological high-risk T1-CRC criteria, creating risk for misclassification as low-risk T1-CRC. This has serious implications, as most participants will not proceed to oncological staging in low-risk patients and adjuvant surgery nor radiological surveillance is considered. On the other hand, oncological surveillance in patients with a locally resected high-risk T1-CRC who do not wish adjuvant surgery is highly variable emphasizing the need for a uniform surveillance protocol.

Efficacy of preemptive endoscopic submucosal dissection and surgery for synchronous colorectal neoplasms

BACKGROUND AND AIM

If patients with surgically resectable colorectal cancershave synchronous colorectal neoplasms that are difficult to remove by endoscopic mucosal resection, preemptive endoscopic submucosal dissection (ESD) can avoid excessive colorectal resection. The aim of this study was to evaluate the efficacy of the strategy of preemptive ESD and surgery for synchronous colorectal neoplasms.

METHODS

Patients who underwent preemptive ESD and surgery for synchronous colorectal neoplasms between September 2002 and December 2017 were enrolled in this retrospective cohort study. The proportion of cases in which extended surgery could be avoided following curative ESD was calculated. Clinicopathological characteristics were evaluated for all patients and long-term outcomes were analyzed for patients who underwent curative ESD and surgery.

RESULTS

A total of 45 consecutive patients with 47 endoscopically-resected lesions and 46 surgically-resected lesions were retrospectively evaluated. Curative ESD was achieved in 44 lesions (93.6%) and an extended surgical procedure could be avoided in 42 patients (93.3%). Intraoperative perforation occurred in two lesions (4.3%), delayed perforation in one lesion (2.1%), and delayed bleeding in two lesions (4.3%). Final stages were as follows: stage 0, 3 patients (7.1%); stage I, 23 patients (54.8%); stage II, 3 patients (7.1%); stage III, 12 patients (28.6%); and stage IV, 1 patient (2.4%). The 5-year overall survival rates of patients with all pathological stages, stage 0-II, and stage III-IV were 93.7%, 100%, and 79.1%, respectively.

CONCLUSION

The strategy of preemptive ESD and surgery for synchronous colorectal neoplasms is minimally invasive and has a favorable prognosis.

The effect of non-curative endoscopic resection on cT1N0M0 colorectal carcinoma patients who underwent additional surgery

BACKGROUND AND AIM

Radical surgery is recommended for T1 colorectal cancer with non-curative endoscopic resection. However, there is still insufficient evidence about whether the non-curative endoscopic resection prior to surgical resection affects the short-term and long-term outcomes of patients. The purpose of this study was to investigate the effect of non-curative endoscopic resection before surgical resection on short-term and long-term outcomes in patients with T1 colorectal cancer.

PATIENTS AND METHODS

Patients with clinical T1N0M0 (cT1N0M0) colorectal cancer who underwent direct surgery or additional radical surgery after non-curative endoscopic resection were collected. We evaluated postoperative complications and long-term prognosis between the two groups.

RESULTS

From 2011 to 2017, 779 patients were clinically diagnosed with T1N0M0 colorectal cancer at Zhongshan Hospital. We assessed patients who underwent additional surgery following the prior non-curative endoscopic resection (n = 145) and patients who underwent radical surgery directly (n = 336). There was no significant difference in 5-year OS (99.3% vs. 99.4%, P = 0.866) and 5-year DFS (97.2% vs. 97.3%, P = 0.909) between the two groups. The total complication rate was slightly higher in prior endoscopic resection group (15.2% vs. 9.5%, P = 0.111). The 5-year OS and 5-year DFS of patients who refused additional surgery (n = 95) were significantly lower than ER prior to surgery group (For OS, 92.6% vs. 99.3%, P = 0.017; for DFS, 91.2% vs. 97.2%, P = 0.021).

CONCLUSION

In patients who underwent additional surgery, non-curative endoscopic resection of cT1 colorectal carcinoma did not have adverse effect on short-term and long-term outcomes. Additional surgery should be recommended in patients who received non-curative 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.

Lymphovascular Infiltration, Not Depth of Invasion, is the Critical Risk Factor of Metastases in Early Colorectal Cancer: Retrospective Population-based Cohort Study on Prospectively Collected Data, Including Validation

OBJECTIVE

To identify clinical and histopathological risk factors of LNM in T1 CRC.

SUMMARY OF BACKGROUND DATA

The requisite of additional surgery after locally resected T1 CRC is dependent on the risk of LNM. Depth of submucosal invasion is used as a key predictor of lymphatic metastases although data are conflicting on its actual impact.

METHODS

Retrospective population-based cohort study on prospectively collected data on all patients with T1 CRC undergoing surgical resection in Sweden, 2009-2017 and Denmark 2016-2018. The Danish cohort was used for validation. Potential risk factors of LNM investigated were; age, sex, tumor location, submucosal invasion, grade of differentiation, mucinous subtype, lymphovascular, and perineural invasion.

