lymph node ratio as a prognostic factor in patients with stage III rectal cancer treated with total mesorectal excision followed by chemoradiotherapy

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.

Prognostic implication of metastatic lymph node ratio in node-positive rectal cancer

PURPOSE

The aim of this study was to evaluate the prognostic significance of the ratio between metastatic and examined lymph nodes (LNs) in patients with stage III rectal cancer.

METHODS

A review was made of 175 (male, 98) patients with stage III rectal cancer of R0 resection. LN disease was stratified both by the American Joint Committee on Cancer/International Union Against Cancer nodal classification (pN) and by quartiles of the lymph node ratio (LNR). Disease-free survivals (DFS) were made using Kaplan-Meier curves and assessed by the log rank test and multivariate analysis was performed using the Cox proportional hazards model.

RESULTS

Patients ranged in age from 29 to 83 (median, 60) years with median follow-up of 47 months (range, 13 to 181 months). months. There was a significant correlation between the number of metastatic LNs and the LNR (r = 0.8681, P < 0.0001). Cut-off points of LNR quartiles best to separate patients with regard to 5-year DFS were between quartile 2 and 3, and between 3 and 4 (LNR1, 2, and 3); the 5-year DFS according to such stratification was 89.6%, 55.8%, and 18.2% in LNR1, 2, and 3, respectively (P < 0.0001). Cox model identified the LNR as the most significant independent prognostic covariate; LNR2 showed 3.6 times (95% confidence interval [CI], 1.682 to 7.584; P = 0.0009) and LNR3, 18.7 times (95% CI, 6.872 to 50.664; P < 0.0001) more risky than LNR1.

CONCLUSION

This study suggests that ratio-based LN staging, which reflects the number of LNs examined and the quality of LN dissection, is a simple and reliable system for prognostic LN stratification in patients with stage III rectal cancer.

Prognostic Significance of Lymph Node Ratio in Stage III Rectal Cancer

Purpose

Although nodal metastasis is the most powerful prognostic factor in rectal cancer, marked heterogeneity exists within stage III rectal cancer. Recent studies of rectal cancer have shown a prognostic superiority of the lymph node ratio (LNR) compared with N stage. The purpose of this study was to investigate the prognostic value of the LNR in the era of the 7th edition of the TNM classification.

Methods

We included 190 patients who underwent a curative resection for rectal cancer with nodal metastasis. The patients were divided into four groups on the basis of statistically calculated cut-off values as 0.21, 0.32, and 0.61.

Results

The LNR was an independent risk factor for overall survival (OS; P = 0.008) and for systemic recurrence-free survival (SRFS; P = 0.002). However, the LNR was not a predictive factor for local recurrence. When the N stage of the sixth TNM staging system was separately analyzed as a covariate, the LNR was also found to be a predictive factor for both OS and SRFS (P = 0.012 and P = 0.004, respectively). A LNR value of 0.21 offered the best cut off to separate patients into two prognostic groups.

Conclusion

The defined cut-off values of the LNR were an independent risk factor for OS and distant metastasis-free survival in patients with rectal cancer, irrespective of the sixth or the seventh version of the TNM classification, and the LNR should be considered as a prognostic variable in any future staging system.

Prognostic implications of lymph node metastases in carcinoma of the body and tail of the pancreas

OBJECTIVE

The current classification of pancreatic cancer is based only on anatomic location of metastatic lymph nodes (LNs). On the other hand, the number of metastatic LNs has been used in staging of colorectal, esophageal, and gastric cancers. The aim of this study was to assess the prognostic impact of the number or ratio of the metastatic LNs in pancreatic body and tail carcinoma.

METHODS

Eighty-five patients with pancreatic body and tail adenocarcinoma who underwent pancreatectomy were included. Location, number, ratio of metastatic LNs, and the survival of patients were analyzed.

RESULTS

Forty patients with LN metastasis had poor prognosis (P = 0.007). The prognoses of patients with 5 or more metastatic LNs were poorer than those with less than 5 metastatic LNs (P = 0.046), and patients with a metastatic LN ratio of 0.2 or more had the worst prognosis. Multivariate analysis revealed that 5 or more metastatic LNs and metastatic LN ratio of 0.2 or more were independent prognostic factors for survival (P = 0.0015 and P = 0.014, respectively).

