Metastatic lymph node ratio as an independent prognostic variable in colorectal cancer: study of 113 patients. Tech Coloproctol. 2009;13:113-121. [PMID: 19484349 DOI: 10.1007/s10151-009-0467-5]

Risk factors for the prognosis of colon cancer

A study on clinical outcomes and prognostic factors in T4N0M0 colon cancer patients after R0 resection revealed that ileostomy, T stage, right hemicolectomy, irregular follow-up, and CA199 level were independent risk factors affecting overall survival. T4-stage cancer invades the entire thickness of the intestinal tract, increasing the difficulty of treatment and the risk of recurrence, and requires a combination of chemotherapy, immunotherapy, and targeted therapy to control the spread of cancer cells. The prognosis of right hemicolectomy is significantly worse than that of left hemicolectomy, and right hemicolectomy is an independent risk factor for a poor prognosis. Advanced age, histopathological type, and lymph node metastasis are also risk factors for colon cancer.

INFLUENCE OF NEOADJUVANT THERAPY ON THE RATIO OF LYMPH NODES

BACKGROUND

To evaluate the relationship between the ratio of affected lymph nodes (LNR) and clinical and anatomopathological variables in patients with rectal adenocarcinoma submitted or not to neoadjuvant chemoradiotherapy.

METHODS

The LNR was determined by dividing the number of compromised LNR by the total number of LNR dissected in the surgical specimen. Patients were divided into two groups: with QRT and without QRT. In each group, the relationship between LNR and the following variables was evaluated: degree of cell differentiation, depth of invasion in the rectal wall, angiolymphatic /perineural invasion, degree of tumor regression and occurrence of metastases. The LNR was evaluated in patients with more than 1, LNR (LNR >12) or less (LNR<12) in the surgical specimen with overall survival (OS) and disease-free survival (DFS). The results were expressed as the mean with the respective standard deviation. Qualitative variables were analyzed using Fisher's exact test, while quantitative variables were analyzed using the Kruskal -Wallis and Mann-Whitney tests. The significance level was 5%.

RESULTS

We evaluated 282 patients with QRT and 114 without QRT, between 1995-2011. In the QRT Group, LNR showed a significant association with mucinous tumors (P=0.007) and degree of tumor regression (P=0.003). In both groups, LNR was associated with poorly differentiated tumors (P=0.001, P=0.02), presence of angiolymphatic invasion (P<0.0001 and P=0.01), perineural (P=0.0007, P=0.02), degree of rectal wall invasion (T3>T2; P<0.0001, P=0.02); Compromised LNR (P<0.0001, P<0.01), metastases (P<0.0001, P<0.01). In patients with QRT, LNR<12 was associated with DFS (5.889; 95%CI1.935-19.687; P=0.018) and LNR>12 with DFS and OS (17.984; 95%CI5.931-54.351; P<0.001 and 10.286; 95%CI 2.654-39.854; P=0.007, respectively).

CONCLUSION

LNR was associated with histological aspects of poor prognosis, regardless of the use of QRT. In the occurrence of less than 12 evaluated LNR, the LNR was associated only with the DFS.

BACKGROUND

• Assessment of the lymph nodes during pathological analysis of the surgical specimen is crucial to determine treatment and prognosis.

BACKGROUND

• Neoadjuvance therapy reduces the number of lymph nodes, being lower than recommended, therefore the lymph node ratio can be an alternative analysis for a better prognosis.

Applications of new radiological scores: the Node-rads in colon cancer staging

PURPOSE

The study focuses on the evaluation of the new Node Reporting and Data System 1.0 (Node-rads) scoring accuracy in the assessment of metastatic lymph nodes (LN) in patients with colon carcinoma.

MATERIAL AND METHODS

From April 2021 to May 2022, retrospective chart reviews were performed on 67 preoperative CT (Computed Tomography) of patients undergoing excisional surgery for colon cancer at the Polyclinic of Bari, Italy. Primary endpoints were to assess lymph node size and configuration to express the likelihood of a metastatic site adopting the Node-rads score system, whose categories of risk are defined from 1 (very low) to 5 (very high). The nodal postsurgical histological evaluation was the gold standard. The relationship between Node-rads score, LN size, configuration criteria (texture, border and shape) and the presence of histological metastases was statistically evaluated.

