The lymph node ratio optimises staging in patients with node positive colon cancer with implications for adjuvant chemotherapy

Lymph Node Ratio as a Predictor of Survival for Colon Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Lymph node ratio is the number of lymph nodes with evidence of metastases on pathological review compared to the total number of lymph nodes harvested during oncologic resection. Lymph node ratio is a proven predictor of long-term survival. These data have not been meta-analyzed to determine the prognosis associated with different lymph node ratio cut-offs in colon cancer.

METHODS

Medline, Embase, and CENTRAL were systematically searched. Articles were included if they compared 5-year overall survival (OS) or disease-free survival (DFS) between different lymph node ratios for patients undergoing oncologic resection for stages I-III colon cancer. Pairwise meta-analyses using inverse variance random effects were performed.

RESULTS

From 2587 citations, nine studies with 97,631 patients (female: 51.9%, median age: 61.65 years) were included. A lymph node ratio above .1 resulted in a 49% decrease in the odds of 5-year OS (2 studies; OR: 0.51, 95% CI: 0.49-.53, P < .00001). A lymph node ratio above .25 resulted in a 56% decrease in the odds of 5-year OS (3 studies; OR: 0.44, 95% CI: 0.43-.45, P < .00001). A lymph node ratio above .5 resulted in a 65% decrease in the odds of 5-year OS (3 studies; OR: 0.35, 95% CI: 0.33-.37, P < .00001).

CONCLUSIONS

Lymph node ratios from .1 to .5 are effective predictors of 5-year OS for colon cancer. There appears to be an inverse dose-response relationship between lymph node ratio and 5-year OS. Further study is required to determine whether there is an optimal lymph node ratio cut-off for prognostication and whether it can inform which patients may benefit from more aggressive adjuvant therapy and follow-up protocols.

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.

The Prognostic Significance of Lymph Node Status and Lymph Node Ratio (LNR) on Survival of Right Colon Cancer Patients: a Tertiary Center Experience

BACKGROUND

Colon cancer is a major health problem and is one of the most frequent cancers all over the world. In Egypt, the incidence of colon cancer is relatively low, but its mortality rate is high. Lymphatic spread of colon cancer is one of the most important factors affecting the prognosis of patients. Recently, the lymph node ratio (LNR) has been evaluated as a prognostic parameter for survival. This study aimed at evaluation of nodal status of resected specimens and LNR, as well as its impact on the disease-free survival (DFS) and overall survival (OS) after curative resection of right colon cancer.

METHODS

The institutional registry of the Oncology Center Mansoura University (OCMU) was revised for node-positive right colon cancer cases that were operated in the period between January 2010 and January 2015. Fifty-three patients met the inclusion criteria and were followed up till January 2020.

RESULTS

A total of 766 lymph nodes were excised from the patients. Thirty-two patients (60.4%) had a LN yield of ≥12 LNs with a mean LNR of 0.257 ± 0.27. Multivariate analysis of outcomes showed that LNR was significantly correlated with both DFS (p = 0.015) and OS (p = 0.024). Moreover, the number of resected LNs was also associated with statistically significant relationship with the DFS and OS.

CONCLUSION

Our study confirms the validity of LNR as a prognostic tool that correlates with the survival of patients. Moreover, LNR cutoff values may help predict those of high chance of tumor recurrence.

TRIAL REGISTRATION

MS/20.03.1087 (Institutional IRB), date of registration: March 10, 2020, "retrospectively registered".

Near-infrared fluorescence imaging improves the nodal yield in neck dissection in oral cavity cancer - A randomized study

INTRODUCTION

Lymph node yield (LNY) in neck dissection has been identified as a prognostic factor in oral cavity cancer. The purpose of this study was to investigate the impact of additional use of optical imaging on LNY in therapeutic ND in oral cancer.

