No change in lymph node positivity rate despite increased lymph node yield and improved survival in colon cancer

Prognostic Value of Metastatic Lymph Node Ratio and Identification of Factors Influencing the Lymph Node Yield in Patients Undergoing Curative Colon Cancer Resection

Due to the impact of nodal metastasis on colon cancer prognosis, adequate regional lymph node resection and accurate pathological evaluation are required. The ratio of metastatic to examined nodes may bring an additional prognostic value to the actual staging system. This study analyzes the identification of factors influencing a high lymph node yield and its impact on survival. The lymph node ratio was determined in patients with fewer than 12 or at least 12 evaluated nodes. The study included patients after radical colon cancer resection in UICC stages II and III. For the lymph node ratio (LNR) analysis, node-positive patients were divided into four categories: i.e., LNR 1 (<0.05), LNR 2 (≥0.05; <0.2), LNR 3 (≥0.2; <0.4), and LNR 4 (≥0.4), and classified into two groups: i.e., those with <12 and ≥12 evaluated nodes. The study was conducted on 7012 patients who met the set criteria and were included in the data analysis. The mean number of examined lymph nodes was 22.08 (SD 10.64, median 20). Among the study subjects, 94.5% had 12 or more nodes evaluated. These patients were more likely to be younger, women, with a lower ASA classification, pT3 and pN2 categories. Also, they had no risk factors and frequently had a right-sided tumor. In the multivariate analysis, a younger age, ASA classification of II and III, high pT and pN categories, absence of risk factors, and right-sided location remained independent predictors for a lymph node yield ≥12. The univariate survival analysis of the entire cohort demonstrated a better five-year overall survival (OS) in patients with at least 12 lymph nodes examined (68% vs. 63%, p = 0.027). The LNR groups showed a significant association with OS, reaching from 75.5% for LNR 1 to 33.1% for LNR 4 (p < 0.001) in the ≥12 cohort, and from 74.8% for LNR2 to 49.3% for LNR4 (p = 0.007) in the <12 cohort. This influence remained significant and independent in multivariate analyses. The hazard ratios ranged from 1.016 to 2.698 for patients with less than 12 nodes, and from 1.248 to 3.615 for those with at least 12 nodes. The LNR allowed for a more precise estimation of the OS compared with the pN classification system. The metastatic lymph node ratio is an independent predictor for survival and should be included in current staging and therapeutic decision-making processes.

Intracorporeal Vessel Ligation in Laparoscopic Right Colectomy for Cancer is Associated with Increased Lymph Node Yield

BACKGROUND

This study aimed to compare intra- and extracorporeal division of the vascular pedicle in laparoscopic right colectomy regarding pathological outcomes, short-term morbidity, and local recurrence and distant metastases.

METHODS

Retrospective analysis of an IRB-approved database of all patients who underwent laparoscopic right colectomy for cancer between 01/2011 and 08/2021. Main outcome measures were number of harvested lymph nodes, length of resected colon, R1 rate, positive lymph node ratio, short-term post-operative morbidity, local recurrence, and distant metastases.

RESULTS

Two-hundred seventy-one consecutive patients (136 males) patients underwent laparoscopic right hemicolectomy for cancer during the study period. Vessel ligation was intracorporeal in 171 (63%) and extracorporeal in 100 patients (37%); groups had similar baseline characteristics except for extent of resection as extended right hemicolectomy was significantly more often performed in the intracorporeal group. When the two groups were matched for the extent of resection (standard versus extended right hemicolectomy), the mean number of harvested lymph nodes (28.61 ± 12.04 versus 25.37 ± 10.06, p = 0.04) and median length of the resected colon [26.00 (IQR: 21.00, 32.00) versus 23.00 (IQR: 19.00, 27.00) cm, p = 0.003] were significantly higher in the intracorporeal than in the extracorporeal group. The intracorporeal group required a significantly longer operative time than did the extracorporeal group (168.94 ± 57.9 vs. 139.7 ± 41.3 mins, p = 0.001). No significant differences were noted between the groups in terms of ileus, hemorrhage, surgical site infection, re-operation rates, recurrence, or distant metastases.

CONCLUSION

Intracorporeal vessel ligation in laparoscopic right hemicolectomy was associated with increased lymph node yield and longer specimens, although requiring longer operative times. Postoperative clinical outcomes were similar to outcomes in the extracorporeal ligation group.

