Number of lymph nodes examined and prognosis of TNM stage II colorectal cancer

Examining the relationship between lymph node harvest and survival in patients undergoing colectomy for colon adenocarcinoma

BACKGROUND

Current standards for lymph node harvest in colorectal cancer surgery may be inadequate. Higher lymph node yield may improve survival, but the number of lymph nodes needed to optimize survival is unknown. The objective of this study was to examine the relationship between lymph node yield and overall survival in patients undergoing colectomy for nonmetastatic colon adenocarcinoma.

METHODS

The 2010 to 2014 National Cancer Database was queried for patients undergoing colectomy for nonmetastatic colon adenocarcinoma. Adjusted restricted cubic splines were used to model the nonlinear relationship between lymph node harvest and overall survival. Cox proportional hazard determined independent predictors of overall survival.

RESULTS

A total of 261,423 patients were included. Restricted cubic splines demonstrated that the adjusted improvements in overall survival stabilized after 24 nodes. Patients were divided into: <12, 12 to 23, and ≥24 nodes. On survival analysis, patients with ≥24 nodes had better survival across all N stages compared to other groups (P < .001). Lymph node harvest ≥24 nodes was independently associated with improved overall survival compared to 12 to 23 nodes (hazard ratio 0.82; 95% confidence interval, 0.80-0.85).

CONCLUSION

Lymph node harvest ≥24 nodes is associated with improved survival in colorectal cancer patients. These data may provide indirect evidence for a more extensive lymphadenectomy for colon cancer.

Impact of Age on Risk of Lymph Node Positivity in Patients with Colon Cancer

Background: Lymph node (LN) positivity is a prognostic indicator in patients with colon cancer regardless of age, and age is an important parameter that impacts therapeutic recommendations. But little is known about the impact of age on LN positivity in patients with colon cancer. Methods: We analyzed 257,334 patients with colon cancer diagnosed from SEER database. Logistic regression was used to examine the association of age and LN positivity. Poisson regression was used to evaluate whether age was associated with the number of positive LNs. Results: LN positivity was inversely associated with age (P < .001 for each T stage). Age was predictive of LN positivity after adjustment for number of LNs examined and other covariates (P < .001 for each T stage). Adjusted odds ratios (ORs) for LN positivity for age 20 to 39 vs 80+ were 3.06 for stage T1 (95 % CI, 2.09 to 4.48), 2.46 for stage T2 (95 % CI, 2.00 to 3.02), 1.77 for stage T3 (95 % CI, 1.62 to 1.93), and 1.68 for stage T4 (1.51 to 1.86). Young age was a significant predictor of an increased number of positive LNs (P < .005 for each T stage). Conclusion: Young age at diagnosis is associated with an increased risk of LN positivity. LN examination and resection could aid younger patients more with detection and removal of metastasis. Guidelines that define postdetection interventions may be needed to limit the overtreatment of older patients, who may be vulnerable to unnecessary tests and treatments.

Lymph node yield and tumour subsite are associated with survival in stage I-III colon cancer: results from a national cohort study

BACKGROUND

It has been suggested that apart from tumour and nodal status, a range of patient-related and histopathological factors including lymph node yield and tumour location seems to have prognostic implications in stage I-III colon cancer. We analysed the prognostic implication of lymph node yield and tumour subsite in stage I-III colon cancer.

METHODS

Data on patients with stage I to III adenocarcinoma of the colon and treated by curative resection in the period from 2003 to 2011 were extracted from the Danish Colorectal Cancer Group database, merged with information from the Danish National Patient Register and analysed.

RESULTS

A total of 13,766 patients were included in the analysis. The 5-year overall survival ranged from 59.3% (95% CI 55.7-62.9%) (lymph node yield 0-5) to 74.0% (95% CI 71.8-76.2%) (lymph node yield ≥ 18) for patients with stage I-II disease (p < 0.0001) and from 36.4% (95% CI 29.8-43.0%) (lymph node yield 0-5) to 59.4% (95% CI 56.6-62.2%) (lymph node yield ≥ 18) for patients with stage III disease (p < 0.0001). The 5-year overall survival for tumour side left/right was 59.3% (95% CI 57.9-60.7%)/64.8% (CI 63.4-66.2%) (p < 0.0001). In the seven colonic tumour subsites, the 5-year overall survival ranged from 56.6% (95% CI 51.8-61.4%) at splenic flexure to 65.8% (95% CI 64.5-67.2%) in the sigmoid colon (p < 0.0001). In a cox regression analysis, lymph node yield and tumour side right/left were found to be prognostic factors. Tumours at the hepatic and splenic flexures had an adverse prognostic outcome.

CONCLUSION

For stage I-III colon cancer, a lymph node yield beyond the recommended 12 lymph nodes was associated with improved survival. Both subsite in the right colon, as well as subsite in the left colon, turned out with adverse prognostic outcome questioning a simple classification into right-sided and left-sided colon cancer.

Effect of activated carbon nanoparticles on lymph node harvest in patients with colorectal cancer

AIM

The aim was to examine the effect of activated carbon nanoparticles (ACNs) on lymph node retrieval in colorectal cancer (CRC) patients.

METHODS

This prospective randomized study of 80 subjects was performed between March 2016 and December 2016. Eighty patients with CRC were randomly divided into two groups, the ACN group and a control group. The patients in the ACN group were subjected to 1 ml of ACN injection in the subserosa around the tumour before colectomy and D3 lymphadenectomy. The patients in the control group received the same procedure without the injection of ACNs. After surgery, lymph nodes were isolated, and the greatest dimensions were measured by the same pathologist.

RESULTS

The average number of lymph nodes harvested from each patient was markedly more in the ACN group (31.3 ± 8.1) than in the control group (21.9 ± 5.3; P < 0.001), and the average number of lymph nodes less than 5 mm in greatest dimension was significantly more in the ACN group (11.9 ± 4.9) than in the control group (4.1 ± 2.4; P < 0.001). The ACN group (15/40) had a higher rate of Stage III patients compared to the control group (6/39; P = 0.026). Besides, the greatest dimension of 32.8% metastatic lymph nodes was less than 5 mm.

CONCLUSION

There is significant upstaging following the use of ACNs, which could find more involved nodes. Therefore, ACNs can be used as a tracer to harvest more lymph nodes in CRC patients, with improvement in the accuracy of pathological staging.

Prognostic Significance of D3 Lymph Node for Survival in Patients With Colorectal Cancer

BACKGROUND

The aim of this study was to investigate the prognostic value of D3 lymph node (TSLN) for the survival of patients with colorectal cancer.

METHODS

A total of 156 patients with R0 resected colorectal cancer were selected from 2011 to 2015 to carry out a retrospective study. The survival rate according to the groups of positive lymph node number (N: 1-3, N2: 4-6, N3: ≥7) and TSLN (TSLN [-], TSLN [+]) was analyzed. The influences of covariates on the 5-year overall survival (OS) and 5-year disease-free survival (DFS) were determined by the Cox proportional risk model of backward stepwise analysis. Kaplan-Meier survival analysis was used to draw survival curves between and within groups.

RESULTS

During the median follow-up period (44.0 months), the 5-year DFS rate and OS rate were 45.0% and 46.0%, respectively. Survival analysis of the TSLN group showed that the 5-year OS rate and 5-year DFS rate in the TSLN (+) group (20.0 and 16.2%, respectively) were significantly lower than those in the TSLN (-) group (68.3 and 51.6%, respectively) (P < 0.001). The 5-year OS rate and DFS rate of the TSLN (+) and TSLN (-) subgroups in the N1 group were 16.7%, 33.3%, 56.7%, and 55.7%, respectively (P < 0.001). Multivariate analysis showed that positive lymph node, TSLN, and Pathological T stage were independent prognostic factors of DFS and OS for 5 years. Patients in the TSLN (+) group had a poorer prognosis.

CONCLUSIONS

TSLN metastasis is an independent factor influencing the prognosis of patients, and patients with TSLN (+) have a poor prognosis. As an independent prognostic factor, this factor should be considered when evaluating the prognosis of patients.

