Accuracy of determining nodal negativity in colorectal cancer on the basis of the number of nodes retrieved on resection

Sufficient Regional Lymph Node Examination for Staging Adenocarcinoma of the Appendix

BACKGROUND

The presence of lymph node (LN) metastasis is a known negative prognostic factor in appendix cancer (AC) patients. However, currently the minimum number of LNs required to adequately determine LN negativity is extrapolated from colorectal studies and data specific to AC is lacking. We aimed to define the lowest number of LNs required to adequately stage AC and assess its impact on oncologic outcomes.

METHODS

Patients with stage II-III AC from the National Cancer Database (NCDB 2004-2019) undergoing surgical resection with complete information about LN examination were included. Multivariable logistic regression assessed the odds of LN positive (LNP) disease for different numbers of LNs examined. Multivariable Cox regressions were performed by LN status subgroups, adjusted by prognostic factors, including grade, histologic subtype, surgical approach, and documented adjuvant systemic chemotherapy.

RESULTS

Overall, 3,602 patients were included, from which 1,026 (28.5%) were LNP. Harvesting ten LNs was the minimum number required without decreased odds of LNP compared with the reference category (≥ 20 LNs). Total LNs examined were < 10 in 466 (12.9%) patients. Median follow-up from diagnosis was 75.4 months. Failing to evaluate at least ten LNs was an independent negative prognostic factor for overall survival (adjusted hazard ratio 1.39, p < 0.01).

CONCLUSIONS

In appendix adenocarcinoma, examining a minimum of ten LNs was necessary to minimize the risk of missing LNP disease and was associated with improved overall survival rates. To mitigate the risk of misclassification, an adequate number of regional LNs must be assessed to determine LN status.

Colorectal resections for malignancy: A pilot study comparing conventional vs freehand robot-assisted laparoscopic colectomy

BACKGROUND

Laparoscopic colectomy is widely accepted as a safe operation for colorectal cancer, but we have experienced resistance to the introduction of the FreeHand® robotic camera holder to augment laparoscopic colorectal surgery.

AIM

To compare the initial results between conventional and FreeHand® robot-assisted laparoscopic colectomy in Trinidad and Tobago.

METHODS

This was a prospective study of outcomes from all laparoscopic colectomies performed for colorectal carcinoma from November 29, 2021 to May 30, 2022. The following data were recorded: Operating time, conversions, estimated blood loss, hospitalization, morbidity, surgical resection margins and number of nodes harvested. All data were entered into an excel database and the data were analyzed using SPSS ver 20.0.

RESULTS

There were 23 patients undergoing colectomies for malignant disease: 8 (35%) FreeHand®-assisted and 15 (65%) conventional laparoscopic colectomies. There were no conversions. Operating time was significantly lower in patients undergoing robot-assisted laparoscopic colectomy (95.13 ± 9.22 vs 105.67 ± 11.48 min; P = 0.045). Otherwise, there was no difference in estimated blood loss, nodal harvest, hospitalization, morbidity or mortality.

CONCLUSION

The FreeHand® robot for colectomies is safe, provides some advantages over conventional laparoscopy and does not compromise oncologic standards in the resource-poor Caribbean setting.

A 3 M Evaluation Protocol for Examining Lymph Nodes in Cancer Patients: Multi-Modal, Multi-Omics, Multi-Stage Approach

Through meticulous examination of lymph nodes, the stage and severity of cancer can be determined. This information is invaluable for doctors to select the most appropriate treatment plan and predict patient prognosis; however, any oversight in the examination of lymph nodes may lead to cancer metastasis and poor prognosis. In this review, we summarize a significant number of articles supported by statistical data and clinical experience, proposing a standardized evaluation protocol for lymph nodes. This protocol begins with preoperative imaging to assess the presence of lymph node metastasis. Radiomics has replaced the single-modality approach, and deep learning models have been constructed to assist in image analysis with superior performance to that of the human eye. The focus of this review lies in intraoperative lymphadenectomy. Multiple international authorities have recommended specific numbers for lymphadenectomy in various cancers, providing surgeons with clear guidelines. These numbers are calculated by applying various statistical methods and real-world data. In the third chapter, we mention the growing concern about immune impairment caused by lymph node dissection, as the lack of CD8 memory T cells may have a negative impact on postoperative immunotherapy. Both excessive and less lymph node dissection have led to conflicting findings on postoperative immunotherapy. In conclusion, we propose a protocol that can be referenced by surgeons. With the systematic management of lymph nodes, we can control tumor progression with the greatest possible likelihood, optimize the preoperative examination process, reduce intraoperative risks, and improve postoperative quality of life.

The pathological role of C-X-C chemokine receptor type 4 (CXCR4) in colorectal cancer (CRC) progression; special focus on molecular mechanisms and possible therapeutics

Colorectal cancer (CRC) is comprised of transformed cells and non-malignant cells including cancer-associated fibroblasts (CAF), endothelial vasculature cells, and tumor-infiltrating cells. These nonmalignant cells, as well as soluble factors (e.g., cytokines), and the extracellular matrix (ECM), form the tumor microenvironment (TME). In general, the cancer cells and their surrounding TME can crosstalk by direct cell-to-cell contact and via soluble factors, such as cytokines (e.g., chemokines). TME not only promotes cancer progression through growth-promoting cytokines but also provides resistance to chemotherapy. Understanding the mechanisms of tumor growth and progression and the roles of chemokines in CRC will likely suggest new therapeutic targets. In this line, a plethora of reports has evidenced the critical role of chemokine receptor type 4 (CXCR4)/C-X-C motif chemokine ligand 12 (CXCL12 or SDF-1) axis in CRC pathogenesis. In the current review, we take a glimpse into the role of the CXCR4/CXCL12 axis in CRC growth, metastasis, angiogenesis, drug resistance, and immune escape. Also, a summary of recent reports concerning targeting CXCR4/CXCL12 axis for CRC management and therapy has been delivered.

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.

Exploration of a modified stage for pN0 colon cancer patients

Exploring a modified stage (mStage) for pN0 colon cancer patients. 39,637 pN0 colon cancer patients were collected from the SEER database (2010–2015) (development cohort) and 455 pN0 colon cancer patients from the Second Affiliated Hospital of Harbin Medical University (2011–2015) (validation cohort). The optimal lymph nodes examined (LNE) stratification for cancer-specific survival (CSS) was obtained by X-tile software in the development cohort. LNE is combined with conventional T stage to form the mStage. The novel N stage was built based on the LNE (N0a: LNE ≥ 26, N0b: LNE = 11–25 and N0c: LNE ≤ 10). The mStage include mStageA (T1N0a, T1N0b, T1N0c and T2N0a), mStageB (T2N0b, T2N0c and T3N0a), mStageC (T3N0b), mStageD (T3N0c, T4aN0a and T4bN0a), mStageE (T4aN0b and T4bN0b) and mStageF (T4aN0c and T4bN0c). Cox regression model showed that mStage was an independent prognostic factor. AUC showed that the predictive accuracy of mStage was better than the conventional T stage for 5-year CSS in the development (0.700 vs. 0.678, P < 0.001) and validation cohort (0.649 vs. 0.603, P = 0.018). The C-index also showed that mStage had a superior model-fitting. Besides, calibration curves for 3-year and 5-year CSS revealed good consistencies between observed and predicted survival rates. For pN0 colon cancer patients, mStage might be superior to conventional T stage in predicting the prognosis.

Outcomes of Non-metastatic Colon Cancer: A Single-Center Experience

Background

Colorectal cancer (CRC) is the most common gastrointestinal cancer. In the Saudi Cancer Registry, CRC ranked as the most common cancer in men and the third most common cancer in women. Data regarding the stage of CRC at presentation and patient demographics and outcomes in Saudi Arabia are lacking. This study aimed to investigate the prevalence, survival, and mortality rates of patients with non-metastatic CRC in a tertiary care hospital in Saudi Arabia. 

Methods

We conducted a retrospective chart review of patients diagnosed with adenocarcinoma of the colon or rectum at King Abdulaziz University Hospital between 2013 and 2017. Patients aged ≥18 years who presented with non-metastatic CRC and underwent curative resection were included. Patients with rectal cancer or metastatic colon cancer were excluded. Data on demographic characteristics, histopathological findings, tumor-node-metastasis stage, biomarkers, and surgical interventions were collected. Recurrence-free survival was defined as the time from surgery to the date of recurrence or death. All statistical analyses were performed using Stata/IC 15.1 (StataCorp, College Station, TX, USA).