METHODS

Consecutive patients with oral squamous cell carcinoma with clinical neck metastasis planned for primary tumor resection were randomized to conventional neck dissection or near-infrared fluorescence (NIRF)-guided neck dissection, respectively. In the intervention group, patients were injected with ICG-Nanocoll prior to surgery. Intraoperatively, an optical hand-held camera system was used for lymph node identification. Also, NIRF imaging of the neck specimen was performed, and optical signals were pinned with needle markings to guide the pathological examination. The endpoint of the study was LNY per neck side in levels Ib-III.

RESULTS

31 patients were included with 18 neck sides in the control group and 18 neck sides in the intervention group for evaluation. During NIRF-guided ND, individual lymph nodes could be identified by a bright fluorescent signal and individual tumor-related drainage patterns could be observed in the neck. The LNY in the intervention group was significantly higher compared to the control group (p = 0.032) with a mean of 24 LN (range: 12-33 LN in levels Ib-III compared to 18 LN (range: 10-36 LN) in the control group, respectively.

CONCLUSIONS

NIRF-guided ND significantly improved the nodal yield compared to the control group. Intraoperative real-time optical imaging enabled direct visualization of tumor-related drainage patterns within the neck lymphatics.

Predictive Value of the Number of Harvested Lymph Nodes and Cut-Off for Lymph Node Ratio in the Prognosis of Stage II and III Colorectal Cancer Patients

Purpose/aim: The appropriate staging of colorectal cancer requires at least 12 lymph nodes to be sampled. We evaluated whether lymph node sampling (LNS) and lymph node ratio (LNR) can predict the prognosis of stage II-III patients.

MATERIALS AND METHODS

This is a retrospective study on 432 patients classified in LNS ≥12 and LNS <12. Disease-free survival (DFS) was computed using the Kaplan-Meier method. We stratified stage III patients into 4 quartiles base on LNR values. To determine the optimal LNR cut-off, receiver operating characteristic (ROC) curve analysis was performed.

RESULTS

There was a positive association between the number of lymph node sampled and the number of metastatic lymph nodes (p < 0.01). Among stage II patients, the DFS was 81% for LNS ≥ 12 and 72% for LNS < 12 (p = 0.158). Among stage III patients, the DFS was 58% (p < 0.001). We found a significant association between LNR quartiles and relapse in stage III patients but only in the LNS ≥ 12 group. ROC curve analysis indicated an ideal LNR cut-off value at 0.194 (sensitivity 65% and specificity 61%). The DFS of patients with LNR below 0.194 was 71%, and that of patients with LNR above 0.194 was 45% (log-rank test, p < 0.001). In the patients with LNS ≥ 12, the cut-off of 0.257 could predict recurrence (specificity 86%).

CONCLUSIONS

Stage II patients with LNS < 12 tend to have shorter DFS than stage II patients with LNS ≥ 12. In stage III patients, an appropriate LNR cut-off is a better prognostic predictor than LNR quartile, especially in patients with LNS ≥ 12.

The lymph node status as a prognostic factor in colon cancer: comparative population study of classifications using the logarithm of the ratio between metastatic and nonmetastatic nodes (LODDS) versus the pN-TNM classification and ganglion ratio systems

Background

pN stage in the TNM classification has been the “gold standard” for lymph node staging of colorectal carcinomas, but this system recommends collecting at least 12 lymph nodes for the staging to be reliable. However, new prognostic staging systems have been devised, such as the ganglion quotients or lymph node ratios and natural logarithms of the lymph node odds methods. The aim of this study was to establish and validate the predictive and prognostic ability of the lymph node ratios and natural logarithms of the lymph node odds staging systems and to compare them to the pN nodal classification of the TNM system in a population sample of patients with colon cancer.

Methods

A multicentric population study between January 2004 and December 2007. The inclusion criteria were that the patients were: diagnosed with colon cancer, undergoing surgery with curative intent, and had a complete anatomopathological report. We excluded patients with cancer of the rectum or caecal appendix with metastases at diagnosis. Survival analysis was performed using the Kaplan–Meier actuarial method and the Log-Rank test was implemented to estimate the differences between groups in terms of overall survival and disease-free survival. Multivariate survival analysis was performed using Cox regression.