Examined lymph node numbers influence prognosis in rectal cancer treated with neoadjuvant therapy

Background

The number of lymph nodes examined (LNe) is often insufficient in patients with rectal cancer (RC) treated with neoadjuvant therapy; however, its prognostic value remains controversial. Thus, we retrospectively explored whether LNe had an influence on staging and prognosis and investigated whether there was a cut-off value for better prognosis in patients with RC treated with neoadjuvant therapy.

Methods

Data were collected from seven prospective hospital databases in China from July 2002 to May 2018. Binary logistic regression models were used to predict lymph node metastasis. The cut-off value for LNe was determined using X-tile 3.6.1. Survival outcomes and risk factors were analyzed using the log-rank test and Cox regression model.

Results

A total of 482 patients were included, of whom 459 had complete overall survival (OS) information. Using the percentile method, the total number of lymph nodes examined (TLNe) was 14-16 (40th-60th percentile), and the proportion of patients with lymph node metastasis reached a maximum of 48.1%. Cox multivariate analysis showed that the odds ratio (OR) remained the highest when TLNe was 14-16 (OR = 3.379, P = 0.003). The 3-year and 5-year OS were 85.4% and 77.8%, respectively. Negative lymph nodes examined (NLNe) of ≤6 was an independent risk factor for 3-year and 5-year OS (3-year OS 71.1% vs. 85.9%, P = 0.004; 5-year OS 66.3% vs. 74.3%, P = 0.035). Subgroup analysis for patients with ypN + showed that higher 3-year and 5-year OS were achieved when the TLNe was >10, 78.8% vs. 54.0% (P = 0.005), and 60.8% vs. 36.0% (P = 0.012), respectively. Patients with ypN0M0 had a higher 5-year OS when the TLNe was >19 (P = 0.055).

Conclusion

The TLNe and NLNe influenced the staging accuracy and demonstrated prognostic value in patients with RC treated with neoadjuvant therapy.

Pattern of recurrence and survival after D2 right colectomy for cancer: is there place for a routine more extended lymphadenectomy?

BACKGROUND

Conventional Right Colectomy with D2 lymphadenectomy (RC-D2) currently represent the most common surgical treatment of right-sided colon cancer (RCC). However, whether it should be still considered a standard of care, or replaced by a routine more extended D3 lymphadenectomy remains unclear. In the present study, we aim to critically review the patterns of relapse and the survival outcomes obtained from our 11-year experience of RC-D2.

METHODS

Clinical data of 489 patients who underwent RC-D2 for RCC at two centres, from January 2009 to January 2020, were retrospectively reviewed. Patients with synchronous distant metastases and/or widespread nodal involvement at diagnosis were excluded. Post-operative clinical-pathological characteristics and survival outcomes were evaluated including the pattern of disease relapse.

RESULTS

We enrolled a total of 400 patients with information follow-up. Postoperative morbidity was 14%. The median follow-up was 62 months. Cancer recurrence was observed in 55 patients (13.8%). Among them, 40 patients (72.7%) developed systemic metastases, and lymph-node involvement was found in 7 cases (12.8%). None developed isolated central lymph-node metastasis (CLM), in the D3 site. The estimated 3- and 5-year relapse-free survival were 86.1% and 84.4%, respectively. The estimated 3- and 5-year cancer-specific OS were 94.5% and 92.2%, respectively.

CONCLUSIONS

The absence of isolated CLM, as well as the cancer-specific OS reported in our series, support the routine use of RC-D2 for RCC. However, D3 lymphadenectomy may be recommended in selected patients, such as those with pre-operatively known CLM, or with lymph-node metastases close to the origin of the ileocolic vessels.

Primary tumour immune response and lymph node yields in colon cancer

Background

The mechanism underlying improved survival in non-metastatic colon cancer with higher lymph node (LN) yield is unknown. This study aimed to identify whether molecular features in the primary tumour were predictive of LN yield.

Methods

Clinical, genomic, transcriptomic, proteomic and methylation data of non-metastatic, colon cancers studied in The Cancer Genome Atlas were interrogated for associations with LN yield. Based on maximal survival effects, patients were segregated into high (>15) and low (≤15) LN yield. Gene set enrichment analysis was performed on transcriptomic changes to identify biological processes associated with LN yield. Correlations were validated in an independent set of Stage II colon cancers.

Results

High LN yield was found predictive of overall and disease-free survival. There was no association of higher LN yield and increasing nodal positivity. High LN yield was strongly linked with gene expression changes associated with the adaptive and dendritic cell immune response. This association was most prominent in node-negative cancers. Analogous findings were reproduced in the validation dataset.