CONCLUSION

These results indicate that the number and the ratio of metastatic LNs can be used to predict poor patient survival and as a staging strategy.

Prognostic value of lymph node ratio in stage III colorectal cancer

AIM

Recent reports show that a positive metastatic to examined lymph nodes ratio (LNR) has prognostic value in malignancies. This study aimed to evaluate the prognostic value of LNR in patients having resection for stage III colorectal cancer.

METHOD

From January 2000 to December 2006, patients who underwent resection for stage III colorectal carcinoma were included. All clinicopathological and follow-up data were prospectively collected. The impact of LNR and other clinicopathological factors on survival were evaluated.

RESULTS

The study included 533 (52.3% male) patients with a median age of 70 years. The median number of lymph nodes harvested and the median number of positive lymph nodes examined were 11 and 2, respectively. The median LNR was 0.263 (range, 0.03-1). After a median follow up of 52.65 months, the 5-year overall survival and disease-free survival were 55.9% and 49.4%. The patients were stratified into four groups according to LNR quartiles (1, LNR ≤ 0.125; 2, 0.125<LNR≤0.263; 3, 0.263<LNR≤0.500; 4, LNR>0.500). The 5-year overall and disease-free survival were 72.8%, 63.1%, 50.0%, 39.6% (P<0.001) and 68.5%, 54.1%, 47.2%, 29.9% (P<0.001), respectively, with increasing LNR groups. On multivariate analysis, age, T stage and LNR were independent predictors of both overall and disease-free survival. Subgroup analysis revealed that the LNR had a prognostic value for disease-free survival irrespective of number of lymph nodes harvested and location of tumour.

CONCLUSION

The LNR is an independent prognostic factor for survival in colorectal cancer and is superior to the pN category in TNM staging.

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.

Quantitative analysis and prediction of regional lymph node status in rectal cancer based on computed tomography imaging

OBJECTIVES

To quantitatively evaluate regional lymph nodes in rectal cancer patients by using an automated, computer-aided approach, and to assess the accuracy of this approach in differentiating benign and malignant lymph nodes.

METHODS

Patients (228) with newly diagnosed rectal cancer, confirmed by biopsy, underwent enhanced computed tomography (CT). Patients were assigned to the benign node or malignant node group according to histopathological analysis of node samples. All CT-detected lymph nodes were segmented using the edge detection method, and seven quantitative parameters of each node were measured. To increase the prediction accuracy, a hierarchical model combining the merits of the support and relevance vector machines was proposed to achieve higher performance.

RESULTS

Of the 220 lymph nodes evaluated, 125 were positive and 95 were negative for metastases. Fractal dimension obtained by the Minkowski box-counting approach was higher in malignant nodes than in benign nodes, and there was a significant difference in heterogeneity between metastatic and non-metastatic lymph nodes. The overall performance of the proposed model is shown to have accuracy as high as 88% using morphological characterisation of lymph nodes.

CONCLUSIONS

Computer-aided quantitative analysis can improve the prediction of node status in rectal cancer.

Prognostic impact of the lymph node ratio in rectal cancer patients who underwent preoperative chemoradiation

AIM

The purpose of this study was to investigate the prognostic impact of the lymph node ratio (LNR) in ypN-positive rectal cancer patients who received preoperative chemoradiation (preop-CRT).

METHODS

A total of 75 patients diagnosed as node-positive after undergoing preop-CRT followed by curative resection were enrolled. Patients were categorized into two groups based on their median LNR, 0.143.

RESULTS

The median metastatic and retrieved lymph node numbers were 2.0 (range: 1-79) and 18.0 (range: 5-80). Abdominoperineal resection, circumferential resection margin involvement and higher LNR were proven to be independent adverse prognostic factors affecting survival in the multivariate analysis including LNR as a covariate. Of the 47 patients with ypN1, 35 (74.5%) showed a lower LNR (N1G1) and 12 (25.5%) showed a higher LNR (N1G2). The N1G1 group showed better overall survival than the N1G2 group (P = 0.018). There was no difference between the survival rates of the N1G2 group and the ypN2 group (P = 0.987).

CONCLUSIONS

LNR is an independent prognostic factor after preop-CRT for rectal cancer. LNR showed better prognosis stratification than the ypN stage. Therefore, LNR should be considered as an additional prognostic factor in node-positive rectal cancer after preop-CRT.