Results

Among 260 patients diagnosed with CRC, 82 were included based on the inclusion/exclusion criteria. Among those patients, 65.9% were men and 47.5% were Saudi citizens. The mean age at the time of diagnosis was 60.8 years. Fifty-three patients (64.6%) had left-sided colon cancer. The mean tumor diameter was 52.6 mm. Most colon tumors were T3 lesions (71.3%), and 41% of patients did not have lymph node involvement (N0). Most patients (85.1%) underwent open surgery. In the multivariate analysis, only resection margin status and N stage (hazard ratio: 17.7 and 3.7, respectively) were identified as statistically significant factors affecting the recurrence-free survival. The one-, two-, and five-year recurrence-free rates were 80.5%, 66.5%, and 57.1%, respectively, and the one-, two-, and five-year and overall survival rates were 90.3%, 82.5%, and 82.5%, respectively.

Conclusions

We showed significant reductions in recurrence-free and overall survival within the first two years after surgical resection. Further prospective studies are needed to explore predictors.

Prognostic impact of the number of resected lymph node on survival in Colorectal Cancer

Introduction Colorectal Cancer (CRC) is the third most common cancer and the second leading cause of death in Western countries. In Portugal, in the North, emerges as the second most common cancer. The presence of lymph node metastasis is an important predictor of overall and disease-free survival and several studies recommend the evaluation of at least 12–14 regional lymph nodes, as it contributes to improve cancer staging and patient outcomes.

Aims Epidemiological characterization of the studied population and identify a possible relationship between the number of lymph nodes evaluated in the surgical specimen and survival.

Methods We preceded to the study of 1065 CCR patients, submitted to surgical resection between 1 January 2000 and 31 August 2012, in Braga Hospital.

Discussion/Conclusion The results of the epidemiological characterization of this population are coincident with those described in the literature. It was observed a significant correlation between age, tumor size, serosal invasion, differentiation, tumor penetration, venous and lymphatic invasion, metastasis, TNM stage and the number of lymph nodes evaluated. However, we did not observe a statistically significant correlation between patient survival and number of lymph nodes evaluated (p > 0.05). A possible explanation is the practice of oncologists, addressing patients with less than 12 nodes identified in the surgical specimen as “N-positive” and undergoing adjuvant therapy. A better harvest and careful analysis of lymph nodes would lead to more accurate staging, avoiding overtreatment and side effects associated, and allow better economic management of hospital resources, in real N0 patients.

Prognostic significance of lymph node yield in patients with synchronous colorectal carcinomas

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines recommend examination of a minimum of 12 lymph nodes (LNs) for accurate staging of a single case of colorectal cancer. However, the guidelines do not support the examination of LNs in synchronous colorectal carcinoma (SCC). This study aimed to investigate the association between lymph node yield and the prognosis of SCC patients.

METHODS

Synchronous colorectal carcinoma patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database over a 10-year interval (2004 to 2013). Systematic dichotomization for optimal cut-off point identification was performed using X-tile. The baseline for the two LNs groups generated was balanced using the propensity score matching (PSM) method.

RESULTS

A total of 4616 patients met the inclusion criteria. The cut-off number for lymph node retrieved from a single patient was 15 and 12 for the first- and second-time diagnosis of SCC, respectively. Age, T category, N category, tumor grade, tumor site, tumor size, and radiation sequence were not balanced in the two groups. After adjusting the baseline in the two groups, the same results were observed. Age, T category, N category, tumor site had a partial effect on lymph node yield. There might be some biological characteristics of the tumor that influence lymph node yield.

CONCLUSIONS

Retrieval of fewer than 15 LNs at the first time of SCC diagnosis indicates worse SCC prognosis. Because factors such as manner of surgical examination influence SCC prognosis, specimens should be preserved for at least 6 months to enable reevaluation should there be a need. Irb: IRB approval is not required because the SEER data are freely accessible.

A retrospective study on the impact of the number of resected lymph nodes on the survival outcome of stage IV rectal cancer patients after preoperative therapy

Background

There is no consensus on the optimal number of examined LNs for stage IV rectal cancer patients after preoperative therapy. We aimed to explore the impact of the number of resected lymph nodes (LNs) on the survival outcomes of stage IV rectal cancer patients after preoperative therapy.

Methods

Clinicopathologic data of 556 patients diagnosed with stage IV rectal cancer between 1st January, 2010 and 31st December, 2015 from the Surveillance, Epidemiology, and End Results (SEER) database after preoperative therapy were reviewed. The patients were further divided into two groups: the ≥15 resected LNs group and <15 resected LNs group based on the X-tile software analysis results of the number of resected LNs.

Results

Both univariate and multivariate regression analyses revealed that the number of resected LNs and N status were significantly positively correlated with the survival outcome of the patients. Patients in the ≥15 resected LNs group had a significant better cancer-specific survival (CSS) (P=0.003) than those in the <15 resected LNs group. The 3-year CSS rate was 63.2% for patients with ≥15 resected LNs compared with 55.7% for those with <15 resected LNs. The 5-year CSS rate was 50.2% and 30.5% for patients in the ≥15 resected LNs group and those in the <15 resected LNs group, respectively.

Conclusions

The number of resected LNs is an important independent prognostic factor that influences the survival outcome of stage IV rectal cancer patients after receiving preoperative therapy.

The quality of lymph node harvests in extralevator abdominoperineal excisions

Background

Lymph node (LN) harvest in colorectal cancer resections is a well-recognised prognostic factor for disease staging and determining survival, particularly for node-negative (N0) diseases. Extralevator abdominoperineal excisions (ELAPE) aim to prevent “waisting” that occurs during conventional abdominoperineal resections (APR) for low rectal cancers, and reducing circumferential resection margin (CRM) infiltration rate. Our study investigates whether ELAPE may also improve the quality of LN harvests, addressing gaps in the literature.

Methods

This retrospective observational study reviewed 2 sets of 30 consecutive APRs before and after the adoption of ELAPE in our unit. The primary outcomes are the total LN counts and rates of meeting the standard of 12-minimum, particularly for those with node-negative disease. The secondary outcomes are the CRM involvement rates. Baseline characteristics including age, sex, laparoscopic or open surgery and the use of neoadjuvant chemoradiotherapy were accounted for in our analyses.

Results

Median LN counts were slightly higher in the ELAPE group (16.5 vs. 15). Specimens failing the minimum 12-LN requirements were almost significantly fewer in the ELAPE group (OR 0.456, P = 0.085). Among node-negative rectal cancers, significantly fewer resections failed the 12-LN standard in the ELAPE group than APR group (OR 0.211, P = 0.044). ELAPE led to a near-significant decrease in CRM involvement (OR 0.365, P = 0.088). These improvements were persistently observed after taking into account baselines and potential confounders in regression analyses.

Conclusion

ELAPE provides higher quality of LN harvests that meet the 12-minimal requirements than conventional APR, particularly in node-negative rectal cancers. The superiority is independent of potential confounding factors, and may implicate better clinical outcomes.

Minimally invasive complete mesocolic excision and central vascular ligation (CME/CVL) for right colon cancer

Total mesorectal excision (TME) is the standard of care in rectal cancer surgery. Complete mesocolic excision and central vascular ligation (CME and CVL) are surgical concepts that are extrapolated from the principles of TME. Increasingly adopted by surgical units worldwide, laparoscopic CME/CVL for right sided colon cancer is a challenging procedure that requires meticulous dissection by the surgeon and detailed knowledge of the colonic vascular anatomy. This review article addresses the main issues pertaining to this surgical technique and also discusses steps on how to perform this operation safely.

Harvest of at least 18 lymph nodes is associated with improved survival in patients with pN0 colon cancer: a retrospective cohort study

PURPOSE

To investigate the correlation between number of retrieved lymph nodes (rLNs) and prognosis and further ascertain the optimal number of rLNs with a beneficial survival impact in patients with pN0 colon cancer.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was searched for pN0 colon cancer cases. X-Tile software and Kaplan-Meier survival analysis were applied to determine the optimal number of rLNs based on the minimal probability (P) value and the largest χ² value. Univariate analyses and Cox proportional hazard regression model were used to investigate the relationship between rLN number and overall survival. Multiple analyses were conducted to assess the prognostic predictive ability of the identified optimal rLN cut-off value under different stratifications. Nomograms were established based on the independent prognostic factors selected by the multivariate analysis to predict 3- and 5-year overall survival rates of pN0 patients.