RESULTS

All surgical specimens examined had correlation with Node-rads score. They were significantly more likely to present nodes micrometastasis those patients with (a) spherical LN shape (82.8%), (b) with lymph node necrosis (100%), (c) irregular borders (87%) and (d) the LN short axis more than 10 mm (61.9%).

CONCLUSIONS

Our experience highlights how the Node-rads system proposes an intuitive and effective definition of criteria to standardize the lymph node radiological reports in colon cancer disease. Further studies are needed to streamline the classification of the nodal and peripheral LN in all the oncological imaging.

Colon tumor CD31 expression is associated with higher disease-free survival in patients with metabolic syndrome

Metabolic syndrome (MS) is recognized as a risk factor for colon cancer (CC). However, how does the interplay between metabolic dysfunction caused by MS and its individual components affect CC microenvironment and prognosis remains unexplored. Angiogenesis and lymphangiogenesis are fundamental processes for tumor progression and dissemination, ensuring oxygen and nutrient delivery and supporting one of the most important pathways of tumor dissemination, contributing to metastasis. Thus, our aim was to evaluate whether the expression of molecular biomarkers involved in angiogenic and lymphangiogenic processes influenced CC clinicopathological features and prognosis in patients with MS. Clinical and pathological data of 300 patients submitted to CC surgical resection at a single tertiary hospital were retrospectively retrieved from hospital records. Tumor tissue microarrays of archived paraffin-embedded blocks were used to assess CD31, VEGF-A and D2-40 tissue expression by immunohistochemistry. The percentage of stained area was quantified by computerized morphometric analysis. No association between tissue expression of angiogenesis and lymphangiogenesis biomarkers and tumor clinical and pathological characteristics was found. However, in subgroup analysis of patients with MS, dysglycemia was associated with lower D2-40 expression (p = 0.007) and high waist-circumference was associated with higher D2-40 (p = 0.0029) and VEGF-A expression (p = 0.026). In an adjusted Cox proportional hazard model CD31 expression was significantly associated with greater disease-free survival (HR=0.62; 95% CI: 0.41-0.95, p = 0.028). No association was found between D2-40 and VEGF-A expression and CC prognosis. Our data reinforces previous reports that suggest the potential use of CD31 as a CC prognostic biomarker. Additionally, our data further supports the evidence for an interplay between metabolic dysfunction, tumor microenvironment, and vascularization pathways.

Pattern of Rectal Cancer Recurrence Following Potentially Curative Surgical Treatment

Survival in rectal cancer has been related mainly to clinical and pathological staging. Recurrence is the most challenging issue when surgical treatment of rectal cancer is concerned. This study aims to establish a recurrence pattern for rectal adenocarcinoma submitted to surgical treatment between June 2003 and July 2021. After applying the exclusion criteria to 305 patients, 166 patients were analyzed. Global recurrence was found in 18.7% of them, while 7.8% have had local recurrence. Recurrences were diagnosed from 5 to 92 months after the surgical procedure, with a median of 32.5 months. Follow-up varied from 6 to 115 months. Recurrence, in literature, is usually between 3 and 35% in 5 years and shows a 5-year survival rate of only 5%. In around 50% of cases, recurrence is local, confined to the pelvis. This study was consonant with the literature in most aspects evaluated, although a high rate of local recurrence remains a challenge in seeking better surgical outcomes.

Prognostic implications of ENE and LODDS in relation to lymph node-positive colorectal cancer location

•

This is the first study on LODDS and ENE together. The current study showed that LODDS and ENE are liable prognostic parameters of CRC or CC.

•

ENE is an independent influencing factor on the prognosis of both CRC and CC, and the prognostic impact of ENE was observed in both CRC and CC.

•

The frequency of ENE increases from the proximal (right) to the distal (left) colon as well as the rectum.

Background

Extranodal extension (ENE) and log odds of positive lymph nodes (LODDS) are associated with the aggressiveness of both colon and rectal cancers. The current study evaluated the clinicopathological significance and the prognostic impact of ENE and LODDS in the colon and rectal patients independently.

Methods

The clinical and histological records of 389 colorectal cancer (CRC) patients who underwent curative surgery were reviewed.