The prognostic value of lymph node ratio after neoadjuvant chemoradiation and rectal cancer surgery

BACKGROUND

Neoadjuvant chemotherapy decreases total lymph nodes harvested and possibly affects lymph node staging after total mesorectal excision in patients with rectal cancer.

OBJECTIVE

This study aimed to compare staging by lymph node ratio with staging by absolute number of positive lymph nodes.

DESIGN

This study is a retrospective cohort review.

SETTING

: A tertiary care referral center was the setting for this investigation.

PATIENTS

A total of 281 consecutive patients who underwent neoadjuvant chemoradiation and total mesorectal excision after histologically confirmed rectal cancer between January 1, 1998 and December 31, 2008 were included in this study.

MAIN OUTCOME MEASURES

Lymph node ratio is the number of positive lymph nodes divided by the total number of lymph nodes within one sample. Risk categories of low (0 to < 0.09); medium (0.09 to < 0.36); and high (≥ 0.36) for lymph node ratio were chosen by significance with the use of Cox proportional hazards models. These categories were then used in a reclassification table and compared with positive lymph node stage: low (0 positive nodes), medium (1-3 nodes), and high (> 3) by 5-year mortality rates.

RESULTS

The majority (87%) of patients were concordant in risk assessment. Thirty patients were downstaged to lower risk lymph node ratio categories without showing actual lower mortality rates. Seven patients were upstaged to a high-risk lymph node ratio category with a supporting higher 5-year mortality rate. When limiting the analysis to those with fewer than 12 nodes, 136 (95%) patients were concordant in risk assessment; all 30 incorrectly downstaged patients were removed, but the 7 correctly upstaged patients remained.

CONCLUSIONS

Patients who undergo neoadjuvant chemoradiation before rectal cancer surgery frequently have fewer than 12 lymph nodes harvested despite maintaining vigorous surgical standards. Lymph node ratios may provide excellent prognostic value and are possibly a better independent staging method than absolute positive lymph node counts when less than 12 lymph nodes are harvested after neoadjuvant treatment.

Ratio of metastatic to resected lymph nodes enhances to predict survival in patients with stage III colorectal cancer

BACKGROUND

The objective of this study was to assess the value of metastatic lymph node ratio in predicting prognosis of patients with stage III colorectal cancer.

METHODS

From 2000 to 2005 inclusively, a total of 626 patients featuring stage III colorectal cancer underwent curative resection. These patients were stratified into LNR groups: 1 (0 < LNR ≤ 0.1); 2 (0.1 < LNR ≤ 0.25); 3 (0.25 < LNR ≤ 0.5); and 4 (LNR > 0.5). The follow-up was closed in April 2010. Kaplan-Meier survival curve and log-rank test were used to evaluate the prognostic value of LNR. A Cox regression model was used for multivariate analyses.

RESULTS

With a median follow-up period of 42.2 months, 5-year overall survival for groups LNR1, LNR2, LNR3, and LNR4 was 73%, 64%, 44%, and 22%, respectively. In the multivariate analysis, the LNR was an independent prognostic factor for survival (P < 0.001). LNR remained statistically significant (P < 0.001), both in patients with colon and rectum cancer regardless of the number of lymph nodes retrieved (≥12 or < 12). The survival rate of ratio group LNR1 was better than ratio group LNR4 (P < 0.001) for patients with the same IIIB or IIIC staging.

CONCLUSIONS

LNR is an accurate prognostic method for patients with stage III colorectal cancer. We proposed an algorithm to incorporate LNR into current AJCC staging system to form new staging.

Metastatic lymph node ratio in stage III rectal cancer; prognostic significance in addition to the 7th edition of the TNM classification

AIMS

Optimal staging in rectal cancer is indispensable for the decision on further treatment and estimation of prognosis. This study assesses the prognostic capacity of the metastatic lymph node ratio (LNR) in addition to the new TNM classification.

METHODS

LNR was determined, in stage III patients from the Dutch TME-trial. Six year median follow up data from the trial database were used to analyse the relation of LNR to overall survival (OS) and local recurrence (LR). The relation of LNR to lymph node yield was assessed and appropriate cut off values of LNR for clinical use were determined.

