A nodal positivity constant: new perspectives in lymph node evaluation and colorectal cancer. World J Surg. 2013;37:878-882. [PMID: 23242459 DOI: 10.1007/s00268-012-1891-7]

Prognostic and predictive value of examined lymph node count in stage III colorectal cancer: a population based study

BACKGROUND

The role of tumor-draining lymph nodes in the progression of malignant tumors, including stage III colorectal cancer (CRC), is critical. However, the prognostic and predictive value of the number of examined lymph nodes (ELNs) are not fully understood.

METHODS

This population-based study retrospectively analyzed data from 106,843 patients with stage III CRC who underwent surgical treatment and registered in three databases from 2004 to 2021. The Surveillance, Epidemiology, and End Results (SEER) cohort was divided using into training and test cohorts at a ratio of 3:2. We employed restricted cubic spline (RCS) curves to explore nonlinear relationships between overall survival (OS) and ELNs counts and performed Cox regression to evaluate hazard ratios across different ELNs count subtypes. Additional validation cohorts were utilized from the First Affiliated Hospital, Sun Yat-sen University and The Cancer Genome Atlas (TCGA) under the same criteria. Outcomes measured included OS, cancer-specific survival (CSS), and progression-free survival (PFS). Molecular analyses involved differential gene expression using the "limma" package and immune profiling through CIBERSORT. Tissue microarray slides and multiplex immunofluorescence (MIF) were used to assess protein expression and immune cell infiltration.

RESULTS

Patients with higher ELNs counts (≥ 17) demonstrated significantly better long-term survival outcomes across all cohorts. Enhanced OS, CSS, and PFS were notably evident in the LN-ELN group compared to those with fewer ELNs. Cox regression models underscored the prognostic value of higher ELNs counts across different patient subgroups by age, sex, tumor differentiation, and TNM stages. Subtype analysis based on ELNs count revealed a marked survival benefit in patients treated with adjuvant chemotherapy in the medium and large ELNs counts (≥ 12), whereas those with fewer ELNs showed negligible benefits. RNA sequencing and MIF indicated elevated immune activation in the LN-ELN group, characterized by increased CD3+, CD4+, and CD8 + T cells within the tumor microenvironment.

CONCLUSIONS

The number of ELNs independently predicts survival and the immunological landscape at the tumor site in stage III CRC, underscoring its dual prognostic and predictive value.

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.

Lymph node stain after radical resection of rectal cancer mainly increased the harvest of mini lymph node: A randomized controlled trial

AIM

The lymph node status plays an important role in rectal cancer, which depends on adequate lymph node harvest. Lymph node stain techniques increase the lymph node harvest. The aim of this prospective study is to investigate which subgroups of lymph nodes harvested were increased mostly.

METHODS

From May 2020 to May 2022, 172 stage II-III rectal cancer patients were randomized to methylene blue (MB) stained group or unstained group to retrieve the lymph nodes. Methylene blue solution was injected into the inferior mesenteric artery, we dissected lymph nodes by palpation and sight. The lymph nodes were divided into 3 groups depending on the anatomy (main lymph nodes, superior rectal and perirectal lymph nodes (SPLNs), and pericolic lymph nodes located beyond 10 cm proximal to the tumor), and 3 groups depending on the short diameter of the nodes (big: ≥ 5 mm, small: 5-2 mm, mini: ≤ 2 mm).

RESULTS

The number of lymph nodes harvested with MB was significantly higher (22.0 (14.8, 32.0) vs 14.5 (11.0, 22.0); p < 0.001) without difference in positive patients or number of positive nodes. The positive rate of the big node was 3.5%, the small node was 1.9%, and the mini node was 0.2%. In the subgroup analysis, the median number of mini lymph nodes in the MB-stained group was significantly more than that of the unstained group (median (IQR): 9.0 (6.0, 14.0) vs 4.0 (2.0,6.0), p < 0.001); and the median number of SPLNs in the MB-stained group were significantly more than that of the unstained group (median (IQR): 15.0 (9.0, 19.0) vs 10.0 (6.0, 13.3), p < 0.001); these differences were existing in both patients with and without neoadjuvant treatments.