Positive impact of the negative lymph node count on the survival rate of stage III colon cancer with pN1 and right-side disease

Background: We aimed to investigate the role of the negative lymph node count (NLN) as a predictor of prognosis in patients with stage III colon cancer.

Methods: We conducted a retrospective study on patients who were diagnosed with stage III colon cancer at Sun Yat-sen University Cancer Center. According to the number of negative lymph nodes, all patients were divided into the low or high NLN group. Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method and log-rank test between the two groups. Univariate and multivariate Cox proportional hazards models were used to evaluate the risk factors for survival.

Results: The time-dependent receiver operating characteristic (ROC) curve showed that the optimal cutoff value of NLN was nine. In total, 167 and 298 patients were distributed into the low and high NLN groups, respectively. Patients in the high NLN group tended to present with a greater proportion of right-side colon cancer and pN1 stage disease, superior DFS (P < 0.001) and OS (P = 0.001) than those in the low NLN group. Multivariable analyses confirmed increased NLN as a positive prognostic variable, independent of other potential confounding factors. Subgroup analysis showed that in patients with a right-side location, those with 9 or fewer negative lymph nodes had a 5-year OS rate of 35.4% versus 77.1% in those with more than 9 negative lymph nodes evaluated (P < 0.001). For patients with stage pN1, those with NLN ≤9 exhibited an inferior 5-year OS rate than those with NLN > 9 (71.1% vs 84.8%, respectively; P = 0.009). There was no association between the number of negative lymph nodes identified and survival for patients with stage pN2 and left-side disease.

Conclusion: NLN is an important prognostic factor for stage III colon cancer patients with right-side and stage pN1 disease other than for patients with stage pN2 and left-side disease, which can be partly explained in terms of inflammation and immunity.

A Review of Current Challenges in Colorectal Cancer Reporting

Context.—

Pathologic assessment of colorectal cancer resection specimens plays an important role in postsurgical management and prognostication in patients with colorectal cancer. Challenges exist in the evaluation and reporting of these specimens, either because of difficulties in applying existing guidelines or related to newer concepts.

Objective.—

To address challenging areas in colorectal cancer pathology and to provide an overview of the literature, current guidelines, and expert recommendations for the handling of colorectal cancer resection specimens in everyday practice.

Data Sources.—

PubMed (US National Library of Medicine, Bethesda, Maryland) literature review; reporting protocols of the College of American Pathologists, the Royal College of Pathologists of the United Kingdom, and the Japanese Society for Cancer of the Colon and Rectum; and classification manuals of the American Joint Committee on Cancer and the Union for International Cancer Control.

Conclusions.—

This review has addressed issues and challenges affecting quality of colorectal cancer pathology reporting. High-quality pathology reporting is essential for prognostication and management of patients with colorectal cancer.

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 Prognostic Impact of the Metastatic Lymph Nodes Ratio in Colorectal Cancer

Background: This study was designed to validate the prognostic significance of the ratio of positive to examined lymph nodes (LNR) in patients with colorectal cancer. Methods: 218,314 patients from the SEER database and 1,811 patients from the three independent multicenter were included in this study. The patients were divided into 5 groups on a basis of previous published LNR: LNR0, patients with no metastatic lymph nodes; LNR1, patients with the LNR between 0.1 and 0.17; LNR2, patients with the LNR between 0.18 and 0.41; LNR3, patients with the LNR between 0.42 and 0.69; LNR4, patients with the LNR >0.7. The 5-year OS and CSS rate were estimated using Kaplan-Meier method and the survival difference was tested using log-rank test. Multivariate Cox analysis was used to further assess the influence of the LNR on patients' outcome. Results: The 5-year OS rate of patients within LNR0 to LNR4 group was 71.2, 55.8, 39.3, 22.6, and 14.6%, respectively (p < 0.001) in the SEER database. While the 5-year OS rate of those with LNR0 to LNR4 was 75.2, 66.1, 48.0, 34.0, and 17.7%, respectively (p < 0.001) in the international multicenter cohort. In the multivariate analysis, LNR was demonstrated to be a strong prognostic factor in patients with < 12 and ≥12 metastatic lymph nodes. Furthermore, the LNR had a similar impact on the patients' prognosis in colon cancer and rectal cancer. Conclusion: The LNR allowed better prognostic stratification than the positive node (pN) in patients with colorectal cancer and the cut-off values were well validated.

ypTNM category combined with AJCC tumor regression grade for screening patients with the worst prognosis after neoadjuvant chemoradiation therapy for locally advanced rectal cancer

Background

The purpose of this study was to investigate the value of the postsurgical pathological T and N (ypTN) category combined with the American Joint Committee on Cancer-tumor regression grade (AJCC-TRG) in evaluating the prognosis of neoadjuvant chemoradiation therapy (NeoCRT) for locally advanced rectal cancer (LARC) to screen for a subgroup of patients with the worst prognosis.

Patients and methods

In total, 265 patients with LARC were enrolled in the trial. All patients received NeoCRT. Total mesorectal excision was performed 6-8 weeks after the completion of radiotherapy. The surgical specimens were re-evaluated based on the AJCC-TRG (seventh edition) and the AJCC-tumor-node-metastasis (TNM; seventh edition) systems. We followed up these patients and calculated their overall survival (OS), disease-free survival (DFS), local recurrence-free survival (RFS), and distant metastasis (DM)-free survival (MFS) rates through the Kaplan-Meier analysis. The logrank test was further applied to evaluate the predictive value of the ypTN stage combined with AJCC-TRG for several survival indexes.

Results

The median follow-up period was 65.1 months. The 5-year OS, DFS, RFS, and MFS rates were 79.4%, 68.8%, 94.4%, and 76.5%, respectively. There were significant differences in OS, DFS, and MFS rates among different ypT+AJCC-TRG and ypN+AJCC-TRG subgroups. The 5-year OS, DFS, and MFS rates for ypT3-4+TRG 1 and ypT3-4+TRG2-3 subgroups were 73.9% vs 65.3%, 61.2% vs 52.9%, and 65.0% vs 61.5%, respectively. The 5-year OS, DFS, and MFS rates for ypN1-2+TRG 0-1 and ypN1-2+TRG2-3 subgroups were 64.8% vs 54.1%, 44.9% vs 41.7%, and 61.4% vs 46.3%, respectively.

Conclusion

The ypTNM category combined with the AJCC-TRG can more accurately evaluate the prognosis of patients with LARC and identify the subgroup of patients with the worst prognosis and high risk of developing DM, thereby demonstrating clinical significance in guiding individualized postoperative adjuvant therapy and follow-up for LARC.

The impact of the number of harvested central lymph nodes on the lymph node ratio

OBJECTIVE

The purpose of this study was to analyze the impact of lymph node harvest on the lymph node ratio (LNR).

METHODS

We retrospectively reviewed 106 patients diagnosed preoperatively with PTMC (papillary thyroid microcarcinoma), no evidence of central or lateral neck nodal metastasis, and who underwent a total thyroidectomy and bilateral central lymph node neck dissection (CND).

RESULTS

The median number of retrieved lymph nodes in the central compartments was 7±6.59 (range: 1-42). The mean number of metastatic lymph nodes in the central compartments on pathology was 1.1±1.79 (range: 0-7). The high node volume group (>7) had a significantly higher rate of central lymph node (CLN) metastasis than the low node volume group (≤7) in the final pathologic report (p<0.001). With the linear regression method, the number of CLN metastasis increased as the number of retrieved lymph nodes increased (correlation coefficient=0.286, p=0.003). The multivariate analysis confirmed the number of retrieved lymph nodes in the central compartments was a risk factor for high LNR (p=0.008, odds ratio 3.737). The rates of vocal fold palsy and hypoparathyroidism did not differ according to the number of retrieved lymph nodes.

CONCLUSION

The lymph node ratio in the final pathologic report is larger when a greater number of lymph nodes are retrieved during the central compartment neck dissection.

