Metastatic lymph node ratio is a more precise predictor of prognosis than number of lymph node metastases in stage III colon cancer

Lymph node ratio is a more robust predictor of overall survival than N stage in stage III colorectal adenocarcinoma

BACKGROUND

Lymph node ratio (LNR) may offer superior prognostic stratification in colorectal adenocarcinoma compared with N stage. However, candidate cutoff ratios require validation. We aimed to study the prognostic significance of LNR and its optimal cutoff ratio.

METHODS

We reviewed the pathology records of all patients with stage III colorectal adenocarcinoma who were managed at the King Hussein Cancer Center between January 2014 and December 2019. We then studied the clinical characteristics of the patients, correlates of lymph node count, prognostic significance of positive lymph nodes, and value of sampling additional lymph nodes.

RESULTS

Among 226 included patients, 94.2% had ≥ 12 lymph nodes sampled, while 5.8% had < 12 sampled lymph nodes. The median number of lymph nodes sampled varied according to tumor site, neoadjuvant therapy, and the grossing pathologist's level of training. According to the TNM system, 142 cases were N1 (62.8%) and 84 were N2 (37.2%). Survival distributions differed according to LNR at 10% (p = 0.022), and 16% (p < 0.001), but not the N stage (p = 0.065). Adjusted Cox-regression analyses demonstrated that both N stage and LNR at 10% and 16% predicted overall survival (p = 0.044, p = 0.010, and p = 0.001, respectively).

CONCLUSIONS

LNR is a robust predictor of overall survival in patients with stage III colorectal adenocarcinoma. At a cutoff ratio of 0.10 and 0.16, LNR offers better prognostic stratification in comparison with N stage and is less susceptible to variation introduced by the number of lymph nodes sampled, which is influenced both by clinical variables and grossing technique.

Risk and prognostic factors in patients with colon cancer with liver metastasis

OBJECTIVE

The most common site of metastasis in patients with colon cancer is the liver. This study aimed to identify patients with colon cancer at high risk of developing liver metastasis and to explore their prognosis.

METHODS

The clinical characteristics, treatment methods and survival outcomes of patients diagnosed with colon cancer from 2010 to 2015 were identified from the Surveillance, Epidemiology and End Results (SEER) database. Patients were divided into two groups according to the presence of liver metastasis, and multivariate logistic and Cox regression models were used to identify risk and prognostic factors.

RESULTS

A total of 60,018 patients with colon cancer were selected from the SEER database. The incidence of liver metastasis was 9.2%. African American ethnicity, poor differentiation, higher tumor stage, higher lymph node ratio, and lung metastases were common factors associated with both liver metastasis risk and prognosis.

CONCLUSIONS

Metastasectomy might improve survival among patients with colon cancer with resectable liver metastasis lesions and no other organ involvement.

Beyond N staging in colorectal cancer: Current approaches and future perspectives

Traditionally, lymph node metastases (LNM) evaluation is essential to the staging of colon cancer patients according to the TNM (tumor-node-metastasis) system. However, in recent years evidence has accumulated regarding the role of emerging pathological features, which could significantly impact the prognosis of colorectal cancer patients. Lymph Node Ratio (LNR) and Log Odds of Positive Lymph Nodes (LODDS) have been shown to predict patients' prognosis more accurately than traditional nodal staging and it has been suggested that their implementation in existing classification could help stratify further patients with overlapping TNM stage. Tumor deposits (TD) are currently factored within the N1c category of the TNM classification in the absence of lymph node metastases. However, studies have shown that presence of TDs can affect patients' survival regardless of LNM. Moreover, evidence suggest that presence of TDs should not be evaluated as dichotomic but rather as a quantitative variable. Extranodal extension (ENE) has been shown to correlate with presence of other adverse prognostic features and to impact survival of colorectal cancer patients. In this review we will describe current staging systems and prognostic/predictive factors in colorectal cancer and elaborate on available evidence supporting the implementation of LNR/LODDS, TDs and ENE evaluation in existing classification to improve prognosis estimation and patient selection for adjuvant treatment.

A Prediction Model for Tumor Recurrence in Stage II–III Colorectal Cancer Patients: From a Machine Learning Model to Genomic Profiling

Background: Colorectal cancer (CRC) is one of the most prevalent malignant diseases worldwide. Risk prediction for tumor recurrence is important for making effective treatment decisions and for the survival outcomes of patients with CRC after surgery. Herein, we aimed to explore a prediction algorithm and the risk factors for postoperative tumor recurrence using a machine learning (ML) approach with standardized pathology reports for patients with stage II and III CRC. Methods: Pertinent clinicopathological features were compiled from medical records and standardized pathology reports of patients with stage II and III CRC. Four ML models based on logistic regression (LR), random forest (RF), classification and regression decision trees (CARTs), and support vector machine (SVM) were applied for the development of the prediction algorithm. The area under the curve (AUC) of the ML models was determined in order to compare the prediction accuracy. Genomic studies were performed using a panel-targeted next-generation sequencing approach. Results: A total of 1073 patients who received curative intent surgery at the National Cheng Kung University Hospital between January 2004 and January 2019 were included. Based on conventional statistical methods, chemotherapy (p = 0.003), endophytic tumor configuration (p = 0.008), TNM stage III disease (p < 0.001), pT4 (p < 0.001), pN2 (p < 0.001), increased numbers of lymph node metastases (p < 0.001), higher lymph node ratios (LNR) (p < 0.001), lymphovascular invasion (p < 0.001), perineural invasion (p < 0.001), tumor budding (p = 0.004), and neoadjuvant chemoradiotherapy (p = 0.025) were found to be correlated with the tumor recurrence of patients with stage II–III CRC. While comparing the performance of different ML models for predicting cancer recurrence, the AUCs for LR, RF, CART, and SVM were found to be 0.678, 0.639, 0.593, and 0.581, respectively. The LR model had a better accuracy value of 0.87 and a specificity value of 1 in the testing set. Two prognostic factors, age and LNR, were selected by multivariable analysis and the four ML models. In terms of age, older patients received fewer cycles of chemotherapy and radiotherapy (p < 0.001). Right-sided colon tumors (p = 0.002), larger tumor sizes (p = 0.008) and tumor volumes (p = 0.049), TNM stage II disease (p < 0.001), and advanced pT3–4 stage diseases (p = 0.04) were found to be correlated with the older age of patients. However, pN2 diseases (p = 0.005), lymph node metastasis number (p = 0.001), LNR (p = 0.004), perineural invasion (p = 0.018), and overall survival rate (p < 0.001) were found to be decreased in older patients. Furthermore, PIK3CA and DNMT3A mutations (p = 0.032 and 0.039, respectively) were more frequently found in older patients with stage II–III CRC compared to their younger counterparts. Conclusions: This study demonstrated that ML models have a comparable predictive power for determining cancer recurrence in patients with stage II–III CRC after surgery. Advanced age and high LNR were significant risk factors for cancer recurrence, as determined by ML algorithms and multivariable analyses. Distinctive genomic profiles may contribute to discrete clinical behaviors and survival outcomes between patients of different age groups. Studies incorporating complete molecular and genomic profiles in cancer prediction models are beneficial for patients with stage II–III CRC.