CONCLUSION

Intra-arterial injection of MB can significantly increase the number of lymph nodes harvested in rectal cancers, especially those mini lymph nodes. However, methylene blue staining did not significantly increase the number of positive lymph nodes and the proportion of patients with more than 12 lymph nodes, or affect lymph node staging accuracy after radical resection of rectal cancer.

Lymph node regression grading of locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

Neoadjuvant chemoradiotherapy (nCRT) and total rectal mesenteric excision are the main standards of treatment for locally advanced rectal cancer (LARC). Lymph node regression grade (LRG) is an indicator of prognosis and response to preoperative nCRT based on postsurgical metastatic lymph node pathology. Common histopathological findings in metastatic lymph nodes after nCRT include necrosis, hemorrhage, nodular fibrosis, foamy histiocytes, cystic cell reactions, areas of hyalinosis, residual cancer cells, and pools of mucin. A number of LRG systems designed to classify the amount of lymph node regression after nCRT is mainly concerned with the relationship between residual cancer cells and regressive fibrosis and with estimating the number of lymph nodes existing with residual cancer cells. LRG offers significant prognostic information, and in most cases, LRG after nCRT correlates with patient outcomes. In this review, we describe the systematic classification of LRG after nCRT, patient prognosis, the correlation with tumor regression grade, and the typical histopathological findings of lymph nodes. This work may serve as a reference to help predict the clinical complete response and determine lymph node regression in patients based on preservation strategies, allowing for the formulation of more accurate treatment strategies for LARC patients, which has important clinical significance and scientific value.

Long-term outcomes after extra-levator versus conventional abdominoperineal excision for low rectal cancer

Purpose

Extralevator (ELAPE) and abdominoperineal excision (APE) are two major surgical approaches for low rectal cancer patients. Although excellent short-term efficacy is achieved in patients undergoing ELAPE, the long-term benefits have not been established. In this study we evaluated the safety, pathological and survival outcomes in rectal cancer patients who underwent ELAPE and APE.

Methods

One hundred fourteen patients were enrolled, including 68 in the ELAPE group and 46 in the APE group at the Beijing Chaoyang Hospital, Capital Medical University from January 2011 to November 2020. The baseline characteristics, overall survival (OS), progression-free survival (PFS), and local recurrence-free survival (LRFS) were calculated and compared between the two groups.

Results

Demographics and tumor stage were comparable between the two groups. The 5-year PFS (67.2% versus 38.6%, log-rank P = 0.008) were significantly improved in the ELAPE group compared to the APE group, and the survival advantage was especially reflected in patients with pT3 tumors, positive lymph nodes or even those who have not received neoadjuvant chemoradiotherapy. Multivariate analysis showed that APE was an independent risk factor for OS (hazard ratio 3.000, 95% confidence interval 1.171 to 4.970, P = 0.004) and PFS (hazard ratio 2.730, 95% confidence interval 1.506 to 4.984, P = 0.001).

Conclusion

 Compared with APE, ELAPE improved long-term outcomes for low rectal cancer patients, especially among patients with pT3 tumors, positive lymph nodes or those without neoadjuvant chemoradiotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01692-y.

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.

Incidence and management of patients with colorectal cancer and synchronous and metachronous colorectal metastases: a population-based study

Background

This population‐based study aimed to examine the incidence, patterns and results of multimodal management of metastatic colorectal cancer.

Methods

A retrospective population‐based study was conducted on patients with metastatic colorectal cancer in Central Finland in 2000–2015. Clinical and histopathological data were retrieved and descriptive analysis was conducted to determine the pattern of metastatic disease, defined as synchronous, early metachronous (within 12 months of diagnosis of primary disease) and late metachronous (more than 12 months after diagnosis). Subgroups were compared for resection and overall survival (OS) rates.