RESULTS

A total of 6269 pN0 colon cancer patients who underwent surgical therapy were finally included for analysis. Harvest of at least 18 lymph nodes was determined as the optimal rLN number. This cut-off rLN value (< 18 versus ≥ 18) was identified as an independent prognostic factor (P < 0.001) of overall survival via multivariate analysis. Similar findings were obtained in patients with retrieval of at least 12 lymph nodes (18 > rLNs ≥ 12 versus rLNs ≥ 18) stratified into several groups.

CONCLUSIONS

The number of rLNs was identified as an independent prognostic factor for pN0 colon cancer. Retrieval of at least 18 lymph nodes was associated with favorable prognosis in patients with pN0 colon cancer, and should, therefore, be regarded as an alternative cut-off value for survival analysis.

Robotic complete mesocolic excision using indocyanine fluorescence imaging in colorectal cancer: A case study and technical approach

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Complete mesocolic excision confers a possible survival advantage in right sided colorectal cancer.

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Indocynanine Green (ICG) Fluorescence Imaging may allow for more targeted lymph node clearances.

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Robotic surgery allows for these nodes to be removed with an MIS approach.

Introduction

Colorectal cancer is the second most common malignancy in developed countries and accurate staging is vital for determining the most appropriate management plan, in particular, whether adjuvant chemotherapy is recommended in addition to surgical resection. There is currently no consensus regarding standard practice for lymph node resection in colorectal cancer although there is increasing evidence to support the use of sentinel lymph node mapping to target lymph node sampling and facilitate ultra-staging of nodes.

Presentation of case

We present the case of a 49 year old female who underwent a robotic right hemicolectomy and complete mesocolic excision for caecal adenocarcinoma using indocyanine fluorescence imaging (ICG FI) to guide nodal dissection.

Discussion

ICG FI may be useful for sentinel lymph node mapping in colorectal cancer. This technique can assist to identify the first draining lymph nodes and permit ultra-staging of lymph nodes.

Conclusion

While there is still limited evidence to support ICG FI, the current body of literature suggests that it is likely to be a feasible and sensitive technique for guiding sentinel lymph node sampling in colorectal cancer.

Impact of negative lymph nodes on colon cancer survival and exploring relevant transcriptomics differences through real-world data analyses

Background

The prognostic role and underlying heterogeneity of negative lymph nodes (NLNs) on colon cancer is not well understood. The purpose of this study was to construct NLN-based prognostic models and reveal relevant mechanisms affecting NLNs by analyzing omic data.

Methods

This inception cohort study included 314,398 colon cancer patients from the US Surveillance, Epidemiology, and End Results (SEER) database. Receiver operating characteristic (ROC) curve was used to determine the cut-off of NLNs. Nomograms were constructed and validated using SEER data and the Cancer Genome Atlas (TCGA) data, respectively. The differentially expressed genes (DEGs) were analyzed using edgeR. Enrichment analyses were performed by Metascape.

Results

Multivariate analysis confirmed the high NLN had improved cancer-specific survival (CSS) and overall survival (OS) compared to low NLN [hazard ratio (HR) =0.610, 95% confidence interval (CI), 0.601-0.620] for CSS and (HR =0. 682, 95% CI, 0.674-0.690) for OS. Nomograms were established for CSS and OS with the c-statistic 0.790 (95% CI, 0.788-0.792) for CSS and 0.734 (95% CI, 0.732-0.736) for OS. High NLN was associated with less B cell (P=0.002) and macrophage infiltration (P<0.0001), high microsatellite instability (MSI) (OR =4.325, P=0.001), and hypermutation (OR =4.285, P=0.001; high vs. low). Transcriptomics analysis demonstrated histone modifiers were the most significant different biological processes between the high and low NLN group.

Conclusions

The NLN-based models can aid in personalized risk stratification for colon cancer. This study postulates that high NLN may represent a biological subtype with less macrophage infiltration, high MSI status, hypermutation, and histone modifier gene enriched expression, and thus warrants further investigation.

Accuracy of nodal staging is influenced by sidedness in colon cancer

Background

Adequate lymph node (LN) sampling is critical for accurate nodal staging in colon cancer (CC), particularly for T3N0 disease as current guidelines recommend considering adjuvant chemotherapy when less than 12 LNs are examined. The impact of sidedness on nodal staging accuracy in patients with T3N0 disease has not been previously studied.

Methods

Patients with pathologic T3 CC were identified from a prospective multicenter international trial of ultrastaging in CC. The probability of true nodal negativity (TNN) based on the number of LN examined was calculated for right and left CC. These results were then validated in a cohort of patients with similar inclusion criteria selected from the National Cancer Database (NCDB) between 2006 and 2014.

Results

Three hundred and seventy patients met the inclusion criteria in the trial cohort; 48% were LN-negative. Of 153,945 patients in the NCDB, 57% were LN-negative. The probability of TNN when 12 LNs were examined was 68% for right and 64% for left CC in the trial cohort and 77% and 72% in the NCDB. The number of LNs needed to achieve any given probability of TNN was significantly different between right and left CC in both the trial (P<0.001) and the NCDB (P<0.001).

Conclusions

In both a prospective multicenter trial and the NCDB, sidedness influences the number of LNs needed to predict nodal negativity in CC. Current guidelines regarding the minimum number of LNs needed to accurately stage patients with T3N0 CC may need to be re-evaluated by taking into consideration the tumor sidedness.

Nomograms predicting survival and recurrence in colonic cancer in the era of complete mesocolic excision

Background

More extensive lymphadenectomy may improve survival after resection of colonic cancer. Nomograms were created predicting overall survival and recurrence for patients who undergo D2-D3 lymph node dissection, and their validity determined.

Methods

This was a multicentre study of patients with colonic cancer who underwent resection with D2-D3 lymph node dissection in Japan. Inclusion criteria included R0 resection. A training cohort of patients operated on from 2007 to 2008 was analysed to construct prognostic models predicting survival and recurrence. Discrimination and calibration were performed using an external validation cohort from the Japanese colorectal cancer registry (procedures in 2005-2006).

Results

The training cohort consisted of 2746 patients. Predictors of survival were: age (hazard ratio (HR) 1·04), female sex (HR 0·71), depth of tumour invasion (HR 1·15, 1·22, 2·96 and 3·14 for T2, T3, T4a and T4b respectively versus T1), lymphatic invasion (HR 1·11, 1·15 and 2·95 for ly1, ly2 and ly3 versus ly0), preoperative carcinoembryonic antigen (CEA) level (HR 1·21, 1·59 and 1·99 for 5·1-10·0, 10·1-20·0 and 20·1 and over versus 0-5·0 ng/ml), number of metastatic lymph nodes (HR 1·07), number of lymph nodes examined (HR 0·98) and extent of lymphadenectomy (HR 0·23, 0·13 and 0·11 for D1, D2 and D3 versus D0). Predictors of recurrence were: female sex (HR 0·82), macroscopic type (HR 3·82, 4·56, 6·66, 7·74 and 3·22 for types I, II, III, IV and V versus type 0), depth of invasion (HR 1·25, 2·66, 5·32 and 6·43 for T2, T3, T4a and T4b versus T1), venous invasion (HR 1·43, 3·05 and 4·79 for v1, v2 and v3 versus v0), preoperative CEA level (HR 1·39, 1·43, 1·56 and 1·85 for 5·1-10·0, 10·1-20·0, 20·1-40·0 and 40·1 or more versus 0-5 ng/ml), number of metastatic lymph nodes (HR 1·07) and number of lymph nodes examined (HR 0·98). The validation cohort comprised 4446 patients. The internal and external validated Harrell's C-index values for the nomogram predicting survival were 0·75 and 0·74 respectively. Corresponding values for recurrence were 0·78 and 0·75.

Conclusion

These nomograms could predict survival and recurrence after curative resection of colonic cancer.