Conclusion

The study shows a strong association of an activated immune response in tumours with a high LN yield. Immunogenic tumours have a better prognosis, likely explaining the survival benefit with higher LN yields.

Pathological Features and Prognostication in Colorectal Cancer

The prognostication of colorectal cancer (CRC) has traditionally relied on staging as defined by the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) TNM staging classifications. However, clinically, there appears to be differences in survival patterns independent of stage, suggesting a complex interaction of stage, pathological features, and biomarkers playing a role in guiding prognosis, risk stratification, and guiding neoadjuvant and adjuvant therapies. Histological features such as tumour budding, perineural invasion, apical lymph node involvement, lymph node yield, lymph node ratio, and molecular features such as MSI, KRAS, BRAF, and CDX2 may assist in prognostication and optimising adjuvant treatment. This study provides a comprehensive review of the pathological features and biomarkers that are important in the prognostication and treatment of CRC. We review the importance of pathological features and biomarkers that may be important in colorectal cancer based on the current evidence in the literature.

Optimal examined lymph node count in node-negative colon cancer should be determined

Background: We aimed to investigate the association between optimal examined lymph node (ELNs) and overall survival to determine the optimal cutoff point. Methods: Cox models and locally weighted scatterplot smoothing were used to fit hazard ratios and explore an optimal cutoff point based on the Chow test. Results: Overall survival increased significantly with the corresponding increase in the number of ELNs after adjusting for covariates. In Chow's test, the optimal cutoff point for node-negative colon cancer was 15, which was validated in both cohorts after controlling for confounders (Surveillance, Epidemiology, and End Results database: hazard ratio: 0.701, p < 0.001; single-center: HR: 0.563, p = 0.031). Conclusions: We conservatively suggest that the optimal number of ELNs for prognostic stratification is 15 in node-negative colon cancer.

Complete mesocolic excision versus conventional surgery for colon cancer: A systematic review and meta-analysis

AIM

Complete mesocolic excision (CME) lacks consistent data advocating operative superiority compared to conventional surgery for colon cancer. We performed a systematic review and meta-analysis, analysing population characteristics and perioperative, pathological and oncological outcomes.

METHODS

D3 extended lymphadenectomy dissection was considered comparable to CME, and D2 and D1 dissection to be comparable to conventional surgery. Outcomes reviewed included lymph node yield, R1 resection, overall complications, overall survival and disease-free survival.

RESULTS

In all, 3039 citations were identified; 148 studies underwent full-text reviews and 31 matched inclusion criteria: total cohort 26 640 patients (13 830 CME/D3 vs. 12 810 conventional). Overall 3- and 5-year survival was higher in the CME/D3 group compared with conventional surgery: relative risk (RR) 0.69 (95% CI 0.51-0.93, P = 0.016) and RR 0.78 (95% CI 0.64-0.95, P = 0.011) respectively. Five-year disease-free survival also demonstrated CME/D3 superiority (RR 0.67, 95% CI 0.52-0.86, P < 0.001), with similar findings at 1 and 3 years. There were no statistically significant differences between the CME/D3 and conventional group in overall complications (RR 1.06, 95% CI 0.97-1.14, P = 0.483) or anastomotic leak (RR 1.02, 95% CI 0.81-1.29, P = 0.647).

CONCLUSIONS

Meta-analysis suggests CME/D3 may have a better overall and disease-free survival compared to conventional surgery, with no difference in perioperative complications. Quality of evidence regarding survival is low, and randomized control trials are required to strengthen the evidence base.

The assessment of risk factors for long-term survival outcome in ypN0 patients with rectal cancer after neoadjuvant therapy and radical anterior resection

BACKGROUND

The main negative prognostic factors in patients with rectal cancer after radical treatment include regional lymph node involvement, lymphovascular invasion, and perineural invasion. However, some patients still develop cancer recurrence despite the absence of the above risk factors. The aim of the study was to assess clinicopathological factors influencing long-term oncologic outcomes in ypN0M0 rectal cancer patients after neoadjuvant therapy and radical anterior resection.

METHODS

A retrospective survival analysis was performed on a group of 195 patients. We assessed clinicopathological factors which included tumor regression grade, number of lymph nodes in the specimen, Charlson comorbidity index (CCI), and colorectal anastomotic leakage (AL).