Results

We analysed 548 patients. For the overall survival, the lymph node ratios and natural logarithms of the lymph node odds curves were easier to discriminate because their separation was clearer and more balanced. For disease-free survival, the discrimination between the pN0 and pN1 groups was poor, but this phenomenon was adequately corrected for the lymph node ratios and natural logarithms of the lymph node odds curves which could be sufficiently discriminated to be able to estimate the survival prognosis.

Conclusions

Lymph node ratios and natural logarithms of the lymph node odds techniques can more precisely differentiate risk subgroups from within the pN groups. Of the three methods tested in this study, the natural logarithms of the lymph node odds was the most accurate for staging non-metastatic colon cancer. Thus helping to more precisely adjust and individualise the indication for adjuvant treatments in these patients.

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.

The lymph node ratio does not provide additional prognostic information compared with the N1/N2 classification in Stage III colon cancer

AIM

The ratio of positive nodes to total nodes, the lymph node ratio (LNR), is a proposed alternative to the current N1/N2 classification of nodal disease. The true clinical benefit of adopting the LNR, however, has not been definitively demonstrated. This study compared the LNR with the current N1/N2 classification of Stage III colon cancer.

METHOD

Patients with Stage III colon cancer were identified from a prospectively maintained database (1996-2012). The specificity and sensitivity of the N1/N2 classification in the prediction of overall survival were determined using R. A cut-off point for the LNR was determined by setting the specificity the same as for the N1/N2 classification. The sensitivity of the two methods was then compared, and bootstrapping 1000-fold was performed. This was then repeated for disease-specific survival.

RESULTS

The specificity and sensitivity of the N1/N2 classification in predicting 3-year overall survival in this cohort (n = 402) was 62.2% and 52.1%, respectively. The cut-off point for the LNR was determined to be 0.27 for these data. On comparing LNR with the N1/N2 classification showed that for a given specificity, the LNR did not provide a statistically significant improvement in sensitivity (52.8% vs 52.1%, P = 0.31). For disease-specific death at 3 years, the specificity and sensitivity were 60.8% and 54.6%, respectively. The LNR did not provide a statistically significant improvement (55.4% vs 54.6%, P = 0.44).

CONCLUSION

Both the N1/N2 system and the LNR predict survival in colon cancer, but both have low specificity and sensitivity. The LNR does not provide additional prognostic value to current staging for overall or disease-specific survival for a given cut-off point.

Prognosis of patients with colonic carcinoma before, during and after implementation of complete mesocolic excision

Background

The implementation of complete mesocolic excision (CME) for colonic cancer was accompanied by other important changes, including more patients with early diagnosis by screening and the introduction of adjuvant chemotherapy in patients with stage III disease. The contribution of CME remains unclear.

Methods

In this observational study, data from patients with stage I–III colonic carcinoma were analysed by comparing five time intervals: 1978–1984 (pre-CME), 1985–1994 (CME development), 1995–2002 (CME implementation), 2003–2009 (CME) and 2010–2014 (CME), with a special focus on indicators of process and outcome quality.

Results

During the observed periods, the median age of patients increased (from 65 to 67 years), there were more right-sided carcinomas (from 17·0 to 32·4 per cent), more stage I disease (from 14·0 to 27·7 per cent) and fewer patients with regional lymph node metastases (from 42·7 to 32·0 per cent). The proportion of patients with pN0 disease and at least 12 examined regional lymph nodes increased (from 84·8 to 100 per cent) as did the R0 resection rate (from 97·0 to 100 per cent). Overall morbidity increased, whereas the in-hospital mortality rate was stable (range 1·8–3·7 per cent). Use of adjuvant chemotherapy in stage III colonic carcinoma increased from 0 to 79 per cent. The improvement in outcome quality was more evident in stage III than in stage I–II tumours. In stage III, the 5-year locoregional recurrence rate decreased from 14·8 to 4·1 per cent (P = 0·046) and the 5-year cancer-related survival rate increased from 61·7 to 80·9 per cent (P = 0·010).