Modelling the probability of erroneous negative lymph node staging in patients with colon cancer

BACKGROUND

Patients in who with insufficient number of analysed lymph nodes (LNs) are more likely to receive an incorrect LN staging. The ability to calculate the overall probability of undiagnosed LN involvement errors in these patients could be very useful for approximating the real patient prognosis and for giving possible indications for adjuvant treatments. The objective of this work was to establish the predictive capacity and prognostic discriminative ability of the final error probability (FEP) among patients with colon cancer and with a potentially incorrectly-staged LN-negative disease.

METHODS

This was a retrospective multicentric population study carried out between January 2004 and December 2007. We used a mathematical model based on Bayes' theorem to calculate the probability of LN involvement given a FEP test result. Cumulative sum graphs were used to calculate risk groups and the survival rates were calculated, by month, using the Kaplan-Meier method.

RESULTS

A total of 548 patients were analysed and classified into three risk groups according to their FEP score: low-risk (FEP < 2%), intermediate-risk (FEP 2%-15%), and high-risk (FEP > 15%). Patients with LN involvement had the lowest overall survival rate when compared to the three risk groups. This difference was statistically significant for the low- and intermediate-risk groups (P = 0.002 and P = 0.004, respectively), but high-risk group presented similar survival curves to pN+ group (P = 0.505). In terms of disease-free survival, the high-risk group presented similar curves to the intermediate-risk group until approximately 60 months' follow-up (P = 0.906). After 80 months' follow-up, the curve of high-risk group coincided with that of the pN+ group (P = 0.172). Finally, we summarized the FEP according to the number of analysed LNs and accompanied by a contour plot which represents its calculation graphically.

CONCLUSIONS

The application of Bayes' theorem in the calculation of FEP is useful to delimit risk subgroups from among patients without LN involvement.

The relation between oncologic outcomes and metastatic lymph node location following laparoscopic resection of stage III colon cancer

PURPOSE

Colon cancers are staged by assessing more than 12 lymph nodes, but there is still a controversy over the number of lymph nodes. Only a few studies of metastatic lymph node position in colon cancer have been published with its significance not completely understood. This study aimed to compare survival rates according to metastatic lymph node position following radical lymph node dissection for stage III colon cancers.

METHODS

This retrospective study evaluated data prospectively collected at a tertiary teaching hospital from 349 patients who underwent laparoscopic colectomy with radical node dissection between December 2009 and December 2014. Lymph nodes were numbered and classified into lymph node metastasis (LNM) groups LNM1, LNM2, and LNM3 and their short- and long-term outcomes were compared.

RESULTS

The LNM1, LNM2, and LNM3 groups included 229, 94, and 26 patients, respectively. Patient characteristics differed by locations (p < 0.001). A mean 34.6 lymph nodes were harvested, and a mean 2.6, 5, and 9 metastatic nodes were identified, respectively (p < 0.001), a finding that is proportional to the cancer stage (tau-b = 0.284, p < 0.001; rho = 0.3, p < 0.001). The 5-year disease-free survival rate did not differ among the three groups; however, the LNM3 group had the poorest overall and cancer-specific survival rates. Risk factors associated with cancer-specific survival rate were identified with neural invasion, poorly differentiated tumors, and the location of pathologic lymph nodes (LNM).

CONCLUSION

Metastatic lymph node location affects oncologic outcomes of stage III colon cancer. The patients for LNM3 metastasis should receive a more aggressive adjuvant treatment.

Carnoy's solution fixation with compression significantly increases the number of lymph nodes yielded from colorectal cancer specimens

BACKGROUND AND OBJECTIVES

Carnoy's fixation and compression represents a novel technique to enhance lymph node evaluation and accuracy of staging after colorectal cancer resection.

METHODS

This study was performed in all adults undergoing colorectal cancer operations by Kaiser Permanente surgeons at two separate facilities. Patients were assigned to either location based upon surgeon and patient availability. One group of patients had their lymph nodes examined with current standard manual technique (MT). The other group had their specimens fixed with Carnoy's solution and then compressed (CT) to assess for lymph nodes.

RESULTS

A total of 157 patients were enrolled. Seventy-eight patient specimens underwent MT and 79 patient specimens underwent the new compression technique (CT). CT resulted in a significant increase in total lymph node yield per specimen (37.6 ± 18.5 nodes with CT vs 18.9 ± 8.8 nodes with MT; P < 0.0001). CT also resulted in sufficient lymph node sampling (>12 nodes) in all 79 patients in the group compared with 13 of 78 patients (17%) with an insufficient lymph node evaluation in the MT group ( P = 0.0002).

CONCLUSION

This study demonstrated that Carnoy's fixation with compression can significantly increase lymph node yields in colorectal cancer specimens and allow for a higher rate of adequate lymph node sampling.

The Number of Natural Killer Cells in the Largest Diameter Lymph Nodes Is Associated with the Number of Retrieved Lymph Nodes and Lymph Node Size, and Is an Independent Prognostic Factor in Patients with Stage II Colon Cancer

OBJECTIVE

We previously reported that the largest diameter of retrieved lymph nodes (LNs) correlates with the number of LNs and is a prognostic factor in stage II colon cancer. We examine whether T, B, and natural killer (NK) cells in LNs are related to the number of LNs and survival.

METHODS

The subjects comprised 320 patients with stage II colon cancer. An LN with the largest diameter was selected in each patient. The positive area ratios of cells that stained for CD3 and CD20, and the numbers of CD56-positive cells were measured.

RESULTS

The CD3-positive area ratio was 0.39 ± 0.08 and CD20-positive area ratio was 0.42 ± 0.10. The mean number of CD56-positive cells was 19.3 ± 22.7. The area ratios of B cells and T cells and the number of NK cells were significantly related to the sizes of the largest diameter LNs. The number of NK cells significantly correlated with the number of LNs and was an independent prognostic factor. On multivariate analysis, pathological T stage (T4 or T3; HR 4.71; p < 0.001) and the number of CD56-positive cells (high or low; HR 0.22; p < 0.001) were found to be independent prognostic factors.

CONCLUSIONS

The number of NK cells in the largest diameter LNs can most likely be used as a predictor of recurrence.

Lymph node ratio is an independent prognostic factor for rectal cancer after neoadjuvant therapy: A meta-analysis

OBJECTIVE

With neoadjuvant therapy increasingly used in advanced rectal cancer, the lymph node ratio (LNR) has been strongly considered to indicate cancer-specific survival in recent years, and a comprehensive evaluation of a large number of studies is deficient. The objective of our study is to pool enough eligible studies to assess the relationship between LNR and prognosis of advanced rectal cancer after neoadjuvant therapy.

METHODS

A systematic search was done in the PubMed and EmBase databases (through 1 March 2017) that reported LNR in colorectal cancer after neoadjuvant therapy. The first two authors independently conducted the study selection and data extraction. All statistical analyses were conducted using STATA 13.0 (College Station, Texas).

RESULTS

Thirteen studies with 4023 participants were included in the meta-analysis, and all were published after 2011. A high LNR was assessed to be a predictor of poor overall survival in rectal cancer after neoadjuvant therapy (HR: 2.94, 95% CI:1.97 to 3.91, P < 0.001). Similarly, a high LNR was related to poor disease-free survival (HR: 2.83, 95% CI: 1.82 to 3.85, P < 0.001). With respect to recurrence, the HRs of 3.25, 1.93, and 2.11 also showed a strong relationship between high LNR and poor local, distant, and total recurrences.

CONCLUSIONS

Our present study demonstrates that a high LNR can predict poor survival in advanced rectal cancer. We suggest well-designed clinical trials to prospectively assess LNR as an independent predictor of rectal cancer survival.

Reconsideration of the optimal minimum lymph node count for young colon cancer patients: a population-based study

BACKGROUND

Currently, young colon cancer (CC) patients continue to increase and represent a heterogeneous patient group. The aim of this study was to explore the optimal minimum lymph node count after CC resection for young patients.

METHODS

We performed a comprehensive search of the Surveillance, Epidemiology, and End Results (SEER) database, 2360 CC patients aged from 20 to 40 were analyzed. X-tile was used to determine the optimal cut-off point of lymph node based on survival outcomes of young patients. The cancer specific survival (CSS) was estimated with Kaplan-Meier method, the Cox proportional hazards regression model was used to analyse independent prognostic factors and exact 95% confidence intervals (CIs).