RESULTS

In the univariate analysis, AL and CCI > 3 had a significant negative impact on disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS). After the division of ALs into early and late ALs, it was found that only patients with late ALs had a significantly worse survival. The multivariate Cox regression analysis showed that CCI > 3 was a significant adverse risk factor for DFS (HR 5.78, 95% CI 2.15-15.51, p < 0.001), DSS (HR 7.25, 95% CI 2.25-23.39, p < 0.001), and OS (HR 3.9, 95% CI 1.72-8.85, p = 0.001). Similarly, late ALs had a significant negative impact on the risk of DFS (HR 5.05, 95% CI 1.97-12.93, p < 0.001), DSS (HR 10.84, 95% CI 3.44-34.18, p < 0.001), and OS (HR 4.3, 95% CI 1.94-9.53, p < 0.001).

CONCLUSIONS

Late AL and CCI > 3 are the factors that may have an impact on long-term oncologic outcomes. The impact of lymph node yield on understaging was not demonstrated.

T stage-dependent lymph node and distant metastasis and the accuracy of lymph node assessment in rectal cancer

Objective

To analyze data obtained in a representative number of patients with primary rectal cancer with respect to lymph node diagnostics and related tumor stages.

Methods

In pT2-, pT3-, and pT4 rectal cancer lesions, the impact of investigated lymph nodes on the frequency of pN+ status, the cumulative risk of metachronous distant metastases, and overall survival was studied by means of a prospective multicenter observational study over a defined period of time.

Results

From 2000 to 2011, the proportion of surgical specimens with ≥ 12 investigated lymph nodes increased significantly, from 73.6% to 93.2% (p < 0.001; the number of investigated lymph nodes from 16.2 to 20.8; p < 0.001). Despite this, the percentage of pN+ rectal cancer lesions varied only non-significantly (39.9% to 45.9%; p = 0.130; median, 44.1%). For pT2-, pT3-, and pT4 rectal cancer lesions, there was an increasing proportion of pN+ findings correlating significantly with the number of investigated lymph nodes up to n = 12 investigated lymph nodes. Only in pT3 rectal cancer was there a significant increase in pN+ findings in case of > 12 lymph nodes (p = 0.001), but not in pT2 (p = 0.655) and pT4 cancer lesions (p = 0.256). For pT3pN0cM0 rectal cancer, the risk of metachronous distant metastases and overall survival did not depend on the number of investigated lymph nodes.

Conclusion

In rectal cancer, at least n = 12 lymph nodes are to be minimally investigated. The investigation of fewer lymph nodes is associated with a higher risk of false-negative pN0 findings. In particular, in pT3 rectal cancer, the investigation of more than 12 lymph nodes lowers the risk of false-negative pN0 findings. An upstaging effect by the investigation of a possibly maximal number of lymph nodes could not be detected.

Has the increase in the regional nodes evaluated improved survival rates for patients with locoregional colon cancer?

Background: The guidelines for colon cancer surgery have been evolving over the past three decades. The advances in colectomy have focused mainly on the number of regional nodes evaluated (RNE).

Methods: Data in this retrospective analysis were extracted from the Surveillance, Epidemiology, and End Results (SEER) linked database.

Results: Rapid growth of RNE (the median rising from 10 (6-16) to 17 (13-23)) occurred from 2000 to 2009. The rate of colon cancer patients with positive lymph nodes following colectomy was greatly decreasing only in the group with RNE greater than 12 after 2000. Patients with T4 and/or N+ cannot obtain survival benefit from the increasing trend of RNE. The apparent survival benefit for T1-3N0 patients may result from augmented false negatives in patients from previous periods.

Conclusions: The golden period of surgical development in colon cancer, using RNE as an alternative indicator, occurred in the first decade of the 21st century. Although a more extensive lymph node evaluation is able to reduce the risk of underestimated staging, the increase of RNE does not provide survival benefits for locoregional colon cancer. A proper reduction in the scope of lymph node dissection may be reasonable in radical surgery for colon cancer.

Small Molecules for Multi-Wavelength Near-Infrared Fluorescent Mapping of Regional and Sentinel Lymph Nodes in Colorectal Cancer Staging