Recurrence Risk After Up-to-Date Colon Cancer Staging, Surgery, and Pathology: Analysis of the Entire Swedish Population

BACKGROUND

Developments in the quality of care of patients with colon cancer have improved surgical outcome and thus the need for adjuvant chemotherapy.

OBJECTIVE

To investigate the recurrence rate in a large population-based cohort after modern staging, surgery, and pathology have been implemented.

DESIGN

This was a retrospective registry study.

SETTINGS

Data from patients included in the Swedish Colorectal Cancer Registry covering 99% of all cases and undergoing surgery for colon cancer stages I to III between 2007 and 2012 were obtained.

PATIENTS

In total, 14,325 patients who did not receive any neoadjuvant treatment, underwent radical surgery, and were alive 30 days after surgery were included.

MAIN OUTCOME MEASURES

Tumor and node classification and National Comprehensive Cancer Network-defined risk factors for recurrence were used to assess overall and stage-specific 5-year recurrence rates.

RESULTS

The median follow-up of nonrecurrent cases was 77 months (range, 47-118 mo). The 5-year recurrence rate was 5% in stage I, 12% in stage II, and 33% in stage III patients. In patients classified as having pT3N0 cancer with no or 1 risk factor, the 5-year recurrence rates were 9% and 11%. Risk factors for shorter time to recurrence were male sex, more advanced pT and pN classification, vascular and perineural invasion, emergency surgery, lack of central ligature, short longitudinal resection margin, postoperative complications, and, in stage III, no adjuvant chemotherapy.

LIMITATIONS

The registry does not contain some recently identified factors of relevance for recurrence rates, and some late recurrences may be missing.

CONCLUSIONS

The recurrence rate is less than that previously observed in historical materials, but current, commonly used risk factors are still useful in evaluating recurrence risks. Stratification by pT and pN classification and the number of risk factors enables the identification of large patient groups characterized by such a low recurrence rate that it is questionable whether adjuvant treatment is motivated. See Video Abstract at http://links.lww.com/DCR/A663.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The prognostic significance of lymph node size in node-positive colon cancer

OBJECTIVES

To (i) show the outcome benefits of enlarged lymph nodes in node-positive colon cancer cases, as it was shown previously in negative node cases; (ii) disprove the stage migration theory and (iii) list the factors affecting lymph node size and yield.

METHODS

A retrospective study including 234 node-positive colon cancer cases was scheduled and performed. All recovered lymph nodes (6969) from 234 cases were microscopically examined in regard to (a) lymph node size (b) presence of metastasis (c) extent of intra-nodal metastasis. On the basis of resulting data, a statistical analysis was performed.

RESULTS

Metastases occurred in all size categories, though more often in larger lymph nodes. Fifty-one percent of all metastasised nodes were 2 to 6 mm in size. Approximately half of all nodes >10 mm were microscopically free of cancer. Cases with a small lymph node metastasis to lymph node size ratio (MSR) had a better prognosis than others: 85 months (95% CI: 72-97) vs. 67 months (95% CI: 47-88), p <0.001 (mean, overall survival). To differentiate between cases with the same ratio but different absolute lymph nodes sizes, we divided the cases into two groups that differed in their number of moderate to large lymph nodes. The group with more moderate to large lymph nodes showed a clear outcome benefit: 104 months (95% CI: 86-122) vs. 66 months (95% CI: 54-77), p = 0.014 (mean, overall survival).

CONCLUSIONS

Metastasised lymph nodes affect all size categories, and large lymph nodes are not always metastasised. The combination of enlarged lymph nodes and a small lymph node metastasis to lymph node size ratio (MSR) is associated with a better prognosis than others. When enlarged lymph nodes were considered as surrogate markers of an effective local immune response due to nodal hyperplasia, the immune system could be seen as the confounder affecting both lymph node size and prognosis. Our results are pointing in this direction and, along with other reasons, are challenging the stage migration theory.

Role of lymph node yield and lymph node ratio in predicting outcomes in non-metastatic colorectal cancer

Background

Lymph node yield (LNY) of 12 or more in resection of colorectal cancer is recommended in current international guidelines. Although a low LNY (less than 12) is associated with poorer outcome in some studies, its prognostic value is unclear in patients with early‐stage colorectal or rectal cancer with a complete pathological response following neoadjuvant therapy. Lymph node ratio (LNR), which reflects the proportion of positive to total nodes obtained, may be more accurate in predicting outcome in stage III colorectal cancer. This study aimed to identify factors correlating with LNY and evaluate the prognostic role of LNY and LNR in colorectal cancer.

Methods

An observational study was performed on patients with colorectal cancer treated at three hospitals in Melbourne, Australia, from January 2010 to March 2016. Association of LNY and LNR with clinical variables was analysed using linear regression. Disease‐free (DFS) and overall (OS) survival were investigated with Cox regression and Kaplan–Meier survival analyses.

Results

Some 1585 resections were analysed. Median follow‐up was 27·1 (range 0·1–71) months. Median LNY was 16 (range 0–86), and was lower for rectal cancers, decreased with increasing age, and increased with increasing stage. High LNY (12 or more) was associated with better DFS in colorectal cancer. Subgroup analysis indicated that low LNY was associated with poorer DFS and OS in stage III colonic cancer, but had no effect on DFS and OS in rectal cancer (stages I–III). Higher LNR was predictive of poorer DFS and OS.

Conclusion

Low LNY (less than 12) was predictive of poor DFS in stage III colonic cancer, but was not a factor for stage I or II colonic disease or any rectal cancer. LNR was a predictive factor in DFS and OS in stage III colonic cancer, but influenced DFS only in rectal cancer.

Lymph node ratio as a valuable prognostic factor for patients with colorectal liver-only metastasis undergoing curative resection

Background

Recent studies have suggested that the lymph node ratio (LNR) is a prognostic indicator for various malignancies. However, LNR has not been evaluated in colorectal liver-only metastasis (CRLM). This study aimed to investigate the prognostic value of LNR in patients with CRLM after curative resection.

Patients and methods

We retrospectively investigated the clinicopathologic features of 154 CRLM patients who underwent curative resection between 2005 and 2015. We classified patients into low and high groups based on their LNR by using the X-tile software. Survival curves were plotted through Kaplan–Meier method and compared by log-rank test. Cox proportional hazards analysis was performed to identify the factors associated with recurrence-free survival (RFS) and overall survival (OS).

Results

The patients were divided into two groups in which 124 patients were identified as LNR ≤0.33 and 30 patients as LNR >0.33. Compared to low LNR, high LNR was significantly associated with poor 3-year RFS (47.2% vs 16.7%, P=0.001) and OS (72.8% vs 45.3%, P=0.003) rates. Multivariate analysis indicated that the LNR was an independent predictor for 3-year RFS (hazard ratio, 2.124; 95% CI, 1.339–3.368; P=0.001) and OS (HR, 2.287; 95% CI, 1.282–4.079; P=0.005). However, the node (N) stage and lymph node distribution were not significantly associated with the 3-year RFS (P=0.071, P=0.226) or OS (P=0.452, P=0.791) in patients with CRLM.

Conclusion

This study demonstrated that LNR was an independent predictor for 3-year RFS and OS in patients with CRLM who underwent curative resection and that its prognostic value was superior to that of N stage and lymph node distribution.

Prognostic impact of the number of lymph nodes examined in different stages of colorectal mucinous adenocarcinoma

BACKGROUND

Mucinous adenocarcinoma (MC) is a special kind of colorectal adenocarcinoma that occurs more frequently in young patients and females, but the prognostic effect of lymph nodes in MC patients is unclear. This population-based study was conducted to analyze the prognostic value of the number of lymph nodes examined in different stages of colorectal MC.

METHODS

We included 17,001 MC patients from the Surveillance, Epidemiology, and End Results program database between 2003 and 2013, of which 12,812 (75%) had >12 lymph nodes examined.