RESULTS

Using X-tile analysis, 22-node measure was identified as the optimal choice for CC patients aged < 40. The 5-year CSS were 85.8% and 80.9% for patients examining ≥22 nodes and < 22 nodes. Furthermore, we identified that examining < 22 nodes was an independent adverse prognostic factor in patients aged < 40. In addition, the revised 22-node measure could examine more positive nodes than the standard 12-node measure in young patients.

CONCLUSIONS

For young colon cancer patients, the lymph node examination should be differently evaluated. We suggest that 22-node measure may be more suitable for CC patients aged < 40.

TRIAL REGISTRATION

Retrospectively registered.

Prognostic value of total number of lymph nodes retrieved differs between left-sided colon cancer and right-sided colon cancer in stage III patients with colon cancer

Background

The consensus is that a minimum of 12 lymph nodes should be analyzed at colectomy for colon cancer. However, right colon cancer and left colon cancer have different characteristics, and this threshold value for total number of lymph nodes retrieved may not be universally applicable.

Methods

The data of 63,243 patients with colon cancer treated between 2004 and 2012 were retrieved from the National Cancer Institute’s Surveillance, Epidemiology, and End Results database. Multivariate Cox regression analysis was used to determine the predictive value of total number of lymph nodes for survival after adjusting for lymph nodes ratio. The predictive value in left-sided colon cancer and right-sided colon cancer was compared. The optimal total number of lymph nodes cutoff value for prediction of overall survival was identified using the online tool Cutoff Finder. Survival of patients with high total number of lymph nodes (≥12) and low total number of lymph nodes (< 12) was compared by Kaplan–Meier analysis.

Results

After stratifying by lymph nodes ratio status, total number of lymph nodes≥12 remained an independent predictor of survival in the whole cohort and in right-sided colon cancer, but not in left-sided colon cancer. The optimal cutoff value for total number of lymph nodes was determined to be 11. Low total number of lymph nodes (< 11) was associated with significantly poorer survival after adjusting for lymph nodes ratio in all subgroups except in the subgroup with high lymph nodes ratio (0.5–1.0).

Conclusions

Previous reports of the prognostic significance of total number of lymph nodes on node-positive colon cancer were confounded by lymph nodes ratio. The 12-node standard for total number of lymph nodes may not be equally applicable in right-sided colon cancer and left-sided colon cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4431-5) contains supplementary material, which is available to authorized users.

Whether regional lymph nodes evaluation should be equally required for both right and left colon cancer

Despite the adequacy of nodal evaluation was gradually improved for colon cancer, the disparity in nodal examination for right colon cancer (RCC) and left colon cancer (LCC) still begs the question of whether 12 nodes is an appropriate threshold for both RCC and LCC. From Surveillance, Epidemiology, and End-Results (SEER) database, we identified 53897 RCC patients and 11822 LCC patients. Compared with LCC patients, RCC patients examined more lymph nodes (18.7 vs 16.3), and more likely to examine ≥12 nodes (P<0.001), whereas RCC patients showed lower rates of node positivity (P<0.001). To balance the nodal disparity between RCC and LCC, we revised the 12-node measure based on different tumor locations. With the X-tile, we determined 15 as the optimal node number for RCC and 11 for LCC. To validate the availability of this revised nodal evaluation, the 5-year cancer specific survival (CSS) was calculated according to the optimal node number in RCC and LCC patients, Cox's regression model were used to further assess the prognostic value of this revised nodal evaluation. The results showed that 5-year CSSs were significantly improved for RCC patients with ≥15 lymph nodes, and also for LCC patients with ≥11 lymph nodes (P<0.001). This revised nodal evaluation could also improve the rate of nodal positivity and long-term survival in both RCC and LCC patients compared with 12-node measure. Therefore, the lymph node examination should be discriminately evaluated for RCC and LCC, instead of using 12-node measure to colon cancer as a whole.

Assessing the adequacy of lymph node yield for different tumor stages of colon cancer by nodal staging scores

Background

According to the current official guidelines, at least 12 lymph nodes (LNs) are qualified as an adequate sampling for colon cancer patients. However, patients evaluated with less nodes were still common in the United States, and the prevalence of positive nodal disease may be under-estimated because of the false-negative assessment. In this study, we present a statistical model that allows preoperative determination of the minimum number of lymph nodes needed to confirm a node-negative disease with certain confidence.

Methods

Adenocarcinoma colon cancer patients with stage T1-T3, diagnosed between 2004 and 2013, who did not receive neoadjuvant therapies and had at least one lymph node pathologically examined, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. A beta binomial distribution was used to estimate the probability of an occult nodal disease is truly node-negative as a function of total number of LNs examined and T stage.

Results

A total of 125,306 patients met study criteria; and 47,788 of those were node-positive. The probability of falsely identifying a patient as node-negative decreased with an increasing number of nodes examined for each stage, and was estimated to be 72% for T1 and T2 patients with a single node examined and 57% for T3 patients with a single node examined. To confirm an occult nodal disease with 90% confidence, 3, 8, and 24 nodes need to be examined for patients from stage T1, T2, and T3, respectively.

Conclusions

The false-negative rate of diagnosed node negative, together with the minimum number of examined nodes for adequate staging, depend preoperatively on the clinical T stage. Predictive tools can recommend a threshold on the minimum number of examined nodes regarding to the favored level of confidence for each T stage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3491-2) contains supplementary material, which is available to authorized users.

Lymph node yield after rectal resection in patients treated with neoadjuvant radiation for rectal cancer: A systematic review and meta-analysis

BACKGROUND

The lymph node status represents a major prognostic factor in colorectal cancer. However, it was demonstrated that neoadjuvant chemoradiotherapy (CRT) decreases the numbers of lymph nodes in the specimen. Several studies describe less than 12 lymph nodes in the resected specimen of rectal cancer patients after neoadjuvant radiation. This meta-analysis quantifies the influence of neoadjuvant CRT or radiotherapy (RT) only on the lymph node yield in rectal cancer patients.

METHODS

We performed a systematic review and searched PubMed, EMBASE and the Cochrane Library without any language restriction from 1st of January 1980 until 31st March 2015. Two reviewers examined all publications independently and extracted the relevant data if the study assessed lymph node counts or positive lymph node yields of patients who received neoadjuvant treatment compared with patients who did not receive neoadjuvant treatment. Meta-analyses were conducted to quantify the mean difference in lymph node yield.

RESULTS

A total of 34 articles (including 37 datasets) were included in the meta-analyses. Neoadjuvant CRT resulted in a mean reduction of 3.9 lymph nodes (95% confidence interval [CI] 3.7-4.1) and an average reduction in harvested positive lymph nodes of 0.7 (95% CI 0.2-1.2) compared with patients who received no neoadjuvant therapy. Individuals who received neoadjuvant RT had, in average, 2.1 lymph node less (95% CI 1.7-2.5) resected compared with their counterparts who received no neoadjuvant treatment.

CONCLUSIONS

Neoadjuvant CRT or RT only in rectal cancer patients leads to a decrease in lymph node harvest of approximately four and two lymph nodes, respectively. We therefore stress the importance of intensifying all efforts from involved subspecialities (i.e. surgeons and pathologists) to reach the benchmark harvest of 12 resected lymph nodes according to current guidelines.

Exploration of the Optimal Minimum Lymph Node Count after Colon Cancer Resection for Patients Aged 80 Years and Older

The elderly colon cancer (CC) patients are increasing and represent a heterogeneous patient group. The objectives of this study were to identify the features of lymph node examination and to explore the optimal minimum lymph node count after CC resection for patients aged ≥80. Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 65719 CC patients in stage I-III between 2004 and 2012, 26.0% of patients were aged ≥80. The median node count decreased with increasing age, which were 25.5, 20.2, 17.8 and 16.9 for patients aged 20–39, 40–59, 60–79, and ≥80. The rate of ≥12 nodes and the rate of node positivity for patients aged ≥80 were obviously lower than younger patients. Using X-tile analysis, we determined 9 nodes as the optimal node count for patients aged ≥80. Then, we compared the 5-year cancer specific survival (CSS) between patients with ≥9 nodes and <9 nodes. The results showed the 5-year CSSs were improved for patients with ≥9 nodes. Furthermore, the rate of node positivity and survival under the 9-node measure were equal to 12-node measure. Therefore, the lymph node examination should be discriminately evaluated for elder patients, and 9-node measure was available for patients aged ≥80.