Assessing lymph node (LN) status during tumor resection is fundamental for the staging of colorectal cancer. Current guidelines require a minimum of 12 LNs to be harvested during resection and ultra-staging regional lymph nodes by sentinel lymph node (SLN) assessment is being extensively investigated. The current study presents novel near-infrared (NIR) fluorescent dyes for simultaneous pan lymph node (PanLN; regional) and SLN mapping. PanLN-Forte was intravenously injected in mice and assessed for accumulation in regional LNs. SLN800 was injected intradermally in mice, after which the collection and retention of fluorescence in SLNs were measured using indocyanine green (ICG) and its precursor, SLN700, as references. LNs in the cervical, inguinal, jejunal, iliac, and thoracic basins could clearly be distinguished after a low dose intravenous injection of PanLN-Forte. Background fluorescence was significantly lower compared to the parent compound ZW800-3A (p < 0.001). SLN700 and SLN800 specifically targeted SLNs with fluorescence being retained over 40-fold longer than the current clinically used agent ICG. Using SLN700 and SLN800, absolute fluorescence in SLN was at least 10 times higher than ICG in second-tier nodes, even at 1 hour post-injection. Histologically, the fluorescent signal localized in the LN medulla (PanLN-Forte) or sinus entry (SLN700/SLN800). PanLN-Forte and SLN800 appear to be optimal for real-time NIR fluorescence imaging of regional and SLNs, respectively.

The re-evaluation of optimal lymph node yield in stage II right-sided colon cancer: is a minimum of 12 lymph nodes adequate?

PURPOSE

Adequate lymphadenectomy is critical for accurate nodal staging and planning adjuvant therapy in colon cancer. However, the optimal lymph node (LN) yield for stage II right-sided colon cancer (RSCC) is still unclear. This population-based study aimed to determine the optimal LN yield associated with survival and LN positivity in patients with stage II RSCC.

METHODS

All patients with stage II-III RSCC were identified from the Surveillance, Epidemiology, and End Results database over a 10-year interval (2006-2015). The optimal threshold for LN yield was explored using an outcome-oriented approach based on survival and LN positivity.

RESULTS

The median number of LNs examined for all 17,385 patients with stage II RSCC was 17 (IQR 12-23). Nineteen LNs were determined as the optimal cut-off point to maximize survival benefit from lymphadenectomy. Increased LN yield was associated with a gradual increase in the risk of node positivity, with no change after 19 nodes. Compared with patients with 19 or more LNs examined, the group with fewer LNs had a significantly poor cancer-specific survival (< 12 nodes: hazard ratio (HR) 2.26, P < 0.001; 12-18 nodes: HR 1.58, P < 0.001) and overall survival (< 12 nodes: HR 1.80, P < 0.001; 12-18 nodes: HR 1.31, P < 0.001). Similar survival results were found in the validation cohort. Patients with older age, small tumor size, and appendix and transverse colon cancer were more likely to receive inadequate LN harvest.

CONCLUSION

A minimum of 19 LNs is needed to be examined for optimal survival and adequate node staging in lymph node-negative RSCC.

MicroRNA‑500a‑5p inhibits colorectal cancer cell invasion and epithelial‑mesenchymal transition

The development of malignant tumors is a series of complex processes, the majority of which have not been elucidated. The aim of the present study was to investigate the microRNAs (miRNAs/miR) that affect the migration and invasion abilities of CRC cells. Our previous reports have revealed that miR‑500a‑5p suppressed CRC cell growth and malignant transformation. The present study demonstrated that overexpression of miR‑500a‑5p reduced the expression of vimentin, while increasing the expression of E‑cadherin. Inhibition of miR‑500a‑5p resulted in spindle‑like morphological changes and reorganization of F‑actin in CRC cells. Furthermore, miR‑500a‑5p attenuated the transforming growth factor‑β signaling pathway in EMT. Additionally, emodin inhibited the miR‑500a‑5p inhibitor and suppressed the EMT process. In animal models of metastasis using nude mice, EMT and LoVo cell metastasis was modulated by miR‑500a‑5p. Therefore, the findings of the present study demonstrated that miR‑500a‑5p is associated with a positive therapeutic outcome in terms of invasion/migration of CRC cells and mesenchymal‑like cell changes.

How does lymph node yield affect survival outcomes of stage I and II colon cancer?

Background

According to the American Joint Committee on Cancer staging for cancer of the colon, a minimum of 12 lymph nodes (LN) has to be sampled for accurate staging. This has bearing on the long-term prognosis and the need for adjuvant chemotherapy. The aim of this study was to revisit the association of lymph node yield and the long-term survival in patients with stages I and II, i.e. node-negative, colon cancer.

Method

Consecutive patients who underwent elective or emergency curative resections for cancer of colon between the years 2003 and 2012 were retrospectively reviewed. Only patients with stage I or II diseases (AJCC 8th edition) were included. They were analysed in three groups, LN<12, LN12-19 and LN≥20. Their clinic-pathological characteristics were compared. The disease-free (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared with the log-rank test.

