Role of lymph node yield and lymph node ratio in predicting outcomes in non-metastatic colorectal cancer

True significance of the number of retrieved lymph nodes in stage II colon cancer resected by minimally invasive surgery: Influence of tumor sidedness

BACKGROUND

In patients with stage II colon cancer (CC) undergoing minimally invasive surgery, the association between the clinical significance of lymph node yield and tumor localization remains unknown. We aimed to determine the optimal number of lymph nodes to be retrieved based on tumor localization in patients with stage II CC undergoing minimally invasive surgery.

METHODS

This was a multicenter retrospective study. Overall, 263 patients with stage II CC who underwent laparoscopic surgery between January 1, 2008 and December 31 were enrolled. The primary outcome was the optimal number of lymph nodes retrieved based on tumor localization.

RESULTS

The median number of retrieved lymph nodes was 30 and 26 in the right-(n = 125) and left-sided (n = 138) CC groups, respectively (p = .0007). Inadequate dissection (<12 nodes) occurred in 4.2% of patients: 1.6% in the right-sided CC group and 6.5% in the left-sided CC group. Multivariate Cox regression analysis showed a decreasing trend in adjusted hazard ratios with increasing nodes, with an optimal cutoff of 15 lymph nodes in the left-sided CC group (adjusted hazard ratio, 5.868; 95% confidence interval, 1.247-27.62; p = .02). Lymph node yield was not independently associated with survival in the right-sided CC group.

CONCLUSIONS

For patients with left-sided stage II CC undergoing laparoscopic surgery, aiming for at least 15 retrieved lymph nodes may be optimal for accurate staging and prognostic assessment. The optimal lymph node yield likely varies based on tumor location, requiring further investigation in right-sided CC.

Colon cancer: the 2023 Korean clinical practice guidelines for diagnosis and treatment

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Combination of the Ratio Between Negative and Harvested Lymph Nodes and Metastatic Lymph Node Count as a Prognostic Indicator in Stage III Colon Cancer: A Retrospective Cohort Study

BACKGROUND

This study aimed to investigate the relationship between the ratio of negative lymph nodes (NLN) number to the number of metastatic lymph nodes (MLN) and the harvested lymph nodes (HLN) number ratio survival rate and compare its prognostic value.

METHODS

This retrospective cohort study included 207 stage III colon cancer patients between 2010 and 2018 at a single center. NLN/MLN and NLN/HLN cut-off values were determined with the receiver operating characteristic (ROC) curve according to 5-year survival. The patients were divided into high-risk and low-risk groups according to the cut-off value. These 2 groups were evaluated according to the clinicopathological data of the patients.

RESULT

The time-dependent ROC curve showed the optimal cut-off values of NLN as 3.86 and .79, respectively. These values show 83 patients in the high-risk group and 124 in the low-risk group. There was no difference between the groups in tumor localization and T stage. According to Kaplan-Meier survival analysis, mean survival was 35.88 months in the high-risk group and 50.18 months in the low-risk group. The risk of death in the high-risk group was 305% compared to the low-risk group (Hazard Ratio: 3.05, 95% 1.91 - 4.88) (P < .001).

CONCLUSION

NLNs are among the critical prognostic factors in colon cancer. Although NLNs have a positive correlation with the survival rate of the patients, there is no statistical difference in tumor T stage and localization.

Modifications to the video-assisted thoracoscopic surgery technique reduce 1-year mortality and postoperative complications in intrathoracic tumors

OBJECTIVE

The purpose of the study is to analyze the immediate outcomes and results of video-assisted thoracoscopic lobectomy and lung resection performed in the surgical department of the AOC between 2014 and 2018.

METHODS

For the period from 2014 to 2018, 118 patients with peripheral lung cancer were operated on in the surgical department of the AOC. The following operations were performed: lobectomy in 92 cases (78%), of which: upper lobectomy, 44 (47.8%); average lobectomy, 13 (14.1%); lower lobectomy, 32 (35%); bilobectomy, 3 (3.3%). All patients underwent extensive lymphadenectomy on the side of the operation. In 22 patients, for various reasons, preservation of thoracotomy was performed.

RESULTS

The absence of N0 lymph node damage was observed in 82 patients (70%), the first-order lymph node damage N1 in 13 (11%), N2 in 13 (11%), N3 in 5 (4%), and NX in 5 (4%). Histological examination revealed: squamous cell carcinoma - 35.1%, adenocarcinoma - 28.5%, undifferentiated carcinoma - 8.3%, NSCLC - 5.6%, NEO - 4.6%, sarcoma - 1.8%. At the same time, in 12.7% of patients, mts was detected - lung damage, and in 3.4%, malignant cells were not detected. Most patients were activated on the first day after surgery.

CONCLUSION

An analysis of the direct results of the study allows us to conclude that video-assisted thoracoscopic surgery is a highly effective, minimally invasive, safe method for treating peripheral lung cancer, which allows us to recommend it for wider use in oncological practice.

Association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

Clinical practice guidelines recommend retrieving at least 12 lymph nodes for correct staging in colorectal cancer. However, it is difficult to retrieve adequate lymph nodes because of various factors. We aimed to evaluate the association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer.

DESIGN

Systematic review and meta-analysis of primary studies.

DATA SOURCES

PubMed, Embase, Cochrane and Web of Science were searched from January 2016 to June 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that evaluated the association between retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer were included.

DATA EXTRACTION AND SYNTHESIS

OR with 95% conference intervals was extracted and pooled.

RESULTS

A total of 54 studies containing 2 05 821 patients were included in this meta-analysis. The results showed that fewer nodes were retrieved from elderly patients (OR=0.70, 95% CI (0.54 to 0.90), p=0.005), and from tumours located in the left colon than in the right colon (OR=0.43, 95% CI (0.33 to 0.56), p<0.001). More lymph nodes were obtained from females than males (OR=1.15, 95% CI (1.04 to 1.28), p=0.006), from the advanced T stage (T3+T4) than T1+T2 stage (OR=1.57, 95% CI (1.25 to 1.97), p<0.001) and from the N2 stage than N0 stage (OR=1.32, 95% CI (1.15 to 1.51), p<0.001). Body mass index, ethnicity, N1 stage, M stage, tumour differentiation and lymph-vascular invasion were not significantly associated with the lymph node yield.

CONCLUSIONS

The study results suggest that clinicians have an increased opportunity to retrieve sufficient lymph nodes for accurate pathological staging to guide treatment decisions in patients with colorectal cancer who are young, female, with tumours located in the right colon, advanced T stage and N2 stage.

