Lymph node counts, rates of positive lymph nodes, and patient survival for colon cancer surgery in Ontario, Canada: a population-based study

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.

Comparison of conventional unstained lymph nodal harvesting vs methylene blue-stained lymph nodal harvesting in colorectal specimen in staging left-sided colorectal carcinoma: a randomized controlled trial

BACKGROUND

The management and prognosis of colorectal carcinomas (CRCs) are related to the stage of the disease, which, in turn, relies on the lymph node harvest from the surgical specimen. The guidelines recommend that at least 12 lymph nodes are required, which is not achieved in most resections. In this study, we propose a method to improve the lymph node yield in such cases. This study aimed to determine whether ex vivo injection of methylene blue into the inferior mesenteric artery or its branches improves lymph node retrieval in left-sided CRCs.

METHODS

This study was conducted as a single-center, double-blinded, superiority randomized controlled trial. Patients who underwent elective surgery for left-sided CRCs with curative intent were randomized into 2 groups: stained and unstained. The sample size was calculated as 66. In all patients, details of disease stage, history of neoadjuvant therapy, and number of isolated lymph nodes were recorded.

RESULTS

The mean number of lymph nodes extracted from the stained group was significantly higher than that from the unstained group (15.9 ± 5.2 vs 9.1 ± 5.7, respectively; P < .001). Among the patients who had received neoadjuvant therapy, the yield was higher in the stained group (P < .001). The yield was found to be greater in patients who had undergone upfront surgery than in those who had undergone neoadjuvant therapy, even in the stained group (100% vs 66.7%, respectively).

CONCLUSION

The use of methylene blue injection into resected specimens of left-sided CRCs significantly improved the lymph node yield.

Prognostic Value of Metastatic Lymph Node Ratio and Identification of Factors Influencing the Lymph Node Yield in Patients Undergoing Curative Colon Cancer Resection

Due to the impact of nodal metastasis on colon cancer prognosis, adequate regional lymph node resection and accurate pathological evaluation are required. The ratio of metastatic to examined nodes may bring an additional prognostic value to the actual staging system. This study analyzes the identification of factors influencing a high lymph node yield and its impact on survival. The lymph node ratio was determined in patients with fewer than 12 or at least 12 evaluated nodes. The study included patients after radical colon cancer resection in UICC stages II and III. For the lymph node ratio (LNR) analysis, node-positive patients were divided into four categories: i.e., LNR 1 (<0.05), LNR 2 (≥0.05; <0.2), LNR 3 (≥0.2; <0.4), and LNR 4 (≥0.4), and classified into two groups: i.e., those with <12 and ≥12 evaluated nodes. The study was conducted on 7012 patients who met the set criteria and were included in the data analysis. The mean number of examined lymph nodes was 22.08 (SD 10.64, median 20). Among the study subjects, 94.5% had 12 or more nodes evaluated. These patients were more likely to be younger, women, with a lower ASA classification, pT3 and pN2 categories. Also, they had no risk factors and frequently had a right-sided tumor. In the multivariate analysis, a younger age, ASA classification of II and III, high pT and pN categories, absence of risk factors, and right-sided location remained independent predictors for a lymph node yield ≥12. The univariate survival analysis of the entire cohort demonstrated a better five-year overall survival (OS) in patients with at least 12 lymph nodes examined (68% vs. 63%, p = 0.027). The LNR groups showed a significant association with OS, reaching from 75.5% for LNR 1 to 33.1% for LNR 4 (p < 0.001) in the ≥12 cohort, and from 74.8% for LNR2 to 49.3% for LNR4 (p = 0.007) in the <12 cohort. This influence remained significant and independent in multivariate analyses. The hazard ratios ranged from 1.016 to 2.698 for patients with less than 12 nodes, and from 1.248 to 3.615 for those with at least 12 nodes. The LNR allowed for a more precise estimation of the OS compared with the pN classification system. The metastatic lymph node ratio is an independent predictor for survival and should be included in current staging and therapeutic decision-making processes.

Immune microenvironment and lymph node yield in colorectal cancer

BACKGROUND

Lymph node (LN) harvesting is associated with outcomes in colonic cancer. We sought to interrogate whether a distinctive immune milieu of the primary tumour is associated with LN yield.

METHODS

A total of 926 treatment-naive patients with colorectal adenocarcinoma with more than 12 LNs (LN-high) were compared with patients with 12 or fewer LNs (LN-low). We performed immunohistochemistry and quantification on tissue microarrays for HLA class I/II proteins, beta-2-microglobulin (B2MG), CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E.

RESULTS

The LN-high group was comprised of younger patients, longer resections, larger tumours, right-sided location, and tumours with deficient mismatch repair (dMMR). The tumour microenvironment showed higher CD8+ cells infiltration and B2MG expression on tumour cells in the LN-high group compared to the LN-low group. The estimated mean disease-specific survival was higher in the LN-high group than LN-low group. On multivariate analysis for prognosis, LN yield, CD8+ cells, extramural venous invasion, perineural invasion, and AJCC stage were independent prognostic factors.

CONCLUSION

Our findings corroborate that higher LN yield is associated with a survival benefit. LN yield is associated with an immune high microenvironment, suggesting that tumour immune milieu influences the LN yield.

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.

Comparison of robotic versus laparoscopic right colectomy node retrieval in the obese population

Data are scarce comparing robotic and laparoscopic colectomy node retrieval based on body mass index or age. With differences in anastomosis, mobilization, and ligation between these approaches, obese and/or elderly patients undergoing robotic surgery may have differences in node yield compared to laparoscopy. A retrospective review was conducted between four institutions from February 1, 2019 through August 1, 2021, during which 144 right colectomies were performed. Benign pathology, open colectomies, and conversions to open were excluded. All included surgeons had at least five patients to ensure experience. The population was categorized by a robotic or laparoscopic approach. Records were reviewed focusing on age, body mass index, surgical approach, anastomosis, pathology, and node count. The node count was then compared by body mass index and age between the robotic or laparoscopic approach to identify differences. After applied exclusions and outlier analysis, our final sample consisted of 80 patients. Both body mass index and age were significant, (p = 0.002 and p = 0.005, respectively). Body mass index ≤ 25.0 and age < 60 years old had higher average node counts. These variables interacted, (p = 0.003); those with both < 60 years old and body mass index ≤ 25 showed the greatest number of nodes (36.9). Laparoscopy yielded more nodes in ≥ 60 years old than robotics (27.4 verses 20.9), though this was not significant (p = 0.68). Node retrieval in overweight and obese patients did not differ between approaches (p = 0.48). Both body mass index and age influence the number of nodes that can be extracted in right hemicolectomies by experienced surgeons.

Retrospective Cohort Analysis of the Effect of Age on Lymph Node Harvest, Positivity, and Ratio in Colorectal Cancer

Introduction: Colon cancer among young patients has increased in incidence and mortality over the past decade. Our objective was to determine if age-related differences exist for total positive nodes (TPN), total lymph node harvest (TLH), and lymph node ratio (LNR). Material and Methods: A retrospective review of stage III surgically resected colorectal cancer patient data in the National Cancer Database (2004−2016) was performed, reviewing TPN, TLH, and LNR (TPN/TLH). Results: Unadjusted analyses suggested significantly higher levels of TLH and TPN (p < 0.0001) in younger patients, while LNR did not differ by age group. On adjusted analysis, TLH remained higher in younger patients (<35 years 1.56 (CI 95 1.54, 1.59)). The age-related effect was less pronounced for LNR (<35 years 1.16 (CI 95 1.13, 1.2)). Conclusion: Younger patients have increased TLH, even after adjusting for known confounders, while age does not have a strong independent impact on LNR.

Pattern of recurrence and survival after D2 right colectomy for cancer: is there place for a routine more extended lymphadenectomy?