Results

There was a total of 659 patients included in the analysis. Twelve or more LN were found in 65.6% of the specimens. The mean follow-up was 83.9 months. LN≥20 had significantly better DFS (p = 0.015) and OS (p = 0.036), whereas LN<12 had similar DFS and OS when compared to LN12-19. The advantage in DFS and OS were mainly seen in those with stage II diseases. A lymph node yield of greater than 20 was one of the predictors of favourable DFS, hazard ratio 0.358; 95% CI 0.170–.756, p = 0.007.

Conclusion

The lymph node yield had a significant association with survival outcomes. A lymph node yield of 20 or more was associated with better survival outcomes. On the other hand, lymph node yield less than 12 was not shown to have inferior survival outcomes when compared to those between 12 and 19.

Neoadjuvant Chemotherapy is Associated with Lower Lymph Node Counts in Colon Cancer

Adequate lymphadenectomy is associated with improved survival in patients who undergo oncologic resection of colorectal cancer and has been identified as a quality metric. Neoadjuvant chemotherapy has been found to be associated with collection of <12 lymph nodes in patients with rectal cancer. The purpose of this study was to evaluate patient and operative risk factors for inadequate lymph node retrieval during oncologic colectomy. The 2014 American College of Surgeons National Surgical Quality Improvement Program Participant Use File data set for oncologic colectomy (n = 9077) was analyzed. Patient- and operation-related factors were assessed by univariate and multivariate regression analyses to determine factors associated with the number of lymph nodes collected. Adequate lymphadenectomy was defined by collection of >12 lymph nodes. Of 9077 patients with a diagnosis of colon cancer who underwent colectomy, a minimum of 12 lymph nodes was harvested in 7897 (87%). Significant factors independently associated with inadequate lymphadenectomy included preoperative chemotherapy, emergent surgery, and T1 tumors (all P < 0.05). A large majority of patients who undergo colectomy for colon cancer have at least 12 lymph nodes collected. Preoperative chemotherapy is a major risk factor for inadequate lymph node retrieval. Recognition of factors associated with inadequate lymphadenectomy may improve colectomy lymph node yield and survival in patients with colon cancer.

Method of pedicle division during laparoscopic right hemicolectomy affects lymph node yield and short-term outcomes

BACKGROUND

Several ways of performing laparoscopic right hemicolectomy (RHC) have evolved. The vascular pedicle can be divided into extracorporeal (RHC-EC) or intracorporeal (RHC-IC). It is not known whether vessel ligation during RHC-EC is as central as during RHC-IC. We compare these approaches in terms of pathological and short-term clinical outcomes.

METHODS

Patients undergoing elective laparoscopic RHC in a single centre (July 2013-September 2016) were identified. Data collection included operative details, length of stay, complications, specimen parameters including number and involvement of lymph nodes and recurrence.

RESULTS

One hundred and sixty-nine patients were included (94 RHC-IC, 75 RHC-EC). For caecal and ascending colon cancers, mesocolic width was greater after RHC-IC than RHC-EC (7.9 cm versus 6.6 cm, P < 0.05), as was lymph node yield (19.5 versus 17.3, P < 0.05). There was no significant difference in length of colon resected, distal resection margin, number of positive nodes, proportion of node-positive tumours and R1 rate. Operative duration was higher for RHC-IC (163 min versus 91 min, P < 0.001), as was incidence of ileus (35% versus 15%, P < 0.05). Length of stay also tended to be higher (7.4 days versus 6.0 days, P = 0.19). There was no difference in disease recurrence (follow-up 12 months). Body mass index was positively correlated with lymph node yield for RHC-EC, but not for RHC-IC.

CONCLUSION

Lymph node yield after laparoscopic RHC is adequate, whether the vascular pedicle is taken intracorporeal or extracorporeal, supporting the use of both approaches. RHC-IC yields more lymph nodes and greater mesocolic width, but involves a longer operation and higher incidence of ileus.

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.

T4N0 colon cancers should be treated like T3N1 disease

Background

Patients with positive lymph nodal involvement in colon cancer have always been deemed to fare worse than those without. However, questions have been increasingly raised on the true prognosis of T4N0 disease. We conducted this study to investigate how T4N0 disease would compare with T3N1 disease.

Methods

All patients with colon cancer treated from 2008 to 2014 was collected. Preoperative, intraoperative and histological information was compared between patients with T4N0 and T3N1 disease. Variables which significantly differed were included in multivariate analysis for recurrence and survival. Kaplan-Meier curves and cox regression analysis for time to recurrence and survival were evaluated.