RESULTS

One hundred fifty out of the 1439 included patients (10%) had LNM. LVI (P < 0.001), perineural invasion (P < 0.001), mucinous subtype (P = 0.006), and age <60 years (P < 0.001) were identified as independent risk factors whereas deep submucosal invasion was only a dependent (P = 0.025) risk factor and not significant in multivariate analysis (P = 0.075). The incidence of LNM was 51/882 (6%) in absence of the independent risk factors. The Danish validation cohort, confirmed our findings regarding the role of submucosal invasion, LVI, and age.

CONCLUSIONS

This is a large study on LNM in T1 CRC, including validation, showing that LVI and perineural invasion, mucinous subtype, and low age constitute independent risk factors, whereas depth of submucosal invasion is not an independent risk factor of LNM. Thus, our findings provide a useful basis for management of patients after local excision of early CRC.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer

The number of deaths from colorectal cancer in Japan continues to increase. Colorectal cancer deaths exceeded 50,000 in 2016. In the 2019 edition, revision of all aspects of treatments was performed, with corrections and additions made based on knowledge acquired since the 2016 version (drug therapy) and the 2014 version (other treatments). The Japanese Society for Cancer of the Colon and Rectum guidelines 2019 for the treatment of colorectal cancer (JSCCR guidelines 2019) have been prepared to show standard treatment strategies for colorectal cancer, to eliminate disparities among institutions in terms of treatment, to eliminate unnecessary treatment and insufficient treatment and to deepen mutual understanding between healthcare professionals and patients by making these guidelines available to the general public. These guidelines have been prepared by consensuses reached by the JSCCR Guideline Committee, based on a careful review of the evidence retrieved by literature searches and in view of the medical health insurance system and actual clinical practice settings in Japan. Therefore, these guidelines can be used as a tool for treating colorectal cancer in actual clinical practice settings. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. Controversial issues were selected as clinical questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here, we present the English version of the JSCCR guidelines 2019.

Japan Gastroenterological Endoscopy Society guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also several types of precarcinomatous adenomas. It is important to establish practical guidelines wherein preoperative diagnosis of colorectal neoplasia and selection of endoscopic treatment procedures are appropriately outlined and to ensure that actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society compiled colorectal endoscopic submucosal dissection/endoscopic mucosal resection guidelines by using evidence-based methods in 2014. The first edition of these guidelines was published 5 years ago. Accordingly, we have published the second edition of these guidelines based on recent new knowledge and evidence.

Recurrence and cancer-specific mortality after endoscopic resection of low- and high-risk pT1 colorectal cancers: a meta-analysis

BACKGROUND AND AIMS

Clinical management after complete endoscopic resection of pT1 colorectal cancers (CRCs) is still under debate. Follow-up data are heterogeneous and poorly reported, resulting in variable clinical management. Our aim was to meta-analyze recurrence and cancer-specific mortality (CSM) occurring after endoscopic resection of low- and high-risk pT1 CRCs undergoing conservative (nonsurgical) management.

METHODS

Literature was systematically searched until February 2019 for studies describing patients with pT1 CRCs, histologically classifiable as low or high risk, endoscopically resected without complementary surgery and with ≥12 months of follow-up. Pooled cumulative incidence (and incidence rate when specific follow-up intervals were available) of recurrence and CSM were calculated separately for low- and high-risk pT1 CRCs. Quality, publication bias, and heterogeneity were explored.

RESULTS

Pooled cumulative incidences of recurrence and CSM among high-risk lesions (5 studies, 571 patients) were, respectively, 9.5% (95% confidence interval [CI], 6.7%-13.3%; I² = 38.4%) and 3.8% (95% CI, 2.4%-5.8%; I² = 0%), whereas among low-risk lesions (7 studies, 650 patients) they were, respectively, 1.2% (95% CI, .6%-2.5%; I² = 0%) and .6% (95% CI, .2%-1.7%; I² = 0%). Pooled incidence rates of recurrence and CSM among high-risk lesions (3 cohorts, 237 patients) were, respectively, 11 (95% CI, 2-20; I² = 43.3%) and 4 (95% CI, 1-7; I² = 0%) per 1000 patient-years, whereas among low-risk lesions (3 cohorts, 229 patients) they were 3 (95% CI, 0-6; I² = 0%) and 2 (95% CI, 0-4; I² = 0%) per 1000 patient-years, respectively. No publication bias or significant heterogeneity was found.

CONCLUSIONS

Pooled estimates of adverse events after endoscopic resection of pT1 CRCs suggest a conservative approach for low-risk lesions. In high-risk lesions, increased surgical risk might justify a conservative management, whereas fitness for surgery makes surgical completion appropriate.