BACKGROUND

Conventional Right Colectomy with D2 lymphadenectomy (RC-D2) currently represent the most common surgical treatment of right-sided colon cancer (RCC). However, whether it should be still considered a standard of care, or replaced by a routine more extended D3 lymphadenectomy remains unclear. In the present study, we aim to critically review the patterns of relapse and the survival outcomes obtained from our 11-year experience of RC-D2.

METHODS

Clinical data of 489 patients who underwent RC-D2 for RCC at two centres, from January 2009 to January 2020, were retrospectively reviewed. Patients with synchronous distant metastases and/or widespread nodal involvement at diagnosis were excluded. Post-operative clinical-pathological characteristics and survival outcomes were evaluated including the pattern of disease relapse.

RESULTS

We enrolled a total of 400 patients with information follow-up. Postoperative morbidity was 14%. The median follow-up was 62 months. Cancer recurrence was observed in 55 patients (13.8%). Among them, 40 patients (72.7%) developed systemic metastases, and lymph-node involvement was found in 7 cases (12.8%). None developed isolated central lymph-node metastasis (CLM), in the D3 site. The estimated 3- and 5-year relapse-free survival were 86.1% and 84.4%, respectively. The estimated 3- and 5-year cancer-specific OS were 94.5% and 92.2%, respectively.

CONCLUSIONS

The absence of isolated CLM, as well as the cancer-specific OS reported in our series, support the routine use of RC-D2 for RCC. However, D3 lymphadenectomy may be recommended in selected patients, such as those with pre-operatively known CLM, or with lymph-node metastases close to the origin of the ileocolic vessels.

Is a cutoff value of 12 still useful in stage II right-sided colon cancer without risk factors?

Purpose

Various clinical practice guidelines recommend at least 12 regional lymph nodes should be removed for resected colon cancer. According to a recent study, the lymph node yield (LNY) in colon cancer surgery in the last 20 years has tended to increase from 14.91 to 21.30. However, it is unclear whether these guidelines adequately reflect recent findings on the number of harvested lymph nodes in colon cancer surgery. The aim of this study is to assess the impact of an LNY of more than 25 on survival in right-sided colon cancer.

Methods

We included 285 patients who underwent a right hemicolectomy during the period from January 2010 through December 2015. Patients were divided into two groups (<25 nodes and ≥25 nodes). Primary endpoints included 5-year and 10-year survival including disease-free and overall.

Results

We found that survival outcomes of patients with a harvest of ≥25 nodes were not significantly different compared with a <25 group. Large tumor size (5 cm) is significantly associated with poor 5-year and 10-year overall survival.

Conclusion

Survival outcomes of patients with a harvest of ≥25 nodes were not significantly different compared with the <25 group in stage II colon cancer with no risk.

Primary tumour immune response and lymph node yields in colon cancer

Background

The mechanism underlying improved survival in non-metastatic colon cancer with higher lymph node (LN) yield is unknown. This study aimed to identify whether molecular features in the primary tumour were predictive of LN yield.

Methods

Clinical, genomic, transcriptomic, proteomic and methylation data of non-metastatic, colon cancers studied in The Cancer Genome Atlas were interrogated for associations with LN yield. Based on maximal survival effects, patients were segregated into high (>15) and low (≤15) LN yield. Gene set enrichment analysis was performed on transcriptomic changes to identify biological processes associated with LN yield. Correlations were validated in an independent set of Stage II colon cancers.

Results

High LN yield was found predictive of overall and disease-free survival. There was no association of higher LN yield and increasing nodal positivity. High LN yield was strongly linked with gene expression changes associated with the adaptive and dendritic cell immune response. This association was most prominent in node-negative cancers. Analogous findings were reproduced in the validation dataset.

Conclusion

The study shows a strong association of an activated immune response in tumours with a high LN yield. Immunogenic tumours have a better prognosis, likely explaining the survival benefit with higher LN yields.

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.

The prognostic value of lymph node ratio in comparison to positive lymph node count in penile squamous cell carcinoma

PURPOSE

Penile cancer is a rare male neoplasm with a wide variation in its global incidence. In this study, the prognostic value of lymph node ratio (LNR) was compared to that of positive lymph node count (PLNC) in penile squamous cell carcinoma.

METHODS

A total of 249 patients with penile squamous cell carcinoma were enrolled from The Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015. The X-tile program was used to calculate the optimal cut-off values of LNR and PLNC that discriminate survival. We used the χ² or the Fisher exact probability test to assess the association between clinical-pathological characteristics and LNR or PLNC. Univariate and multivariate Cox regression analyses were performed to identify independent prognostic factors for survival. Spearman correlation analysis was used to determine the correlation between LNR and PLNC.

RESULTS

We found that patients with high LNR tended to have advanced N stage, the 7th AJCC stage, and higher pathological grade, while patients with high PLNC had advanced N stage and the 7th AJCC stage. Univariate Cox regression analysis revealed that the N stage, M stage, the 7th AJCC stage, lymph-vascular invasion, LNR, and PLNC were significantly associated with prognosis. Multivariate Cox regression analysis demonstrated that LNR rather than PLNC was an independent prognostic factor for cancer-specific survival. Subgroup analysis of node-positive patients showed that LNR was associated with CSS, while PLNC was not.

CONCLUSION

LNR was a better predictor for long-term prognosis than PLNC in patients with penile squamous cell carcinoma.

The Value of Sentinel Lymph Node Mapping for the Staging of Node-Negative Colon Cancer: Propensity Score and Mediation Analyses

Objectives

Mediation analysis to assess the protective impact of sentinel lymph node (SLN) mapping on prognosis and survival of patients with colon cancer through a more precise evaluation of the lymph node (LN) status.

Background

Up to 20% of patients with node-negative colon cancer develop disease recurrence. Conventional histopathological LN examination may be limited in describing the real metastatic burden of LN.

Methods

Data of 312 patients with stage I & II colon cancer was collected prospectively. Patients were either staged using intraoperative SLN mapping with multilevel sectioning and immunohistochemical staining of the SLN or conventional techniques. The value of the SLN mapping for the detection of truly node-negative patients was assessed using Cox regression and mediation analysis.

Results

SLN mapping was performed in 143 patients. Disease recurrence was observed in 13 (9.1%) patients staged with SLN mapping and in 27 (16%) staged conventionally. Five-year overall survival (OS) rate was 82.7% (95% confidence interval [CI], 76.5-89.4%) with SLN mapping compared with 65.8% (95% CI, 58.8-73.7%). Five-year cancer-specific survival (CSS) was 95.1% (95% CI, 91.3-99.0%) with SLN mapping compared with 92.5% (95% CI, 88.0-97.2%). Node-negative staging with SLN mapping was associated with significantly better OS (hazard ratio [HR], 0.64; 95% CI, 0.56-0.72; P < 0.001) and CSS (HR, 0.49; 95% CI, 0.39-0.61; P < 0.001) in multivariate analysis. Mediation analysis confirmed a direct protective effect of SLN mapping on OS (HR, 0.78; 95% CI, 0.52-0.96; P < 0.01) and disease-free survival (DFS) (HR, 0.75; 95% CI, 0.48-0.89; P < 0.01).

Conclusions

Staging performed by SLN mapping with multilevel sectioning provides more accurate results than conventional staging. The observed clinically relevant and statistically significant benefit in OS and DFS is explained by a more accurate detection of positive LN by SLN mapping.

