The risk of lymph node metastasis in T1 colorectal cancer: new parameters to assess the degree of submucosal invasion

Long-term outcomes of endoscopic submucosal dissection for T1b colorectal cancer

BACKGROUND

Endoscopic submucosal dissection (ESD) is a standardized procedure for intramucosal and slightly invasive submucosal colorectal cancers (CRC). However, the role of ESD for T1b (depth of submucosal invasion: ≥1,000 μm) CRC remains unclear. This study aimed to investigate the long-term efficacy and safety of ESD for T1b CRC.

METHODS

This study involved 50 patients with T1b CRC who underwent ESD, including 31 who received subsequent surgery (ESD + surgery group) and 19 who reported comorbidities or refused subsequent surgery (ESD-alone group). The clinical outcomes, lymph node metastasis (LNM) rate, and recurrence and survival rates were determined.

RESULTS

All the patients achieved en-bloc resection, and 41 patients achieved R0 resection. The mean tumor diameter was 31.2 ± 11.9 mm. LNM was detected in 3 (6%) cases, demonstrating high-grade tumor budding (Bd 2/3) and invasion depth of >1,500 um. LNM was significantly correlated with tumor budding (P = 0.030). The overall median follow-up period was 41.00 ± 27.69 months and 33.16 ± 19.05 months in the ESD-alone and ESD + surgery groups, respectively (P = 0.241). Two patients in the ESD group had local recurrence and two patients died. Patients in the ESD + surgery group reported no local recurrence, distant metastasis, or disease-related death. Recurrence (P = 0.074) and survival rates (P = 0.072) were not significantly different between the two groups.

CONCLUSIONS

The LNM rate was exceedingly low in patients with T1b. ESD is an effective and safe method for these patients. The necessity of additional surgical treatment after ESD should be comprehensively determined following the patient's characteristics.

Histological Risk Factors for Lymph Node Metastasis in pT1 Colorectal Cancer: Does Submucosal Invasion Depth Really Matter?

OBJECTIVE

After endoscopic resection of colorectal cancer with submucosal invasion (pT1 CRC), additional surgical treatment is recommended if deep submucosal invasion (DSI) is present. This study aimed to further elucidate the risk factors for lymph node metastasis (LNM) in patients with pT1 CRC, especially the effect of DSI on LNM.

METHODS

Patients with pT1 CRC who underwent lymph node dissection were selected. The Chi-square test and multivariate logistic regression were used to analyze the relationship between clinicopathological characteristics and LNM. The submucosal invasion depth (SID) was measured via 4 methods and analyzed with 3 cut-off values.

RESULTS

Twenty-eight of the 239 patients presented with LNM (11.7%), and the independent risk factors for LNM included high histological grade (P=0.003), lymphovascular invasion (LVI) (P=0.004), intermediate to high budding (Bd 2/3) (P=0.008), and cancer gland rupture (CGR) (P=0.008). Moreover, the SID, width of submucosal invasion (WSI), and area of submucosal invasion (ASI) were not significantly different. When one, two, three or more risk factors were identified, the LNM rates were 1.1% (1/95), 12.5% (7/56), and 48.8% (20/41), respectively.

CONCLUSION

Indicators such as the SID, WSI, and ASI are not risk factors for LNM and are subjective in their measurement, which renders them relatively inconvenient to apply in clinical practice. In contrast, histological grade, LVI, tumor budding and CGR are relatively straightforward to identify and have been demonstrated to be statistically significant. It would be prudent to focus on these histological factors rather than subjective measurements.

Predictors of early colorectal cancer metastasis to lymph nodes: providing rationale for therapy decisions

With the improvement of national health awareness and the popularization of a series of screening methods, the number of patients with early colorectal cancer is gradually increasing, and accurate prediction of lymph node metastasis of T1 colorectal cancer is the key to determining the optimal therapeutic solutions. Whether patients with T1 colorectal cancer undergoing endoscopic resection require additional surgery and regional lymph node dissection is inconclusive in current guidelines. However, we can be sure that in early colorectal cancer without lymph node metastasis, endoscopic resection alone does not affect the prognosis, and it greatly improves the quality of life and reduces the incidence of surgical complications while preserving organ integrity. Therefore, it is vital to discriminate patients without lymph node metastasis in T1 colorectal cancer, and this requires accurate predictors. This paper briefly explains the significance and shortcomings of traditional pathological factors, then extends and states the new pathological factors, clinical test factors, molecular biomarkers, and the risk assessment models of lymph node metastasis based on artificial intelligence.

Refining Risk Criteria May Substantially Reduce Unnecessary Additional Surgeries after Local Resection of T1 Colorectal Cancer

BACKGROUND

The low positive predictive value for lymph node metastases (LNM) of common practice risk criteria (CPRC) in T1 colorectal carcinoma (CRC) leads to manyunnecessary additional surgeries following local resection. This study aimed to identify criteria that may improve on the CPRC.

METHODS

Logistic regression analysis was performed to determine the association of diverse variables with LNM or 'poor outcome' (LNM and/or distant metastases and/or recurrence) in a single center T1 CRC cohort. The diagnostic capacity of the set of variables obtained was compared with that of the CPRC.