RESULTS

Compared to the group with insufficient lymph nodes examined, patients with more lymph nodes (>12) examined tended to come from east and central America, were more frequently female and young, were diagnosed after 2008, had larger-sized tumors of less differentiated grade and in later stages, had not received radiation therapy and had more positive nodal status. Patients with more lymph nodes (>12) examined demonstrated significantly better survival than those with insufficient lymph nodes examined only in stages II and III (stage II: overall, P<0.001; cancer-specific, P<0.001; stage III: overall, P=0.093; cancer-specific, P=0.032), even though the overall (P<0.001) and cancer-specific survival (P<0.001) showed significant differences between the two groups. Both univariate (overall, HR=0.739, 95% CI=0.703-0.777, P<0.001; cancer-specific, HR=0.742, 95% CI=0.698-0.788, P<0.001) and multivariate (overall, HR=0.601, 95% CI=0.537-0.673, P<0.001; cancer-specific, HR=0.582, 95% CI=0.511-0.664, P<0.001) Cox proportional hazards models verified the association between >12 lymph nodes examined and better survival.

CONCLUSION

More number of lymph nodes (.12) examined significantly increased the survival probability of MC patients in stages II and III, but had no significant influence on patients in stages I and IV, indicating the effect of number of lymph nodes examined was a stage-dependent prognostic factor in clinical utility.

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

Background

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

Extent of lymph node dissection improves survival in prostate cancer patients treated with radical prostatectomy without lymph node invasion

PURPOSE

To assess the effect of pelvic lymph node dissection (PLND) extent on cancer-specific mortality (CSM) in prostate cancer (PCa) patients without lymph node invasion (LNI) treated with radical prostatectomy (RP).

METHODS

Within the Surveillance, Epidemiology, and End results (SEER) database (2004-2014), we identified patients with D'Amico intermediate- or high-risk characteristics who underwent RP with PLND, without evidence of LNI. First, multivariable logistic regression models tested for predictors of more extensive PLND, defined as removed lymph node count (NRN) ≥75th percentile. Second, Kaplan-Meier analyses and multivariable Cox regression models tested the effect of NRN ≥75th percentile on CSM. Finally, survival analyses were repeated using continuously coded NRN.

RESULTS

In 28 147 RP and PLND patients without LNI, 67.3% versus 32.7% exhibited D'Amico intermediate- or high-risk characteristics. The median NRN was 6 (IQR 3-10), the 75th percentile defined patients with NRN ≥11. Patients with NRN ≥11 had higher rate of cT2/3 stage (29.8 vs 26.1%), GS ≥8 (25.7 vs 22.4%), and respectively more frequently exhibited D'Amico high-risk characteristics (34.6 vs 32.1%). In multivariable logistic regression models predicting the probability of more extensive PLND (NRN ≥11), higher biopsy GS, higher cT stage, higher PSA, more recent year of diagnosis, and younger age at diagnosis represented independent predictors. At 72 months after RP, CSM-free rates were 99.5 versus 98.1% for NRN ≥11 and NRN ≤10, respectively and resulted in a HR of 0.50 (P = 0.01), after adjustment for all covariates. Similarly, continuously coded NRN achieved independent predictor status (HR: 0.955, P = 0.01), where each additional removed lymph node reduced CSM risk by 4.5%.

CONCLUSION

More extensive PLND at RP provides improved staging information and consequently is associated with lower CSM in D'Amico intermediate- and high-risk PCa patients without evidence of LNI. Hence, more extensive PLND should be recommended in such individuals.

Rectal cancer and the pathologist

Examination of the rectum by pathologists is instrumental in the management of patients affected by rectal carcinoma. That role includes evaluation of multiple gross and microscopic features that convey prognostic implications. The analysis is based on the authors' experience handling rectal specimens along with review of the pertinent literature in these areas: margins of excision, quality of the mesorectum, diligence and techniques to sample lymph nodes, tumor budding, grading of residual amount of carcinoma after preoperative therapy, vascular/perineural invasion, and staging the tumor. Pathologists must communicate the findings in a clear manner. Evaluation of margins and completeness of mesorectum are markers of the quality of surgical excision. The number of lymph nodes obtained and examined is dependent in great part on the diligence of the pathologist finding them in the mesenteric adipose tissue. There are grades for budding and response to prior chemoradiation therapy. The location of vascular invasion (extramural vs. intramural) may predict aggressive behavior. Pathologists proactively are to choose sections of tumor for molecular testing. Meticulous macro- and microscopic evaluation of specimens for rectal carcinoma by pathologist is needed to determine an accurate assessment of staging and other prognostic factors. The modern pathologists play a pivotal part in the care and management of patients suffering from rectal adenocarcinoma. That role goes from the initial histological diagnosis to the gross and microscopic examination of the excised specimens. Based on that examination pathologists issue statements that not only evaluate the quality of the surgical procedure, but also through the application of molecular tests they give light on prognostic factors and information for therapeutic purposes.

The impact of log odds of positive lymph nodes (LODDS) in colon and rectal cancer patient stratification: a single-center analysis of 323 patients

Log odds of positive nodes (LODDS), defined as the log of the ratio between the number of positive nodes and the number of negative nodes, has been recently introduced as a tool in predicting prognosis. This study aims to establish the effective and prognostic value of LODDS in predicting the survival outcome of CRC patients undergoing surgical resection. The study population is represented by 323 consecutive patients with primary colon or rectal adenocarcinoma thatunderwent curative resection. LODDS values were calculated by empirical logistic formula, log(pnod + 0.5)/(tnod - pnod + 0.5). It was defined as the log of the ratio between the number of positive nodes and the number of negative nodes. The patients were divided into three groups: LODDS0 (≤ - 1.36), LODDS1 (> - 1.36 ≤ - 0.53) and LODDS2 (> - 0.53). Kaplan-Meier curve analyses showed 3-year OS rates of the patients staged by LODDS classification. These values were 88.3, 74.8 and 61.8% for LODDS0, LODDS1 and LODDS2, respectively (P ≤ 0.001). In a multivariate analysis, LODDS is an independent prognostic factor of 3-year OS. This is in contrast to pN stage and lymph node ratio, which shows no statistical significance. ROC analyses showed that LODDS predicted OS better than lymph node ratio. LODDS classification has a better prognostic effect than pN stage and lymph node ratio. LODDS offers a finer stratification and accurately predicts survival of CRC patients.

Comparison of the short-term outcomes of reduced-port laparoscopic surgery and conventional multiport surgery in colon cancer: a propensity score matching analysis

Purpose

The feasibility of reduced-port laparoscopic surgery (RPS) in colon cancer remains uncertain. This study aimed to compare the short-term outcomes of RPS and multiport surgery (MPS) in colon cancer using propensity score matching analysis.

Methods

A total of 302 patients with colon cancer who underwent laparoscopic anterior resection (AR) (n = 184) or right hemicolectomy (RHC) (n = 118) by a single surgeon between January 2011 and January 2017 were included. Short-term outcomes were compared between RPS and MPS.

Results

Seventy-three patients in the AR group and 23 in the RHC group underwent RPS. After propensity score matching, the RPS and MPS groups showed similar baseline characteristics. In the AR group, patients who underwent RPS (n = 72) showed a shorter operation time (114.4 ± 28.7 minutes vs. 126.7 ± 34.5 minutes, P = 0.021) and a longer time to gas passage (3.6 ± 1.7 days vs. 2.6 ± 1.5 days, P = 0.005) than MPS (n = 72). Similarly, in the RHC group, the operation time was shorter (112.6 ± 26.0 minutes vs. 146.5 ± 31.2 minutes, P = 0.005), and the time to first flatus was longer (2.7 ±1.1 days vs. 3.8 ± 1.3 days, P = 0.004) in the RPS group (n = 23) than in the MPS group (n = 23). Other short-term outcomes were similar for RPS and MPS in both the AR and RHC groups.

Conclusion

The short-term outcomes of RPS were found to be acceptable compared to those of MPS in colon cancer surgery.