Results

Of 1671 patients, 296 (17·7 per cent) had synchronous metastases, and 255 (19·6 per cent) of 1302 patients with resected stage I–III tumours developed metachronous metastases (94 early and 161 late metastases). Liver, pulmonary and intraperitoneal metastases were the most common sites. The commonest metastatic patterns were a combination of liver and lung metastases. The overall metastasectomy rate for patients with synchronous metastases was 16·2 per cent; in this subgroup, 3‐ and 5‐year OS rates after any resection were 63 and 44 per cent respectively, compared with 7·1 and 3·3 per cent following no resection (P < 0·001). The resection rate was higher for late than for early metachronous disease (28·0 versus 17 per cent respectively; P = 0·048). Three‐ and 5‐year OS rates after any resection of metachronous metastases were 78 and 62 per cent respectively versus 42·1 and 18·2 per cent with no metastasectomy (P < 0·001). Similarly, 3‐ and 5‐year OS rates after any metastasectomy for early metachronous metastases were 57 and 50 per cent versus 84 and 66 per cent for late metachronous metastases (P = 0·293).

Conclusion

The proportion of patients with metastatic colorectal cancer was consistent with that in earlier population‐based studies, as were resection rates for liver and lung metastases and survival after resection. Differentiation between synchronous, early and late metachronous metastases can improve assessment of resectability and survival.

Assessing the adequacy of lymph node yield for different tumor stages of colon cancer by nodal staging scores

Background

According to the current official guidelines, at least 12 lymph nodes (LNs) are qualified as an adequate sampling for colon cancer patients. However, patients evaluated with less nodes were still common in the United States, and the prevalence of positive nodal disease may be under-estimated because of the false-negative assessment. In this study, we present a statistical model that allows preoperative determination of the minimum number of lymph nodes needed to confirm a node-negative disease with certain confidence.

Methods

Adenocarcinoma colon cancer patients with stage T1-T3, diagnosed between 2004 and 2013, who did not receive neoadjuvant therapies and had at least one lymph node pathologically examined, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. A beta binomial distribution was used to estimate the probability of an occult nodal disease is truly node-negative as a function of total number of LNs examined and T stage.

Results

A total of 125,306 patients met study criteria; and 47,788 of those were node-positive. The probability of falsely identifying a patient as node-negative decreased with an increasing number of nodes examined for each stage, and was estimated to be 72% for T1 and T2 patients with a single node examined and 57% for T3 patients with a single node examined. To confirm an occult nodal disease with 90% confidence, 3, 8, and 24 nodes need to be examined for patients from stage T1, T2, and T3, respectively.

Conclusions

The false-negative rate of diagnosed node negative, together with the minimum number of examined nodes for adequate staging, depend preoperatively on the clinical T stage. Predictive tools can recommend a threshold on the minimum number of examined nodes regarding to the favored level of confidence for each T stage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3491-2) contains supplementary material, which is available to authorized users.

Population-based study to re-evaluate optimal lymph node yield in colonic cancer

BACKGROUND

It is well established that lymph node (LN) yield in colonic cancer resection has prognostic significance, although optimal numbers are not clear. Here, LN thresholds associated with both LN positivity and survival were evaluated in a single population-based data set.

METHODS

Treatment records were linked to the Ontario Cancer Registry to identify a 25 per cent random sample of all patients with stage II/III colonic cancer between 2002 and 2008. Multivariable regression and Cox models evaluated factors associated with LN positivity and cancer-specific survival (CSS) respectively. Optimal thresholds were obtained using sequential regression analysis.