Number of negative lymph nodes with a positive impact on survival of stage III colon cancer; a retrospective observation study for right side and left side colon

Background

The purpose was to examine the effect of negative lymph nodes (NLN) number on survival in stage III colon cancer. To reduce the interference of acute inflammation, we included patients with stage III colon cancer who had undergone elective surgery and excluded those who had tumor perforation, obstruction, ischemia, or massive tumor bleeding.

Methods

This retrospective cohort study included 2244 patients with stage III colon cancer between 1995 and 2016 at a single center. The effect of NLN on 5-year relapse-free survival (RFS), 5-year overall survival (OS), and comparison of multivariate factors was assessed according to tumor locations.

Results

The two optimal cutoff values of NLN for proximal and distal colon, namely 27 and 12, were determined by plotting the time-dependent receiver operating characteristic curve. Overall, 499 of 891 and 1020 of 1353 patients with right-side and left-side colon cancer, respectively, had high NLN. In right-side colon cancer, patients with high NLN (≥ 27) had superior OS (74.9% vs. 62.7%, P <  0.001) and RFS (75.0% vs. 61.9%, P <  0.001) than did those with low NLN. Moreover, in left-side colon cancer, patients with high NLN (≥12) experienced significantly superior OS (80.8% vs. 68.6%, P <  0.001) and RFS (77.3% vs. 66.2%, P <  0.001) than did those with low NLN. Among the different subgroups of stage III colon cancer, the high NLN group showed significantly superior RFS and OS in stage IIIB (RFS: 77.0% vs. 68.0%, P = 0.001; OS: 78.6% vs. 67.9%, P <  0.001) and IIIC (RFS: 58.2% vs. 44.1%, P = 0.001; OS: 65.7% vs. 51.1%, P <  0.001) colon cancer. However, in stage IIIA colon cancer, high NLN only showed survival benefit in OS (91.5% vs. 89.8%, P = 0.041). Multivariate analyses confirmed that high NLN, high carcinoembryonic antigen (≥ 5 ng/mL) level, and stage IIIC status are three independent prognostic factors in both the proximal and distal colon.

Conclusions

NLN is a crucial prognostic factor for stage III colon cancer in various tumor locations or in the subgroups of stage III disease. In advanced stage III colon cancer, the importance of NLN and its role in anti-cancer immune response could be highlighted.

Is there a relationship between length of resection and lymph-node ratio in colorectal cancer?

Background

The prognosis of colorectal cancer depends on the number of positive lymph nodes (LN+) and the total number of lymph nodes resected (rLN). This represents the lymph-node ratio (LNR). The aim of our study is to assess how the length of the resected specimen (RL) influences the prognostic values of the LNR.

Methods

We conducted a retrospective study of all the patients operated on for colorectal cancer from 2000 to 2015 at our institution. Pathology details were analysed. The total number of rLN, the number of LN+, and the LNR were calculated and measured against the RL. The receiver-operating characteristic (ROC) curve of patients with LN+ was calculated.

Results

Of the 670 patients included in our study, 337 were men (50.3%) and the mean age was 69.2 years. The correlation with prognosis of the LNR is greater than that of the LNR adjusted to RL (LNR/RL), both in subjects with positive nodes (n = 312) and in all cases (n = 670). The LNR presents a higher prognostic value than LNR/RL and RL in patients with LN+ except for metastatic recurrence, for which the predictive value appears slightly higher for LNR/RL. The statistical significance of the maximal divergence in Kaplan-Meier survival plots was demonstrated for the LNR (P = 0.043), not for LNR/RL (P = 0.373) and RL alone (P = 0.314).

Conclusion

An increase in RL causes an increase in the number of harvested lymph nodes without affecting the number of LN+, thus representing a confounding factor that could alter the prognostic value of the LNR. Prospective larger-scale studies are needed to confirm these findings.

Lymph node ratio, an independent prognostic factor for patients with stage II-III rectal carcinoma

BACKGROUND

Identification of the proper surgical method and the most reliable prognostic parameters of rectal carcinomas is a challenging issue. The aim of this paper was to determine the possible prognostic role of the number of harvested lymph nodes versus lymph node ratio (LNR) in patients with rectal carcinomas, and the proper value of LNR that can be used as prognostic parameter.