Conclusion

With CME, the quality indicators of process and outcome quality improved, especially in stage III colonic carcinoma. Adjuvant chemotherapy in stage III and multidisciplinary approaches in patients with metachronous distant metastases contributed to further outcome improvement.

Mesenteric root dissection with individualized ileo-colic vessel ligation versus mesenteric pedicle stapling

BACKGROUND

Numerous factors have been associated with the number of lymph nodes retrieved during laparoscopic colectomy. This study compared the impact of vascular pedicle ligation method on the number of retrieved lymph nodes in patients undergoing laparoscopic right hemicolectomy for cancer. Mesenteric root dissection with individualized vessel ligation was compared to en bloc vascular root stapling.

METHODS

Data were retrospectively collected from a database of patients' charts including operative and pathological reports. All patients that underwent laparoscopic colectomy in a single department were identified. Patients that underwent elective laparoscopic right hemicolectomy for cancer were further evaluated. The impact of the method used for ileo-colic vascular transection, age, gender, nodes status, T stage, BMI and the operating surgeon on the number of retrieved lymph nodes was studied.

RESULTS

Among 239 laparoscopic colectomies, 75 patients underwent elective laparoscopic right colectomy for cancer. Ileo-colic vascular transection was routinely performed at the level of the inferior border of the pancreas. In total, 34 patients underwent ileo-colic vascular root dissection with individualized vessel ligation and 41 underwent vascular root stapling. No difference was found in the mean number of retrieved lymph nodes between pedicle dissection and vascular root stapling (18.7 ± 5.9 vs. 19.6 ± 7.9, P = 0.396), and in the rate of patients who had 12 nodes or more (97.1 vs. 92.7 %, P = 0.401). BMI above 30 was associated with decreased number of retrieved nodes (P = 0.001).

CONCLUSIONS

No difference was found in the number of retrieved lymph nodes between ileo-colic vascular root dissection with individual vessel ligation and vascular root stapling in patients undergoing laparoscopic right hemicolectomy for cancer. High BMI was associated with decreased number of retrieved nodes in both groups. A standard approach regarding the level of mesenteric root transection, regardless of the ligation approach, leads to adequate lymph node harvesting by different surgeons.

Serosal surfaces, mucin pools, and deposits, oh my: challenges in staging colorectal carcinoma

Colorectal carcinoma is the third most common cancer in the United States. Proper and standardized pathologic staging is vital for prognostic assessment and impacts therapeutic decisions. The Tumor Node Metastasis (TNM) staging system was developed by the American Joint Committee on Cancer (AJCC) to be a data-driven, evidence-based staging system providing an accurate prediction of outcome. The AJCC 7th edition (2010) included several changes clarifying some issues and leading to new controversies. We aim to address selected challenging issues in tumor T staging, neoadjuvant treatment effects in rectal cancer, and definition of lymph node vs tumor deposit. Serosal involvement in colorectal cancer is staged as T4, which is associated with decreased survival and may impact additional therapy decisions. Although careful sampling and sectioning are helpful, challenges remain in interpretation of tumor within 1 mm of serosal surface with a reaction. Elastic stain as a surrogate marker for serosal invasion has been studied, but its usefulness remains unclear. Some unique issues in rectal cancer include the presence of serosa in proximal but not in distal tumors and post-neoadjuvant effects. Tumor should be staged based on tumor cells rather than acellular mucin pools. Additionally, tumor response should be graded only in primary tumor but not in lymph nodes or metastatic sites. The distinction between tumor deposits and lymph nodes has been modified in AJCC TNM from using size in the 5th edition, to the round contour in the 6th edition, to only features of residual lymph node architecture in the 7th edition. Interobserver variability remains but tumor deposits should be documented when present. The number of deposits should not be added to the total number of positive lymph nodes, and the N1c designation should only be used in cases without any positive lymph nodes. Future clarification will likely evolve as more data become available.