RESULTS

On adjusted analysis of 5508 eligible patients, younger age (P < 0·001), left-sided tumours (P = 0·003), higher T category (P < 0·001) and greater LN yield (relative risk 0·89, 95 per cent c.i. 0·81 to 0·97; P = 0·007) were associated with a greater likelihood of LN positivity. Regression analyses with multiple thresholds suggested no substantial increase in LN positivity beyond 12-14 LNs. Cox analysis of stage II disease showed that lower LN yield was associated with a significant increase in the risk of death from cancer (CSS hazard ratio range 1·55-1·74; P < 0·001) compared with a greater LN yield, with no significant survival benefit beyond a yield of 20 LNs. Similarly, for stage III disease, a lower LN yield was associated with an increase in the risk of death from cancer (CSS hazard ratio range 1·49-2·20; P < 0·001) versus a large LN yield. In stage III disease, there was no observed LN threshold for survival benefit in the data set.

CONCLUSION

There is incongruity in the optimal LN evaluation for colonic cancer. Although the historically stated threshold of 12 LNs may ensure accurate staging in colonic cancer, thresholds for optimal survival are associated with far greater yields.

Laparoscopic Wide Mesocolic Excision and Central Vascular Ligation for Carcinoma of the Colon

Background and Aims:

The principle of complete mesocolic excision for colon cancer has been introduced to improve oncologic outcome. However, this approach is scantily discussed for laparoscopic surgery and there is a lack of randomized trials. This study examined oncologic and clinical outcome after laparoscopic wide mesocolic excision and central vascular ligation for colon cancer.

Material and Methods:

This is a review of prospectively gathered data from a single-institution colorectal cancer database. This study was conducted in the Central Hospital of Central Finland. From January 2003 to December 2011, 222 patients underwent laparoscopic colonic resections with wide mesocolic excision and central vascular ligation in the multimodal setting. The main measures of outcome were cancer recurrence and survival, with early recovery, 30d-mortality and morbidity, reoperation, readmission, and late complications as secondary outcomes.

Results:

The median follow-up was 5.5 (interquartile range (IQR) = 3.7–8.0) years. The 5-year overall survival for all 222 patients was 80.2% and disease-specific survival was 87.5%, and for those 210 R0-patients with stage I–III disease, 83.9% and 91.3%, respectively. The 5-year disease-free survival was 85.8%: stage I was 94.7%, stage II was 90.8%, and stage III was 75.6% ( p = 0.004). Increasing lymph node ratio significantly decreased the 5-year disease-free survival. Conversion rate to open surgery was 12.2%. Thirty-day mortality was 1.3% and morbidity, 19.7%. Median postoperative hospital stay was 5 (IQR = 3–7) days.

Conclusion:

Laparoscopic wide mesocolic excision and central vascular ligation for colon cancer resulted in good long-term oncologic outcome. Randomized trials are needed to show that laparoscopic complete mesocolic excision technique would become the standard of care for the carcinoma of the colon.

Ex Vivo Intra-arterial Methylene Blue Injection in Rectal Cancer Specimens Increases the Lymph-Node Harvest, Especially After Preoperative Radiation

BACKGROUND

The examination of as large a number of lymph nodes as possible in rectal carcinoma resectates is important for exact staging. However, after neoadjuvant radiochemotherapy (RCT), it can be difficult to obtain a sufficient number of lymph nodes. We therefore investigated whether staining with methylene blue via the inferior mesenteric artery can lead to an increase in the yield of lymph nodes in rectal carcinoma tissue after neoadjuvant RCT.

METHODS

In a prospective, unicentric study rectal carcinoma resectates from three consecutive groups of patients were examined (Group I, no staining; Group II, staining with methylene blue; Group III, again no staining). The numbers of lymph nodes examined were compared (a) between the groups and (b) between patients who had not, or who had, received neoadjuvant RCT.