Results

For the ENE system, 244 patients were in the ENE1 group and 145 in the ENE2 system. Compared with the ENE1 system, the patients included in the ENE2 system were prone to nerve invasion (P < 0.001) and vessel invasion (P < 0.001) with higher TNM (P = 0.009), higher T category (P = 0.003), higher N category (P < 0.001), advanced differentiation (P = 0.013), more number of positive lymph nodes (NPLN) (P < 0.001), more lymph node ratio (LNR) (P < 0.001), and a higher value of LODDS (P < 0.001). ENE was more frequent in patients with left and rectal than right cancer. For the LODDS system, 280 patients were in the LODDS1 group, and 109 in the LODDS2 group. Compared to the LODDS1 group, the patients included in the LODDS2 group were more prone to nerve invasion (P = 0.0351) and vessel invasion (P < 0.001) with a higher rate of N2 stage, less NDLN (P < 0.001), more NPLN (P < 0.001), more LNR (P < 0.001), and a higher value of ENE (P < 0.001). Based on the results in the univariable analysis, the N, NPLN, LNR, LODDS, and ENE were separately incorporated into five different Cox regression models combined with the same confounders. The multivariable Cox regression analysis demonstrated that all the five staging systems were independent prognostic factors for overall survival.

Conclusion

The current study confirmed that the LODDS stage is an independent influence on the prognosis of both CRC and CC patients. ENE is an independent influencing factor on the prognosis of both CRC and CC patients, and the prognostic impact of extracapsular lymph node was observed in both CRC and CC. The frequency of ENE increases from the proximal (right) to the distal (left) colon as well as the rectum. Therefore, combining ENE and LODDS into the current TNM system to compensate for the inadequacy of pN staging needs further investigation.

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.

Visceral obesity is associated with lower stage colon tumors in males without survival advantage

Visceral obesity and systemic inflammatory response (SIR) were suggested to be closely related to colon cancer (CC) oncological and surgical outcomes. The first by producing several soluble factors involved in carcinogenesis and the second for having a key role in the nutritional and functional decline of patients with cancer. Furthermore, gender differences in relative body composition and adipose tissue regional distribution have also been acknowledged to influence CC. The primary aim of this study was to determine whether visceral adiposity, stratified by gender, influenced CC staging and prognosis. As secondary aim, this study evaluated whether visceral adiposity and SIR markers were associated with CC pathological features so that these could be used in clinical practice to predict disease outcomes and potentially influence therapeutic decisions. Case records from patients (n = 300) submitted to CC surgical resection at a single tertiary hospital were retrospectively reviewed to retrieve clinical, laboratory, imaging and pathological data. Visceral fat area was quantified by computerized morphometric analysis in preoperative tomography scans. Visceral obesity was defined as visceral fat area ≥160 cm² for men and ≥80 cm² for women. Preoperative full blood count performed as part of the routine clinical assessment at the hospital laboratory was used to obtain C-reactive protein (CRP) levels and to calculate neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), which were used as SIR markers. One hundred and forty-three (n = 143) patients fulfilled eligibility criteria and were included in the analysis. Patients with high-visceral adipose tissue (vAT) had smaller size CC tumors (p < 0.001), earlier T-stage disease (p = 0.027) and lower nodal involvement (p = 0.039). In gender subgroup analysis, these findings were only confirmed in males. Moreover, male patients with high-vAT also had a lower proportion of metastatic nodes (p = 0.021) and metastatic to dissected lymph node ratio (p = 0.030). Additionally, patients with high-vAT also had lower PLR (p = 0.001). CC survival was not influenced by visceral obesity, gender nor SIR. In conclusion, our study shows that male patients with high visceral adiposity have lower PLR levels and earlier stage tumors. Furthermore, our data suggests that visceral obesity and SIR despite being associated with earlier stage CC tumors do not seem to present a survival advantage.

Effect of Metabolic Syndrome and Individual Components on Colon Cancer Characteristics and Prognosis

Metabolic syndrome (MS) is recognized as a risk factor for colon cancer (CC). However, whether the cluster of metabolic changes that define MS also influence CC prognosis remains unclear. Thus, our aim was to investigate whether the presence of MS or any of the MS individual components could provide prognostic information on tumor phenotype and survival outcomes. Clinical and pathological data from patients with CC (n = 300) who underwent surgical resection at a single tertiary hospital were retrospectively collected to evaluate presence of MS components and diagnostic criteria, CC phenotype and disease outcomes. Patients were allocated into two groups according to the presence or absence of MS (n = 85 MS vs n = 83 non-MS). The overall prevalence of MS individual components was 82.7% for increased waist-circumference (WC), 61.3% for high blood pressure (BP), 48.8% for low HDL-cholesterol, 39.9% for high fasting glucose, and 33.9% for hypertriglyceridemia. Patients in the MS group presented smaller tumors (p = 0.006) with lower T-stage (p = 0.002). High BP (p = 0.029) and hypertriglyceridemia (p = 0.044) were associated with a smaller tumor size, while low-HDL (p = 0.008) was associated with lower T-stage. After propensity score matching using age, tumor size and staging as covariates high-BP (p = 0.020) and WC (p = 0.003) were found to influence disease-free survival, but not overall survival. In conclusion, despite MS being an established risk factor for CC, our data does not support the hypothesis that MS components have a negative impact on disease extension or prognosis. Nevertheless, a protective role of BP and lipid lowering drugs cannot be excluded.