Clinicopathological factors associated with synchronous distant metastasis and prognosis of stage T1 colorectal cancer patients

It is rare and understudied for patients with stage T1 colorectal cancer to have synchronous distant metastasis. This study was to determine the clinicopathological factors associated with distant metastasis and prognosis. T1 colorectal cancer patients diagnosed between 2010 and 2015 were obtained from the SEER database. Logistic regression was applied to determine risk factors related to distant metastasis. Cox-proportional hazard models were used to identify the prognostic factors for patients with distant metastasis. Among 21,321 patients identified, 359 (1.8%) had synchronous distant metastasis and 1807 (8.5%) had lymph node metastasis. Multivariate analysis revealed that younger age, positive serum CEA, larger tumor size, positive tumor deposit, perineural invasion, lymph node metastasis, histology of non-adenocarcinoma and poorer differentiation were significantly associated with the increased risk of synchronous distant metastasis. Older age, female, Black, positive CEA, positive lymph node metastasis, positive tumor deposit, larger tumor size, no chemotherapy, inadequate lymph node harvesting and no metastasectomy were correlated with worse survival in these patients with synchronous distant metastasis. Patients with metastasis to the liver displayed the highest rate of positive CEA. We conclude that T1 colorectal cancer patients with multiple risk factors need thorough examinations to exclude synchronous distant metastasis. Chemotherapy, adequate lymph node cleaning and metastasectomy are associated with improved survival for those patients with distant metastases. Positive serum CEA may be useful in predicting distant metastases in patients at stage T1.

Prognostic and Predictive Cross-Roads of Microsatellite Instability and Immune Response to Colon Cancer

Understanding molecular features of colon cancer has shed light on its pathogenesis and progression. Over time, some of these features acquired clinical dignity and were incorporated in decision making. Namely, microsatellite instability (MSI) due to mismatch repair of defects, which primarily was adopted for the diagnosis of Lynch syndrome, became recognized as the biomarker of a different disease type, showing a less aggressive behavior. MSI tumors harbor high amounts of tumor infiltrating lymphocytes (TILs) due to their peculiar load in neoantigens. However, microsatellite stable colon cancer may also show high amounts of TILs, and this feature is as well associated with better outcomes. High TIL loads are in general associated with a favorable prognosis, especially in stage II colon cancer, and therein identifies a patient subset with the lowest probability of relapse. With respect to post-surgical adjuvant treatment, particularly in stage III, TILs predictive ability seems to weaken along with the progression of the disease, being less evident in high risk patients. Moving from cohort studies to the analysis of a series from clinical trials contributed to increase the robustness of TILs as a biomarker. The employment of high TIL densities as an indicator of good prognosis in early-stage colon cancers is strongly advisable, while in late-stage colon cancers the employment as an indicator of good responsiveness to post-surgical therapy requires refinement. It remains to be clarified whether TILs could help in identifying those patients with node-positive cancers to whom adjuvant treatment could be spared, at least in low-risk groups as defined by the TNM staging system.

Small Molecules for Multi-Wavelength Near-Infrared Fluorescent Mapping of Regional and Sentinel Lymph Nodes in Colorectal Cancer Staging

Assessing lymph node (LN) status during tumor resection is fundamental for the staging of colorectal cancer. Current guidelines require a minimum of 12 LNs to be harvested during resection and ultra-staging regional lymph nodes by sentinel lymph node (SLN) assessment is being extensively investigated. The current study presents novel near-infrared (NIR) fluorescent dyes for simultaneous pan lymph node (PanLN; regional) and SLN mapping. PanLN-Forte was intravenously injected in mice and assessed for accumulation in regional LNs. SLN800 was injected intradermally in mice, after which the collection and retention of fluorescence in SLNs were measured using indocyanine green (ICG) and its precursor, SLN700, as references. LNs in the cervical, inguinal, jejunal, iliac, and thoracic basins could clearly be distinguished after a low dose intravenous injection of PanLN-Forte. Background fluorescence was significantly lower compared to the parent compound ZW800-3A (p < 0.001). SLN700 and SLN800 specifically targeted SLNs with fluorescence being retained over 40-fold longer than the current clinically used agent ICG. Using SLN700 and SLN800, absolute fluorescence in SLN was at least 10 times higher than ICG in second-tier nodes, even at 1 hour post-injection. Histologically, the fluorescent signal localized in the LN medulla (PanLN-Forte) or sinus entry (SLN700/SLN800). PanLN-Forte and SLN800 appear to be optimal for real-time NIR fluorescence imaging of regional and SLNs, respectively.

The re-evaluation of optimal lymph node yield in stage II right-sided colon cancer: is a minimum of 12 lymph nodes adequate?

PURPOSE

Adequate lymphadenectomy is critical for accurate nodal staging and planning adjuvant therapy in colon cancer. However, the optimal lymph node (LN) yield for stage II right-sided colon cancer (RSCC) is still unclear. This population-based study aimed to determine the optimal LN yield associated with survival and LN positivity in patients with stage II RSCC.

METHODS

All patients with stage II-III RSCC were identified from the Surveillance, Epidemiology, and End Results database over a 10-year interval (2006-2015). The optimal threshold for LN yield was explored using an outcome-oriented approach based on survival and LN positivity.

RESULTS

The median number of LNs examined for all 17,385 patients with stage II RSCC was 17 (IQR 12-23). Nineteen LNs were determined as the optimal cut-off point to maximize survival benefit from lymphadenectomy. Increased LN yield was associated with a gradual increase in the risk of node positivity, with no change after 19 nodes. Compared with patients with 19 or more LNs examined, the group with fewer LNs had a significantly poor cancer-specific survival (< 12 nodes: hazard ratio (HR) 2.26, P < 0.001; 12-18 nodes: HR 1.58, P < 0.001) and overall survival (< 12 nodes: HR 1.80, P < 0.001; 12-18 nodes: HR 1.31, P < 0.001). Similar survival results were found in the validation cohort. Patients with older age, small tumor size, and appendix and transverse colon cancer were more likely to receive inadequate LN harvest.

CONCLUSION

A minimum of 19 LNs is needed to be examined for optimal survival and adequate node staging in lymph node-negative RSCC.

Can Ex Vivo Magnetic Resonance Imaging of Rectal Cancer Specimens Improve the Mesorectal Lymph Node Yield for Pathological Examination?

Supplemental digital content is available in the text.

The aim of this study was to use 7 T ex vivo magnetic resonance imaging (MRI) scans to determine the size of lymph nodes (LNs) in total mesorectal excision (TME) specimens and to increase the pathological yield of LNs with MR-guided pathology.

Identification of Risk Factors Associated With Stage III Disease in Nonmetastatic Colon Cancer: Results From a Prospective National Cohort Study

Purpose

This study aimed to identify possible patient- and tumor-related factors associated with risk of TNM stage III disease in nonmetastatic colon cancer.

Methods

The associations between stage III disease and age, sex, lymph node yield, pathological tumor (pT) stage, tumor subsite, type of surgery, and priority of surgery were assessed in a nationwide cohort of 13,766 patients treated with curative resection of colon cancer. Each level of age, lymph node yield, and pT stage was compared to the preceding level.

Results

Age, lymph node yield, pT stage, tumor subsite, and priority of surgery were associated with stage III disease. Odds ratios (95% confidence interval [CI]) were as follows: age < 65/65–75 years: 1.28 (95% CI, 1.15–1.43) and 65–75/ > 75 years: 1.22 (95% CI, 1.13–1.32); lymph node yield 0–5/6–11: 0.60 (95% CI, 0.50–0.72), lymph node yield 6–11/12–17: 0.84 (95% CI, 0.76–0.93), and lymph node yield 12–17/ ≥ 18: 0.97 (95% CI, 0.89–1.05); pT1/pT2: 0.74 (95% CI, 0.57–0.95), pT2/pT3: 0.35 (95% CI, 0.30–0.40), and pT3/pT4: 0.49 (95% CI, 0.47–0.54). Only tumors of the transverse colon were independently associated with lower risk of stage III disease than tumors in the sigmoid colon (sigmoid colon: 1, transverse colon: 0.84 [95% CI, 0.73–0.96]; elective surgery: 1, acute surgery: 1.43 [95% CI, 1.29–1.60]).

Conclusion

In this study, stage III disease in colon cancer was significantly associated with age, lymph node yield, pT stage, tumor subsite, and priority of surgery but was not associated with right-sided location compared with stage I and II cancers.