MATERIALS AND METHODS

A retrospective study was performed in 186 consecutive patients with rectal carcinomas that underwent surgical resection. The LNR was calculated for cases from stage II-III, and was correlated with classic prognostic parameters and overall survival (OS).

RESULTS

A statistically significant difference was found between LNR of 0.15 and OS (p = 0.03), respectively LNR > 0.15 and TNM stage (p < 0.0001), but also tumor infiltration level (p < 0.05). The number of harvested lymph nodes was not correlated with the tumor stage (r = 0.148, p = 0.06) and this parameter did not influence the OS, when the number of 12 or 14 lymph nodes was used as the ideal value (p = 0.6 and p = 0.66, respectively).

CONCLUSION

In patients with rectal carcinomas that underwent preoperative chemoradiotherapy, a LNR of 0.15 is a parameter with independent prognostic value, comparing with the number of harvested lymph nodes. The specific LNR should be calculated in larger cohorts.

Defining the Role of Lymphadenectomy for Pancreatic Neuroendocrine Tumors: An Eight-Institution Study of 695 Patients from the US Neuroendocrine Tumor Study Group

BACKGROUND

Preoperative factors that reliably predict lymph node (LN) metastases in pancreatic neuroendocrine tumors (PanNETs) are unclear. The number of LNs needed to accurately stage PanNETs has not been defined.

METHODS

Patients who underwent curative-intent resection of non-functional PanNETs at eight institutions from 2000 to 2016 were analyzed. Preoperative factors associated with LN metastases were identified. A procedure-specific target for LN retrieval to accurately stage patients was determined.

RESULTS

Of 695 patients who underwent resection, 33% of tumors were proximal (head/uncinate) and 67% were distal (neck/body/tail). Twenty-six percent of patients (n = 158) had LN-positive disease, which was associated with a worse 5-year recurrence-free survival (RFS; 60% vs. 86%; p < 0.001). The increasing number of positive LNs was not associated with worse RFS. Preoperative factors associated with positive LNs included tumor size ≥ 2 cm (odds ratio [OR] 6.6; p < 0.001), proximal location (OR 2.5; p < 0.001), moderate versus well-differentiation (OR 2.1; p = 0.006), and Ki-67 ≥ 3% (OR 3.1; p < 0.001). LN metastases were also present in tumors without these risk factors: < 2 cm (9%), distal location (19%), well-differentiated (23%), and Ki-67 < 3% (16%). Median LN retrieval was 13 for pancreatoduodenectomy (PD), but only 9 for distal pancreatectomy (DP). Given that PD routinely includes a complete regional lymphadenectomy, a minimum number of LNs to accurately stage patients was not identified. However, for DP, removal of less than seven LNs failed to discriminate 5-year RFS between LN-positive and LN-negative patients (less than seven LNs: 72% vs. 83%, p = 0.198; seven or more LNs: 67% vs. 86%; p = 0.002).

CONCLUSIONS

Tumor size ≥ 2 cm, proximal location, moderate differentiation, and Ki-67 ≥ 3% are preoperative factors that predict LN positivity in resected non-functional PanNETs. Given the 9-23% incidence of LN metastases in patients without such risk factors, routine regional lymphadenectomy should be considered. PD inherently includes sufficient LN retrieval, while DP should aim to remove seven or more LNs for accurate staging.

A competing-risks nomogram for predicting probability of death from CRC in Chinese Han patients with Stage I-III CRC

Background

Many patients with colorectal cancer are elderly with competing comorbidities. When constructing nomogram for assessing survival, we should consider the influence of competing risk. A competing-risks nomogram was developed to estimate the probability of death due to colorectal cancer for patients after curative surgery.

Methods

A total of 2442 patients with non-metastatic colorectal cancer were included to develop competing-risks nomogram. Competing-risks nomogram were established based on the results of Fine and Gray competing-risks proportional hazards model. To maximize the accuracy of prediction, model selection was not carried out, and non-linear continuous variables were flexibly modeled with restricted cubic splines. The nomogram was internal-validated by bootstrapping, and externally validated with a separate database of 299 patients from The Cancer Genome Atlas. The performance of this model was assessed by concordance index and a calibration curve.

Results

There were 332 patients died of colorectal cancer and 46 died of other causes during the follow-up period. Age, T stage, N stage, histological type, tumor location, adjuvant chemotherapy, preoperative carcinoembryonic antigen, lymph vascular invasion, lymph node ratio and sample lymph nodes were integrated into competing-risks nomogram. The competing-risks nomogram for predicting probability of death due to colorectal cancer with a concordance index of 0.768, ameliorating the stratification provided by the seventh edition tumor-node-metastasis staging system of the American Joint Committee on Cancer (AJCC). The concordance index for validation dataset was 0.783.

Conclusion

We developed and externally validated a competing-risks nomogram for Chinese Han patients with non-metastatic colorectal cancer, which could provide probability of death from colorectal cancer in the presence of competing risks.

Survival nomograms for stage III colorectal cancer

The postoperative survival of patients with stage III colorectal cancer (CRC) various obviously. We sought to develop novel nomograms for predicting the survival of these patients after radical surgery and postoperative chemotherapy.A total of 620 consecutive patients with stage III CRC who underwent curative resection and postoperative chemotherapy between January 2009 and December 2015 were retrospectively collected and randomly allocated to the training (n = 372) or validation cohort (n = 248). Clinicopathological factors were collected and analyzed. On the basis of data from 372 patients in the training set, predictive factors for overall survival (OS) and disease-free survival (DFS) were identified using multivariate Cox regression and used to construct nomograms. The predictive performance of the nomograms was assessed by concordance index (C-index) and calibration plots. An external cohort of 248 patients was used to validate the nomograms. Furthermore, nomogram performance was compared with the performance of T and N stage stratification.Tumor differentiation grade, lymph node metastasis ratio, intravascular emboli (IVE), preoperative serum carcinoembryonic antigen (CEA) level, albumin to globulin ratio (AGR), T stage and N stage were significant prognostic factors for OS on multivariate analysis; whereas, Tumor differentiation grade, lymph node metastasis ratio, IVE, AGR and N stage were significant for DFS. Nomograms to predict 3- and 5-year OS and DFS were established that performed well (C-indexes of 0.734 [95% CI, 0.691-0.779] for OS and 0.699 [95% CI, 0.657-0.740] for DFS prediction), and nomogram accuracy was confirmed in the validation cohort. Furthermore, model comparison proved that the nomograms were superior to risk stratification by T and N stage for stage III CRC.We propose 2 practical nomograms for stage III CRC patients that provide more accurate prognostic predictions and should be helpful for guiding individualized treatment and postoperative surveillance.