Positive lymph node ratio is an important index to predict long-term survival for advanced esophageal squamous carcinoma patients (II∼III) with R0 resection--a SEER-based analysis

Background

Esophageal squamous carcinoma (ESCC) is one of the most malignant cancers in the world due to nodal metastasis. Therefore, a reasonable nodal staging system is extremely important for further treatment strategies. Recently the positive lymph node ratio (PLNR) is an important prognostic factor in various solid tumors.

Method

In this study, we investigated the clinical significance of the PLNR in stage II∼III ESCC patients. We collected the pathological characteristics of 272 stage II∼III ESCC patients from the SEER database from 2004-2016. ROC curves were used to calculate the best cutoff value of the PLNR; Pearson's Chi-square (χ2) and Fisher's exact probability tests were used to compare the clinical baseline and characteristics of patients. For continuous variables, Student's t-test and ANOVA were performed to evaluate statistical significance. Clinical outcomes were estimated by using the Kaplan‒Meier method and log-rank test. Furthermore, univariate and multivariate Cox regression models were utilized to analyze independent prognostic factors of ESCC patients.

Results

Consequently, advanced ESCC patients were effectively stratified into two groups by prognosis using a PLNR cutoff value of 0.15 (P value = 0.04). The median survival time of patients with PLNR <0.15 (n = 145) was much higher than that of patients (n = 127) in the PLNR ≥0.15 group (20.0 vs. 13.0 months, P value < 0.0001). Notably, the PLNR significantly predicted the prognosis of ESCC patients with stage N1 (P value 0.01) and stage III (P value < 0.001) disease. The multivariate Cox proportional hazard model showed that T stage (HR 1.33, 95 % CI 0.97-1.82), tumor size >45 mm (HR 1.32, 95 % CI 1.02-1.70), N stage (HR 1.41, 95 % CI 0.98-2.01) and PLNR ≥0.15 (HR 1.35, 95 % CI 0.87-1.74) were independent risk factors for prognostic prediction in ESCC patients. Meanwhile, 117 II∼III ESCC patients from Shaanxi Provincial People's Hospital shown that the overall survival with a PLNR <0.15 (n = 96) was significantly longer than that with a PLNR ≥0.15 (n = 21) .

Conclusions

The PLNR is useful for accurately predicting clinical outcomes and determining postoperative strategies.

Lymph node level ratio as a predictor of survival in oral cavity squamous cell carcinoma

OBJECTIVE

To evaluate whether nodal yields and ratios based on level serves as prognostic indicators in patients with oral cavity squamous cell carcinoma undergoing neck dissection.

MATERIALS AND METHODS

A retrospective analysis of 342 patients with oral cavity squamous cell carcinoma treated surgically between 1998 and 2017 were included.Demographics and clinicopathologic data were collated. Disease specific survival and overall survival were analyzed via Kaplan-Meier method and log-rank test as well as univariable and multivariable Cox models.

RESULTS

Total nodal yield is associated with improved overall and disease specific survival (p < 0.01). Total positive nodal yield (p < 0.01), positive nodal ratio per level (p < 0.001), and identification of <4 lymph nodes/level (p < 0.001) are associated with worse disease specific survival and overall survival. A ratio of at least 4 lymph nodes/level dissected yields the maximal hazard ratio on for both disease specific and overall survival optimizes the Kaplan-Meier split between survival groups. After controlling for sex, age, margin status, disease stage, extranodal extension, perineural invasion, and lymphovascular invasion as fixed covariates in the Cox models, a nodal level ratio of 4 lymph nodes/level provides hazard ratio (95% CI) of 3.59 (1.69, 7.60); p < 0.0006) for disease free survival and 2.90 (1.54, 5.46; p < 0.001) for overall survival.

CONCLUSION

Nodal level ratio of < 4 lymph nodes/level is associated with worse disease specific and overall survival in oral cavity squamous cell carcinoma. This level-specific metric may prove useful qualitatively and in predicting survival in oral cavity cancer with broader utility to address variations in levels of neck dissection performed.

Prognostic value of the lymph node ratio in surgically treated stage III colorectal cancer patients with high numbers of harvested lymph nodes

BACKGROUND

The lymph node ratio (LNR), defined as the number of positive lymph nodes (LN) divided by the total number of harvested LN, has been demonstrated to be an independent factor in the prognosis of surgically treated colorectal cancer (CRC) patients. This study aims to establish the prognostic value of LNR in stage III CRC patients with high numbers of LN removed.

METHODS

Stage III CRC patients who underwent curative resections over an 8-year period were included to the study. Demographics, clinicopathological features, surgical as well as recurrence and survival outcomes were recorded and statistically analyzed. Calculations for LNR were carried out as a function of percentage rates and Cox proportional hazards regression analyses were performed to determine its effect on disease-free and overall survival.

RESULTS

Among a total of 493 surgically treated CRC cases, 104 patients were included to the study consisting of 68 (65.4%) men and 36 (34.6%) women with a median age of 64 (inter-quartile range: 55-74) years. The mean number of harvested LN was 31.6 ± 21.0 (range: 12-103). Multivariate Cox regression analyses proved LNR to be a significant factor in both disease-free and overall survival (p = 0.007 and p = 0.003, respectively). Forward elimination analyses showed that a 1% increase in LNR resulted with a 2% increase in both the risks of recurrence and mortality.

CONCLUSIONS

The LNR may be assessed as an adjunct to the current staging systems for the prediction of oncological outcomes and survival of surgically treated stage III CRC patients.

Lymph node yield in colorectal cancer specimens and its impact on pathological staging: Does number matter?

Introduction

Regional lymph node involvement is an important predictor of outcome in colorectal cancer (CRC). The lymph node yield in resected specimens varies from case to case.

Aim

To assess whether clinicopathologic factors have an impact on the number of lymph nodes harvested from surgical resection specimens of CRCs To assess whether the total number of lymph nodes retrieved has a bearing on the positivity of lymph nodes and hence the N category.

Materials and Methods

All resection specimens of treatment naïve CRC received in the department of pathology during a 2 year period (2017-2019) were reviewed. The lymph node yield was correlated with age, sex, type of surgical procedure, length of resected segment, tumor location, histological type and grade, T and N categories. The statistical tests used were Spearman rank, Mann-Whitney U, Kruskal-Wallis, and Chi-square tests.

Results

A total of 51 resections were studied. The mean age was 59.64 years with 72.55% being male. About 76.47% were hemicolectomies and 23.52% were rectosigmoid surgeries. The lymph node yield ranged from 0 to 38, the mean being 12.67. None of the parameters studied had a significant correlation with the lymph node yield except histological grade, specimens with higher-grade tumors yielding more number of nodes (P = 0.0242). There was no significant correlation between node positivity and the average number of lymph nodes (P = 0.0883). There was no significant correlation between total yield in cases with ≥12 lymph nodes and N category (P = 0.180). Furthermore, there was no significant correlation between total yield in node-positive cases with ≥12 lymph nodes and N category (P = 0.216). There was no significant difference in the sizes of the lymph nodes in node-positive and negative cases (P = 0.3930 and 0.2355, respectively).