Factors affecting the number of lymph nodes retrieved after colo-rectal cancer surgery: A prospective single-centre study

BACKGROUND

The number of harvested lymph nodes (LNs) in colorectal cancer surgery relates to oncologic radicality and accuracy of staging. In addition, it affects the choice of adjuvant therapy, as well as prognosis. The American Joint Committee on Cancer defines at least 12 LNs harvested as adequate in colorectal cancer resections. Despite the importance of the topic, even in high-volume colorectal centres the rate of adequacy never reaches 100%. The aim of this study was to identify factors that affect the number of harvested LNs in oncologic colorectal surgery.

MATERIALS AND METHODS

We prospectively collected all consecutive patients who underwent colorectal cancer resection from January 1st 2013 to December 31st 2017 at Emergency Surgery Unit St Orsola University Hospital of Bologna.

RESULTS

Six hundred and forty-three consecutive patients (382 elective, 261 emergency) met the study inclusion criteria. Emergency surgery and laparoscopic approach did not have a significant influence on the number of harvested LNs. The adequacy of lymphadenectomy was negatively affected by age >80 (OR 3.47, p < 0.001), ASA score ≥3 (OR 3.48, p < 0.001), Hartmann's or rectal resection (OR 3.6, p < 0.001) and R1-R2 resection margins (OR 3.9, p = 0.006), while it was positively affected by T-status ≥3 (OR 0.33 p < 0.001).

CONCLUSION

Both the surgical technique and procedure regimen did not affect the number of lymphnodes retrieved. Age >80 and ASA score ≥3 and Hartmann's procedure or rectal resection showed to be risk factors related to inadequate lymphadenectomy in colorectal cancer surgery.

How does lymph node yield affect survival outcomes of stage I and II colon cancer?

Background

According to the American Joint Committee on Cancer staging for cancer of the colon, a minimum of 12 lymph nodes (LN) has to be sampled for accurate staging. This has bearing on the long-term prognosis and the need for adjuvant chemotherapy. The aim of this study was to revisit the association of lymph node yield and the long-term survival in patients with stages I and II, i.e. node-negative, colon cancer.

Method

Consecutive patients who underwent elective or emergency curative resections for cancer of colon between the years 2003 and 2012 were retrospectively reviewed. Only patients with stage I or II diseases (AJCC 8th edition) were included. They were analysed in three groups, LN<12, LN12-19 and LN≥20. Their clinic-pathological characteristics were compared. The disease-free (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared with the log-rank test.

Results

There was a total of 659 patients included in the analysis. Twelve or more LN were found in 65.6% of the specimens. The mean follow-up was 83.9 months. LN≥20 had significantly better DFS (p = 0.015) and OS (p = 0.036), whereas LN<12 had similar DFS and OS when compared to LN12-19. The advantage in DFS and OS were mainly seen in those with stage II diseases. A lymph node yield of greater than 20 was one of the predictors of favourable DFS, hazard ratio 0.358; 95% CI 0.170–.756, p = 0.007.

Conclusion

The lymph node yield had a significant association with survival outcomes. A lymph node yield of 20 or more was associated with better survival outcomes. On the other hand, lymph node yield less than 12 was not shown to have inferior survival outcomes when compared to those between 12 and 19.

Deep cervical fascia as an anatomical landmark of lingual lymph nodes: An anatomic and histologic study

OBJECTIVES

We aimed to discuss the definition of lingual lymph nodes based on the deep cervical fascia anatomy.

METHODS

A total of 11 cadavers were histopathologically evaluated. Specimens were dissected into serial stepwise cross-sections. The deep cervical fascia and lymph nodes were evaluated by staining the cross-sections with Elastica van Gieson and hematoxylin and eosin stains, respectively. The gross anatomy of the deep cervical fascia was evaluated in 1 cadaver after bilateral dissection.

RESULTS

A single severely degenerated medial lingual lymph node (MLLN) was identified in the lingual septum of 1 cadaver. A single lateral lingual lymph node (LLLN) was identified in 1 cadaver, between the genioglossus and the hyoglossus. The superficial layer of deep cervical fascia (SLDF) was found to split into two layers encapsulating the submandibular gland. The deeper portion of this fascia was in close contiguity with the hyoglossus and formed the boundary between the mouth and the neck. The SLDF was found to be discontinuous with the area between the sublingual space and the submandibular gland.

CONCLUSIONS

The SLDF could serve as an anatomical landmark for lingual lymph nodes, since it is considered to be the demarcating boundary during neck dissection. When lymph nodes that are located deeper than the SLDF were defined as lingual lymph nodes, 1 MLLN and 1 LLLN were identified.

Prognostic significance of number versus location of positive mesenteric nodes in stage iii colon cancer

INTRODUCTION

Debate persists on the ideal extent of lymphadenectomy for colon cancer (CC). Specifically, it is unknown whether the anatomical location of positive lymph nodes (LN) has any independent prognostic significance. We assessed the prognostic value of positive LN location in stage III CC patients who underwent extensive (D3) lymphadenectomy.

METHODS

Patients from Kanagawa Cancer Center, Japan, who underwent D3 dissection for CC from 2000 to 16 were analyzed. Mesenteric LN were classified according to location as paracolic (L1), intermediate (L2), or central (L3). Recurrence-free survival (RFS) and the corresponding hazard function were evaluated with their trends over the L groups. Multivariate Cox models were used to evaluate the association of LN location with RFS.

RESULTS

Four hundred forty-six stage III patients were analyzed. The mean number of examined/positive nodes per patient was 42.5/2.6 in L1 (n = 310), 40.9/4.8 in L2 (n = 111), and 44.0/9.8 in L3 (n = 25). RFS was worse for L3 vs. L2 (HR: 2.00, 95%CI [1.05-3.75], p = 0.034) and for L3 vs. L1 (2.62 [1.45-4.71], p = 0.001), but not significantly different between L2 and L1 (1.32 [0.89-1.5], p = 0.17). In a multivariate model adjusting for age, tumor size, and number of lymph nodes harvested T-stage (p < 0.001), adjuvant therapy (p < 0.0038), lymphatic invasion (p = 0.023), and LNR (p = 0.038) were significantly associated with RFS, but not L level or tumor location.

CONCLUSION

The anatomical location of invaded LN does not significantly correlate with RFS in CC, after adjusting for potential confounders. Central LN are infrequently invaded and confer a worse RFS.

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

Background

Lymph node yield (LNY) of 12 or more in resection of colorectal cancer is recommended in current international guidelines. Although a low LNY (less than 12) is associated with poorer outcome in some studies, its prognostic value is unclear in patients with early‐stage colorectal or rectal cancer with a complete pathological response following neoadjuvant therapy. Lymph node ratio (LNR), which reflects the proportion of positive to total nodes obtained, may be more accurate in predicting outcome in stage III colorectal cancer. This study aimed to identify factors correlating with LNY and evaluate the prognostic role of LNY and LNR in colorectal cancer.

Methods

An observational study was performed on patients with colorectal cancer treated at three hospitals in Melbourne, Australia, from January 2010 to March 2016. Association of LNY and LNR with clinical variables was analysed using linear regression. Disease‐free (DFS) and overall (OS) survival were investigated with Cox regression and Kaplan–Meier survival analyses.

Results

Some 1585 resections were analysed. Median follow‐up was 27·1 (range 0·1–71) months. Median LNY was 16 (range 0–86), and was lower for rectal cancers, decreased with increasing age, and increased with increasing stage. High LNY (12 or more) was associated with better DFS in colorectal cancer. Subgroup analysis indicated that low LNY was associated with poorer DFS and OS in stage III colonic cancer, but had no effect on DFS and OS in rectal cancer (stages I–III). Higher LNR was predictive of poorer DFS and OS.

Conclusion

Low LNY (less than 12) was predictive of poor DFS in stage III colonic cancer, but was not a factor for stage I or II colonic disease or any rectal cancer. LNR was a predictive factor in DFS and OS in stage III colonic cancer, but influenced DFS only in rectal cancer.