Prognostic role of the lymph node ratio in node positive colorectal cancer: a meta-analysis

The lymph node ratio (LNR) (i.e. the number of metastatic lymph nodes divided by the number of totally resected lymph nodes) has recently emerged as an important prognostic factor in colorectal cancer (CRC). However, the tumor node metastasis (TNM) staging system for colorectal cancer does not consider it as a prognostic parameter. Therefore, we conducted a meta-analysis to evaluate the prognostic role of the LNR in node positive CRC. A systematic search was performed in PubMed, Embase and the Cochrane Library for relevant studies up to November 2015. As a result, a total of 75,838 node positive patients in 33 studies were included in this meta-analysis. Higher LNR was significantly associated with shorter overall survival (OS) (HR = 1.91; 95% CI 1.71–2.14; P = 0.0000) and disease free survival (DFS) (HR = 2.75; 95% CI: 2.14–3.53; P = 0.0000). Subgroup analysis showed similar results. Based on these results, LNR was an independent predictor of survival in colorectal cancer patients and should be considered as a parameter in future oncologic staging systems.

Population-based screening improves histopathological prognostic factors in colorectal cancer

INTRODUCTION

Diagnosis of colorectal cancer (CRC) based on clinical symptoms is usually established in its advanced stages. One strategy for reducing mortality is the early detection and removal of preneoplastic and initial neoplastic lesions, even before the first symptoms appear, by means of population-based screening campaigns. The aim of the present study is to determine whether CRC diagnosed via a screening campaign has more favourable histopathological prognostic factors than when diagnosed in the symptomatic phase.

MATERIAL AND METHODS

The prospective study of all the patients undergoing programmed CRC surgery at the JM Morales Meseguer Hospital (Spain) is between 2004 and 2010. The patients were divided into two groups: one diagnosed from clinical symptoms and one through a screening campaign. The following factors were compared: tumour size; degree of tumour invasion of the wall; lymph node, perineural and lymphovascular involvement; tumour stage; and grade of differentiation.

RESULTS

Compared to the symptomatic group, the screen-detected patients had smaller-sized tumours (lesions of less than 5 cm in 84 vs 69.55%, p < 0.001), a lower degree of colorectal wall invasion (T0-1 in 36 vs 9.02%, p < 0.001), less lymph node involvement (N0 in 72 vs 58.76%, p > 0.05), less vascular invasion (7.20 vs 15.22%, p = 0.79) and less perineural invasion (6.4 vs 20.70%, p < 0.001). The TNM staging in the screening group was lower than in the symptomatic group (stage 0-1 in 50.40 vs 18.58%, p < 0.001).

CONCLUSIONS

CRC diagnosed through a population-based screening programme presents more favourable histopathological characteristics than that diagnosed from the appearance of symptoms.

A lymph node ratio of 10% is predictive of survival in stage III colon cancer: a French regional study

Lymph node ratio (LNR) (positive lymph nodes/sampled lymph nodes) is predictive of survival in colon cancer. The aim of the present study was to validate the LNR as a prognostic factor and to determine the optimum LNR cutoff for distinguishing between "good prognosis" and "poor prognosis" colon cancer patients. From January 2003 to December 2007, patients with TNM stage III colon cancer operated on with at least of 3 years of follow-up and not lost to follow-up were included in this retrospective study. The two primary endpoints were 3-year overall survival (OS) and disease-free survival (DFS) as a function of the LNR groups and the cutoff. One hundred seventy-eight patients were included. There was no correlation between the LNR group and 3-year OS (P=0.06) and a significant correlation between the LNR group and 3-year DFS (P=0.03). The optimal LNR cutoff of 10% was significantly correlated with 3-year OS (P=0.02) and DFS (P=0.02). The LNR was not an accurate prognostic factor when fewer than 12 lymph nodes were sampled. Clarification and simplification of the LNR classification are prerequisites for use of this system in randomized control trials. An LNR of 10% appears to be the optimal cutoff.

Clinico-pathological factors influencing lymph node yield in colorectal cancer and impact on survival: analysis of New Zealand Cancer Registry data

BACKGROUND

Lymph node yield (LNY) and lymph node ratio (LNR) are recognized as independent prognostic factors in colorectal cancer (CRC).

OBJECTIVES

To examine the relationship between LNY and other clinico-pathological variables, and the prognostic value of LNY and LNR on patient survival in CRC.

METHODS

The clinico-pathological and survival data for patients diagnosed from January 2000 to July 2012 were retrieved from the New Zealand Cancer Registry. Multiple linear regression was used to identify clinico-pathological factors influencing LNY, and Cox regression was used to determine the association between LNY and LNR and patient survival.

RESULTS

14,646 patients were included in the study (mean age 70.3 years, 50.1% male). Mean LNY was 17.4. Younger age, right-sided disease, higher T stage, female sex and no neoadjuvant radiotherapy (rectal cancer) were all associated with higher LNY (P ≤ 0.001). Overall survival in Stage I-III disease increased with higher LNY (for LNY ≥ 12, HR = 0.67, 95% CI 0.64-0.72; P < 0.001). Survival in Stage III-IV disease was inversely related to LNR (HR = 0.56, 95% CI 0.51-0.62; P < 0.001).