Results

Seventy-eight patients had T4N0 colon cancer, while 160 had T3N1 disease. Vascular invasion, lymphatic invasion, total lymph node yield, and the administration of adjuvant chemotherapy were identified as variables for evaluation. Over a median follow-up of 41.4 (range, 21.6-65.0) months for T4N0 patients and 42.4 (range, 21.1-63.8) months for T3N1 patients, there was no statistically significant difference in the association of stage of cancer with survival [overall survival (OS): 0.97 (95% CI, 0.38-2.45), P=0.94]. Kaplan-Meier curves also showed no difference in time to death (P=0.867). There was no statistically significant difference in the time to death [hazard ratio (HR): 0.56 (95% CI, 0.20-1.55), P=0.26].

Conclusions

T4N0 colon cancers have similar outcomes to T3N1 disease and should be considered as stage III disease in future classification. Patients diagnosed with T4N0 disease should receive similar treatment as those with T3N1 disease and counselled accordingly.

Lymph node evaluation for colon cancer in routine clinical practice: a population-based study

BACKGROUND

Guidelines recommend that 12 or more lymph nodes (lns) be evaluated during surgical resection of colon cancer. Here, we report ln yield and its association with survival in routine practice.

METHODS

Electronic records of treatment were linked to the population-based Ontario Cancer Registry to identify all patients with colon cancer treated during 2002-2008. The study population (n = 5508) included a 25% random sample of patients with stage ii or iii disease. Modified Poisson regression was used to identify factors associated with ln yield; Cox models were used to explore the association between ln yield and overall (os) and cancer-specific survival (css).

RESULTS

During 2002-2008, median ln yield increased to 17 from 11 nodes (p < 0.001), and the proportion of patients with 12 or more nodes evaluated increased to 86% from 45% (p < 0.001). Lymph node positivity did not change over time (to 53% from 54%, p = 0.357). Greater ln yield was associated with younger age (p < 0.001), less comorbidity (p = 0.004), higher socioeconomic status (p = 0.001), right-sided tumours (p < 0.001), and higher hospital volume (p < 0.001). In adjusted analyses, a ln yield of less than 12 nodes was associated with inferior os and css for stages ii and iii disease [stage ii os hazard ratio (hr): 1.36; 95% confidence interval (ci): 1.19 to 1.56; stage ii css hr: 1.52; 95% ci: 1.26 to 1.83; and stage iii os hr: 1.45; 95% ci: 1.30 to 1.61; stage iii css hr: 1.54; 95% ci: 1.36 to 1.75].

CONCLUSIONS

Despite a temporal increase in ln yield, the proportion of cases with ln positivity has not changed. Lymph node yield is associated with survival in patients with stages ii and iii colon cancer. The association between ln yield and survival is unlikely to be a result of stage migration.

Knockdown of FOXK1 alone or in combination with apoptosis-inducing 5-FU inhibits cell growth in colorectal cancer

Forkhead box K1 (FOXK1) is a member of the FOX transcription factor family, which plays an important role in oncogenesis. However, the exact function and mechanism of FOXK1 in human colorectal cancers (CRCs) remain unclear. In the present study, we first screened for potential FOXK1 target genes by ectopically expressing FOXK1 in SW480 cells and examined the subsequent changes in the expression levels of major oncogenes using RT-PCR. We also evaluated the effects of FOXK1 regulation on growth and apoptosis. In addition, we investigated the biological impact of FOXK1 knockdown on CRC cells in vitro and in vivo. We found that FOXK1 overexpression increased the expression of multiple oncogenes in vitro. FOXK1 promoted serum-dependent and anchorage-dependent and -independent cell growth. Knockdown of FOXK1 induced G0/G1 cell cycle arrest in CRC cells. Moreover, FOXK1 suppression induced apoptosis and increased cell susceptibility to 5-fluorouracil (5-FU)-induced apoptosis. Furthermore, a xenograft model was established to explore FOXK1 shRNA-mediated tumorigenesis in vivo. A strong antitumorigenic effect of FOXK1-shRNA was enhanced when combined with 5-FU treatment. These findings implicate FOXK1 as a cell cycle and growth modulator that inhibits apoptosis in colon cancer cells. FOXK1-shRNA may serve as a novel and potent therapeutic agent, alone or with 5-FU, against colon cancer.

The Evaluation of More Lymph Nodes in Colon Cancer Is Associated with Improved Survival in Patients of All Ages

Background

Improvement in survival of patients with colon cancer is reduced in elderly patients compared to younger patients. The aim of this study was to investigate whether the removal of ≥ 12 lymph nodes can explain differences in survival rates between elderly and younger patients diagnosed with colon cancer.