Negative to positive lymph node ratio is a superior predictor than traditional lymph node status in stage III colorectal cancer

Negative lymph node counts has recently attracted attention as a prognostic indicator in colorectal cancer (CRC). But little is known about prognostic significance of negative to positive lymph node ratio (NPR) in CRC. Our aim was to determine impact of NPR on oncological outcomes in patients with stage III CRC. This retrospective study included 2,256 patients with stage III CRC under curative resection at Fudan university Shanghai cancer center. Kaplan-Meier methods and multivariable Cox regression models were built for the analysis of survival outcomes and risk factors. Accuracy of the NPR was assessed with the Harrell's concordance-index(C-index).X-tile program identified 2.38 or 0.55/2.38 as the optimal cutoff value for NPR to divide the cohort into high/low risk or high/middle/low risk subsets in terms of CRC cause specific survival (CCSS). In a multivariate analysis, NPR was significant independent prognostic factors for CCSS (P<0.05), notably, N classification was not an independently prognostic factor (P>0.05). Further analysis found NPR could give detailed prognostic classification for both N1 and N2 stage (P<0.05). Interestingly, patients in N2+ NPR >2.38 stage have similar survival outcome with N1+ NPR >2.38 stage (χ2=0.030, P=0.863), and better than those at N1+ NPR ≤2.38 and N2+ NPR ≤2.38 stage (P<0.001). The TN_NPRM stage was more accurate for predicting CCSS (C-index = 0.659) than current TNM stage system(C-index = 0.628) (P<0.001). Collectively, NPR was an independent prognostic factor for stage III CRC patients, it could provide more accurate prognostic information than the current node stage system.

Radiotherapy for stage IIA rectal cancer may not benefit all

This study sought to determine whether additional radiotherapy is necessary in patients after optimal surgery for stage IIA rectal cancer and how the different covariates influence the efficacy of radiotherapy. The first primary rectal cancer was identified from the 1988–December 2013 Surveillance, Epidemiology and End Results database. We identified 13647 patients with IIA rectal cancer, in which 39.6% received neo-adjuvant radiotherapy and in another 14.96% patients the adjuvant radiotherapy were performed. Neo-adjuvant or adjuvant radiotherapy group had better survival with 10-Year cancer-specific survival estimates as 75.1% and 73.8% compared to 68.4% of no radiotherapy group (P < 0.01). Adjusted hazard ratio (HR) demonstrated neo-adjuvant and adjuvant radiotherapy (HR: 0.814 and 0.848) were all associated with significantly decreased risk for cancer death. However, radiotherapy did not seem to yield the same survival benefit in selected population. Adjusted stratified analysis demonstrated patients with increasing age, relative large tumor size, and more retrieved regional lymph nodes had no additional benefit for cancer specific survival based on radiation use. In conclusions, unselected patients with stage IIA rectal cancer receiving radiotherapy experienced better survival in comparison to patients without radiation. However, additional radiotherapy is not beneficial for all.

Prognostic impact of the length of the longitudinal resection margin in colon cancer

AIM

Although several guidelines recommend a longitudinal resection margin (LRM) of at least 5 cm, the impact of the LRM on survival is still unknown. The study assessed the prognostic significance of the LRM in patients with colon cancer.

METHOD

We retrospectively reviewed 1343 primary colon cancer patients without distant metastasis who underwent curative resection between January 2004 and December 2012. Patients were classified into three groups: LRM < 3 cm (n = 186), LRM ≥ 3 and <5 cm (n = 376) and LRM ≥5 cm (n = 781). Clinicopathological characteristics and the oncological outcome in the three groups were compared.

RESULTS

The median LRM length was 5.0 cm (range 0.5-26.0 cm). With increasing LRM, the number of retrieved lymph nodes (LNs) tended to increase (19.5 ± 12.0, 22.1 ± 12.8 and 30.0 ± 16.2; P < 0.001). After a median follow-up period of 45 (1-128) months, 3-year disease-free survival (DFS) (89.2%, 89.0% and 87.0%; P = 0.629) and 5-year overall survival (OS) (89.0%, 92.1% and 91.8%; P = 0.679) were not significantly different between the three groups. When confounders were adjusted, LRM was not significantly associated with either DFS or OS, but the number of retrieved LNs (< 12) was an independent risk factor for both DFS (hazard ratio 1.748, 95% confidence interval 1.048-2.917) and OS (hazard ratio 1.929, 95% confidence interval 1.046-3.559).

CONCLUSION

LRM was not associated with oncological outcome, but care should be taken to obtain an adequate number of LNs for better survival.

Laparoscopic versus open surgery for rectal cancer: A meta-analysis of classic randomized controlled trials and high-quality Nonrandomized Studies in the last 5 years

OBJECTIVE

To present a meta-analysis of high-quality published reports comparing laparoscopic rectal resection (LRR) and open rectal resection (ORR) for rectal cancer.

METHODS

Studies that compared LRR and ORR and were published within the last 5 years were identified. All eligible randomized controlled trials (RCTs) and non-randomized comparative trials (NRCTs) were evaluated based on the Jadad score, the Cochrane risk of bias assessment tool and modified Methodological Indices for Nonrandomized Studies (MINORS). The mean differences (MD) and odds ratios (OR) were used to compare the operative time, blood loss, mortality, complications, harvested lymph nodes, hospital stay, distal resection margin, and circumferential resection margin. The risk ratio (RR) method was used to examine recurrence and survival.

RESULTS

Fourteen studies were identified and included 7 RCTs and 7 NRCTs and 4353 patients (2251 LRR, 2102 ORR). Although the operation time of the LRR group was obviously longer than that of the conventional surgery group (MD = 25.64, 95%CI = [5.17,46.10], P = 0.01), LRR was associated with fewer overall complications (OR = 0.67, 95%CI = [0.52,0.87], P = 0.002), less blood loss (MD = -66.49, 95%CI = [-88.31, -44.66], P < 0.00001), shorter postoperative hospital stays (OR = -1.26,95%CI = [-2.45, -0.07],P = 0.004) and shorter bowel function recovery times (MD = -0.93, 95%CI = [-1.27,-0.58], P < 0.00001). Moreover, the difference in the DRM was statistically clear (MD = 0.14, 95%CI = [0.02,0.27], P = 0.03). However, no significant differences between the LRR and ORR groups were observed in terms of the number of lymph nodes harvested, mortality, positive CRM, local and distal recurrence, or overall and disease-free survival.

CONCLUSIONS

This study indicates that there are no significant differences between LRR and ORR in terms of survival and pathological outcomes with the exception of the DRM. Moreover, this study suggests that LRR can be performed safely and elicits faster recovery times compared with conventional surgery.

Lymph node retrieval in colorectal cancer: determining factors and prognostic significance

PURPOSE

The study aimed to analyze clinicopathological factors that determine the extent of lymph node retrieval and to evaluate its prognostic impact in patients with colorectal cancer (CRC).

METHODS

The number of retrieved lymph nodes was analyzed in 381 CRC specimens. Lymph node count was related to different clinicopathological variables by binary logistic regression. Progression-free survival (PFS) and cancer-specific survival (CSS) were determined using the Kaplan-Meier method and Cox regression models.

RESULTS

The median number of retrieved lymph nodes was 20 (mean 21 ± 10, range 1-65) in right-sided, 13 (16 ± 10, 1-66) in left-sided, and 15 (18 ± 11, 3-64) in rectal tumors. The number of retrieved lymph nodes was independently associated with T-classification (p < 0.001), N-classification (p = 0.014), and tumor size (p = 0.005) as well as right-sided tumor location (p = 0.012). There was no association with age, sex, tumor grade, mismatch-repair status, and lymph or blood vessel invasion. The longer the surgical specimen, the higher were the numbers of retrieved and positive lymph nodes (p < 0.001, respectively). In patients with locally advanced (T3/T4) tumors (n = 283), analysis of more than 12 lymph nodes was independently associated with PFS (HR = 0.63, p = 0.025) and CSS (HR = 0.54, p = 0.004). In the subset of T3/T4 N0 patients (n = 130), analysis of more than 12 lymph nodes similarly proved to be an independent predictor of outcome (PFS, HR = 0.48, p = 0.046; OS, HR = 0.41, p = 0.026).