External validation of the pathological nodal staging score in upper tract urothelial carcinoma: A population-based study

OBJECTIVES

To externally validate our previously developed pathological nodal staging model (pNSS) that allows quantification of the likelihood that a patient with pathologic node-negative status has, indeed, no lymph node metastasis (LNM).

PATIENTS AND METHODS

We analyzed data from 2,768 patients treated with radical nephroureterectomy (RNU) and lymph node dissection (LND) using the Surveillance, Epidemiology, and End Results database from 1988 to 2010. We estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed a new pNSS. Then, we compared these findings with those of the initial cohort.

RESULTS

The mean and median numbers of lymph node (LN) removed were 5 and 2, respectively (interquartile range = 5) in the validation cohort, though 66.5% of the patients (n = 1814) were pN0. Similar to the development cohort, the probability of missing a LNM decreased as the number of nodes examined increased in the validation cohort. If only a single node was examined, 35% of patients would be misclassified as pN0 while harboring LNM. Even when 5 nodes were examined, 8% would be misclassified. The probability of having a positive node increased with advancing pathological T stage in both the cohorts. Patients with pT0-Ta-Tis-T1 disease in both cohorts would have more than a 95% chance of a correct pathologic nodal staging with 2 examined nodes. However, if a patient has pT3-T4 disease, more than 12 examined LNs are needed to reach 95% accuracy.

CONCLUSIONS

We confirmed that the number of examined nodes needed for adequate staging depends on pT category. We externally validated our previous pNSS in a population-based database, which could help in the clinical decision-making regarding adjuvant chemotherapy administration.

Pattern of tumour growth of the primary colon cancer predicts long-term outcome after resection of liver metastases

OBJECTIVE

To identify significant predictive factors for overall survival (OS) and disease-free survival (DFS) after liver resection for colon cancer metastases, with special focus on features of the primary colon cancer, such as lymph node ratio (LNR), vascular invasion, and perineural invasion.

METHODS

Patients operated for colonic cancer liver metastases between 2006 and 2014 were included. Details on patient characteristics, the primary colon cancer operation and metastatic disease were collected. Multivariate analysis was performed to select predictive variables for OS and DFS.

RESULTS

Median OS and DFS were 67 and 20 months, respectively. 1-, 3- and 5-year OS were 97, 76, and 52%. 1-, 3- and 5-year DFS were 65, 42, and 37%. Multivariate analysis showed LNR to be an independent predictive factor for DFS but not for OS. Other identified predictive factors were vascular and perineural invasion of the primary colon cancer, size of the largest metastasis and severe complications after liver surgery for OS, and perineural invasion, number of liver metastases and preoperative CEA-level for DFS. Traditional N-stage was also considered to be an independent predictive factor for DFS in a separate multivariate analysis.

CONCLUSIONS

LNR and perineural invasion of the primary colon cancer can be used as a prognostic variable for DFS after a concomitant liver resection for colon cancer metastases. Vascular and perineural invasion of the primary colon cancer are predictive for OS.

Variability in the lymph node retrieval after resection of colon cancer: Influence of operative period and process

The purpose of this study was to evaluate variations in the number of retrieved lymph nodes (LNs) over time and to determine the factors that influence the retrieval of <12 LNs during colon cancer resection.Patients with colon cancer who were surgically treated between 1997 and 2013 were identified from our institutional tumor registry. Patient, tumor, and pathologic variables were evaluated. Factors that influenced the retrieval of <12 LNs were evaluated using multivariate logistic regression modeling, including time effects.In total, 6967 patients were identified. The median patient age was 61 years (interquartile range [IQR] = 45-79 years) and 58.4% of these patients were male. The median number of LNs retrieved was 21 (IQR = 14-29), which increased from 14 (IQR = 11-27) in 1997 to 26 (IQR = 19-34) in 2013. The proportion of patients with ≥12 retrieved LNs increased from 72% in 1997 to 98.8% in 2013 (P < 0.00001). This corresponded to the more recent emphasis on a multidisciplinary approach to adequate LN evaluation. The number of retrieved LNs was also found to be associated with age, sex, tumor location, T stage, and operative year. Tumor location and T stage influenced the number of retrieved LNs, irrespective of the operative year (P < 0.05). Factors including a tumor location in the sigmoid/left colon, old age, open resection, earlier operative year, and early T stage were more likely to be associated with <12 recovered LNs (P < 0.5; chi-squared test) (P < 0.001).The total number of retrieved LNs may be influenced by tumor location and T stage of a colon cancer, irrespective of the year of surgery. LN retrieval after colon cancer resection has increased in recent years due to a better awareness of its importance and the use of multidisciplinary approaches.

Impact of age on the prognostic value of number of lymph nodes retrieved in patients with stage II colorectal cancer

PURPOSE

A small number of lymph nodes retrieved (NLNR) is a known risk factor in stage II colorectal cancer. NLNR is influenced by age, but little is known about whether the impact of small NLNR on survival differs with age. This retrospective study sought to determine such impact in elderly patients with stage II colorectal cancer.

METHODS

We reviewed data for 2100 patients with stage II colorectal cancer who underwent surgery without adjuvant chemotherapy between January 1997 and December 2003. The optimal cutoff value of NLNR for survival was determined, and the impact of small NLNR on survival was analyzed. The association between age and NLNR was evaluated. The relation between age and risk of small NLNR with respect to survival was then assessed to determine the impact of small NLNR on elderly patients' survival.

RESULTS

The optimal cutoff value of NLNR was determined as 6. The small NLNR group (SNG) showed significantly worse prognosis than the large NLNR group (LNG) (p < 0.001). Age, surgical method, and scope of lymph node dissection were significantly associated with NLNR. A potential interaction was noted between age and risk of small NLNR in relation to relapse-free survival (RFS). Five-year RFS was significantly worse in SNG than in LNG for elderly patients (41.7 and 76.4 %, respectively; p < 0.001) but not for non-elderly patients (75.9 and 84.6 %, respectively; p = 0.083).

CONCLUSIONS

NLNR <6 was identified to be an important prognostic factor for elderly patients with stage II colorectal cancer.

Intranodal Mapping Using Carbon Dye Results in More Accurate Lymph Node Staging in Colon Cancer Patients

INTRODUCTION

Small nodal tumor infiltrates (SNTI)-defined as isolated tumor cells and micrometastases-are associated with worse disease-free and overall survival in stage I and II colon cancer patients. Their detection, however, remains challenging. The objective of the present study was to evaluate whether there is a correlation between the location of SNTI and phagocytosed carbon dye particles in sentinel lymph nodes (SLN) of colon cancer patients.

MATERIALS AND METHODS

Isosulfan blue and carbon dye were injected intraoperatively near the tumor to mark the SLN. Serial sections of SLN were stained with hematoxylin-eosin and immunohistochemistry. Intranodal distribution of phagocytosed carbon particles was compared to the presence of SNTI.

RESULTS

Of a cohort of 159 patients, 24 patients had SNTI in their lymph nodes (LN). SNTI were found in a total of 116 LN of which 66 were SLN and 50 were non-SLN. In 59, these 116 LN with SNTI phagocytosed carbon dye were found (50.9 %). Phagocytosed carbon dye was identified significantly more often in SLN (49 of 66 SNTI positive SLN) compared to 10 of 50 SNTI positive non-SLN (p < 0.001). In 52 out of 59 LN (88.1 %), phagocytosed carbon dye was in close proximity to SNTI.

CONCLUSIONS

In the majority of patients, SNTI are located in the same SLN compartment as phagocytosed carbon dye particles. Our investigation provides evidence that the use of carbon dye facilitates SNTI detection and improves LN staging in colon cancer. Therefore, the concept of intranodal mapping-which has been previously described for melanoma-can be extended to colon cancer patients.

Clinicopathological characteristics of young patients with sporadic colorectal cancer

PURPOSE

To evaluate the clinicopathological features of and prognosis associated with sporadic colorectal cancer (CRC) in Japanese patients younger than 40 years old.

METHODS

The subjects of this study were patients with sporadic stage 0-III CRC, who underwent curative resection between 2004 and 2012 at the Cancer Institute Hospital. Clinicopathological characteristics and survival were compared between the young (<40 years; n = 81) and older groups (≥40 years; n = 2257).