Are ADC values of readout-segmented echo-planar diffusion-weighted imaging (RESOLVE) correlated with pathological prognostic factors in rectal adenocarcinoma?

Background

Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values as imaging biomarkers of rectal cancer are currently a hot research spot. The use of ADC values for preoperative judgment of pathological features in rectal cancer has been generally accepted. The image quality evaluation of conventional diffusion is severe deformation, and the measurement of ADC values can easily lead to bias. Readout-segmented echo-planar diffusion-weighted imaging (RESOLVE) provides high signal-to-noise ratio images and significantly reduces distortions caused by magnetosensitive effects. The purpose of this study was to explore the correlations between ADC values of RESOLVE and pathological prognostic factors in rectal adenocarcinoma.

Methods

We collected pathological data of 89 patients with pathologically confirmed rectal adenocarcinoma who directly underwent surgical resection without receiving adjuvant therapy. The patients were grouped according to the pathologic type, gross classification, degree of differentiation, TN stage, and immunohistochemical expression of epidermal growth factor receptor (EGFR).

Results

RESOLVE ADC values of rectal cancer were measured at b = 800, and correlations between the RESOLVE ADC values obtained in different groups were analysed. We found that RESOLVE ADC values in the ulcer-type group were significantly higher than those in the eminence-type group.

Conclusion

RESOLVE ADC values in different pathologic types of rectal cancer were significantly different. RESOLVE ADC values in the EGFR-positive group were significantly lower than those in the EGFR-negative group. There was no significant difference in RESOLVE ADC values between different degrees of pathologic differentiation, TN stages, and positive or negative lymph nodes. The quantitative description of RESOLVE ADC values could be used to assess the biological behaviour of rectal adenocarcinoma.

Trends in lymph node excision and impact of positive lymph node ratio in patients with colectomy for primary colon adenocarcinoma: Population based study 1988 to 2011

BACKGROUND

Studies suggest increased lymph node excision in patients with colon cancer portends improved survival. Guidelines recommend excising 12 or more lymph nodes during colectomy. There is an inverse correlation between the positive lymph node ratio and survival in patients of these patients.

OBJECTIVE

We sought to determine whether colon cancer patients have adequate lymph node excision and whether positive lymph node ratio can be used as a guiding factor for their treatment plan.

DESIGN

Retrospective, Observational.

SETTINGS

United States, 1988-2011.

PATIENTS

Utilizing the Surveillance, Epidemiology, and End Results registry, we identified 318,323 patients who underwent colectomy for colonic adenocarcinoma. Patients were stratified by age, tumor stage, tumor grade, race, ratio of positive nodes, and year of diagnosis.

MAIN OUTCOME MEASURES

We determined the percentage of patients undergoing lymph node excision and mean number of nodes excised by year of diagnosis. In patients with adequate lymph node excision, positive lymph node ratio versus overall and cancer-specific survival was evaluated.

RESULTS

302,620 patients (95%) had at least 1 lymph node excised and 164,583 patients (52%) had 12 or more lymph nodes excised. This correlates to an increase from approximately 30% in 1988 to 80% by 2011. The mean number of nodes excised doubled from 9 to 18 in the entire cohort over the timeframe studied. On multivariate analysis, the 4 year cluster of diagnosis was the largest predictor of receipt of adequate lymph node excision with a 1.68 times higher odds per 4-year increase from 1988 (95% CI 1.67-1.69, p < 0.001). Higher positive lymph node ratio correlated with significantly worse overall and cancer-specific survival in those who had 12 or more lymph nodes excised. At a positive lymph node ratio of 0.16, there is a 15.7% increased rate of cancer specific mortality.