RESULTS

605 patients were analyzed. 278 underwent pre-operative radiotherapy. 82 patients developed a local recurrence and 289 distant metastases. LNR was an independent risk factor for OS, hazard ratio (HR) 2.10 (95% CI 1.35-3.27) (in addition to age >= 65 years, involved circumferential resection margin (CRM) and new TNM stage) and LR, HR 2.25 (95% CI 1.02-4.56) (in addition to pre-operative radiotherapy and involved CRM). LNR is predictive of OS and LR from a lymph node yield of more than one and more than five respectively. A LNR value of 0.60 offers the best cut off to identify high risk patients (5-years OS was 61 vs. 32%, HR 2.45 (95% CI 1.96-3.08) and 5-years LR rate 12.6 versus 16.3%, HR 1.65 (95% CI 1.03-2.64)).

CONCLUSIONS

LNR is an independent risk factor for OS and LR in addition to the 7th edition of the TNM classification. It can aid in predicting prognosis and identifying patients that should be considered for adjuvant treatment.

Prognostic value of the lymph node ratio in stage III colorectal cancer: a systematic review

BACKGROUND

Although nodal invasion represents one of the most powerful prognostic indicators in colorectal cancer, marked heterogeneity exists within stage III patients. Recently, the lymph node ratio (LNR), defined as the ratio of the number of positive nodes over the total number of examined nodes, was proposed to stratify outcome in stage III patients.

METHODS

A systematic search was performed for studies examining the prognostic significance of the LNR in colon or rectal cancer. Individual studies were assessed for methodological quality and summary data extracted. Hazard ratios from multivariate analyses were entered in a fixed-effects meta-analysis model.

RESULTS

In total, 16 studies were identified including 33,984 patients with stage III colon or rectal cancer. In all identified studies, the LNR was identified as an independent prognostic factor in patients with stage III cancer of the colon or rectum. The prognostic separation obtained by the LNR was superior to that of the number of positive nodes (N stage). The pooled hazard ratios for overall and disease-free survival were 2.36 (95% confidence interval, 2.14-2.61) and 3.71 (95% confidence interval, 2.56-5.38), respectively.

CONCLUSIONS

The LNR allows superior prognostic stratification in stage III colorectal cancer and should be validated in prospective studies.

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.

Ratio of metastatic to resected lymph nodes as a prognostic factor in node-positive colorectal cancer

BACKGROUND

This study was designed to assess the prognostic value of the ratio of metastatic to resected lymph nodes (lymph node ratio [LNR]) in patients with node-positive colorectal cancer (CRC).

METHODS

From May 1998 to December 2007, data from a total of 514 patients who underwent curative surgery for CRC with proven lymph node metastases were analyzed. Patients were categorized into four groups on the basis of quartiles: LNR1 (<0.09), LNR2 (between 0.09 and 0.18), LNR3 (>0.18 and <0.34), and LNR4 (≥0.34).

RESULTS

The median numbers of resected and metastatic nodes were 14 (range, 2-67) and 2 (range, 1-31), respectively. With a median follow-up period of 48.5 months, the 5-year overall survival rates of patients with LNR1, LNR2, LNR3, and LNR4 were 79, 72, 62, and 55%, respectively (P < 0.001); the 5-year disease-free survival rates of patients with LNR1, LNR2, LNR3, and LNR4 were 73, 67, 54, and 42%, respectively (P < 0.001). In the multivariate analysis, the LNR was an independent prognostic factor for both overall (P = 0.012) and disease-free survival (P = 0.009), as were pT and pN category. LNR remained statistically significant both in patients with <12 and with >12 nodes retrieved.

CONCLUSIONS

In addition to the conventional pT and pN categories, the LNR was a predictor of both the overall and disease-free survival in patients with node-positive CRC. It may compensate for an inadequate lymph node dissection in surgery for CRC.

Locally advanced rectal cancer: from molecular profiling to clinical practice. A literature review: Part 2

Colorectal cancer is the third most common cause of cancer deaths worldwide. The management of rectal cancer has undergone, and continues to undergo, significant evolutions. In the last two decades, new multimodality strategies have been developed. The ability to predict tumor response before treatment could significantly impact the selection of patients for preoperative combined-modality therapy, as well as potentially modify postoperative treatment plans. The present review analyzes the new molecular targets that could be involved in predicting response and prognosis.