CONCLUSION

LNY is influenced by patient age, site of disease and T stage. LNY (Stage I-II) and LNR (Stage III-IV) have independent prognostic value in CRC.

Prognosis impact of the lymph node ratio in patients with colon adenocarcinoma: a single-centre experience

PURPOSE

Recently, the positive lymph node ratio (LNR) is considered a new prognostic parameter on survival and time to progression for patients with colon cancer. The aim of this study was to determine the prognostic impact of the LNR as an independent factor for overall survival (OS) and disease-free survival (DFS) in patients with colon cancer regardless of their clinical stage.

METHODS

We retrospectively identified 85 consecutive patients diagnosed with colon adenocarcinoma treated in our centre during 2010. We categorized patients according to a LNR cutoff of 0.25. Three-year OS and DFS were determined according to the Kaplan-Meier method. A Cox proportional model was used to assess the influence of other prognostic variables on each outcome.

RESULTS

After median follow-up of 34.8 months, neither median OS nor DFS has been reached by any of the subgroups. Nevertheless, patients with a LNR ≥ 0.25 exhibited a higher risk of death (hazard ratio, 3.10; 95 % confidence interval (CI), 1.38-7.01; log-rank test: p = 0.006) and a shorter interval without progression (hazard ratio, 6.59; 95 % CI, 1.96-22.15; log-rank test: p = 0.002.) than patients with LNR < 0.25. After adjusting for prespecifed variables, the impact of a LNR ≥ 0.25 was independently associated with OS (hazard ratio, 2.8; 95 % CI, 1.01-7.73; p = 0.04) and DFS (hazard ratio, 7.07; 95 % CI, 1.23-40.45; p = 0.03).

CONCLUSIONS

LNR was independently associated with OS and DFS in patients with colon adenocarcinoma regardless of its clinical stage.

Importance of metastatic lymph node ratio in non-metastatic, lymph node-invaded colon cancer: a clinical trial

Background

The aim of this study was to evaluate the prognostic importance of the metastatic lymph node ratio for stage III colon cancer patients and to find a cut-off value at which the overall survival and disease-free survival change.

Material/Methods

Patients with pathological stage III colon cancer were retrospectively evaluated for: age; preoperative values of Crp, Cea, Ca 19-9, and Afp; pathologic situation of vascular, perineural, lymphatic, and serosal involvement; and metastatic lymph node ratio values were calculated.

Results

The study included 58 stage III colon cancer patients: 20 (34.5%) females and 38 (65.5%) males were involved in the study. Multivariate analysis was applied to the following variables to evaluate significance for overall survival and disease-free survival: age, Crp, Cea, perineural invasion, and metastatic lymph node ratio. The metastatic lymph node ratio (<0.25 or ≥0.25) is the only independent variable significant for overall and disease-free survival.

Conclusions

Metastatic lymph node ratio is an ideal prognostic marker for stage III colon cancer patients, and 0.25 is the cut-off value for prognosis.

The prognostic value of lymph node ratio and updated TNM classification in rectal cancer patients with adequate versus inadequate lymph node dissection

BACKGROUND

The aim of this study was to clarify whether the lymph node ratio (LNR) is superior to the updated TNM classification regarding the prognosis of stage III rectal cancer patients who have not undergone neoadjuvant therapy. The TNM system is based on the absolute number of lymph nodes involved, and the LNR takes into account involved and examined nodes.

METHODS

In 237 patients with stage III rectal cancer, we evaluated prognostic factors for 5-year overall survival (OS), disease-free survival (DFS), and risk of distant metastases (DM) using the Kaplan-Meier method, with patients divided based on adequate versus inadequate lymph node dissection (≥12 vs. <12 lymph nodes examined). The updated TNM divides patients into four groups (1, 2-3, 4-6, and ≥7 involved nodes), while LNR divides patients into quartiles. Multivariate Cox regression analyses were performed.

RESULTS

Among patients with adequate lymph node dissection, the distributions within the two systems were in agreement in 141/178 (79.2 %, kappa 0.721), and the predictive values for OS, DFS, and DM were similar. In patients with inadequate lymph node dissection, the classifications of both systems were concordant in only 13/59 (22 %, kappa 0.021). The pN system significantly under-staged patients, while the LNR classification was a better predictor of OS, DFS, and DM.

CONCLUSIONS

In patients with adequate lymph node dissection, LNR staging does not add substantial information to the predictions of updated TNM lymph node staging. However, in patients with inadequate lymph node harvesting, the LNR compensates for the under-staging of the TNM classification and provides a better estimation of prognosis than the updated TNM system.

Prognostic value of lymph node ratios in node positive rectal cancer treated with preoperative chemoradiation

BACKGROUND

To investigate the impact of the lymph node ratio (LNR) on the prognosis of patients with locally advanced rectal cancer undergoing pre-operative chemoradiation.

METHODS

Clinicopathologic and follow up data of 128 patients with stage III rectal cancer who underwent curative resection from 1996 to 2007 were reviewed. The patients were divided into two groups according to the lymph node ratio: LNR ≤ 0.2 (n=28), and >0.2 (n=100). Kaplan-Meier and the Cox proportional hazard regression models were used to evaluate the prognostic effects according to LNR.