Conclusion

Among the parameters affecting lymph node yield, the current study found a significant correlation between histological grade and lymph node yield. There was no significant difference in the size of lymph nodes between node-positive and negative cases. The total lymph node yield did not have a bearing on node positivity and this shows that a lower lymph node yield may be accepted as adequate after thorough examination of the specimen.

Evaluating prognostic value and stage migration effects using a positive lymph node ratio in adenocarcinoma of the esophagogastric junction

BACKGROUND

Adenocarcinoma of the esophagogastric junction (AEG) is increasing worldwide. Lymph node metastasis is an important clinical issue in AEG patients. This study investigated the usefulness of a positive lymph node ratio (PLNR) to stratify prognosis and evaluate stage migration.

METHODS

We retrospectively analysed 117 consecutive AEG patients (Siewert type I or II) who received a lymphadenectomy between 2000 and 2016.

RESULTS

A PLNR cut-off value of 0.1 most effectively stratified patient prognosis into two groups (P < 0.001). Also, prognosis could be clearly stratified into four groups: PLNR = 0, 0 < PLNR < 0.1, 0.1 ≤ PLNR < 0.2, and 0.2 ≤ PLNR (P < 0.001, 5-year survival rates (88.6%, 61.1%, 34.3%, 10.7%)). A PLNR ≥ 0.1 significantly correlated with tumour diameter ≥ 4 cm (P < 0.001), tumour depth (P < 0.001), greater pathological N-status (P < 0.001), greater pathological Stage (P < 0.001), and oesophageal invasion length ≥ 2 cm (P = 0.002). A PLNR ≥ 0.1 was a poor independent prognostic factor (hazard ratio 6.47, P < 0.001). The PLNR could stratify prognosis if at least 11 lymph nodes were retrieved. A 0.2 PLNR cut-off value discriminated a stage migration effect in pN3 and pStage IV (P = 0.041, P = 0.015) patients; PLNR ≥ 0.2 might potentially diagnose a worse prognosis and need meticulous follow-up post-surgery.

CONCLUSION

Using PLNR, we can evaluate the prognosis and detect higher malignant cases who need meticulous treatments and follow-up in the same pStage.

Impact of DNA mismatch repair proteins deficiency on number and ratio of lymph nodal metastases in colorectal adenocarcinoma

BACKGROUND

Approximately 15 % of colorectal adenocarcinomas (CRCs) are characterized by an altered expression of DNA mismatch repair (MMR) proteins (i.e. MMR deficiency [MMRd]). Lymph node ratio (LNR) represents one of the most important prognostic markers in non-advanced CRCs. No significant data are available regarding LNR distribution depending on MMR status.

PURPOSE OF THE STUDY

The aim of the present work was to compare pathological and clinical characteristics of MMRd tumors versus MMR proficient (MMRp) cases. Particular attention was paid to how these molecular sub-groups relate to the LNR.

MATERIALS AND METHODS

A mono-Institutional series of 1037 consecutive surgically treated stage I-IV CRCs were retrospectively selected and data were obtained from pathological reports. Cases were characterized for MMR/MSI status by means of immunohistochemistry or for microsatellite instability (MSI) analysis.

RESULTS

MMRd/MSI tumors (n = 194; 18.7 %) showed significant differences in comparison to MMRp lesions for sex (female prevalence 50.5 % vs 40.7 %; p = 0.013), age (74.2 vs 69.2; p < 0.001), location (right side; p < 0.001), diameter (larger than MMRp; p < 0.001), growth pattern (expansive pattern of growth; p < 0.001), peri- (p = 0.0002) and intra-neoplastic (p = 0.0018) inflammatory infiltrate, presence of perineural invasion (p < 0.001), stage (lower stage at presentation; p < 0.001), grade (higher prevalence of high-grade tumors; p < 0.001), and LNR (lower; p < 0.001).

CONCLUSIONS

MMRd/MSI tumors are a distinct molecular CRC subtype characterized by a significantly lower LNR in comparison to MMRp lesions. These data further support the prognostic impact of MMRd/MSI status in early-stage CRCs.

Assessing the Association Between Endoscopic Tattooing and Lymph Node Yield in Rectal Cancer

INTRODUCTION

Preoperative endoscopic tattooing is an effective tool for intraoperative tumor localization in colon cancer. Endoscopic tattooing in rectal cancer may have unidentified benefits on lymph node yield, making it easier for pathologists to identify nodes during histopathologic assessment. There remains concern that tattoo ink may alter anatomical planes, increasing surgical difficulty.

METHODS

Retrospective chart reviews from 2016 to 2021 of n = 170 patients presenting with rectal cancer were divided into two groups: with (n = 79) and without (n = 91) endoscopic tattoos. Demographics, operative details, tumor characteristics, prior chemoradiation, and pathologic details were collected. Primary outcome was total lymph node yield. Secondary outcomes were rates of adequate (> 12) nodes, margin status, and operative variables including operative time.

RESULTS

No differences between pathologic stage, tumor height, high inferior mesenteric artery ligation, operative times, conversion rate, or surgical approach (open versus minimally invasive) were noted between groups. Receipt of neoadjuvant chemoradiation was less frequent in the endoscopic tattooing group (53.2% versus 76.9%, P ≤ 0.001). Total node number and rate of adequate lymph node yield were higher with endoscopic tattooing (20.5 ± 7.6 versus 16.8 ± 6.6 lymph nodes and 100.0% versus 83.5% adequate lymph node harvest, both P ≤ 0.001). Rates of positive circumferential and distal margins and complete total mesorectal excision were also similar. Regression analysis identified endoscopic tattooing (Incidence Risk Ratio 1.17, 95% confidence interval 1.04-1.31) and operative time more than 300 min (Incidence Risk Ratio 0.88, 95% confidence interval 0.77-0.99) had significant effects on lymph node harvest. Removal of patients with inadequate lymph node yield resulted in similar rates of total and positive lymph nodes.

CONCLUSIONS

Endoscopic rectal tattooing is associated with increased lymph node yield (including after neoadjuvant chemoradiotherapy) without sacrificing oncologic or perioperative outcomes, although this effect is inconsistent when only considering patients with an adequate lymph node yield.