RESULTS

The study comprised 161 cases. Poorly differentiated clusters (PDC) and tumor budding grade > 1 (TB > 1) were the only independent variables associated with LNM. The area under the curve (AUC) for these criteria was 0.808 (CI 95% 0.717-0.880) compared to 0.582 (CI 95% 0.479-0.680) for CPRC. TB > 1 and lymphovascular invasion (LVI) were independently associated with 'poor outcome', with an AUC of 0.801 (CI 95% 0.731-0.859), while the AUC for CPRC was 0.691 (CI 95% 0.603-0.752). TB > 1, combined either with PDC or LVI, would reduce false positives between 41.5% and 45% without significantly increasing false negatives.

CONCLUSIONS

Indicating additional surgery in T1 CRC only when either TB > 1, PDC, or LVI are present could reduce unnecessary surgeries significantly.

Risk assessment in pT1 colorectal cancer

Colorectal cancer (CRC) is a common malignancy worldwide and tumour stage is closely related to clinical outcome. A small but significant proportion of submucosal-invasive (ie, pT1) CRC are associated with regional lymph node metastases (LNM) and a worse prognosis. The likelihood of LNM in pT1 CRC needs to be balanced against the operative risk and costs of surgical resection when determining the best patient management. A wide range of histopathological and clinical factors may affect LNM risk in this setting. This script provides a comprehensive overview of the tumour and patient-associated features that have been linked to LNM risk in pT1 CRC. Some of the features are well established within the literature and are included in published guidelines, while others are novel and emerging in nature. Odds ratios for LNM that are associated with key predictive features are provided where appropriate, and published models developed as an aid to the calculation of LNM risk are discussed.

Are the width, length, depth, and area of submucosal invasion predictive of lymph node metastasis in pT1 colorectal cancer?

PURPOSE

Submucosa-limited (pathological T1, pT1) colorectal cancers (CRCs) pose a continuing challenge in the choice of treatment options, which range from local excision to radical surgery. The aim of this study was to evaluate the morphometric and morphologic risk factors associated with regional lymph node metastasis (LNM) in pT1 CRC.

METHODS

We performed a histological review of patients who underwent oncological resection between 2016 and 2022. Tumor grade, budding, poorly differentiated clusters (PDCs), cancer gland rupture, lymphovascular invasion (LVI), and presence of deep submucosal invasion (DSI), as well as width, length, total area, and area of DSI, were evaluated as potential risk factors for LNM.

RESULTS

A total of 264 cases of colon and rectal carcinomas with invasion into the submucosal layer (pT1) were identified. LNM was found in 46 of the 264 cases (17.4%). All morphometric parameters, as well as DSI (P=0.330), showed no significant association with LNM. High grade adenocarcinoma (P=0.050), budding (P=0.056), and PDCs (P<0.001) were associated with LNM. In the multivariate analysis, LVI presence remained the only significant independent risk factor (odds ratio, 15.7; 95% confidence interval, 8.5-94.9; P<0.001).

CONCLUSION

The DSI of T1 CRC, as well as other morphometric parameters of submucosal tumor spread, held no predictive value in terms of LNM. LVI was the only independent risk factor of LNM.

Treatment for T1 colorectal cancers substratified by site and size: "horses for courses"

Background

Owing to advances in diagnostic technology, the diagnosis of T1 colorectal cancers (CRCs) continues to increase. However, the optimal management of T1 CRCs in the Western Hemisphere remains unclear due to limited population-based data directly comparing the efficacy of endoscopic therapy (ET) and surgical resection (SR). The purpose of this study was to report outcome data from a large Western cohort of patients who underwent ET or SR for early CRCs.

Methods

The SEER-18 database was used to identify patients with T1 CRCs diagnosed from 2004 to 2018 treated with ET or SR. Multivariable logistic regression models were employed to identify variables related to lymph node metastasis (LNM). Rates of ET and 1-year relative survival were calculated for each year. Effect of ET or SR on overall survival and cancer-specific survival was compared using Kaplan-Meier method stratified by tumor size and site.

Results

A total of 28,430 T1 CRCs patients were identified from 2004 to 2018 in US, with 22.7% undergoing ET and 77.3% undergoing SR. The incidence of T1 CRCs was 6.15 per 100,000 person-years, with male patients having a higher incidence. Left-sided colon was the most frequent location of tumors. The utilization of ET increased significantly from 2004 to 2018, with no significant change in 1-year relative survival rate. Predictors of LNM were age at diagnosis, sex, race, tumor size, histology, grade, and location. The 5-year relative survival rates were 91.4 and 95.4% for ET and SR, respectively. Subgroup analysis showed that OS and CSS were similar between ET and SR in T1N0M0 left-sided colon cancers with tumors 2 cm or less and in rectal cancers with tumors 1 cm or less.

Conclusion

Our study showed that ET was feasible and safe for patients with left-sided T1N0M0 colon cancers and tumors of 2 cm or less, as well as T1N0M0 rectal cancers and tumors of 1 cm or less. Therefore, the over- and under-use of ET should be avoided by carefully selecting patients based on tumor size and site.