CONCLUSIONS

Despite improvement in the performance of lymph node excision in patients undergoing colectomy for colon adenocarcinoma since 1988, only 80% of patients had adequate lymph node excision in 2011. Increasing positive lymph node ratio predicts significantly worse cancer-specific survival and a ratio of 0.16 may be considered an indication for a more aggressive therapeutic plan.

CATEGORY

Colorectal/Anal Neoplasia.

Clinical Significance of International Union Against Cancer pN Staging and Lymph Node Ratio in Node-Positive Colorectal Cancer after Advanced Lymph Node Dissection

BACKGROUND

Lymph node retrieval in colorectal cancer can be improved by using advanced histopathological techniques like methylene blue-assisted lymph node dissection, which results in a doubling or even tripling of the lymph node count in comparison with conventional lymph node dissection techniques. However, it is not clear whether the established lymph node staging systems are suitable for predicting patients' prognoses under these circumstances.

OBJECTIVE

The aim of this study was to determine whether the current lymph node staging systems are suitable when advanced dissection methods are used.

DESIGN

This is a retrospective cohort study.

SETTING AND PATIENTS

We formed a study group (methylene blue-assisted lymph node dissection) of 293 patients and a control group (conventional lymph node dissection) of 232 patients, each with node-positive cases. Conventional pN staging according to the International Union Against Cancer, seventh edition, and lymph node ratio were applied.

MAIN OUTCOME MEASURES

Overall survival was compared by using the different staging systems in a uni- and multivariable fashion.

RESULTS

The lymph node ratio values were reduced in the advanced methylene blue-assisted lymph node dissection group in comparison with the conventional lymph node dissection group (0.1 vs 0.3, p < 0.001). Although pN staging proved to be reliable, the cutoff values for lymph node ratio staging had to be adapted. The new cutoffs (0.07, 0.15, and 0.34) were prognostic. However, multivariable analysis revealed pN staging and vascular invasion, but not lymph node ratio, as independently prognostic in the methylene blue-assisted lymph node dissection group.

LIMITATIONS

The study group and historical control group are not perfectly balanced because the case number in the stage III subgroup of the control group is small.

CONCLUSIONS

pN staging proved to be a robust prognostic marker in colorectal cancer under the circumstances of improved lymph node harvest. After adaptation of the cutoff values, lymph node ratio is also prognostic but not superior to pN staging.

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.

Proposal of new classification for stage III colon cancer based on the lymph node ratio: analysis of 4,172 patients from multi-institutional database in Japan

BACKGROUND

We retrospectively examined the optimal lymph node ratio (LNR) cutoff value and attempted to construct a new classification using the LNR in stage III colon cancer.

METHODS

The clinical and pathological data of 4,172 patients with histologically proven lymph node metastasis who underwent curative surgery for primary colon cancer at multiple institutions between 1995 and 2004 were derived from the multi-institutional database of the Japanese Society for Cancer of the Colon and Rectum (JSCCR). We determined independent prognostic factors and constructed a new classification using these factors. Finally, we compared the discriminatory ability between the new classification and the TNM seventh edition (TNM 7th) classification.

RESULTS

The optimal LNR cutoff value was 0.18. Multivariate analysis revealed that year of surgery, age, gender, histological type, TNM 7th T category, lymphatic invasion, venous invasion, TNM 7th N category, and LNR were found to be significant independent prognostic factors. We attempted to construct a new classification based on the combination of TNM 7th T category and LNR. As a result, the cancer-specific survivals were well stratified (P < .0001). According to the Akaike's information criteria value, the new classification was judged to be superior to the TNM 7th classification with respect to both a better fit and lower complexity.

CONCLUSIONS

The optimal LNR cutoff value that was found using the Japanese multi-institutional database and the new classification using LNR are considered to be extremely significant. Therefore, these findings strongly support the application of LNR in the stage classification in stage III colon cancer.

Multivariate Logistic regression analysis of prognostic factors for stage Ⅲ rectal cancer

AIM: To analyze prognostic factors for stage Ⅲ rectal cancer by multivariate Logistic regression analysis.

METHODS: Clinical data for 198 patients with stage Ⅲ rectal cancer who underwent radical resection from June 2013 to June 2008 were analyzed retrospectively. Univariate and multivariate regression analyses were conducted to investigate the relationship of age, gender, gross type, TNM stage, lymph node metastasis, pathological type with prognosis. The patients were divided into two groups based on the extent of lymph node metastasis (33.9% as cutoff) to assess the relationship between lymph node metastasis and postoperative survival.