RESULTS

The median age was 36 years in the young group and 64 years in the older group. Young patients had a lower incidence of right-sided colon cancer (14 vs 28 %) and a higher incidence of rectal cancer (47 vs 32 %; P < 0.0001). The number of retrieved lymph nodes was significantly higher in the young group than in the older group (P = 0.0049). The young patients had similar overall survival and relapse-free survival to their older counterparts, except for overall survival in stage II patients (P = 0.0229). However, multivariate analysis indicated that age was not an independent prognostic factor for overall survival in patients with stage II CRC.

CONCLUSIONS

Young Japanese patients with sporadic CRC have unique characteristics such as a high incidence of rectal cancer and similar pathological features; however, they appear to have comparable survival to older patients.

The effect of neoadjuvant therapy on the size, number, and distribution of mesorectal lymph nodes

The current therapeutic approach to patients with locally advanced rectal cancer is neoadjuvant radiotherapy or chemoradiotherapy followed by total mesorectal excision. We aimed to investigate the number, size, and distribution of metastatic and nonmetastatic lymph nodes within the mesorectum; whether neoadjuvant therapy has any impact on the number and size of the lymph nodes; and the impact of metastatic lymph node localization on overall and disease-free survival. Specimens from 50 consecutive patients with stage II/III rectal cancer receiving either neoadjuvant radiotherapy or chemoradiotherapy were investigated. Lymph node dissection was carried out by careful visual inspection and palpation. The localization of the each lymph node within the mesorectum and the relation with the tumor site were noted. The size and the number of lymph nodes retrieved decreased significantly with neoadjuvant therapy. Majority of the metastatic and nonmetastatic lymph nodes were located at or proximally to the tumor level and posterior side of the mesorectum. No relation was observed between the overall and disease-free survival, and the localization of the metastatic lymph nodes. Presence of lymph node metastases proximal to the tumor level has no impact on survival compared with the presence of lymph node metastasis only in the peritumoral region of the mesorectum. Although neoadjuvant therapy decreases the size and the number of lymph nodes, reaching an ideal number of lymph nodes for accurate staging is still possible with careful naked eye examination and dissection of perirectal fat. As the majority of metastatic and nonmetastatic lymph nodes are located in peritumoral and proximal compartment, and posterior side of the mesorectum, these regions should be the major interest of dissection.

Adequate lymphadenectomy for colorectal cancer: a comparative analysis between open and laparoscopic surgery

Background

In the surgical treatment of colorectal cancer, a lymphadenectomy is considered adequate when at least 12 lymph nodes are removed.

Aim

To evaluate whether videolaparoscopic surgery positively affects the rates of adequate lymphadenectomy.

Methods

An observational study was conducted with patients undergoing either open or videolaparoscopic surgery for colorectal cancer between 2008 and 2013. The following variables were collected: gender, age, tumor site, histology, degree of differentiation, tumor stage, number of lymph nodes removed, and number of lymph nodes affected by the disease.

Results

A total of 62 patients with colorectal cancer were included; 42 (67.7%) received open surgery, and 20 (32.3%) laparoscopic surgery. Regarding lymphadenectomy, a mean of 13 lymph nodes (95% CI: 10-16) were removed in the group that received open surgery, while 19 lymph nodes were removed (95% CI: 14-24) in the laparoscopic surgery group (p=0.021). Adequate lymphadenectomy (removal of at least 12 lymph nodes) was achieved in 58.1% of the total cases, in 50.0% of the patients who received open surgery, and in 75% of those who received laparoscopic surgery. Non-elderly patients and those with an advanced disease stage were more likely to receive an adequate lymphadenectomy (p=0.004 and p=0.035, respectively).

Conclusion

Disease stage and patient age were the factors that had the greatest influence on achieving an adequate lymphadenectomy. The type of surgery did not affect the number of lymph nodes removed.

Influence of extent of lymph node dissection on survival for patients with pT2 colon cancer

PURPOSE

The optimal extent of lymph node dissection for early-stage colon cancer (CC) remains undefined. This study assessed the influence of the extent of lymph node dissection on overall survival (OS) in patients with pT2 CC.

METHODS

We retrospectively examined data from the multi-institutional registry system of the Japanese Society for Cancer of the Colon and Rectum and used a propensity score matching method to balance potential confounders of lymph node dissection. We extracted 463 matched pairs from 1433 patients who underwent major resections for pT2 CC between 1995 and 2004.

RESULTS

Lymph node metastasis was found in 301 (21.0%) of 1433 patients with pT2 CC. In this cohort, significant independent risk factors for lymph node metastasis were lymphatic invasion and venous invasion. Patients who underwent D3 or D2 lymph node dissection did not significantly differ in OS, either among the propensity score-matched cohort (estimated hazard ratio [HR] 0.85, 95% confidence interval [CI] 0.536-1.346, P = 0.484) or in the cohort as a whole (HR 0.720, 95% CI 0.492-1.052, P = 0.089).

CONCLUSIONS

For patients with pT2 CC, D3 lymph node dissection did not add to OS. D2 lymph node dissection may be adequate for pT2 CC.

Prognostic Effect of Ultra-Staging Node-Negative Colon Cancer Without Adjuvant Chemotherapy: A Prospective National Cancer Institute-Sponsored Clinical Trial

BACKGROUND

We recently reported, in a prospective randomized trial, that ultra-staging of patients with colon cancer is associated with significantly improved disease-free survival (DFS) compared with conventional staging. That trial did not control for lymph node (LN) number or adjuvant chemotherapy use.

STUDY DESIGN

The current international prospective multicenter cooperative group trial (ClinicalTrials.gov identifier NCT00949312; "Ultra-staging in Early Colon Cancer") evaluates the 12-LN quality measure and nodal ultra-staging impact on DFS in patients not receiving adjuvant chemotherapy. Eligibility criteria included biopsy-proven colon adenocarcinoma; absence of metastatic disease; >12 LNs staged pathologically; pan-cytokeratin immunohistochemistry (IHC) of hematoxylin and eosin (H&E)-negative LNs; and no adjuvant chemotherapy.

RESULTS

Of 445 patients screened, 203 patients were eligible. The majority of patients had intermediate grade (57.7%) and T3 tumors (64.9%). At a mean follow-up of 36.8 ± 22.1 months (range 0 to 97 months), 94.3% remain disease free. Recurrence was least likely in patients with ≥12 LNs, H&E-negative LNs, and IHC-negative LNs (pN0i-): 2.6% vs 16.7% in the pN0i+ group (p < 0.0001).

CONCLUSIONS

This is the first prospective report to demonstrate that patients with optimally staged node-negative colon cancer (≥12 LNs, pN0i-) are unlikely to benefit from adjuvant chemotherapy; 97% remain disease free after primary tumor resection. Both surgical and pathologic quality measures are imperative in planning clinical trials in nonmetastatic colon cancer.

Ratio of metastatic lymph nodes is more important for rectal cancer patients treated with preoperative chemoradiotherapy

AIM: To evaluate the predictive value of the lymph node (LN) ratio (LNR, number of metastatic LNs/ examined LNs) for recurrence in patients with rectal cancer and to compare its applicability according to preoperative chemoradiotherapy (PCRT).

METHODS: From 2000 to 2009, 967 patients with metastatic LNs after curative resection for locally advanced rectal cancer were identified. Patients were categorized according to PCRT (PCRT vs No PCRT). The cut-off LNR was determined based on the pN1 vs pN2 when the recommended number of LNs was harvested. The 5-year recurrence-free survival (RFS) rates using the Kaplan-Meier method were compared according to p/yp N stage and the LNR in each group.

RESULTS: Among patients with the same p/ypN stage, the 5-year RFS rate differed according to the LNR. In addition, the 5-year RFS rate was significantly different between pN and LNR groups in patients with No PCRT. In PCRT group, however, only LNR was associated with prognosis. On multivariate analysis, both pN and LNR were significant independent prognostic factors for 5-year RFS in the No PCRT group. In the PCRT group, only LNR category was found to be associated with RFS (HR = 2.36, 95%CI: 1.31-3.84, and P = 0.001).

CONCLUSION: The LNR is an important prognostic predictor of RFS in rectal cancer patients especially treated with PCRT. Current pN categories could not discriminate between prognostic groups of RFS after PCRT.