Impact on inadequate lymph node harvest on survival in T4N0 colorectal cancer: A would-be medical center experience in Taiwan

Insufficient lymph node harvest (< 12) may lead to incorrect classification of stage I and II disease. Many studies have indicated a poor prognosis with inadequate lymph node harvest in stages I to III, but few studies have demonstrated the relationship between low lymph node harvest and T4 disease. This study aimed to identify the influence of insufficient number of lymph nodes harvested on survival in T4N0 colorectal cancer. We enrolled patients with T4N0 colorectal cancer who underwent radical resection between 2010 and 2016. A total of 155 patients were divided into 2 groups; 142 patients had ≥ 12 harvested lymph nodes, and the other 13 had < 12 lymph nodes. All patients were followed up for at least 5 years. The primary outcome was the impact of the number of lymph nodes harvested on disease-free survival and overall survival, which were investigated using Kaplan-Meier survival techniques. There were no significant differences in recurrence rate, emergent or elective surgery, laparoscopic or open surgery, or chemotherapy between the 2 groups. Kaplan-Meier analyses showed no statistical differences in 5-year disease-free survival (P = .886) and 5-year overall survival (P = .832) between the groups. There were no significant differences in disease-free survival and overall survival between patients with adequate (≥ 12) and inadequate (< 12) lymph node harvest in T4N0 colorectal cancers.

Lymph node yield less than 12 is not a poor predictor of survival in locally advanced rectal cancer after laparoscopic TME following neoadjuvant chemoradiotherapy

Purpose

Previous studies have confirmed that neoadjuvant chemoradiotherapy (nCRT) may reduce the number of lymph nodes retrieved in rectal cancer. However, it is still controversial whether it is necessary to harvest at least 12 lymph nodes for locally advanced rectal cancer (LARC) patients who underwent nCRT regardless of open or laparoscopic surgery. This study was designed to evaluate the relationship between lymph node yield (LNY) and survival in LARC patients who underwent laparoscopic TME following nCRT.

Methods

Patients with LARC who underwent nCRT followed by laparoscopic TME were retrospectively analyzed. The relationship between LNY and survival of patients was evaluated, and the related factors affecting LNY were explored. To further eliminate the influence of imbalance of clinicopathological features on prognosis between groups, propensity score matching was conducted.

Results

A total of 257 consecutive patients were included in our study. The median number of LNY was 10 (7 to 13) in the total cohort. There were 98 (38.1%) patients with 12 or more lymph nodes harvested (LNY ≥12 group), and 159 (61.9%) patients with fewer than 12 lymph nodes retrieved (LNY <12 group). There was nearly no significant difference between the two groups in clinicopathologic characteristics and surgical outcomes except that the age of LNY <12 group was older (P<0.001), and LNY <12 group tended to have more TRG 0 cases (P<0.060). However, after matching, when 87 pairs of patients obtained, the clinicopathological features were almost balanced between the two groups. After a median follow-up of 65 (54 to 75) months, the 5-year OS was 83.9% for the LNY ≥12 group and 83.6% for the LNY <12 group (P=0.893), the 5-year DFS was 78.8% and 73.4%, respectively (P=0.621). Multivariate analysis showed that only patient age, TRG score and ypN stage were independent factors affecting the number of LNY (all P<0.05). However, no association was found between LNY and laparoscopic surgery-related factors.

Conclusions

For LARC patients who underwent nCRT followed by laparoscopic TME, the number of LNY less than 12 has not been proved to be an adverse predictor for long-term survival. There was no correlation between LNY and laparoscopic surgery-related factors.

Inking outside the box: systematic review on the utility of tattooing lesions in rectal cancer

PURPOSE

Endoscopic tattooing in rectal cancer is infrequently utilized for fear of tattoo ink obscuring anatomical planes, increasing the difficulty of surgical excision. Colon cancer tattooing has demonstrated increased lymph node yields and increased accuracy in establishing adequate margins. Rectal cancer tattooing may be especially helpful after neoadjuvant chemoradiation, where complete clinical responses could limit lesion identification and lymph node yields are typically less robust. We seek to review and identify the effects of tattooing in rectal cancer.

METHODS

A systematic literature search was performed in PubMed, Embase, and SCOPUS. Studies on endoscopic tattooing with cohorts consisting of at least ≥ 25% of rectal cancer patients were selected. Studies focusing solely on rectal cancer were also reviewed separately.

RESULTS

Of 416 studies identified, 10 studies encompassing 2460 patients were evaluated. Seven studies evaluated lymph node yields; five reported beneficial effects of endoscopic tattooing, while two reported no significant difference. Among four studies reporting lesion localization, successful localization rates were between 63 and 100%. Rates of intraoperative endoscopy performed to reevaluate lesion location ranged from 5.7 to 20%. The distal margin was evaluated in two studies, which reported more accurate placement of the distal resection margin after tattooing. When complications of tattooing were documented (7 studies with 889 patients), only five direct complications of endoscopic tattooing were observed (0.6%).

CONCLUSIONS

Although the data is heterogenous, it suggests that endoscopic tattooing in rectal cancer may improve lymph node yields and assist in determining accurate distal margins without high rates of complication. Further research must be completed before practice management guidelines can change.

TRIAL REGISTRATION

No. CRD42021271784.

Construction of a new clinical staging system for colorectal cancer based on the lymph node ratio: A validation study

Aim

This study aims to construct a new staging system for colorectal cancer (CRC) based on the lymph node ratio (LNR) as a supplement to the American Joint Committee on Cancer (AJCC) tumor node metastasis (TNM) staging system for predicting the prognosis of CRC patients with <12 lymph nodes.

Methods

The data of 26,695 CRC patients with <12 lymph nodes were extracted from the Surveillance, Epidemiology, and End Results (SEER) database as a training set. A total of 635 CRC patients were also enrolled from Northern Jiangsu People's Hospital affiliated with Yangzhou University as an independent validation set. Classification and regression tree analysis was used to obtain the LNR cutoff value. Survival curves were estimated using the Kaplan–Meier method, and the log-rank test was used for comparisons of differences among the survival curves. The monotonic decreasing trend of the overall survival curve in the staging system was expressed by the linear correlation degree R.

Results

The 5-year survival rates of patients in the training set based on the AJCC staging system from stage I to stage IV were 75.6% (95%CI: 74.4–76.8), 59.8% (95%CI: 58.6–61.0), 42.1% (95%CI: 34.5–49.7), 33.2% (95%CI: 24.6–41.8), 72.0% (95%CI: 69.1–74.9), 48.8% (95%CI: 47.4–50.2), 26.5% (95%CI: 23.0–30.0), and 11.3% (95%CI: 10.3–12.3). The 5-year survival rates of patients in the training set from stage I to stage IIIC were 80.4%, 72.9%, 59.8%, 48.4%, 32.5%, and 15.0%, according to the TNM + LNR (TNRM) staging system. According to the AJCC staging system, the 5-year survival rates of patients in the validation set from stage I to stage IIIC were 91.3%, 90.8%, 72.6%, 61.3%, 72.4%, 58.1%, and 32.8%. Based on the TNRM staging system, the 5-year survival rates of patients in the validation set from stage I to stage IIIC were 99.2%, 90.5%, 81.4%, 78.6%, 60.2%, and 35.8%.