CONCLUSION

The number of retrieved lymph nodes is associated with higher tumor stage, tumor size, and right-sided location. Low lymph node count indicates adverse outcome in patients with locally advanced (T3/T4) disease.

Less than 12 lymph nodes in the surgical specimen after neoadjuvant chemo-radiotherapy: an indicator of tumor regression in locally advanced rectal cancer?

BACKGROUND

The number of lymph node retrieved in the surgical specimen is important for tumor staging and has paramount impact on prognosis in colorectal cancer and imitates the adequacy of lymph node surgical clearance. The paucity of lymph node yields in patients undergoing resection after preoperative chemo radiotherapy (CRT) in rectal cancer has seen. Lower total number of lymph nodes in the total mesoractal excision (TME) specimen after CRT, could a marker of better tumor response.

METHODS

We retrospectively reviewed the prospectively managed data of patients underwent excision for rectal cancer, who treated by neoadjuvant radiotherapy with or without chemotherapy in locally advanced rectal cancer. From 2010 to 2014, 364 patients underwent rectal cancer surgery, of which ninety-one treated with neoadjuvant treatment. Standard surgical and pathological protocols were followed. Patients were categorized into two groups based on the number of total harvested lymph nodes with group 1, having 12 or more nodes harvested, and group 2 including patients who had <12 lymph nodes harvested. The total number of lymph nodes retrieved from the surgical specimen was correlated with grade of tumor regression with neoadjuvant treatment.

RESULTS

Out of 91 patients, 38 patients (42%) had less than 12 lymph nodes examined in specimen. The difference in median number of lymph nodes was observed significantly as 9 (range, 2-11) versus 16 (range, 12-32), in group 2 and 1, respectively (P<0.01). Patients with fewer lymph node group were comparable with respect to age, BMI, pre-operative staging, neoadjuvant treatment. Pathological complete response in tumor pCR was seen with significantly higher rate (40% vs. 26%, P<0.05) in group 2. As per Mandard criteria, there was significant difference in tumor regression grade (TRG) between both the groups (P<0.05). Among patients with metastatic lymph nodes, median LNR was lower in <12 lymph nodes group at 0.167 (range, 0.09-0.45) versus 0.187 (range, 0.05-0.54), difference was not statistically significant (P=0.81).

CONCLUSIONS

Retrieval of fewer than 12 lymph nodes in surgical specimen of rectal cancer who had received neo-adjuvant radiotherapy with or without chemotherapy should be considered as a good indicator of tumor response with better local disease control, and a good prognostic factor, rather than as a pointer of poor diligence of the surgical and pathological assessment.

Alterations of lymph nodes evaluation after colon cancer resection: patient and tumor heterogeneity should be taken into consideration

Despite the adequacy of nodal evaluation was gradually improved for colon cancer (CC), rare attention has been paid for the effect of patient and tumor heterogeneity on nodal evaluation. We identified 109902 CC patients in stage I-III from Surveillance, Epidemiology, and End-Results (SEER) database during 2004-2013. The lymph nodes evaluations were separately assessed in different patient- and tumor-related features, including gender, age, T stage, histology, tumor differentiation, tumor size and tumor location. The 5-year cancer specific survival (CSS) was calculated with Kaplan-Meier method, log-rank tests were used to compare the differences of CSS in patients with ≥12 and <12 lymph nodes examined. Here, we identified features including gender, age, T stage, tumor differentiation, tumor size and location were independently associated with the median number of lymph node, the rate of ≥12 lymph nodes and the rate of node positivity of CC patients. We then divided CC patients into 29 subgroups according to different patient- and tumor-related features. The median number of lymph node presented a large variance from 12 to 24, the rate of ≥12 lymph nodes increased from 53.2% to 91.2% under the combined effect of patient and tumor heterogeneity. Furthermore, the positive association between increased lymph nodes count and improved survival couldn't be observed in 8261 CC patients with the effect of this heterogeneity. In conclusion, the tumor and patient heterogeneity lead to large alterations of nodal evaluation; we should pay more attention to this effect in clinical practice.

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

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

A validated metabolomic signature for colorectal cancer: exploration of the clinical value of metabolomics

Background:

Timely diagnosis and classification of colorectal cancer (CRC) are hindered by unsatisfactory clinical assays. Our aim was to construct a blood-based biomarker series using a single assay, suitable for CRC detection, prognostication and staging.

Methods:

Serum metabolomic profiles of adenoma (N=31), various stages of CRC (N=320) and healthy matched controls (N=254) were analysed by gas chromatography-mass spectrometry (GC-MS). A diagnostic model for CRC was derived by orthogonal partial least squares-discriminant analysis (OPLS-DA) on a training set, and then validated on an independent data set. Metabolomic models suitable for identifying adenoma, poor prognosis stage II CRC and discriminating various stages were generated.

Results:

A diagnostic signature for CRC with remarkable multivariate performance (R²Y=0.46, Q²Y=0.39) was constructed, and then validated (sensitivity 85% specificity 86%). Area under the receiver-operating characteristic curve was 0.91 (95% CI, 0.87–0.96). Adenomas were also detectable (R²Y=0.35, Q²Y=0.26, internal AUROC=0.81, 95% CI, 0.70–0.92). Also of particular interest, we identified models that stratified stage II by prognosis, and classified cases by stage.

Conclusions:

Using a single assay system, a suite of CRC biomarkers based on circulating metabolites enables early detection, prognostication and preliminary staging information. External population-based studies are required to evaluate the repeatability of our findings and to assess the clinical benefits of these biomarkers.

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

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

Increased lymph node retrieval decreases adjuvant chemotherapy rate for stage II colon cancer

OBJECTIVE

Investigation of lymph nodes in colorectal specimens after surgery due to cancer is important for staging the cancer. There has to be an adequate number of lymph nodes to conclude a node-negative status. Our aim was to investigate if change in fixative could give increased lymph node yield, and if this could result in a potential decrease of adjuvant treatment for stage II patients. In addition, we wanted to evaluate if the change in fixative could potentially affect subsequent molecular testing.

MATERIAL AND METHODS

All resection specimens from one hospital were from 2011 fixed in GEWF while resection specimens from two other hospitals were fixed in conventional buffered formalin. Number of lymph nodes harvested were compared from two periods; 2009/2010 and 2012/2013. In addition, tumors fixed in GEWF and tumors fixed in formalin were tested separately with immunohistochemical staining and molecular testing.

RESULTS

There was a significant increase in lymph node retrieval in specimens fixed in GEWF compared to number of lymph nodes found before the implementation of this fixative (p < 0.001). For hospitals using only formalin, the number of nodes did not increase significantly. Number of positive lymph nodes did not increase. Immunohistochemical staining can be a problem with tumors fixed in GEWF, but DNA quality seems not affected by the changes.

CONCLUSIONS

GEWF enhances lymph node detection in colorectal cancer specimens, leading to fewer patients being falsely defined as high-risk stage II. The loss of stability when staining for MMR-proteins can be overcome by molecular analysis when needed.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TNFRSF10C copy number variation is associated with metastatic colorectal cancer

BACKGROUND

Genetic markers for distant metastatic disease in patients with colorectal cancer (CRC) are not well defined. Identification of genetic alterations associated with metastatic CRC could help to guide systemic and local treatment strategies. We evaluated the association of tumor necrosis factor receptor superfamily member 10C (TNFRSF10C) copy number variation (CNV) with distant metastatic disease in patients with CRC using The Cancer Genome Atlas (TCGA).

METHODS

Genetic sequencing data and clinical characteristics were obtained from TCGA for all available patients with CRC. There were 515 CRC patient samples with CNV and clinical outcome data, including a subset of 144 rectal adenocarcinoma patient samples. Using the TCGA CRC dataset, CNV of TNFRSF10C was evaluated for association with distant metastatic disease (M1 vs. M0). Multivariate logistic regression analysis with odds ratio (OR) using a 95% confidence interval (CI) was performed adjusting for age, T stage, N stage, adjuvant chemotherapy, gender, microsatellite instability (MSI), location, and surgical margin status.