RESULTS: Univariate regression analysis indicated that age, TNM stage, pathological type and lymph node metastasis were factors significantly affecting prognosis of stage Ⅲ rectal cancer. Multivariate regression analysis indicated that the extent of lymph node metastasis, not age, sex, TNM stage, and pathological type, was an independent predictor of survival of patients with stage Ⅲ colorectal cancer.

CONCLUSION: Lymph node metastasis is an important predictor of prognosis of stage Ⅲ rectal cancer.

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.

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.

Integrated ratio of metastatic to examined lymph nodes and number of metastatic lymph nodes into the AJCC staging system for colon cancer

OBJECTIVE

At present, only the number of metastatic lymph nodes (LNs+) is used for the pN category of AJCC TNM system for colon cancer. Recently, the ratio of metastatic to examined lymph nodes (LNR) has been reported to represent powerful independent predictive capacity in colon cancer. We sought to propose a novel category (nLN) which intergrades LNR and LNs+ into the AJCC staging system for colon cancer.

DESIGN

34476 patients from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) dataset with stage III colon cancer were reviewed. Harrell's C statistic was used to evaluate the predictive capacity. The Cox proportional hazards model was used to construct a novel category.

RESULTS

The LNR category had more predictive capacity than the pN category in whole groups of patients (Harrell's C index: 0.6194 vs 0.6113, p = 0.003). Subgroup analysis showed that the LNR category was not better than pN category in predictive capacity if the number of lymph nodes examined was more than 13. We also found that there was significant survival heterogeneity among different pN categories at the same LNR category (P<0.001). The Harrell's C index for our nLN category which intergrades LNR and LNs+ was 0.6228, which was significant higher than that of the pN category (Harrell's C index: 0.6113, P<0.001) or LNR category (Harrell's C index: 0.6194, P = 0.005), respectively.

CONCLUSION

To evaluate the prognosis of colon cancer, our nLN category which intergrades LNR with LNs+ is more accurate than the pN category or LNR category, respectively.

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.

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.

Review of histopathological and molecular prognostic features in colorectal cancer

Prediction of prognosis in colorectal cancer is vital for the choice of therapeutic options. Histopathological factors remain paramount in this respect. Factors such as tumor size, histological type and subtype, presence of signet ring morphology and the degree of differentiation as well as the presence of lymphovascular invasion and lymph node involvement are well known factors that influence outcome. Our understanding of these factors has improved in the past few years with factors such as tumor budding, lymphocytic infiltration being recognized as important. Likewise the prognostic significance of resection margins, particularly circumferential margins has been appreciated in the last two decades. A number of molecular and genetic markers such as KRAS, BRAF and microsatellite instability are also important and correlate with histological features in some patients. This review summarizes our current understanding of the main histopathological factors that affect prognosis of colorectal cancer.

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.

Number of retrieved lymph nodes and survival in node-negative patients undergoing laparoscopic colorectal surgery for cancer

BACKGROUND

The number of retrieved lymph nodes in colorectal cancer resection may have an impact on staging and survival. Examination of at least 12 nodes has become a quality measure for adequate surgical practice. To evaluate the impact of the number of retrieved lymph nodes in laparoscopic colorectal surgery for cancer on node-negative patients' survival.

METHODS

Evaluation of our prospective in-hospital collected data of patients that underwent laparoscopic surgery for curable colorectal cancer over a 5-year period. Long-term data were collected from our outpatient's clinic data and personal contact when necessary.

RESULTS

During a 5-year period since September 2003,173 patients were operated laparoscopically for curable colorectal cancer. Of the 117 patients who were node negative, 85 node-negative patients (72%) had 12 or more evaluated lymph nodes (mean, 18.3 + 2.4), while 32 node-negative patients had less than 12 (mean, 8.3 + 6.2). Patients with fewer than 12 nodes evaluated had significantly more left-sided tumors, while patients with 12 nodes or more had more right-sided tumors. A comparison of 5-year disease free and overall Kaplan-Meier survival curves revealed no statistically significant difference between the two groups.

CONCLUSIONS

Evaluation of less than 12 nodes may not necessarily impact patients' survival in node-negative patients undergoing laparoscopic resection for curable colorectal cancer. A lower number of nodes may be sufficient.

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.