RESULTS

Median numbers of lymph nodes examined and lymph nodes involved by tumour were 10.3 (range 2-28) and 5.8 (range 1-25), respectively, and the median LNR was 0.5 (range, 0-1.6). The 5-year survival rate significantly differed by LNR (≤ 0.2, 69%; >0.2, 19%; Log-rank p value < 0.001). LNR was also a significant prognostic factor of survival adjusted for age, sex, post-operative chemotherapy, total number of examined lymph nodes, metastasis and local recurrence (≤ 0.2, HR=1; >0.2, HR=4.8, 95%CI=2.1-11.1) and a significant predictor of local recurrence and distant metastasis during follow-up independently of total number of examined lymph node.

CONCLUSIONS

Total number of examined lymph nodes and LNR were significant prognostic factors for survival in patients with stage III rectal cancer undergoing pre-operative chemoradiotherapy.

The prognostic value of ratio-based lymph node staging in resected non-small-cell lung cancer

INTRODUCTION

Assessment of lymph node status is a critical issue in the surgical management of non-small-cell lung cancer (NSCLC). We sought to determine the prognostic value of metastatic lymph node ratio (LNR) in patients with radical surgery for NSCLC.

METHODS

We abstracted data from 480 consecutive patients undergoing radical surgery for NSCLC between 2006 and 2008 in our institution. Kaplan-Meier estimated the survival function using the number of metastatic lymph node (MLN) and LNR as categorized variables. The prognostic value of age, sex, smoking status, location of tumor, histology, pathology T stage, pathology N stage, surgical procedure, chemotherapy, MLN, and LNR were assessed using a multivariate Cox proportional hazards model for overall survival (OS) and disease-free survival (DFS).

RESULTS

The median numbers of examined lymph nodes and MLNs were 15 and 5, respectively. Optimal cutpoints of the LNR were calculated as 0, 0 to 0.35, and greater than 0.35. Patients with higher LNR were associated with worse OS and DFS in the whole series, whereas there was no significant difference in the OS and DFS of those patients classified as pathology N2. A multivariate analysis showed that the LNR staging, smoking status, and chemotherapy were revealed to be independent prognostic factors.

CONCLUSIONS

LNR is an independent predictor of survival in patients with NSCLC undergoing radical resection; the prognostic significance is more valuable in patients classified as pathology N1.

Prognostic implications of lymph node yield and lymph node ratio in papillary thyroid carcinoma

BACKGROUND

The lymph node yield (LNY) and the lymph node ratio (LNR) have been shown to be important prognostic factors in oral, colon, and gastric cancers. The role of the LNY and LNR in papillary thyroid cancer (PTC) is unclear. The aims of this study were to determine if a high LNR and a low LNY decrease disease-free survival rates. This study further aimed to determine an optimum nodal yield.

METHODS

A retrospective analysis was conducted of 198 patients with PTC undergoing total thyroidectomy with neck dissection between 1987 and 2011. The LNY and LNR were adjusted by relevant covariates in a multivariate Cox regression analysis with Andersen-Gill extension.

RESULTS

The LNR was associated with a decrease in disease-free survival (hazard ratio 3.2 [95% confidence interval 1.4-7.3], p=0.005). Patients with an LNR of 0.30 or higher had a 3.4 times higher risk of persistent or recurrent disease compared with patients with an LNR of 0.00 ([95% confidence interval 1.1-10.5], p=0.031). Conversely, patients with an LNR of 0.11 or lower had an 80% chance of remaining disease free during 5 years of follow-up. The LNY showed no significant independent effect and an optimum nodal yield was not determined.

CONCLUSIONS

The LNR is an important independent prognostic factor in PTC and can be used in conjunction with existing staging systems. A clinical relevant cut-off point of 0.3 (one positive lymph node out of three total) is proposed. No prognostic implications for LNY were identified.

Prognostic impact of the metastatic lymph node ratio on survival in rectal cancer

Purpose

Lymph-node metastasis is the most important predictor of survival in stage III rectal cancer. The number of metastatic lymph nodes may vary depending on the level of specimen dissection and the total number of lymph nodes harvested. The aim of this study was to evaluate whether the lymph node ratio (LNR) is a prognostic parameter for patients with rectal cancer.

Methods

A retrospective review of a database of rectal cancer patients was performed to determine the effect of the LNR on the disease-free survival (DFS) and the overall survival. Of the total 228 patients with rectal cancer, 55 patients with stage III cancer were eligible for analysis. Survival curves were estimated using the Kaplan-Meier method. Cox regression analyses, after adjustments for potential confounders, were used to evaluate the relationship between the LNR and survival.

Results

According to the cutoff point 0.15 (15%), the 2-year DFS was 95.2% among patients with a LNR < 0.15 compared with 67.6% for those with LNR ≥ 0.15 (P = 0.02). In stratified and multivariate analyses adjusted for age, gender, histology and tumor status, a higher LNR was independently associated with worse DFS.

Conclusion

This study showed the prognostic significance of ratio-based staging for rectal cancer and may help in developing better staging systems. LNR 0.15 (15%) was shown to be a cutoff point for determining survival and prognosis in rectal cancer cases.

The relation between lymph node status and survival in Stage I-III colon cancer: results from a prospective nationwide cohort study

AIM

This study involved a large nationwide Danish cohort to evaluate the hypothesis that a high lymph node harvest has a positive effect on survival in curative resected Stage I-III colon cancer and a low lymph node ratio has a positive effect on survival in Stage III colon cancer.

METHOD

Analysis of overall survival was conducted using a nationwide Danish cohort of patients treated with curative resection of Stage I-III colon cancer. All 8901 patients in Denmark diagnosed with adenocarcinoma of the colon and treated with curative resection in the period 2003-2008 were identified from the Danish Colorectal Cancer Group (DCCG). The impact of lymph node count and lymph node ratio was analysed.