RESULTS

TNFRSF10C CNV in patients with CRC was associated with distant metastatic disease [OR 4.81 (95% CI, 2.13-10.85) P<0.001] and positive lymph nodes [OR 18.83 (95% CI, 8.42-42.09)]; P<0.001) but not MSI (OR P=0.799). On multivariate analysis, after adjusting for pathologic T stage, N stage, adjuvant chemotherapy, gender, and MSI, TNFRSF10C CNV remained significantly associated with distant metastatic disease (OR P=0.018). Subset analysis revealed that TNFRSF10C CNV was also significantly associated with distant metastatic disease in patients with rectal adenocarcinoma (OR P=0.016).

CONCLUSIONS

TNFRSF10C CNV in patients with CRC is associated with distant metastatic disease. With further validation, such genetic profiles could be used clinically to support optimal systemic treatment strategies versus more aggressive local therapies in patients with CRC, including radiation therapy for rectal adenocarcinoma.

Non-surgical factors influencing lymph node yield in colon cancer

There are numerous factors which can affect the lymph node (LN) yield in colon cancer specimens. The aim of this paper was to identify both modifiable and non-modifiable factors that have been demonstrated to affect colonic resection specimen LN yield and to summarise the pertinent literature on these topics. A literature review of PubMed was performed to identify the potential factors which may influence the LN yield in colon cancer resection specimens. The terms used for the search were: LN, lymphadenectomy, LN yield, LN harvest, LN number, colon cancer and colorectal cancer. Both non-modifiable and modifiable factors were identified. The review identified fifteen non-surgical factors: (13 non-modifiable, 2 modifiable) which may influence LN yield. LN yield is frequently reduced in older, obese patients and those with male sex and increased in patients with right sided, large, and poorly differentiated tumours. Patient ethnicity and lower socioeconomic class may negatively influence LN yield. Pre-operative tumour tattooing appears to increase LN yield. There are many factors that potentially influence the LN yield, although the strength of the association between the two varies greatly. Perfecting oncological resection and pathological analysis remain the cornerstones to achieving good quality and quantity LN yields in patients with colon cancer.

CCR6 expression in colon cancer is associated with advanced disease and supports epithelial-to-mesenchymal transition

Background:

Adjuvant chemotherapy offered to treat colon cancer is based on the TNM staging system, which often fails due to molecular heterogeneity and undefined molecular mechanisms independent of TNM. Therefore, identification of markers to better predict therapeutic option and outcome is needed. In this study we have characterised the clinical association of CCR6 with colon cancer and defined CCR6-mediated molecular pathway.

Methods:

Immunohistochemistry, RT-qPCR, western blot and FACS were used to determine expression of CCR6 and/or EMT markers in colon tissues/cells. BrdU assay and trans-well system were used to determine cell proliferation, migration and invasion in response to CCL20.

Results:

CCR6 was higher in cancer cases compared to normal adjacent tissue and expression was associated with nodal status and distant metastasis. Similarly, CCR6 expression was higher in cells derived from node-positive cases and highest expression was in cells derived from metastatic cases. Significant changes in EMT markers, that is, E-cadherin, vimentin, β-catenin, N-cadherin, α-SMA, SNAILl and ZEB1 were observed in response to CCL20 along with decreased proliferation, increased migratory and invasive potential.

Conclusions:

Results suggest CCR6 as a potential therapeutic target as well as biomarker in addition to nodal status for predicting therapeutic option.

Factors affecting number of lymph nodes harvested and the impact of examining a minimum of 12 lymph nodes in stage I-III colorectal cancer patients: a retrospective single institution cohort study of 1167 consecutive patients

BACKGROUND

To identify factors affecting the harvest of lymph nodes (LNs) and to investigate the association between examining a minimum of 12 LNs and clinical outcomes in stage I-III colorectal cancer (CRC) patients.

METHODS

The clinicopathologic features and the number of examined LNs for 1167 stage I-III CRC patients were analyzed to identify factors affecting the number of LNs harvested and the correlations between clinical outcomes and high harvests (≧12 LNs) and low harvests (<12 LNs).

RESULTS

A multivariate analysis showed that age (P = 0.007), tumor size (P = 0.030), and higher T stage (P = 0.001) were independent factors affecting the examinations of LNs in colon cancer and that tumor size (P = 0.015) was the only independent factor in rectal cancer. Patients with low harvests had poorer overall survival with stage II and stage III CRC (stage II: P < 0.0001; III: P = 0.001) and poorer disease-free survival for stages I-III (stage I: P = 0.023; II: P < 0.0001; III: P = 0.001).

CONCLUSIONS

The factors influencing nodal harvest are multifactorial, and an adequate number of examined LNs (≧12) is associated with a survival benefit. Removal of at least 12 LNs will determine the lymph node status reliably.

Effect of preoperative injection of carbon nanoparticle suspension on the outcomes of selected patients with mid-low rectal cancer

BACKGROUND

Carbon nanoparticles show significant lymphatic tropism and can be used to identify lymph nodes surrounding mid-low rectal tumors. In this study, we analyzed the effect of trans anal injection of a carbon nanoparticle suspension on the outcomes of patients with mid-low rectal cancer who underwent laparoscopic resection.

METHODS

We collected the data of 87 patients with mid-low rectal cancer who underwent laparoscopic resection between November 2014 and March 2015 at Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College. For 35 patients in the experimental group, the carbon nanoparticle suspension was injected transanally into the submucosa of the rectum around the tumor 30 min before the operation; 52 patients in the control group underwent the operation directly without the injection of carbon nanoparticle suspension. We then compared the operation outcomes between the two groups.

RESULTS

In the experimental group, the rate of incomplete mesorectal excision was lower than that in the control group, but no significant difference was found (2.9% vs. 7.7%, P = 0.342). The distance between the tumor and the circumferential resection margin was 5.8 ± 1.4 mm in the experimental group and 4.8 ± 1.1 mm in the control group (P = 0.001). The mean number of lymph nodes removed was 28.2 ± 9.4 in the experimental group and 22.7 ± 7.3 in the control group (P = 0.003); the mean number of lymph nodes smaller than 5 mm in diameter was 10.1 ± 7.5 and 4.5 ± 3.7, respectively (P < 0.001). Three patients in the experimental group received lateral lymph node resection. Among the three patients, we retrieved three nodes (one stained node) from the first patient, three nodes (two stained nodes) from the second patient, and two nodes (no stained nodes) from the third patient.

CONCLUSIONS

Injecting a carbon nanoparticle suspension improved the outcomes of patients who underwent laparoscopic resection for mid-low rectal cancer; it also improved the accuracy of pathologic staging. Moreover, for selected patients, this technique narrowed the scope of lateral lymph node dissection.

Assessment of lymph node involvement in colorectal cancer

Lymph node metastasis informs prognosis and is a key factor in deciding further management, particularly adjuvant chemotherapy. It is core to all contemporary staging systems, including the widely used tumor node metastasis staging system. Patients with node-negative disease have 5-year survival rates of 70%-80%, implying a significant minority of patients with occult lymph node metastases will succumb to disease recurrence. Enhanced staging techniques may help to identify this subset of patients, who might benefit from further treatment. Obtaining adequate numbers of lymph nodes is essential for accurate staging. Lymph node yields are affected by numerous factors, many inherent to the patient and the tumour, but others related to surgical and histopathological practice. Good lymph node recovery relies on close collaboration between surgeon and pathologist. The optimal extent of surgical resection remains a subject of debate. Extended lymphadenectomy, extra-mesenteric lymph node dissection, high arterial ligation and complete mesocolic excision are amongst the surgical techniques with plausible oncological bases, but which are not supported by the highest levels of evidence. With further development and refinement, intra-operative lymphatic mapping and sentinel lymph node biopsy may provide a guide to the optimum extent of lymphadenectomy, but in its present form, it is beset by false negatives, skip lesions and failures to identify a sentinel node. Once resected, histopathological assessment of the surgical specimen can be improved by thorough dissection techniques, step-sectioning of tissue blocks and immunohistochemistry. More recently, molecular methods have been employed. In this review, we consider the numerous factors that affect lymph node yields, including the impact of the surgical and histopathological techniques. Potential future strategies, including the use of evolving technologies, are also discussed.