Conclusion

The TNRM staging system successfully eliminated “survival paradox” in the AJCC staging system, which might be superior to the AJCC staging system.

Learning curve analysis for lateral pelvic lymph node dissection in rectal cancers - Outcomes improve with experience

INTRODUCTION

Lateral pelvic lymph node dissection (LPLND) is a technically challenging procedure and its learning curve has not been analysed against an oncologically relevant outcome. The purpose of the study was to determine the learning curve for LPLND in rectal cancers using nodal retrieval as performance measure.

METHODS

Consecutive LPLND for rectal adenocarcinomas from a single institution were retrospectively analysed. Cumulative sum (CUSUM) control charts were used to detect difference in performance with respect to lymph node yield. Negative binomial regression was used to determine factors influencing nodal harvest using Incidence Risk Ratios (IRR). Separate CUSUM curves were generated for open and minimally invasive surgeries (MIS).

RESULTS

One-hundred and twenty patients were included and all received preoperative radiation. MIS was used in 53.3%. Median lymph node yield was 6 with 20% nodal positivity. Increasing experience (IRR - 1.196) and MIS (IRR - 1.586) were the only factors that influenced nodal harvest. CUSUM charts revealed that learning curve was achieved after the 83rd case overall and after the 19 operations in MIS. There was a 20% increase in nodal yield after every 30 MIS LPLND performed.

CONCLUSIONS

Learning curve for LPLND is relatively long and only increasing experience and minimally invasive operations increased nodal yield.

A comparison of extracorporeal side to side or end to side anastomosis following a laparoscopic right hemicolectomy for colon cancer

Background

This study aimed to investigate whether an extracorporeal side‐to‐side (SS) or end‐to‐side (ES) stapled anastomosis impacts short‐term and long‐term outcomes after an oncological laparoscopic right hemicolectomy.

Methods

A retrospective cohort study of prospectively collected data from two Victorian tertiary referral hospitals was performed. Patients who underwent oncological resection for colorectal cancer between February 2010 and September 2020 were selected from the colorectal neoplasia database. Patients were divided into two groups depending on the type of stapled anastomosis: Group 1 (functional end‐to‐end/side‐to‐side (SS)); and Group 2 (end‐to‐side (ES)). Primary outcomes were anastomotic leak, postoperative ileus, mortality and morbidity, length of stay post‐surgery, readmission to hospital, and 30‐day mortality.

Results

This large case series of 1040 patients (SS = 625, ES = 415) demonstrated that the type of stapling technique impacted operative duration and postoperative ileus rates. Patients in the SS group had a faster operation of 108 min rather than 130 min in the ES group (p < 0.001). The SS group were more likely to experience a post‐operative ileus (p < 0.001) with no impact on length of stay (SS, 7 days versus ES, 7 days; p = 0.14). There were no differences between the two groups with respect to lymph node yield, lymph node ratio, anastomotic leaks, return to theatre, 30‐day mortality and 5‐year overall survival.

Discussion

The type of extracorporeal stapled anastomosis following an oncological laparoscopic right hemicolectomy has minimal impact on morbidity and survival outcomes; however, a side‐to‐side stapled anastomosis is more likely to be a faster operation with a higher postoperative ileus rate.

The Effect of Lymph Node Harvest on Prognosis in Locally Advanced Middle-Low Rectal Cancer After Neoadjuvant Chemoradiotherapy

OBJECTIVE

The purpose of this study was to investigate the relationship between lymph node harvest and the prognosis in locally advanced rectal cancer (LARC) patients after neoadjuvant chemoradiotherapy (nCRT).

METHODS

Patients who were diagnosed with clinical LARC and treated with nCRT and radical surgery between June 2008 and July 2017 were included in this study. The relationship between lymph node retrieval and prognosis was analyzed. Other lymph node-related indicators were explored.

RESULTS

A total of 837 patients with a median follow-up of 61 (7-139) months were included in the study. The five-year DFS and OS rates of all patients were 74.9% and 82.3%, respectively. Multivariate survival analysis suggested that dissection of ≥ 12 lymph nodes did not improve OS or DFS. 7 was selected as the best cutoff value for the total number of lymph nodes retrieved by Cox multivariate analysis (χ2 = 10.072, HR: 0.503, P=0.002). Dissection of ≥ 5 positive lymph nodes (PLNs) was an independent prognostic factor for poorer DFS (HR: 2.104, P=0.004) and OS (HR: 3.471, p<0.001). A positive lymph node ratio (LNR) of more than 0.29 was also an independent prognostic factor for poorer DFS (HR: 1.951, P=0.002) and OS (HR: 2.434, p<0.001).

CONCLUSION

The recommends that at least 7 harvested lymph nodes may be more appropriate for LARC patients with nCRT. PLN and LNR may be prognostic factors for LARC patients with ypN+ after nCRT.

Current Perspectives on the Importance of Pathological Features in Prognostication and Guidance of Adjuvant Chemotherapy in Colon Cancer

There is not a clear consensus on which pathological features and biomarkers are important in guiding prognosis and adjuvant therapy in colon cancer. The Pathology in Colon Cancer, Prognosis and Uptake of Adjuvant Therapy (PiCC UP) Australia and New Zealand questionnaire was distributed to colorectal surgeons, medical oncologists and pathologists after institutional board approval. The aim of this study was to understand current specialist attitudes towards pathological features in the prognostication of colon cancer and adjuvant therapy in stage II disease. A 5-scale Likert score was used to assess attitudes towards 23 pathological features for prognosis and 18 features for adjuvant therapy. Data were analysed using a rating scale and graded response model in item response theory (IRT) on STATA (Stata MP, version 15; StataCorp LP). One hundred and sixty-four specialists (45 oncologists, 86 surgeons and 33 pathologists) participated. Based on IRT modelling, the most important pathological features for prognosis in colon cancer were distant metastases, lymph node metastases and liver metastases. Other features seen as important were tumour rupture, involved margin, radial margin, CRM, lymphovascular invasion and grade of differentiation. Size of tumour, location, lymph node ratio and EGFR status were considered less important. The most important features in decision making for adjuvant therapy in stage II colon cancer were tumour rupture, lymphovascular invasion and microsatellite instability. BRAF status, size of tumour, location, tumour budding and tumour infiltrating lymphocytes were factored as lesser importance. Biomarkers such as CDX2, EGFR, KRAS and BRAF status present areas for further research to improve precision oncology. This study provides the most current status on the importance of pathological features in prognostication and recommendations for adjuvant therapy in Australia and New Zealand. Results of this nationwide study may be useful to help in guiding prognosis and adjuvant treatment in colon cancer.