Alterations of lymph nodes evaluation after colon cancer resection: patient and tumor heterogeneity should be taken into consideration

Despite the adequacy of nodal evaluation was gradually improved for colon cancer (CC), rare attention has been paid for the effect of patient and tumor heterogeneity on nodal evaluation. We identified 109902 CC patients in stage I-III from Surveillance, Epidemiology, and End-Results (SEER) database during 2004-2013. The lymph nodes evaluations were separately assessed in different patient- and tumor-related features, including gender, age, T stage, histology, tumor differentiation, tumor size and tumor location. The 5-year cancer specific survival (CSS) was calculated with Kaplan-Meier method, log-rank tests were used to compare the differences of CSS in patients with ≥12 and <12 lymph nodes examined. Here, we identified features including gender, age, T stage, tumor differentiation, tumor size and location were independently associated with the median number of lymph node, the rate of ≥12 lymph nodes and the rate of node positivity of CC patients. We then divided CC patients into 29 subgroups according to different patient- and tumor-related features. The median number of lymph node presented a large variance from 12 to 24, the rate of ≥12 lymph nodes increased from 53.2% to 91.2% under the combined effect of patient and tumor heterogeneity. Furthermore, the positive association between increased lymph nodes count and improved survival couldn't be observed in 8261 CC patients with the effect of this heterogeneity. In conclusion, the tumor and patient heterogeneity lead to large alterations of nodal evaluation; we should pay more attention to this effect in clinical practice.

Lymph node yield in right colectomy for cancer: a comparison of open, laparoscopic and robotic approaches

AIM

Studies have demonstrated a relationship between lymph node (LN) yield and survival after colectomy for cancer. The impact of surgical technique on LN yield has not been well explored.

METHOD

This is a retrospective study of right colectomy (RC) for cancer at a single institution from 2012 to 2014. Exclusion criteria were previous colectomy and emergent and palliative operations. All data were collected by chart review. Primary outcomes were LN yield and the LN to length of surgical specimen (LN-LSS) ratio. Multivariable mixed models were created with surgeon and pathologist as random effects. Sensitivity analyses were performed to exclude Stage IV cancers and to analyse groups on an 'as-treated' basis.

RESULTS

We identified 181 open (O-RC), 163 laparoscopic (L-RC) and 119 robotic (R-RC) right colectomies. O-RC was more commonly performed in women with metastatic disease. The mean LN yield was 28, 29 and 34 in O-RC, L-RC and R-RC, respectively; the respective mean LN-LSS ratios were 0.83, 0.91 and 1.0. The R-RC approach produced a higher LN yield than the other approaches (P < 0.01), and a higher LN-LSS ratio than O-RC (P < 0.01). These findings were unchanged in sensitivity analyses.

CONCLUSION

Robotic right colectomy improves LN yield and the LN-LSS ratio, which may reflect better mesocolic excision. The effect of these findings on survival requires further investigation.

Lymph node evaluation for colon cancer in routine clinical practice: a population-based study

BACKGROUND

Guidelines recommend that 12 or more lymph nodes (lns) be evaluated during surgical resection of colon cancer. Here, we report ln yield and its association with survival in routine practice.

METHODS

Electronic records of treatment were linked to the population-based Ontario Cancer Registry to identify all patients with colon cancer treated during 2002-2008. The study population (n = 5508) included a 25% random sample of patients with stage ii or iii disease. Modified Poisson regression was used to identify factors associated with ln yield; Cox models were used to explore the association between ln yield and overall (os) and cancer-specific survival (css).

RESULTS

During 2002-2008, median ln yield increased to 17 from 11 nodes (p < 0.001), and the proportion of patients with 12 or more nodes evaluated increased to 86% from 45% (p < 0.001). Lymph node positivity did not change over time (to 53% from 54%, p = 0.357). Greater ln yield was associated with younger age (p < 0.001), less comorbidity (p = 0.004), higher socioeconomic status (p = 0.001), right-sided tumours (p < 0.001), and higher hospital volume (p < 0.001). In adjusted analyses, a ln yield of less than 12 nodes was associated with inferior os and css for stages ii and iii disease [stage ii os hazard ratio (hr): 1.36; 95% confidence interval (ci): 1.19 to 1.56; stage ii css hr: 1.52; 95% ci: 1.26 to 1.83; and stage iii os hr: 1.45; 95% ci: 1.30 to 1.61; stage iii css hr: 1.54; 95% ci: 1.36 to 1.75].

CONCLUSIONS

Despite a temporal increase in ln yield, the proportion of cases with ln positivity has not changed. Lymph node yield is associated with survival in patients with stages ii and iii colon cancer. The association between ln yield and survival is unlikely to be a result of stage migration.

A Nomogram to Predict Adequate Lymph Node Recovery before Resection of Colorectal Cancer

Increased lymph node count (LNC) has been associated with prolonged survival in colorectal cancer (CRC), but the underlying mechanisms are still poorly understood. The study aims to identify new predictors and develop a preoperative nomogram for predicting the probability of adequate LNC (≥ 12). 501 eligible patients were retrospectively selected to identify clinical-pathological factors associated with LNC ≥ 12 through univariate and multivariate logistic regression analyses. The nomogram was built according to multivariate analyses of preoperative factors. Model performance was assessed with concordance index (c-index) and area under the receiver operating characteristic curve (AUC), followed by internal validation and calibration using 1000-resample bootstrapping. Clinical validity of the nomogram and LNC impact on stage migration were also evaluated. Multivariate analyses showed patient age, CA19-9, circulating lymphocytes, neutrophils, platelets, tumor diameter, histology and deposit significantly correlated with LNC (P < 0.05). The effects were marginal for CEA, anemia and CRC location (0.05 < P < 0.1). The multivariate analyses of preoperative factors suggested decreased age, CEA, CA19-9, neutrophils, proximal location, and increased platelets and diameter were significantly associated with increased probability of LNC ≥ 12 (P < 0.05). The nomogram achieved c-indexes of 0.75 and 0.73 before and after correction for overfitting. The AUC was 0.75 (95% CI, 0.70–0.79) and the clinically valid threshold probabilities were between 10% and 60% for the nomogram to predict LNC < 12. Additionally, increased probability of adequate LNC before surgery was associated with increased LNC and negative lymph nodes rather than increased positive lymph nodes, lymph node ratio, pN stages or AJCC stages. Collectively, the results indicate the LNC is multifactorial and irrelevant to stage migration. The significant correlations with preoperative circulating markers may provide new explanations for LNC-related survival advantage which is reflected by the implication of regional and systemic antitumor immune responses.

Number of Lymph Nodes in Primary Nodal Basin and a “Second Look” Protocol as Quality Indicators for Optimal Nodal Staging of Colon Cancer

Context.—Evaluation of 12 or more lymph nodes (LNs) is currently used as a quality indicator for adequacy of pathologic examination of colon cancer resections.

Objective.—To evaluate the utility of a focused LN search in the immediate vicinity of the tumor and a “second look” protocol in improving LN staging in colon cancer.

Design.—Lymph nodes were submitted separately from the primary nodal basin (PNB) and secondary nodal basin (SNB) defined as an area less than 5 cm away and an area greater than 5 cm away from the tumor edge, respectively, in 201 consecutive resections (2010–2013). One hundred sixty-eight consecutive tumors (2006–2009) were used as a control group. A second search was performed in all cases that were N0 after the first search.

Results.—In cases that were N0 after the first search, 20.9 ± 10.8 LNs were collected from the PNB, compared to 8.5 ± 9.1 from the SNB. Positive LNs were found in N+ tumors in the PNB in all cases but in only 9% (4 of 46) of SNBs (P &lt; .001). A second search increased node count by an average of 10 additional LNs. In 5 of 114 cases (4.4%), N0 after the first search converted to N+ after a second search that yielded 1 to 4 positive LNs, all of which were in the PNB.

Conclusions.—Emphasis on the number of LNs examined from the PNB and a “second look” protocol improve nodal staging.