The prognostic value of lymph node ratio in a national cohort of rectal cancer patients

OBJECTIVE

To analyze the prognostic implications of the lymph node ratio (LNR) in curative resected rectal cancer.

SUMMARY BACKGROUND DATA

It has been proposed that the LNR has a high prognostic impact in colorectal cancer, but the lymph node ratio has not been evaluated exclusively for rectal cancer in a large national cohort study.

METHODS

All 6793 patients in Denmark diagnosed with stage I to III adenocarcinoma of the rectum, and so treated in the period from 2003 to 2011, were included in the analysis. The cohort was divided into two groups according to whether or not neo-adjuvant treatment had been given.

RESULTS

In a multivariate analysis the pN status, ypN status and lymph node yield were found to be independent prognostic factors for overall survival, irrespective of neo-adjuvant therapy. The LNR was also found to be a significant prognostic factor with a Hazard Ratio ranging from 1.154 (95% CI: 0.930-1.432) (LNR: 0.01-0.08) to 2.974 (95% CI: 2.452-3.606) (LNR > 0.5) in the group of patients who had surgery to begin with and from 1.381 (95% CI: 0.891-2.139) (LNR: 0.01-0.08) to 2.915 (95% CI: 2.244-3.787) (LNR > 0.5) in the group of patients who had neo-adjuvant treatment.

CONCLUSIONS

The LNR reflects the influence on survival from N-status and the lymph node yield and since LNR was shown to be a significant prognostic predictor for overall survival in patients with curatively resected stage III rectal cancer irrespective of neo-adjuvant therapy we recommend that the introduction of LNR should be considered for rectal cancer in a revised TNM classification.

Clinicopathological characteristics of young patients with sporadic colorectal cancer

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Young Age Increases Risk of Lymph Node Positivity in Early-Stage Rectal Cancer

BACKGROUND

The risk of lymph node positivity (LN+) in rectal cancer is a parameter that impacts therapeutic recommendations. We aimed to quantify the effect of younger age on LN+ in rectal cancer.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, patients with rectal cancer diagnosed between 1988 and 2008 were identified. Patients were stage I-III, without preoperative radiotherapy, at least one lymph node examined, and a standard rectal cancer operation performed. The association of age and LN+ status was examined with logistic regression separately for each T stage, adjusting for multiple covariates. Poisson regression was used to evaluate age and number of positive lymph nodes (LNs). All statistical tests were two-sided.

RESULTS

Fifty-six thousand seventy-six patients were identified, including 1194 (2.1%) patients age 20 to 39 years at diagnosis and 4199 (7.5%) patients age 40 to 49 years (defined as young). For each T stage, LN+ was inversely associated with age (all P < .001). For T1, T2, and T3, age remained predictive of LN+ status after adjustment for number of LNs examined and other covariates (P < .001 for each stage). Adjusted odds ratios (ORs) for LN+ for age 20 to 39 vs 60 to 69 were: T1: 1.97(95% confidence interval [CI] = 1.36 to 2.86); T2: 1.48 (95% CI = 1.13 to 1.95); T3: 1.30 (95% CI = 1.10 to 1.53). Young age was a statistically significant predictor of an increased number of LNs positive for stage T2 (P = .042) and T3 (P = .002).

CONCLUSION

In this large national dataset, young age at diagnosis is associated with an increased risk of LN+. This finding merits further investigation and may ultimately impact treatment decision-making for young early-stage patients.

Prognostic and Predictive Model for Stage II Colon Cancer Patients With Nonemergent Surgery: Who Should Receive Adjuvant Chemotherapy?

No ideal prognostic model has been applied to clearly identify which suitable high-risk stage II colon cancer patients with negative margins undergoing nonemergent surgery should receive adjuvant chemotherapy routinely. Clinicopathologic and prognostic data of 333 stage II colon cancer patients who underwent D2 or D3 lymphadenectomy during nonemergent surgery were retrospectively analyzed. Four pathologically determined factors, including adjacent organ involvement (RR 2.831, P = 0.001), histologic differentiation (RR 2.151, P = 0.009), lymphovascular invasion (RR 4.043, P < 0.001), and number of lymph nodes retrieved (RR 2.161, P = 0.011), were identified as independent prognostic factors on multivariate analysis. Importantly, a simple cumulative scoring system clearly categorizing prognostic risk groups was generated: risk score = ∑ coefficient' × status (AOI + histological differentiated + lymphovascular invasion + LNs retrieved). Our new prognostic model may provide valuable information on the impact of lymphovascular invasion, as well as powerfully and reliably predicting prognosis and recurrence for this particular cohort of patients. This model may identify suitable patients with an R0 resection who should receive routine postoperative adjuvant therapy and may help clinicians to facilitate individualized treatment. In this study, we aim to provide an ideal and quantifiable method for clinical decision making in the nonemergent surgical treatment of stage II colon cancer. Our prognostic and predictive model should be applied in multicenter, prospective studies with large sample sizes, in order to obtain a more reliable clinical recommendation.

Pathological Assessment of the AJCC Tumor Regression Grading System After Preoperative Chemoradiotherapy for Chinese Locally Advanced Rectal Cancer

We used American Joint Committee on Cancer (AJCC) Staging Manual system to assess the prognostic significance of tumor regression grading (TRG) for locally advanced rectal cancer (LARC) (T3/4 or N+) patients who were treated with preoperative chemoradiotherapy (CRT).The 4 AJCC-TRG classifications were evaluated on surgical specimens from 295 LARC patients receiving CRT. Overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were estimated using Kaplan-Meier method and Cox regression model.Classifications of TRG 0, 1, 2, and 3 were found in 27.5%, 19.3%, 45.7%, and 7.5% of the resected specimens, respectively. Three-year OS was 95.5% for TRG0, 91.5% for TRG1, 84.8% for TRG2, and 85.7% for TRG3 (P = 0.035). Three-year DFS was 89.0% for TRG0, 74.4% for TRG1, 70.9% for TRG2, and 62% for TRG3 (P = 0.018). By multivariate analysis, AJCC-TRG (P = 0.033), residual lymph node metastasis (ypN+) (P < 0.001) and pretreatment CA19-9 level (P = 0.035) were significant predictors of OS. Pathological T category (P = 0.006) and nodal status (P < 0.001) after CRT were the most important independent prognostic factors for DFS.AJCC-TRG is a prognostic factor for LARC patients receiving CRT, independent of pathological staging.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

Effect of Lymph Node Count on Pathological Stage III Rectal Cancer with Preoperative Radiotherapy

Lymph node (LN) status after surgery for rectal cancer is affected by preoperative radiotherapy. The purpose of this study was to perform a population-based evaluation of the impact of pathologic LN status after neoadjuvant radiotherapy on survival. A total of 1,650 patients receiving neoadjuvant chemotherapy in Surveillance, Epidemiology, and End Results Program (SEER)-registered ypIII stage rectal cancer was analyzed. We identified the optimal cutoff for retrieved LNs as 10 (χ2 = 14.006, P < 0.001), which was validated as an independent prognosis factors in a Cox regression model. Further analysis showed that the LN count was only a prognosis factor with the number from 8 to 16(except for 13).After the number 16, the 5-year survival rate decreased gradually. Collectively, our results confirmed that the number of LNs in yp III stage rectal patients was a prognosis factor only with the numbers from 8 to 16(except for 13). Using the total mesorectal excision technique with an adequate pathologic examination, a large number of LNs retrieved (≥17) might indicate worse tumor response grade and poorer survival.

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

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