The size of retrieved lymph nodes correlates with the number of retrieved lymph nodes and is an independent prognostic factor in patients with stage II colon cancer

PURPOSE

In stage II colon cancer, patients with many retrieved lymph nodes (LNs) have been reported to have better oncological outcomes. We tested the hypothesis that the greater number of retrieved LNs is related to a larger LN size.

METHODS

The subjects comprised 320 patients with stage II colon cancer who underwent curative resection. All operations were elective and were performed by the same surgeons. The maximum long axis and short axis diameters of LNs were measured on hematoxylin-eosin-stained specimens.

RESULTS

A total of 4,744 LNs were evaluated. The number of retrieved LNs was 14.8 ± 10.1 (mean ± SD). The long axis diameter was 4.8 ± 2.6 mm, with a median value of 4.3 mm, a maximum value of 20.4 mm, and a minimum value of 0.6 mm. The corresponding short axis diameters were 3.4 ± 1.7, 3.0, 15.1, and 0.5 mm, respectively. The highest correlation coefficient for the association with the number of LNs was obtained for the maximum value of the long axis diameter (0.59). Multivariate analysis revealed that age, tumor location, pathological T stage, and the maximum long axis diameter were independent prognostic factors. The number of LNs was not a significant factor. Patients with less than 12 LNs and a maximum long axis diameter of less than 10 mm had significantly poorer outcomes (p < 0.001).

CONCLUSION

In patients with stage II colon cancer, the maximum long axis diameter of LNs correlated with the number of LNs and was an independent prognostic factor.

Survival paradox between stage IIB/C (T4N0) and stage IIIA (T1-2N1) colon cancer

BACKGROUND

The survival paradox between stage IIB/C (T4N0) and stage IIIA (T1-2N1) colon cancer remains in the 7th edition of the American Joint Committee on Cancer staging system. This multicenter study aimed to compare the oncologic outcomes of T4N0 and T1-2N1 colon cancers and to investigate the presumptive prognostic factors that might influence the survival paradox.

METHODS

Patients who underwent curative surgery for pT4N0 (n = 224) and pT1-2N1 (n = 135) primary colon cancer between January 1999 and December 2010 at five tertiary referral cancer centers were included for analysis. The clinicopathologic, treatment-related factors, and oncologic outcomes in terms of the 5-year overall survival (5-OS) and 5-year disease-free survival (5-DFS) were compared.

RESULTS

The T4N0 group had significantly worse 5-OS and 5-DFS rates than the T1-2N1 group (5-OS: 84.0 vs. 92.3 %, p = 0.012; 5-DFS: 73.6 vs. 88.0 %, p = 0.001). T4N0 cancers more frequently showed elevated preoperative carcinoembryonic antigen, lower grade of differentiation, larger tumor size, and higher proportions of perineural invasion, microsatellite instability, obstruction, and perforation than T1-2N1 cancers. Peritoneal seeding and liver metastasis were the predominant recurrence pattern in the T4N0 and T1-2N1 groups, respectively (p = 0.042). The T4N0 group showed inferior survival to the T1-2N1 group in postoperative adjuvant chemotherapy (5-OS: 87.1 vs. 93.2 %, p = 0.045; 5-DFS: 76.1 vs. 89.0 %, p = 0.001).

CONCLUSIONS

T4N0 colon cancer had significantly worse oncologic outcomes than T1-2N1 cancer regardless of adjuvant chemotherapy. The survival paradox may result from the biologic aggressiveness of T4N0 colon carcinomas.

Impact of D3 lymph node dissection on survival for patients with T3 and T4 colon cancer

PURPOSE

The clinical significance of D3 lymph node dissection for patients with colon cancer remains controversial. This study aims to clarify the impact of D3 lymph node dissection on survival in patients with colon cancer.

METHODS

This is a retrospective cohort study from a prospectively registered multi-institutional database of colorectal cancer in Japan. Propensity score matching method was applied to balance potential confounders of the treatment. A cohort of 10,098 patients who underwent radical colectomy for pT3 and pT4 colon cancer between 1985 and 1994 were identified. A total of 3,425 propensity score matched pairs were extracted from the entire cohort. The primary outcome measure was overall survival (OS).

RESULTS

In the entire cohort, there was a statistically significant difference in overall survival (OS) between the patients who had D3 and D2 lymph node dissection (p = 0.00003). The estimated hazard ratio (HR) for OS of patients who had D3 versus D2 lymph node dissection was 0.827 (95 % confidence interval, 0.757 to 0.904). In the matched cohort, there was also a significant difference in OS between the two groups (p = 0.0001), and the estimated HR for OS was 0.814 (95 % confidence interval, 0.734 to 0.904).

CONCLUSIONS

We found D3 lymph node dissection for pT3 and pT4 colon cancer to be associated with a significant survival advantage in a large-scale database, even after adjusting potential confounders of lymph node dissection. This finding may provide a rationale for D3 lymph node dissection in radical surgery for pT3 and pT4 colon cancer.

Does reevaluation of colorectal cancers with inadequate nodal yield lead to stage migration or the identification of metastatic lymph nodes?

BACKGROUND

The National Comprehensive Cancer Network recommends routine reevaluation of all stage II colon cancer specimens with fewer than 12 lymph nodes. However, there are few data demonstrating the effect of reevaluation on stage.

OBJECTIVE

The aim of this study was to demonstrate the effect of pathologic reevaluation for colorectal cancers with fewer than 12 lymph nodes on stage.

DESIGN

This study entailed a retrospective review of pathology reports.

SETTINGS

This study was conducted at 2 large multispecialty referral centers.

INTERVENTIONS

Pathologic reevaluation was performed to look for additional lymph nodes.

PATIENTS

All patients with stage I through III colorectal cancers with inadequate lymph node yields who underwent reevaluation from January 1, 2007 through March 31, 2011 were identified.

MAIN OUTCOME MEASURES

We recorded initial pathologic stage and new stage following reevaluation. The following variables before and after reevaluation were also recorded: 1) total lymph node count, 2) metastatic node count, 3) negative node count, and 4) lymph node ratio.

RESULTS

Eighty-three patients underwent pathologic reevaluation from a total of 1682 cancer specimens. Mean nodal yields were 7.2 ± 2.6 on the first pathologic review. On reevaluation, 80% of patients had one or more newly identified nodes. On average, 6.9 ± 9.6 more lymph nodes were identified with a metastatic node detected in 4 of 83 patients (4.8%). After pathologic reevaluation, 1 patient (1.2%) had a change in TNM stage from N1 to N2 disease. The lymph node ratio changed in 13 of 15 patients (87% of stage III cancers). Only 4 of these had a change in lymph node quartile.

LIMITATIONS

The study was limited by its retrospective nature and small sample size.

CONCLUSION

Few patients have a newly discovered metastatic node or stage change following pathologic reevaluation. The effect of pathologic reevaluation on treatment and outcome should be further investigated.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

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.

Comparative analysis between multilevel sectioning with conventional haematoxylin and eosin staining and immunohistochemistry for detecting nodal micrometastases with stage I and II colorectal cancers

Management of patients with stage II colorectal carcinomas remains challenging as 20 - 30% of them will develop recurrence. It is postulated that these patients may harbour nodal micrometastases which are imperceptible by routine histopathological evaluation. The aims of our study were to evaluate (1) the feasibility of multilevel sectioning method utilizing haematoxylin and eosin stain and immunohistochemistry technique with cytokeratin AE1/AE3, in detecting micrometastases in histologically-negative lymph nodes, and (2) correlation between nodal micrometastases with clinicopathological parameters. Sixty two stage I and II cases with a total of 635 lymph nodes were reviewed. Five-level haematoxylin and eosin staining and one-level cytokeratin AE1/AE3 immunostaining were performed on all lymph nodes retrieved. The findings were correlated with clinicopathological parameters. Two (3.2%) lymph nodes in two patients (one in each) were found to harbour micrometastases detected by both methods. With cytokeratin AE1/AE3, we successfully identified four (6.5%) patients with isolated tumour cells, but none through the multilevel sectioning method. Nodal micrometastases detected by both multilevel sectioning and immunohistochemistry methods were not associated with larger tumour size, higher depth of invasion, poorer tumour grade, disease recurrence or distant metastasis. We conclude that there is no difference between the two methods in detecting nodal micrometastases. Therefore it is opined that multilevel sectioning is a feasible and yet inexpensive method that may be incorporated into routine practice to detect nodal micrometastases in centres with limited resources.