Methods

In a population-based cohort study, all patients (N = 41,074) diagnosed with colon cancer stage I to III from 2003 through 2010 from the Netherlands Cancer Registry were included. Age groups were defined as < 66, 66–75 and > 75 years of age. Main outcome measures were overall and relative survival, the latter as a proxy for disease specific survival.

Results

Over an eight years time period there was a 41.2% increase in patients with ≥ 12 lymph nodes removed, whereas the percentage of patients with the presence of lymph node metastases remained stable (35.7% to 37.5%). After adjustment for patient and tumour characteristics and adjuvant chemotherapy, it was found that for patients in which ≥ 12 lymph nodes were removed compared to patients with < 12 lymph nodes removed, there was a statistically significant higher overall survival (< 66: HR: 0.858 (95% CI, 0.789–0.933); 66–75: HR: 0.763 (95% CI, 0.714–0.814); > 75: HR: 0.734 (95% CI, 0.700–0.771)) and relative survival (< 66: RER: 0.783 (95% CI, 0.708–0.865); 66–75: RER: 0.672 (95% CI, 0.611–0.739); > 75: RER: 0.621 (95% CI, 0.567–0.681)) in all three age groups.

Conclusions

The removal of ≥ 12 lymph nodes is associated with an improvement in both overall and relative survival in all patients. This association was stronger in the elderly patient. The biology of this association needs further clarification.

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.

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.

Lymph node hypoplasia is associated with adverse outcomes in node-negative colon cancer using advanced lymph node dissection methods

PURPOSE

Lymph node size as a prognostic parameter has not been investigated well in the past. Recent data, however, have indicated that this parameter could be even more important than the lymph node count.

METHODS

Based on the results of earlier studies, we analyzed the lymph node size and number of node-negative colon cancer patients with regard to survival. Data from 115 node-negative cases of colon cancer were analyzed. Lymph nodes with diameters ≤5 mm were defined as small, and all other lymph nodes were classified as intermediate/large in size and labeled LN5. All of the cases were categorized according to the number of LN5s. The LN5 very low (LN5vl) group included cases with less than two LN5s. All of the other cases were assigned to the LN5 low/high (LN5l/h) group.

RESULTS

The overall survival analysis revealed significantly worse outcomes for the LN5vl group, with a mean survival of 34 months compared to the LN5l/h group, with a mean survival of 40 months (P = 0.022). After adjusting for the pT1/2 and pT3/4 stages, we still found a significant outcome difference (P = 0.012). Multivariate analysis identified LN5vl and T-stage as being independently correlated with the outcome. The vast majority of LN5vl cases (91 %) were located in the left colon. The location itself, however, was not prognostic (P = 0.478).

CONCLUSION

LN5 count, as a marker of immune response, could be shown as being prognostic in node-negative colon cancer. Patients with low LN5 counts showed poor outcomes. These patients could perhaps profit from adjuvant chemotherapy.

Linking surgical specimen length and examined lymph nodes in colorectal cancer patients

AIM

The number of examined lymph nodes (NLN) was associated with survival of stages II and III colorectal cancer (CRC) patients. Guidelines recommend examining at least 12 lymph nodes. This study investigated the influence of surgical specimen length on lymph node harvest and compliance with international guidelines.

MATERIALS AND METHODS

This population-based study included 4,724 cases of surgically treated CRC that were diagnosed from 2002 to 2008. Multivariate analyses were performed for the main study variables (age, gender, diagnosis at screening or in symptomatic patients, cancer site, staging, grading, number of positive nodes, neo-adjuvant treatment for rectal cancer, hospital were surgery was performed). Fractional polynomial models investigated the relationship between continuous variables and outcomes.

RESULTS

The NLN increased over time reaching ≥12 NLN in 64% of cases at the end of the study period. More NLN were associated with young age, right colon cancer, pT3-T4 disease, stages II and III and high grade. Fewer NLN were associated with short surgical specimen length and neo-adjuvant treatment in rectal cancer patients. Use of laparoscopy increased sharply over time.

CONCLUSIONS

NLN increased over time in accordance with international guidelines. Surgical specimen length correlated with NLN which may determine therapeutic choices, particularly in stage II colon cancer. When harvested lymph nodes are under 10 in number and all are negative, chemotherapy is always recommended. As specimen lengths <20 cm were associated with a high risk of inadequate NLN counts, patients are at risk of over-treatment.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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