RESULTS

Overall 5-year survival was 56.8 and 66.6%, (P < 0.0001) for lymph node counts of fewer than 12 and 12 or more, respectively. The percentages of lymph node positive patients in the two groups were 29.8 and 40.3% (P < 0.0001), respectively. When putting the Stage III patients into four subgroups according to the lymph node ratio (cut-off points 1/12, 1/4 and 1/2) we found an overall 5-year survival rate of 68.1, 57.2, 49.3 and 32.4% (P < 0.0001). Lymph node count and lymph node ratio were independent prognostic factors in multivariate analysis.

CONCLUSION

High lymph node count was associated with improved overall survival in colon cancer. Lymph node ratio was superior to N-stage in differentiating overall survival in Stage III colon cancer. Stage migration was observed.

Qualitative and quantitative issues of lymph nodes as prognostic factor in colon cancer

For patients undergoing curative resections for colon cancer, the nodal status represents the strongest prognostic factor, yet at the same time the most disputed issue as well. Consequently, the qualitative and quantitative aspects of lymph node evaluation are thus being scrutinized beyond the blunt distinction between 'node positive' (pN+) and 'node negative' (pN0) disease. Controversy ranges from a minimal or 'least-unit' strategy as exemplified by the 'sentinel node' to a maximally invasive or 'all inclusive' approach by extensive surgery. Ranging between these two extremes of node sampling strategies are factors of quantitative and qualitative value, which may be subject to modification. Qualitative issues may include aspects of lymph node harvest reflected by surgeon, pathologist and even hospital performance, which all may be subject to modification. However, patient's age, gender and genotype may be non-modifiable, yet influence node sample. Quantitative issues may reflect the balance between absolute numbers and models investigating the relationships of positive to negative nodes (lymph node ratio; log odds of positive lymph nodes). This review provides an updated overview of the current controversies and a state-of-the-art perspective on the qualitative and quantitative aspects of using lymph nodes as a prognostic marker in colon cancer.

Dukes C colorectal cancer: is the metastatic lymph node ratio important?

PURPOSE

Although the regional lymph node status is essential for staging of colorectal cancer, the importance of the total number of collected nodes remains controversial. Our aim was to examine the impact of the metastatic lymph node ratio (LNR) on the survival of patients with Dukes C colorectal cancer.

METHODS

All patients with Dukes C histology were selected from a prospectively collected database of all colorectal cancers resected between 1997 and 2007 at our institution. Demographic, histopathological and adjuvant treatment data were collected. The total number of positive lymph nodes was divided by the total number of lymph nodes examined to calculate the LNR. Patients were categorised into LNR groups 1 to 5 according to cut-off points: ≤0.1, 0.21, 0.36, 0.6 and ≥0.61. Survival from the date of operation was calculated using Kaplan-Meier estimates. Multivariate analysis was performed to identify those factors influencing survival.

RESULTS

Of 1,098 patients who underwent colorectal cancer resections, 41% were staged as Dukes C. Sixty-four percent of patients received chemotherapy. The median number of lymph nodes harvested and positive for tumour were 11 (range 1-52) and 4 (range 1-28), respectively. In patients who received chemotherapy, 5-year survival was 69.3% for LNR 1 and 23.6% for LNR 5. When no chemotherapy was given, the 5-year survival was 43.1% for LNR 1 and 8.7% for LNR 5.

CONCLUSIONS

Current evaluation of positive lymph nodes may not accurately stage Dukes C colorectal cancer. The assessment of the LNR is a useful prognostic method in this heterogenous group of patients.

Salvage colectomy for endoscopically removed malignant colon polyps: is it possible to determine the optimal number of lymph nodes that need to be harvested?

AIM

The total number of lymph nodes examined after salvage colectomy for endoscopically removed malignant polyps was evaluated and an attempt was made to determine whether there was an optimal number of lymph nodes that should be harvested.

METHOD

From 2000 to 2009, 531 patients underwent segmental resection for non-metastatic colon cancer. Of these, 22 underwent a salvage colectomy for an endoscopically removed malignant polyp, the main indication for which was a resection margin of < 1 mm. The surgical procedure was identical to that used for all colon cancers.

RESULTS

The mean number of lymph nodes examined was 11.6 ± 7.6 for the 22 patients with an endoscopically removed malignant polyp and 26.2 ± 13.9 for the remaining 509 patients (P = 0.0006). Fewer than 12 lymph nodes were examined in 62 (12%) of the 509 patients and in 13 (59%) of the 22 patients with an endoscopically removed malignant polyp (P < 0.0001). In the group of 22 patients who underwent a salvage colectomy, the total number of lymph nodes examined ranged from 2 to 33. At a mean follow up of 41 ± 15.6 months, no local or distant recurrence was observed in the 22 patients.

CONCLUSION

The total number of lymph nodes examined after colectomy for endoscopically removed malignant polyps varies and is less than the recommended number of 12 in most cases: this does not appear to have long-term prognostic significance. There is no biological reason to explain this clinical observation.

Impact of lymph node retrieval on surgical outcomes in colorectal cancers

BACKGROUND

Adequacy of lymph node sampling is fundamental to the accuracy of nodal status (N-status) assessment in colorectal cancers (CRCs). This study aimed to determine the minimum sampling number to achieve reliable prognosis and to look for any association between the positive lymph node ratio (LNR) and overall survival (OS). Pathological reports of 533 stages I-III CRC patients who underwent curative resection during the period from January 1998 to December 2007 were retrospectively reviewed with regard to the number of lymph nodes obtained for pathological diagnosis (nLN) and number of positive nodes.

RESULTS

The median nLN was 10 nodes and the mean number of positive nodes was 1.7 nodes. On the N-status attribution plot, the cut-off point where the converging curves turned parallel was at 12 nodes. This cut-off was supported by the significant difference in OS between cases with nLN ≥ 12 (5-year OS 73.0%) and those with nLN < 12 (5-year OS 62.7%), (P-value < 0.01). Multivariate analysis showed that both nLN-12 and LNR were independent factors predicting survival probability.