A high lymph node yield in colon cancer is associated with age, tumour stage, tumour sub-site and priority of surgery. Results from a prospective national cohort study

AIM

To determine the relation between patient-related and histopathological factors, as well as the influence of national programs for diagnosing and treatment of colon cancer and a lymph node yield (LNY) ≥ 12.

METHOD

An analysis was carried out of the LNY in a nationwide Danish cohort treated by curative resection of stage I-III colon cancer in the period 2003-2011. The association between a LNY ≥ 12 and age, sex, body mass index, open vs. laparoscopic surgery, acute vs. elective surgery, pT stage, tumour sub-site and year of diagnosis was analysed.

RESULTS

A total of 13,766 patients were eligible for the analysis. In total, 71.4 % of the patients had a LNY ≥ 12. In multivariate analysis, age, pT stage, tumour sub-site and priority of surgery were independently associated with the probability of a LNY ≥ 12. Odds ratios (ORs) were as follows: age <65 1, 65-75 0.685 (confidence interval (CI) 0.586-0.800), >75 0.517 (CI 0.439-0.609); T1 1, T2 2.750 (CI 2.168-3.487), T3 6.016 (CI 4.879-7.418), T4 6.317 (CI 4.950-8.063); right colon 1, left colon 0.568 (0.511-0.633); elective surgery 1, acute surgery 0.748 (CI 0.625-0.894). Moreover, year of diagnosis was associated with the probability of a LNY ≥ 12: OR 1.480 (CI 1.445-1.516) for each increasing year in the study period.

CONCLUSION

A LNY ≥ 12 is significantly associated with age, pT stage, tumour sub-site and priority of surgery. A significant increase in the LNY over the period of the study was observed, probably reflecting the effect of national programmes initiated by the Danish Colorectal Cancer Group.

The Evaluation of More Lymph Nodes in Colon Cancer Is Associated with Improved Survival in Patients of All Ages

Background

Improvement in survival of patients with colon cancer is reduced in elderly patients compared to younger patients. The aim of this study was to investigate whether the removal of ≥ 12 lymph nodes can explain differences in survival rates between elderly and younger patients diagnosed with colon cancer.

Methods

In a population-based cohort study, all patients (N = 41,074) diagnosed with colon cancer stage I to III from 2003 through 2010 from the Netherlands Cancer Registry were included. Age groups were defined as < 66, 66–75 and > 75 years of age. Main outcome measures were overall and relative survival, the latter as a proxy for disease specific survival.

Results

Over an eight years time period there was a 41.2% increase in patients with ≥ 12 lymph nodes removed, whereas the percentage of patients with the presence of lymph node metastases remained stable (35.7% to 37.5%). After adjustment for patient and tumour characteristics and adjuvant chemotherapy, it was found that for patients in which ≥ 12 lymph nodes were removed compared to patients with < 12 lymph nodes removed, there was a statistically significant higher overall survival (< 66: HR: 0.858 (95% CI, 0.789–0.933); 66–75: HR: 0.763 (95% CI, 0.714–0.814); > 75: HR: 0.734 (95% CI, 0.700–0.771)) and relative survival (< 66: RER: 0.783 (95% CI, 0.708–0.865); 66–75: RER: 0.672 (95% CI, 0.611–0.739); > 75: RER: 0.621 (95% CI, 0.567–0.681)) in all three age groups.

Conclusions

The removal of ≥ 12 lymph nodes is associated with an improvement in both overall and relative survival in all patients. This association was stronger in the elderly patient. The biology of this association needs further clarification.

Factors affecting number of lymph nodes harvested and the impact of examining a minimum of 12 lymph nodes in stage I-III colorectal cancer patients: a retrospective single institution cohort study of 1167 consecutive patients

BACKGROUND

To identify factors affecting the harvest of lymph nodes (LNs) and to investigate the association between examining a minimum of 12 LNs and clinical outcomes in stage I-III colorectal cancer (CRC) patients.

METHODS

The clinicopathologic features and the number of examined LNs for 1167 stage I-III CRC patients were analyzed to identify factors affecting the number of LNs harvested and the correlations between clinical outcomes and high harvests (≧12 LNs) and low harvests (<12 LNs).

RESULTS

A multivariate analysis showed that age (P = 0.007), tumor size (P = 0.030), and higher T stage (P = 0.001) were independent factors affecting the examinations of LNs in colon cancer and that tumor size (P = 0.015) was the only independent factor in rectal cancer. Patients with low harvests had poorer overall survival with stage II and stage III CRC (stage II: P < 0.0001; III: P = 0.001) and poorer disease-free survival for stages I-III (stage I: P = 0.023; II: P < 0.0001; III: P = 0.001).

CONCLUSIONS

The factors influencing nodal harvest are multifactorial, and an adequate number of examined LNs (≧12) is associated with a survival benefit. Removal of at least 12 LNs will determine the lymph node status reliably.

The prognostic value of lymph node ratio in colon cancer is independent of resection length

BACKGROUND

Lymph node ratio (LNR), the ratio of tumor-positive lymph nodes (+LN) to the total number of resected lymph nodes (rLN), predicts recurrence and survival in colon cancer. Variations in colonic resection length (RL) may influence rLN, +LN, or both, thereby potentially impacting LNR and its prognostic value in colon cancer.

METHODS

All colon cancer patients treated surgically at our center from 2004 to 2011 were included in an institutional review board-approved data repository (n = 1,039).

RESULTS

Larger RL was associated with increased rLN (ρ = .22; P < .001) but not with +LN (P = .21). In node-positive patients (n = 411), RL-adjusted LNR had weaker correlations with death (ρ = .338 vs .373, both P < .001) or metastatic disease (ρ = .303 vs .345; both P < .001) and a smaller area under the curve (death: .695 vs .715, metastasis: .675 vs .699). Findings were similar in segmental, extended segmental, and total colectomy subgroups.

CONCLUSIONS

Provided that resections are performed following standard oncologic principles, our analysis shows that RL does not significantly impact the prognostic value of LNR in colon cancer. Correcting LNR for RL seems redundant and may even act as noise distorting LNR values.

Assessment of lymph node involvement in colorectal cancer

Lymph node metastasis informs prognosis and is a key factor in deciding further management, particularly adjuvant chemotherapy. It is core to all contemporary staging systems, including the widely used tumor node metastasis staging system. Patients with node-negative disease have 5-year survival rates of 70%-80%, implying a significant minority of patients with occult lymph node metastases will succumb to disease recurrence. Enhanced staging techniques may help to identify this subset of patients, who might benefit from further treatment. Obtaining adequate numbers of lymph nodes is essential for accurate staging. Lymph node yields are affected by numerous factors, many inherent to the patient and the tumour, but others related to surgical and histopathological practice. Good lymph node recovery relies on close collaboration between surgeon and pathologist. The optimal extent of surgical resection remains a subject of debate. Extended lymphadenectomy, extra-mesenteric lymph node dissection, high arterial ligation and complete mesocolic excision are amongst the surgical techniques with plausible oncological bases, but which are not supported by the highest levels of evidence. With further development and refinement, intra-operative lymphatic mapping and sentinel lymph node biopsy may provide a guide to the optimum extent of lymphadenectomy, but in its present form, it is beset by false negatives, skip lesions and failures to identify a sentinel node. Once resected, histopathological assessment of the surgical specimen can be improved by thorough dissection techniques, step-sectioning of tissue blocks and immunohistochemistry. More recently, molecular methods have been employed. In this review, we consider the numerous factors that affect lymph node yields, including the impact of the surgical and histopathological techniques. Potential future strategies, including the use of evolving technologies, are also discussed.

Lymph nodes' evaluation in relation to colorectal cancer staging among African Americans

Background

Lymph nodes’ examination in colorectal cancer (CRC) resection specimens is an important determinant that aids in the accuracy of CRC staging and treatment outcomes. Current guidelines call for the examination of at least 12 lymph nodes (LN) in resected specimens in order to establish accurate staging.

Aim

To investigate lymph nodes’ examination protocol as it relates to accurate CRC staging.