Pathological Features and Prognostication in Colorectal Cancer

The prognostication of colorectal cancer (CRC) has traditionally relied on staging as defined by the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) TNM staging classifications. However, clinically, there appears to be differences in survival patterns independent of stage, suggesting a complex interaction of stage, pathological features, and biomarkers playing a role in guiding prognosis, risk stratification, and guiding neoadjuvant and adjuvant therapies. Histological features such as tumour budding, perineural invasion, apical lymph node involvement, lymph node yield, lymph node ratio, and molecular features such as MSI, KRAS, BRAF, and CDX2 may assist in prognostication and optimising adjuvant treatment. This study provides a comprehensive review of the pathological features and biomarkers that are important in the prognostication and treatment of CRC. We review the importance of pathological features and biomarkers that may be important in colorectal cancer based on the current evidence in the literature.

Prognostic implications of ENE and LODDS in relation to lymph node-positive colorectal cancer location

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This is the first study on LODDS and ENE together. The current study showed that LODDS and ENE are liable prognostic parameters of CRC or CC.

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ENE is an independent influencing factor on the prognosis of both CRC and CC, and the prognostic impact of ENE was observed in both CRC and CC.

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The frequency of ENE increases from the proximal (right) to the distal (left) colon as well as the rectum.

Background

Extranodal extension (ENE) and log odds of positive lymph nodes (LODDS) are associated with the aggressiveness of both colon and rectal cancers. The current study evaluated the clinicopathological significance and the prognostic impact of ENE and LODDS in the colon and rectal patients independently.

Methods

The clinical and histological records of 389 colorectal cancer (CRC) patients who underwent curative surgery were reviewed.

Results

For the ENE system, 244 patients were in the ENE1 group and 145 in the ENE2 system. Compared with the ENE1 system, the patients included in the ENE2 system were prone to nerve invasion (P < 0.001) and vessel invasion (P < 0.001) with higher TNM (P = 0.009), higher T category (P = 0.003), higher N category (P < 0.001), advanced differentiation (P = 0.013), more number of positive lymph nodes (NPLN) (P < 0.001), more lymph node ratio (LNR) (P < 0.001), and a higher value of LODDS (P < 0.001). ENE was more frequent in patients with left and rectal than right cancer. For the LODDS system, 280 patients were in the LODDS1 group, and 109 in the LODDS2 group. Compared to the LODDS1 group, the patients included in the LODDS2 group were more prone to nerve invasion (P = 0.0351) and vessel invasion (P < 0.001) with a higher rate of N2 stage, less NDLN (P < 0.001), more NPLN (P < 0.001), more LNR (P < 0.001), and a higher value of ENE (P < 0.001). Based on the results in the univariable analysis, the N, NPLN, LNR, LODDS, and ENE were separately incorporated into five different Cox regression models combined with the same confounders. The multivariable Cox regression analysis demonstrated that all the five staging systems were independent prognostic factors for overall survival.

Conclusion

The current study confirmed that the LODDS stage is an independent influence on the prognosis of both CRC and CC patients. ENE is an independent influencing factor on the prognosis of both CRC and CC patients, and the prognostic impact of extracapsular lymph node was observed in both CRC and CC. The frequency of ENE increases from the proximal (right) to the distal (left) colon as well as the rectum. Therefore, combining ENE and LODDS into the current TNM system to compensate for the inadequacy of pN staging needs further investigation.

Perioperative and oncologic outcomes in young and octogenarian patients with colorectal cancer: a comparison at the extremes

INTRODUCTION

In colorectal cancer (CRC), surgical outcomes in the young (< 50) and octogenarian populations are believed to be poor due to an aggressive phenotype in the former, and increased frailty in the latter. Given that age-related effects are inversely related between groups, we compared short- and long-term outcomes of young and octogenarian patients with CRC to determine the dominance of one age-related factor over another.

METHODS

A prospectively collected database from 2015 to 2020 of all CRC was analyzed. Cases were divided into metastatic and non-metastatic groups.

RESULTS

Among non-metastatic cases, there were 34 young and 113 octogenarian patients. Mean CEA was higher among octogenarians (11.2 vs 32.8 units/ml; p = 0.041). Octogenarians suffered from more comorbidities than younger counterparts, with increased rates of postoperative UTI (3.3% vs 10.3%; p = 0.246) and pneumonia (3.1% vs 8.8%; p = 0.331). There was no increased rate of reintervention or Clavien-Dindo scores. We noticed a statistically significant higher proportion of extramural vascular invasion (EMVI) (8.8% vs 32.3%; p = 0.003) among the young. When excluding octogenarians who had declined surgery, Kaplan-Meier analysis showed no difference in disease-free (p = 0.290) or overall survival (p = 0.111). Among metastatic cases, there were 21 young and 19 octogenarian patients. Young patients were treated more aggressively with chemotherapy (55.6% vs 12.5%; p = 0.040). There was however no difference in overall survival between groups (p = 0.610).

CONCLUSIONS

Octogenarians may have more comorbidities, but can achieve similar surgical outcomes with younger patients. There is no reason to suspect a more aggressive phenotype in younger patients.

Optimal ICG dosage of preoperative colonoscopic tattooing for fluorescence-guided laparoscopic colorectal surgery

Background

Indocyanine green (ICG) is a multifunctional dye used in tumor localization, tissue perfusion, and lymph node (LN) mapping during fluorescence-guided laparoscopic colorectal surgery.

Purpose

This study aimed to establish the optimal protocol for preoperative endoscopic submucosal ICG injection to perform fluorescence lymph node mapping (FLNM), along with undisturbed fluorescent tumor localization and ICG angiography during a single surgery.

Methods

Colorectal cancer patients (n = 192) were enrolled from May 2017 to December 2019. Colonoscopic submucosal ICG injection was performed 12 to 18 h before surgery. ICG injection protocols were modified based on the total injected ICG (mg) and tattooing site number. The concentrations of ICG were gradually decreased from the standard dose (2.5 mg/ml) to the minimum dose (0.2 mg/ml). Successful FLNM (FLNM-s) was defined as distinct fluorescent LNs observed under NIR camera. The patient’s age, sex, body mass index (BMI), stage, cancer location, obstruction, and laboratory findings were compared between the FLNM-s and failed FLNM (FLNM-f) groups to identify clinical and pathological factors that affect FLNM.

Results

In the ICG dose section of 0.5 to 1 mg, the success rate was highest within all functions including FLNM, fluorescent tumor localization, and ICG angiography. FLNM-s was related to ICG dose (0.5–1 mg), multiple submucosal injections, location of cancer, camera light source, and lower BMI. In the multivariate analysis, camera light source, non-obesity, and multiple injections were independent factors for FLNM-s). The mean total number of harvested LNs was significantly higher in the FLNM-s group than that in the FLNM-f group (p < 0.001). The number of metastatic lymph nodes was comparable between the two groups (p = 0.859).