CONCLUSION

Our data emphasize the importance of lymph node harvesting during the surgical resection of CRCs. In addition, LNR is a strong independent factor associated with CRC survival.

Dukes C colorectal cancer: is the metastatic lymph node ratio important?

PURPOSE

Although the regional lymph node status is essential for staging of colorectal cancer, the importance of the total number of collected nodes remains controversial. Our aim was to examine the impact of the metastatic lymph node ratio (LNR) on the survival of patients with Dukes C colorectal cancer.

METHODS

All patients with Dukes C histology were selected from a prospectively collected database of all colorectal cancers resected between 1997 and 2007 at our institution. Demographic, histopathological and adjuvant treatment data were collected. The total number of positive lymph nodes was divided by the total number of lymph nodes examined to calculate the LNR. Patients were categorised into LNR groups 1 to 5 according to cut-off points: ≤0.1, 0.21, 0.36, 0.6 and ≥0.61. Survival from the date of operation was calculated using Kaplan-Meier estimates. Multivariate analysis was performed to identify those factors influencing survival.

RESULTS

Of 1,098 patients who underwent colorectal cancer resections, 41% were staged as Dukes C. Sixty-four percent of patients received chemotherapy. The median number of lymph nodes harvested and positive for tumour were 11 (range 1-52) and 4 (range 1-28), respectively. In patients who received chemotherapy, 5-year survival was 69.3% for LNR 1 and 23.6% for LNR 5. When no chemotherapy was given, the 5-year survival was 43.1% for LNR 1 and 8.7% for LNR 5.

CONCLUSIONS

Current evaluation of positive lymph nodes may not accurately stage Dukes C colorectal cancer. The assessment of the LNR is a useful prognostic method in this heterogenous group of patients.

Clinical Significance of Lymph Node Ratio in Stage III Colorectal Cancer

Purpose

Recent literature has shown that lymph node ratio is superior to the absolute number of metastatic lymph nodes in predicting the prognosis in several malignances other than colorectal cancer. The aim of this study was to evaluate the prognostic significance of the lymph node ratio (LNR) in patients with stage III colorectal cancer.

Methods

We included 186 stage III colorectal cancer patients who underwent a curative resection over a 10-year period in one hospital. The cutoff point of LNR was chosen as 0.07 because there was significant survival difference at that LNR. The Kaplan-Meier and the Cox proportional hazard models were used to evaluate the prognostic effect according to LNR.

Results

There was statistically significant longer overall survival in the group of LNR > 0.07 than in the group of LNR ≤ 7 (P = 0.008). Especially, there was a survival difference for the N1 patients group (LN < 4) according to LNR (5-year survival of N1 patients was lower in the group of LNR > 0.07, P = 0.025), but there was no survival difference for the N2 group (4 ≥ LN) according to LNR. The multivariate analysis showed that the LNR is an independent prognostic factor.

Conclusions

LNR can be considered as a more accurate and potent modality for prognostic stratifications in patients with stage III colorectal cancer.

Lymph node ratio is a powerful prognostic index in patients with stage III distal rectal cancer: a Japanese multicenter study

PURPOSE

The present study aims to define the prognostic impact of the lymph node ratio (LNR) in patients with stage III distal rectal cancer.

METHODS

We analyzed data from 501 patients who underwent curative resection (total mesorectal excision, TME) for stage III distal rectal cancer at 12 institutions between 1991 and 1998. Patients were divided into four groups according to quartiles based on LNR.

RESULTS

Among the 501 patients, 381 underwent TME with pelvic sidewall dissection (PSD). The median numbers of lymph nodes retrieved with and without PSD were 45 and 17, respectively (P < 0.0001). Forty-nine patients with lymph node retrieved less than 12 were excluded from further analyses. Among various clinicopathological parameters, univariate analysis identified age (P = 0.0059), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0003), and number of positive nodes (P < 0.0001) and LNR (P < 0.0001) as prognostic factors. The Cox proportional hazards model revealed that age (P = 0.014), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0002), and LNR (group 3, P = 0.0012; group 4, P < 0.0001) were independent prognostic factors. When the American Joint Committee on Cancer (AJCC) seventh staging system was added as a covariate, both AJCC stage (P < 0.0001) and LNR (P < 0.0001) were independent prognostic factors.

CONCLUSIONS

Adding the LNR concept to the AJCC cancer staging system will improve accuracy in evaluating the nodal status of distal rectal cancer.

Impact of metastatic lymph node ratio in node-positive colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant diseases in the world. Presently, the most widely used staging system for CRC is the tumor nodes metastasis classification system, which classifies patients into prognostic groups according to the depth of the primary tumor, presence of regional lymph node (LN) metastases, and evidence of distant metastatic spread. The number of LNs with confirmed metastasis is related to the severity of the disease, but this number depends on the number of LNs retrieved, which varies depending on patient age, tumor grade, surgical extent, and tumor site. Numerous studies and a recent structured review have demonstrated associated improvements in the survival of CRC patients with increasing numbers of LNs retrieved for examination. Hence, the impact of lymph node ratio (LNR), defined as the number of metastatic LNs divided by the number of LNs retrieved, has been investigated in various malignancies, including CRC. In this editorial, we review the literature demonstrating the clinicopathological significance of LNR in CRC patients. Some reports have indicated the advantage of considering the LNR compared to the number of LNs retrieved and/or LN status. When the LNR is taken into consideration for survival analysis, the number of LNs retrieved and/or the LN status is not always found to be a prognostic factor. The cut-off points for LNRs were proposed in numerous studies. However, optimal thresholds for LNRs have not yet received consensus. It is still unclear whether the LNR has more prognostic validity than N stage. For all these reasons, the potential advantages of LNRs in the staging system should be investigated in large prospective data sets.