RESULTS

In all, 75 rectal carcinoma preparations were assessed. The yield of lymph nodes investigated before the use of staining (Group I) increased when staining was introduced (Group II), both for the patients without neoadjuvant RCT (20.9 vs. 31.3, p = 0.018) and for those who did receive this (15.0 vs. 35.1; p = 0.003). After withdrawal of the staining procedure (Group III), the lymph-node yield remained high for the patients without neoadjuvant RCT (31.3 vs. 30.4; p = 0.882), but it reverted to a lower value for those who did receive neoadjuvant RCT (35.1 vs. 24.2; p = 0.029). Before the introduction of staining (Group I), significantly fewer lymph nodes were examined for patients who received neoadjuvant RCT (15.0 vs. 20.9; p = 0.039). However, with staining (Group II), no difference was found associated with the use or non-use of neoadjuvant RCT (31.3 vs. 35.1; p = 0.520).

CONCLUSION

The use of methylene blue staining of rectal carcinoma preparations leads to a significant increase in the number of lymph nodes examined after neoadjuvant RCT. This can be expected to improve the accuracy of lymph-node staging of neoadjuvant-treated rectal carcinoma.

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.

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.

Which Lymph Nodes Contain Metastases in Colon Cancer Patients? A Retrospective Histopathological Evaluation of 156 Patients

Background. We hypothesized that a reliable N0 status can be established by sampling and evaluating the largest lymph nodes in the resected large-bowel specimen of patients with colon cancer. Patients and methods. This was a retrospective analysis of all surgical colon cancer patients treated between 2008 and 2010, excluding those who had received neoadjuvant treatment. We analyzed the relationship between lymph node size and the presence of metastasis. Furthermore, we examined other prognostic factors for a histopathological N+ status. Results. Our patient group consisted of 156 patients with a median age of 73 years (range = 29-91 years). A total of 2044 lymph nodes (a median of 12 per patient, range = 2-47 nodes) were harvested, 1803 (88.2%) without and 241 (11.8%) with tumor spread. Using a unique ranking model, we found that in 58 out of the 59 N+ patients (98.3%, 95% confidence interval = 90.9% to 99.9%), the largest tumor-positive node was among the 5 largest lymph nodes in the specimen. The examination of ≥10 lymph nodes had no effect on the chance of finding a positive lymph node compared with examination of <10 nodes ( P = .46). Conclusion. In our study, the N-stage was determined by the 5 largest nodes in almost all specimens. The chance of finding a small tumor-positive node when the larger ones were clean was very small.

Management of nodal disease from colon cancer in the laparoscopic era

PURPOSE

In colon cancer (CC), nodal involvement is the main prognostic factor following potentially curative (R0) resection. The purpose of this study was to examine data from the literature to provide an up-to-date analysis of the management of nodal disease with special reference to laparoscopic treatment.

METHODS

MEDLINE and EMBASE databases were searched for potentially eligible studies published in English up to July 15, 2014.

RESULTS

In CC, nodal involvement is a frequent event and represents the main risk of cancer recurrence. Node negative patients recur in 10-30 % of cases most likely due to underdiagnosed or undertreated nodal disease. Extended colonic resections (complete mesocolic excision with central vascular ligation; D3 lymphadenectomy) provides a survival benefit and better local control. Sentinel lymph node mapping in addition to standard surgical resection represents an option for improving staging of clinical node negative patients. Both extended resection and sentinel lymph node mapping are feasible in a laparoscopic setting.

CONCLUSIONS

Both extended colonic resection and sentinel lymph node mapping should play a role in the laparoscopic treatment of CC with the purpose of improving control and staging of nodal disease.

Lymph node size as a predictor of lymphatic staging in colonic cancer

BACKGROUND

In colonic cancer, the number of harvested lymph nodes is associated with prognosis. The aim of this study was to determine the contribution of small lymph nodes to pathological staging, and to analyse the hypothesis that node size is a confounder in the relationship between prognosis and nodal harvest.

METHODS

Nodal harvest and size were analysed in patients who underwent elective surgery for colonic cancer. Visible and palpable nodes were harvested without fat clearance techniques, and conventional histology was performed.