Risk Factors for Predicting Lymph Node Metastasis in Submucosal Colorectal Cancer

Objectives:

The cornerstone of treating colorectal cancer (CRC) is generally a surgical resection with lymph node (LN) dissection. The tools for predicting lymph node metastasis (LNM) in submucosal (SM) CRC are useful to avoid unnecessary surgical resection.

Methods:

Retrospectively, we analyzed 526 consecutive patients with SM CRC who underwent surgical resection at the Osaka International Cancer Institute, Osaka University Hospital, and Minoh City Hospital, Japan, between 1984 and 2012. The Osaka International Cancer Institute group and the Osaka University Hospital group were randomly divided into a training set and a test set of 2:1. The prediction model was validated in Minoh City Hospital.

Results:

We partitioned patients using three risk factors involved in the presence or absence of LNM in SM CRC: lymphatic invasion (Ly), budding grade (BD) and the depth of submucosal invasion (DSI) (cut-off value 2789 μm) that were significantly different in the multivariate analysis. As a result, a predictive model of “LNM <5%” when “Ly negative and DSI <2789 μm” was evaluated. We similarly partitioned by DSI 3000 μm as easy-to-evaluate values in clinical use. We developed the additional model for predicting LNM is 1.05%, that is, LNM <5%, when there are “Ly negative and DSI <3000 μm.”

Conclusions:

As a limitation, only patients who underwent surgical resection were included in this study. This predictive model could help clinicians and CRC patients decide on the additional surgery required after endoscopic resection.

Supervised Learning Based Systemic Inflammatory Markers Enable Accurate Additional Surgery for pT1NxM0 Colorectal Cancer: A Comparative Analysis of Two Practical Prediction Models for Lymph Node Metastasis

Purpose

Predicting lymph node metastasis (LNM) after endoscopic resection is crucial in determining whether patients with pT1NxM0 colorectal cancer (CRC) should undergo additional surgery. This study was aimed to develop a predictive model that can be used to reduce the current likelihood of overtreatment.

Patients and Methods

We recruited a total of 1194 consecutive CRC patients with pT1NxM0 who underwent endoscopic or surgical resection at the Gezhouba Central Hospital of Sinopharm between January 1, 2006, and August 31, 2021. The random forest classifier (RFC) and generalized linear algorithm (GLM) were used to screen out the variables that greatly affected the LNM prediction, respectively. The area under the curve (AUC) and decision curve analysis (DCA) were applied to assess the accuracy of predictive models.

Results

Analysis identified the top 10 candidate factors including depth of submucosal invasion, neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), platelet-to-neutrophil ratio(PNR), venous invasion, poorly differentiated clusters, tumor budding, grade, lymphatic vascular invasion, and background adenoma. The performance of the GLM achieved the highest AUC of 0.79 (95% confidence interval [CI]: 0.30 to 1.28) in the training cohort and robust AUC of 0.80 (95% confidence interval [CI]: 0.36 to 1.24) in the validation cohort. Meanwhile, the RFC exhibited a robust AUC of 0.84 (95% confidence interval [CI]: 0.40 to 1.28) in the training cohort and a high AUC of 0.85 (95% CI: 0.41 to 1.29) in the validation cohort. DCAs also showed that the RFC had superior predictive ability.

Conclusion

Our supervised learning-based model incorporating histopathologic parameters and inflammatory markers showed a more accurate predictive performance compared to the GLM. This newly supervised learning-based predictive model can be used to determine an individually tailored treatment strategy.

The essential problem of over-measuring the depth of submucosal invasion in pT1 colorectal cancer

A depth of submucosal invasion (DSI) of ≥1000 μm is an important risk factor for lymph node metastasis (LNM) in patients with submucosal invasive (pT1) colorectal cancer (CRC), according to the European Society of Gastrointestinal Endoscopy and the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines. According to the latter, if the location of the muscularis mucosae in the invasive area is not confirmed, the DSI can be measured from the surface. In these cases, a 'remaining intramucosal lesion' (rIL), which is in the invasive area, is sometimes observed. To avoid over-measuring the DSI, we proposed a 'modified DSI' (mDSI), which excludes the rIL from the JSCCR DSI. We investigated the characteristics and effectiveness of the rIL and mDSI by grouping cases with polypoid growth (PG) and non-polypoid growth (NPG) histologically. Three hundred and thirty-nine consecutive patients with pT1 CRC were examined. LNM was detected in 37 cases. The distribution of the DSI and rIL was significantly higher in PG than in NPG cases (P<0.001). There was no difference in the mDSI distribution between the PG-/NPG-type cases. An rIL was observed in 39% (127/301) of cases, in which the location of the muscularis mucosae could not be determined or estimated and the mDIS could be estimated. In 13% (16/127) of cases, the mDSI was effective (JSCCR DSI ≥1000 and mDSI <1000 μm). Among these 16 cases, 11 (69%) did not have risk factors (mDSI, lymphovascular invasion, budding grade, or special histological types) and may have avoided unnecessary surgery.