Methods

We reviewed 216 African American CRC patients from 1996–2013 who underwent CRC resection and met inclusion criteria for this study. The number of retrieved LNs, length of resected specimens, tumor grade, stage, location, size and histology were examined.

Results

The cohort study was made of 49 % males, median age was 63 years and 45 % of patients were at stage III and IV. The median (IQR) number of examined LNs was 15 (10–22) and the rate of patients with more than 12 examined LNs was 64 %. There was a gradual increase in the percentage of patients with adequate number (>12) of examined LNs during the study period (from 60 % in 1996–2000 to 84 % in 2010–2013 period, P = 0.014). Adequate LNs resection was neither associated with shift of stage from II to III (P = 0.3) nor with the changes from stage IIIa to IIIc (P = 0.9). Metastatic LNs were observed in 8 % of samples with LNs (>12) vs. 13 % of samples with <12 examined LNs (P = 0.1). Patients that had pre-surgical treatment (chemotherapy and radiotherapy) before surgery had <12 LNs examined. There was also a trend of having more examined lymph nodes in large tumors.

Conclusions

Our study shows that there has been an increase in the number of lymph nodes examined in CRC resections since the advent of the current quality initiative. However this increase does not seem to affect the stage or percentage of metastatic lymph nodes’ detection in CRC patients.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

Prognostic value of lymph node ratio and extramural vascular invasion on survival for patients undergoing curative colon cancer resection

Background:

Increasing lymph node ratio (LNR) (ratio of metastatic lymph nodes to the total number of harvested lymph nodes) and extramural vascular invasion (EMVI) have been proposed as adverse prognostic indicators in colorectal cancer, although their use remains variable and controversial. The aim of the present study was to assess the prognostic value of LNR and EMVI in predicting survival for patients undergoing curative colon cancer resection.

Methods:

Between 2006 and 2012, 922 patients underwent curative colon cancer resection. Surgical technique and pathological assessment did not change during the study period. Clinical and pathological data were collected from a prospectively maintained database. The primary outcome measure was overall survival and disease-free survival. LNR was separated into five categories based on three previously calculated cutoff values: LNR 0 (no lymph nodes involved), LNR 1 (ratio 0.01<0.17), LNR 2 (ratio 0.18–0.41), LNR 3 (ratio 0.42–0.69), and LNR 4 (ratio >0.70).

Results:

Nine hundred and twenty-two patients underwent colon cancer resection. The median follow-up for survivors was 52.8 months (IQR 34.6–77.6). The median total number of lymph nodes harvested was 16 (IQR13-22). On multivariate analysis, both pN and LNR were strongly associated with overall and disease-free survival. Using the Akaike information criterion (AIC), LNR had greater prognostic value compared with pN. For overall survival, compared with patients in LNR category 0, hazard ratios (95% CI) for those in categories 1, 2, 3 and 4 were 1.37 (1.03,1.82), 2.37 (1.70,3.30), 2.40 (1.57,3.65) and 5.51 (3.16,9.58), respectively. For disease-free survival, patients had hazard ratios (95% CI) of 1.78 (1.25,2.52), 3.79 (2.56,5.61), 2.60 (1.50,4.48) and 4.76 (2.21,10.27), respectively. The presence of EMVI was a significant predictor of decreased overall and disease-free survival (P<0.001).

Conclusions:

This study demonstrated, in the presence of high surgical, oncology and pathological standards, EMVI and increasing LNR were independent predictors of decreased overall and disease-free survival for patients undergoing curative colon cancer resection. LNR was superior to pN stage in predicting overall and disease-free survival.

No change in lymph node positivity rate despite increased lymph node yield and improved survival in colon cancer

AIM

To analyse trends over time in the number of lymph nodes evaluated and in the proportion of node positivity and to investigate the impact on survival for patients with colon cancer.

PATIENTS AND METHODS

8616 patients resected for M0 colon cancer diagnosed in the southern Netherlands between 2000 and 2011 were included in this study. Trends in nodal evaluation and node positivity were analysed. Multivariable logistic regressions were used to assess the influence of period of diagnosis on adequate nodal evaluation (P12 lymph nodes) and no depositivity after adjusting for patient and tumour characteristics. Crude 5-year relative survival was used as an estimate for disease-specific survival.

RESULTS

Overall, the proportion adequate nodal evaluation increased from 13% in 2000–2002 to 59% in 2009–2011 (p < 0.0001), whereas the proportion node positivity remained similar across study periods (approximately 35%). Patients diagnosed in later periods were more likely to have received adequate nodal yield (adjusted Odds ratio (OR) 2009–2011 versus 2000–2002 9.8, 95% Confidence interval (CI) 8.3–11.6). However, the adjusted odds of having node positive disease did not differ between periods of diagnosis. Relative excess risk of dying was independently correlated with the number of lymph nodes evaluated (1–8 LNs versus P12 LNs, N0: 2.2, 95% CI 1.7–2.9; N+: 1.7, 95% CI 1.4–2.0) and period of diagnosis (2009–2011 versus 2000–2002, N+ only: 0.8, 95% CI 0.6–1.0).

CONCLUSION

The reason for improved survival with increased nodal yield is different from simple understaging as the proportion of lymph node positivity remained constant.

The role of adjuvant chemotherapy in stage II colorectal cancer patients

PURPOSE

Adjuvant chemotherapy use in stage II colorectal cancer (CRC) is debated. We evaluated the prognostic significance of clinicopathological features recommended by most guidelines for identifying high-risk stage II CRC and adjuvant chemotherapeutic response.

METHODS

We enrolled 1,039 stage II CRC patients who underwent curative surgery at Taipei Veterans General Hospital from January 2005 to December 2010. Seventy-seven patients who received radiotherapy were excluded. The endpoint was disease-free survival.

RESULTS

Of 962 patients, 37 had stage T4 tumors; 50, lymphovascular invasion; 39, poor differentiation; 249, preoperative carcinoembryonic antigen (CEA) levels >5 ng/mL; and 53 underwent emergent operations. One hundred ninety-four patients received 5-fluorouracil-based adjuvant chemotherapy. During a median follow-up period of 60.2 months, recurrence developed in 110 patients (11.4 %). The 5-year disease-free survival (DFS) was 87.6 %. In multivariate analysis, preoperative CEA >5 ng/ml (p = 0.001), emergent operation for obstruction/perforation (p = 0.008), lymphovascular invasion (p = 0.014), and T4 disease (p = 0.030) were significantly associated with poor DFS. High-risk stage II patients (n = 484) benefited from adjuvant chemotherapy (5-year DFS with and without adjuvant chemotherapy, 87.3 vs. 78.9 %; p = 0.028).

CONCLUSIONS

Adjuvant chemotherapy improved DFS in high-risk stage II CRC patients, but not in low-risk patients.

Lymph node count and prognosis in colorectal cancer: the influence of examination quality

Colorectal cancer guidelines recommend adjuvant chemotherapy in stage II disease when less than 12 lymph nodes are assessed. The recommendation bases on previous studies showing an association of a low lymph node count and adverse outcome. Compared to current standards, however, the quality of lymph node examination in the studies was low. We, therefore, investigated the prognostic role of <12 lymph nodes in cancers diagnosed adherent to current quality measures. Stage I-IV colorectal cancers from 1,899 patients enrolled into a population-based cohort study were investigated for the prognostic impact of a lymph node count <12. The stage specific share of patients diagnosed with ≥12 nodes (stage I-IV: 62, 85, 85, 78%, respectively) was used to compare lymph node examination quality to other studies. We found no impact of a lymph node count <12 on overall, cancer-specific or recurrence-free survival for any tumour stage. Compared to studies reporting an adverse prognostic impact of a low lymph node count in stages II and III the stage-specific shares of patients with ≥12 nodes were markedly higher in this study (85% vs. 24-58% in previous analyses) and this correlated with increased rates of stage III compared to stage II cancers. In conclusion our data indicate, that the previously reported effect of a low lymph node count on the patients' outcomes is eliminated by improved lymph node examination quality and thus question the general applicability of a 12 lymph node cut off for adjuvant chemotherapy decision making in stage II disease.