Conclusions

Preoperative, endoscopic submucosal ICG injection with dose range 0.5 to 1 mg would be optimal protocol for multifunctional ICG applications during fluorescence-guided laparoscopic colorectal surgery.

Metastatic lymph node ratio as a better prognostic tool than the TNM system in colorectal cancer

Background: The minimum number of lymph nodes that should be evaluated in colon cancer to adequately categorize lymph node status is still controversial. The lymph node ratio (LNR) may be a better prognostic indicator. Materials & methods: We studied 1065 patients treated from 1 January 2000 to 31 August 2012. Results: Significant differences in survival were detected according to regional lymph nodes (pN) (p < 0.001) and LNR (p < 0.001). LRN and pN are independent prognostic factors. Spearman correlation analysis showed a significant correlation between the total number of dissected lymph nodes and pN (rs = 0.167; p < 0.001), but the total number of dissected lymph nodes is not significantly correlated with LNR (rs = -0.019; p = 0.550). Interpretation: In this study, LNR seems to demonstrate a superior prognostic value compared with the pN categories, in part due to its greater independence regarding the extent of lymphadenectomy.

Prognostic Impact of Lymph Node Ratio in Patients Undergoing Preoperative Chemoradiotherapy Followed by Curative Resection for Locally Advanced Rectal Cancer

BACKGROUND/AIM

To analyze the prognostic significance of nodal status in patients undergoing preoperative chemoradiotherapy (CRT) followed by curative resection for locally advanced rectal cancer.

PATIENTS AND METHODS

Between 2000 and 2015, 80 consecutive patients with rectal cancer underwent preoperative CRT followed by curative resection. The lymph node ratio (LNR) was defined as the number of positive lymph nodes (LNs) divided by the examined LNs, and log odds of positive lymph nodes (LODDS) was the log of the ratio between positive and negative LNs. The prognostic value of these indicators was evaluated in terms of overall (OS) and disease-free (DFS) survival.

RESULTS

The median follow-up period for patients overall was 59 months (range=11-190 months). The median number of examined LNs and number of positive LNs were 10 (range=1-29) and 2 (range=1-27), respectively, and the median LNR and LODDS values were 0.0 (range=0.0-0.96) and -1.0 (range=-1.7-1.3), respectively. The 5-year OS and DFS were 83% and 64%, respectively. In multivariate analysis, LNR was an independent prognostic factor in terms OS (p=0.041) but not for DFS (p=0.075). LODDS was not significantly associated with OS or DFS. In patients with clinical stage III rectal cancer, LNR was significantly associated with OS and DFS when the number of evaluated LNs was greater than 12 (p=0.038 for OS, p=0.006 for DFS).

CONCLUSION

Our study suggests that LNR is a more effective prognostic factor than LODDS in terms of predicting survival. LNR was a significant predictor for survival for patients with clinical stage III rectal cancer with >12 harvested LNs.

Rectum versus colon: should malignant polyps be treated differently?

BACKGROUND

The management of malignant colorectal polyps removed at endoscopy remains controversial with patients either undergoing surgical resection or regular endoscopic surveillance. Lymph node (LN) metastases occur in 6-16% of patients with malignant polyps. This study assessed the rate of LN metastases in patients undergoing surgical resection for malignant polyps removed endoscopically to determine if there is a difference in the rate of LN metastases between colonic and rectal polyps.

METHODS

A retrospective review of a prospectively maintained database was performed from 2010 to 2018. All patients who underwent surgical resection following endoscopic removal of a malignant colorectal polyp were reviewed. Clinical data including patient demographics and tumour characteristics were examined.

RESULTS

A total of 177 patients underwent surgical resection in the study period. The median age at diagnosis was 65 years (range 22-88 years) with females comprising 52% of the patient cohort (n = 92/177). Polyps were located in the colon in 60.5% of cases with the remainder located in the rectum. The median number of LN harvested was 14 (range 0-44) with malignant LN (including a mesenteric tumour deposit) identified in 8.5% of resection specimens (n = 15/177). Malignant LNs were retrieved in 5.5% of right-sided tumours, 5.6% of left-sided tumours and 12.9% of rectal tumours (P = 0.090).

CONCLUSION

A small proportion of patients with malignant polyps removed endoscopically will have LN metastases. The results of this study suggest that the tumour location might be a useful predictive marker; however, a further study with increased patient numbers is required to properly establish this finding.

Log odds of positive lymph nodes is prognostically equivalent to lymph node ratio in non-metastatic colon cancer

BACKGROUND

Globally, colorectal cancer (CRC) is the third and second leading cancer in men and women respectively with 600,000 deaths per year. Traditionally, clinicians have relied solely on nodal disease involvement, and measurements such as lymph node ratio (LNR; the ratio of metastatic/positive lymph nodes to total number of lymph nodes examined), when determining patient prognosis in CRC. The log odds of positive lymph nodes (LODDS) is a logistic transformation formula that uses pathologic lymph node data to stratify survival differences among patients within a single stage of disease. This formula allows clinicians to identify whether patients with clinically aggressive tumours fall into higher-risk groups regardless of nodal positivity and can potentially guide adjuvant treatment modalities. The aim of this study was to investigate whether LODDS in colon cancer provides better prognostication compared to LNR.

METHODS

A retrospective study of patients on the prospectively maintained Cabrini Monash University Department of Surgery colorectal neoplasia database, incorporating data from hospitals in Melbourne Australia, identified patients entered between January 2010 and March 2016. Association of LODDS and LNR with clinical variables were analysed. Disease-free (DFS) and overall (OS) survival were investigated with Cox regression and Kaplan-Meier survival analyses.

RESULTS

There were 862 treatment episodes identified in the database (402 male, 47%). The median patient age was 73 (range 22-100 years). There were 799 colonic cancers and 63 rectosigmoid cancers. The lymph node yield (LNY) was suboptimal (< 12) in 168 patients (19.5%) (p = 0.05). The 5-year OS for the different LNR groups were 86, 91 and 61% (p < 0.001) for LNR₀ (655 episodes), LNR₁ (128 episodes) and LNR₂ (78 episodes), respectively. For LODDS, they were 85, 91 and 61% (p < 0.001) in LODDS₀ (569 episodes), LODDS₁ (217 episodes) and LODDS₂ (75 episodes) groups (p < 0.001). Overall survival rates were comparable between the LNR and LODDS group and for LNY < 12 and stage III patients when each were sub-grouped by LODDS and LNR.

CONCLUSION

This study has shown for that the prognostic impact of LODDS is comparable to LNR for colon cancer patients. Accordingly, LNR is recommended for prognostication given its ease of calculation.