RESULTS

Metastases were found in 99 of 2043 measured lymph nodes in 150 patients. Lymph nodes smaller than 3 mm were positive in 8.0 per cent of patients (12 of 150), but were the sole reason for upstaging in only 1.3 per cent (2 of 150). No metastases were found among 95 nodes of 1 mm or less. Metastatic nodes were larger than those without metastasis (median (i.q.r.) 5.0 (3.2-7.0) versus 3.8 (2.4-5.2) mm; P < 0·001), but a receiver operating characteristic (ROC) curve did not identify a relevant cut-off point to predict metastatic involvement. A hazard ratio of 0.71 (95 per cent confidence interval 0.50 to 1.01) was suggestive of an association between disease recurrence and increased node size, although not significant (P = 0.056). In patients with N0 disease, there was a correlation between node size and harvest (Pearson's correlation 0.317, P = 0.002), and a nodal yield of at least 12 was associated with a larger median node size (4.3 (3.3-5.0) versus 3.4 (2.7-4.0) mm; P = 0.015).

CONCLUSION

The contribution of lymph nodes smaller than 3 mm to nodal staging is limited. Increased node size is associated with increased nodal yield, and could be a confounder in the relationship between prognosis and nodal harvest in patients with N0 disease.

Extended lymphadenectomy in colon cancer is crucial

No one doubts that lymph node dissection in colon cancer is necessary, it is just the extent of that dissection that is still under debate. As the individual steps of an oncologic operation cannot be separated from each other, analysis of the significance of lymph node dissection alone is difficult. It has been proven that the T category is directly related to the number and central spread of lymph node metastases. Micrometastases and isolated tumor cells may be detected in lymph nodes by using special staining techniques; their presence may worsen prognosis significantly and approximate it to UICC stage III. The numbers of dissected lymph nodes and the ratio of involved versus dissected lymph nodes have been used as markers for quality of surgery and histopathological evaluation. Recent results underscore the importance of technique and extent of dissection. Dissection must be performed along the embryologic planes of the mesocolon and leave them intact. A high vascular tie with preservation of the central hypogastric nerves must be applied in order to achieve the best oncologic results while preserving quality of life. Extended lymphadenectomy is oncologically relevant only when it is combined with removal of the primary tumor with adequate longitudinal clearance, an intact complete mesocolon, and high vascular tie. It is part of a concept in which the tumor-bearing specimen is harvested as an enveloped package to minimize the risk of tumor cell spillage and local recurrence.

Prognostic implications of the lymph node count after neoadjuvant treatment for rectal cancer

BACKGROUND

The aim of this study was to investigate the effect of neoadjuvant chemoradiotherapy on the lymph node yield of rectal cancer surgery.

METHODS

Data for patients who underwent neoadjuvant chemoradiotherapy followed by surgery for resectable rectal cancer from June 1992 to June 2009 were reviewed. The primary outcomes measured were the number of lymph nodes retrieved, their status, and patient survival.

RESULTS

In total, 345 patients underwent neoadjuvant chemoradiotherapy followed by surgery, and 95 patients had surgery alone. Neoadjuvant chemoradiotherapy decreased both the median (range) number of lymph nodes retrieved (7 (1-33) versus 12.5 (0-44) respectively; P < 0.001) and the number of positive lymph nodes (0 (0-11) versus 0 (0-16); P = 0.001). After neoadjuvant chemoradiotherapy, the number of retrieved lymph nodes was inversely correlated with tumour regression, and with the interval between treatment and surgery. The 5-year overall and disease-free survival rates were 86.5 and 79.1 per cent respectively. After neoadjuvant therapy, lymph node status was found to be an independent predictor of survival, whereas the number of retrieved lymph nodes did not represent a prognostic factor for either overall or disease-free survival.

CONCLUSION

Low lymph node count after neoadjuvant chemoradiotherapy for rectal cancer does not signify an inadequate resection or understaging, but represents an increased sensitivity to the treatment.