Increased lymph node yield in colorectal cancer is not necessarily associated with a greater number of lymph node positive cancers

The presence of lymph node metastasis is a key prognostic factor in colorectal cancer and lymph node yield is an important parameter in assessing the quality of histopathology reporting of colorectal cancer excision specimens. This study assesses the trend in lymph node evaluation over time in a single institution and the relationship with the identification of lymph node positive tumours. It compares the lymph node yield of a contemporary dataset compiled from the histopathology reports of 2178 patients who underwent surgery for primary colorectal cancer between 2005 and 2012 with that of a historic dataset compiled from the histopathology reports of 1038 patients who underwent surgery for colorectal cancer at 5 yearly intervals from 1975 to 2000. The mean lymph node yield was 14.91 in 2005 rising to 21.38 in 2012. In 2012 92.9% of all cases had at least 12 lymph nodes examined. Comparison of the mean lymph node yield and proportion of Dukes C cases shows a significant increase (Pearson correlation = 0.927, p = 0.001) in lymph node yield while there is no corresponding significant trend in the proportion of Dukes C cases (Pearson correlation =  -0.138, p = 0.745). This study shows that there is increasing yield of lymph nodes from colorectal cancer excision specimens. However, this is not necessarily associated with an increase number of lymph node positive cancers. Further risk stratifying of colorectal cancer requires consideration of other pathological parameters especially the presence of extramural venous invasion and relevant biomarkers.

Complete mesocolic resection and extended lymphadenectomy for colon cancer: a systematic review

AIM

Complete mesocolic excision (CME) and extended lympha-denectomy (EL) have been proposed as safe procedures for improving colon cancer survival outcomes. The aim of this study was to evaluate the evidence regarding oncological outcomes, morbidity and mortality after such techniques for colon cancer.

METHOD

A systematic review of the literature was conducted to evaluate evidence regarding oncological outcomes, morbidity and mortality after CME or EL. Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The review included original articles reporting outcomes after CME or EL from January 1950 to July 2012.

RESULTS

Twenty-one, predominately retrospective, studies involving 5246 patients (mean age 68.2 years, 56.5% men) were included. Reporting of outcomes was inconsistent. Median follow up was 60 months. The operative mortality rate was 3.2% and the cumulative morbidity rate was 21.5%. The weighted mean local recurrence rate and the 5-year overall and disease-free survival rates were 4.5%, 58.1% and 77.4%, respectively.

CONCLUSION

The available data for CME and EL have numerous fundamental limitations that prohibit adoption. Contemporary controlled studies are required before universal recommendation.

Lymph node retrieval in pancreaticoduodenectomy specimens: does educating the pathologist matter?

BACKGROUND

Many previous studies have suggested that the number of lymph nodes retrieved should serve as a benchmark for assessing the adequacy of the resection. The aim was to retrospectively observe the impact of nodal retrieval after educating the pathologist.

METHODS

Patients undergoing a pancreaticoduodenectomy (PD) between September 2005 and March 2009 were included in the study. The PDs performed between September 2005 and March 2008 were designated as Group A. The pathologists were educated regarding the importance of nodal counts in PD by the surgeon on the 1st April 2008. PDs performed between April 2008 and March 2009 were designated as Group B.

RESULTS

Ninety-eight PDs performed by a single surgeon (D.R.J.) for peri-ampullary malignancy were evaluated. The median number of lymph nodes retrieved in Group A was 11(3-32) nodes. The median number of lymph nodes retrieved in Group B was 22 (10-29) nodes (P < 0.001).The lymph node ratio (positive/total nodes), median number of positive nodes retrieved, and the node positivity (node positive compared to node negative) rate did not change.

DISCUSSION

A single intervention with the pathologists did impact the number of lymph nodes retrieved from PD specimens. However, the lymph node ratio and lymph node positivity rate remained unchanged. The pathologist is critical to nodal retrieval in PD, but the use of this lymph node number for benchmark of surgical adequacy may be simplistic.

Colorectal cancer and lymph nodes: The obsession with the number 12

Lymphadenectomy of colorectal cancer is a decisive factor for the prognostic and therapeutic staging of the patient. For over 15 years, we have asked ourselves if the minimum number of 12 examined lymph nodes (LNs) was sufficient for the prevention of understaging. The debate is certainly still open if we consider that a limit of 12 LNs is still not the gold standard mainly because the research methodology of the first studies has been criticized. Moreover many authors report that to date both in the United States and Europe the number “12” target is uncommon, not adequate, or accessible only in highly specialised centres. It should however be noted that both the pressing nature of the debate and the dissemination of guidelines have been responsible for a trend that has allowed for a general increase in the number of LNs examined. There are different variables that can affect the retrieval of LNs. Some, like the surgeon, the surgery, and the pathology exam, are without question modifiable; however, other both patient and disease-related variables are non-modifiable and pose the question of whether the minimum number of examined LNs must be individually assigned. The lymph nodal ratio, the sentinel LNs and the study of the biological aspects of the tumor could find valid application in this field in the near future.

Increasing the number of lymph nodes examined after colectomy does not improve colon cancer staging

BACKGROUND

Current quality initiatives call for examination of at least 12 lymph nodes in curative colon cancer resections. The aim of this study was to determine if the number of nodes harvested has increased, and if the increased number nodes correlates with improved staging or overall survival.

STUDY DESIGN

A review of the Surveillance, Epidemiology, and End Results program database from 2004-2010 was performed. All patients who underwent colon cancer resection during this date range were analyzed. Number of nodes retrieved, patient stage, overall survival, and overall survival by stage were examined. Multivariable analysis controlled for stage, cancer site, age, year of diagnosis, and number of nodes retrieved. Improved staging was defined as increased detection of stage III patients.

RESULTS

A total of 147,076 patients met inclusion criteria. Median number of nodes analyzed increased sequentially with each year examined, from 12 in 2004 to 17 in 2010. Despite greater number of total nodes obtained and analyzed, there was no increase in the percentage of patients with positive nodes (stage III disease). On multivariable analysis, after controlling for stage, site of disease, age, and year of diagnosis, there was a slight overall survival benefit with increasing nodal retrieval (hazard ratio = 0.987 for each additional node removed; 95% CI, 0.986-0.988; p < 0.001).

CONCLUSIONS

Since quality initiatives have been put in place, there has been an increase in the number of nodes examined in colon cancer resections, but no improvement in staging. The improved survival seen with higher node counts was independent of stage, site of disease, patient age, and year of diagnosis.

Lymph node evaluation in stage IIA colorectal cancer and its impact on patient prognosis: a population-based study

BACKGROUND

The analysis of regional lymph nodes is particularly relevant in patients with stage II colorectal cancer, in whom the role of adjuvant chemotherapy remains unclear. The aim of this study was to assess the relationship between number of examined lymph nodes and survival in patients with stage IIA (pT3N0M0) colorectal cancer, and to determine the optimal number of lymph nodes that should be examined.

METHODS

The study group included all the surgically-treated colorectal cancer patients in stage IIA (n = 657) who were identified through the population-based Cancer Registry of the Province of Modena (Northern Italy), during the period 2002-2006.

RESULTS

The median number of harvested lymph nodes was 19 (range 1-68). Considering, as a reference point, patients with 12 or less lymph nodes, subjects with n ≥ 20 lymph nodes examined showed, in univariate analysis, a significantly higher cancer specific (p = 0.01) and relapse-free survival (p = 0.003). The results were confirmed by multivariate analysis (Cox model).

CONCLUSION

The result suggests that colorectal cancer patients in stage IIA with n ≥ 20 lymph nodes examined exhibit better survival when compared with subjects in whom fewer lymph nodes were examined. The number of 20 lymph nodes is the essential requirement for an oncologic resection of the large bowel.