The prognostic impact of neoadjuvant chemoradiotherapy on lymph node sampling in patients with locally advanced rectal cancer

According to the American Joint Committee on Cancer, at least 12 lymph nodes are required to accurately stage locally advanced rectal cancer (LARC). Neoadjuvant chemoradiation therapy (NACRT) reduces the number of lymph nodes retrieved during surgery. In this study, we evaluated the effect of NACRT on lymph node retrieval and prognosis in patients with LARC. We performed an observational study of 142 patients with LARC. Although our analysis was retrospective, data were collected prospectively. Half the patients were treated with NACRT and total mesorectal excision (TME) and the other half underwent TME only. The number of lymph nodes retrieved and the number of metastatic lymph nodes were significantly reduced in the NACRT group (P > 0.001). In the univariate and multivariate analyses, only NACRT and patient age were significantly associated with reduced lymph node retrieval. The number of metastatic lymph nodes and the lymph node ratio (LNR) both had a significant effect on prognosis when the patient population was examined as a whole (P = 0.003 and P = 0.001, respectively). However, the LNR was the only significant, independent prognostic factor in both treatment groups (P = 0.007 for the NACRT group; P = 0.04 for the no-NACRT group). NACRT improves patient prognosis only when the number of metastatic lymph nodes is reduced. The number of metastatic lymph nodes and the LNR are important prognostic factors. Lymph node retrieval remains an indispensable tool for staging and prognostic assessment of patients with rectal carcinoma treated with NACRT.

4K ultra HD technology reduces operative time and intraoperative blood loss in colorectal laparoscopic surgery

Background: HD systems are routinely used in laparoscopic surgery, 4K ultra HD monitors are mainly available within specialized, high-volume laparoscopic centers. The higher resolution of 4K ultra HD video could upgrade the surgical performance improving intraoperative and post-operative outcomes. Methods: We performed a retrospective comparative analysis of intraoperative parameters and post-operative outcomes in a cohort of patients operated on for elective laparoscopic procedures for colo-rectal cancer during two different time frames: 2017 procedures performed using the Visera Elite full HD technology (® Olympus America, Medical) and the 2018 procedures performed the Visera 4K Ultra HD System (® Olympus America, Medical). Results: There was a statistically significant reduction in operative time in patients operated on with the 4K ultra HD technology compared to HD technology (p < 0.05). Intraoperative blood loss was significantly reduced in patients operated in 2018 (p < 0.05). There were no statistically significant differences in complication rate and postoperative outcomes between the two groups.

Immunohistochemical-based molecular subtyping of colorectal carcinoma using maspin and markers of epithelial-mesenchymal transition

The aim of the present study was to classify colorectal carcinoma (CRC) into molecular subtypes, based on immunohistochemical (IHC) assessments. A total of 112 CRC samples were molecularly classified based on the expression levels of epithelial-mesenchymal transition (EMT)-associated IHC markers. A total of three molecular subtypes were defined: Epithelial, membrane positivity for E-cadherin and β-catenin, negative for vimentin; mesenchymal, E-cadherin-negative, nuclear β-catenin- and vimentin-positive; and hybrid cases, epithelial tumor core and mesenchymal tumor buds. Most of the cases were diagnosed as moderately differentiated adenocarcinoma (n=89; 79.46%). The majority of cases (n=100; 89.28%) exhibited a mismatch repair proficient status (microsatellite stable CRCs). A predominance of epithelial-type (n=51; 45.54%) and hybrid CRCs (n=47; 41.96%) was observed, whereas a few cases (n=14; 12.50%) were classified as mesenchymal-type CRCs. This molecular classification was associated with pathological stage (P<0.01), pT stage (P=0.04), pN stage (P<0.01), the grade of tumor budding (P=0.04), and maspin expression in both the tumor core (P=0.04) and the invasion front (P<0.01). The mesenchymal-type cases predominantly exhibited lymph node metastases, high-grade budding and a tendency towards maspin nuclear predominance. All epithelial-type cases with maspin-only expression (n=18) were non-metastatic. Patients with CRC of the epithelial subtype and those with a lymph node ratio (LNR) ≤0.15 presented the best overall survival, followed by those with hybrid and mesenchymal subtypes. Nuclear maspin positivity was more frequent in cases with a high-budding degree compared with those with a low-budding degree (P=0.03). The EMT-associated molecular classification of CRCs may be used to identify the most aggressive CRCs, which show a mesenchymal phenotype, high-budding degree, maspin nuclear positivity and lymph node metastases. The pN stage, LNR and budding degree of patients, which can be evaluated with maspin expression, remain the most important prognostic factors.

Fat clearance and conventional fixation identified ypN0 rectal cancers following intermediate neoadjuvant radiotherapy have similar long-term outcomes

BACKGROUND

As a prognostic factor for colorectal cancer, lymph node (LN) status, particularly the number of LN harvested, has been demonstrated to be essential in the evaluation of quality control in terms of surgical specimen. Neoadjuvant chemoradiation, however, decreases the LN harvest. Therefore, certain approaches (such as fat clearance or methylene blue) has drawn significant attention in order to raise LN yield.

AIM

To compare the long-term oncologic outcome of ypN0 rectal cancer identified using fat clearance (FC) or conventional fixation (CF) following 30 Gy in 10 fractions (30 Gy/10f) of neoadjuvant radiotherapy (nRT).

METHODS

Three hundred and eighty-two patients with resectable and locally advanced rectal cancer were treated by 30 Gy/10f intermediate nRT (biologically equivalent dose of 36 Gy) plus total mesorectal excision. Two specimen fixation methods (FC or CF) were non-randomly used. The ypN0 status was identified in 124 and 101 patients in the FL and CF groups, respectively. Primary endpoints were local recurrence-free survival (LRFS) and cancer-specific survival (CSS).

RESULTS

The median follow-up of patients was 5.1 years. The median numbers of retrieved LNs in the FC and CF groups were 19.5 (range, 4-47) and 12 (range, 0-44), respectively, with a significant difference (P = 0.000). The percentages of patients with 12 or more retrieved nodes were 82.3% and 50.5% (101/159) in the FC and CF groups, respectively, with a significant difference (P = 0.000). The LRFS at 5 years were 95.7% and 94.6% in the FC and CF groups, respectively, without statistical difference (P = 0.819). The CSS at 5 years were 92.0% and 87.2% in the FC and CF groups, respectively, without statistical difference (P = 0.482).

CONCLUSION

For patients with ypN0 rectal cancer who underwent 30 Gy/10f preoperative radiotherapy, the increased retrieval of LNs using fat clearance is not associated with survival benefit. This time-consuming fixation method has a low efficacy as a routine practice.