Total Node Count Research Articles

An increased total resected lymph node count benefits survival following pancreas invasive intraductal papillary mucinous neoplasms resection: an analysis using the surveillance, epidemiology, and end result registry database.

BackgroundThe therapeutic effect of lymph node dissection for pancreas invasive intraductal papillary mucinous neoplasms (IPMN) remains unclear. The study investigated whether cancer-specific survival (CSS) and overall survival (OS) rates among invasive IPMN patients improve when more lymph nodes are harvested during surgery.Study DesignThe study cohort was retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. The lymph node count was categorized into quartiles. The relationship between lymph node count and survival was analyzed using Kaplan–Meier curves and a Cox proportional-hazards model. The stage migration was assessed by Chi-square tests. Propensity score matching (PSM) was used to minimize confounding variables between groups.ResultsIn total, 1,080 patients with resected invasive IPMNs from 1992 to 2011 were included. Univariate and multivariate Cox models indicated that an increased lymph node count independently improves survival. The Kaplan-Meier and log-rank tests identified 16 nodes as an optimal cut-off value that yielded a significant survival benefit for all invasive IPMN patients. The stage migration effect existed in this cohort. After PSM, the 5-year CSS increased from 36% to 47%, and the median survival rate increased from 30 months to 40 months by increasing the lymph node count to over 16, alone. The 5-year OS rate also provided additional support for this result.ConclusionIncreased lymph node counts were associated with improved survival in invasive IPMN patients. One cut-off value of lymph node count was 16 for this improvement.

Does Reevaluation of Colorectal Cancers With Inadequate Nodal Yield Lead to Stage Migration or the Identification of Metastatic Lymph Nodes?

The National Comprehensive Cancer Network recommends routine reevaluation of all stage II colon cancer specimens with fewer than 12 lymph nodes. However, there are few data demonstrating the effect of reevaluation on stage. The aim of this study was to demonstrate the effect of pathologic reevaluation for colorectal cancers with fewer than 12 lymph nodes on stage. This study entailed a retrospective review of pathology reports. This study was conducted at 2 large multispecialty referral centers. Pathologic reevaluation was performed to look for additional lymph nodes. All patients with stage I through III colorectal cancers with inadequate lymph node yields who underwent reevaluation from January 1, 2007 through March 31, 2011 were identified. We recorded initial pathologic stage and new stage following reevaluation. The following variables before and after reevaluation were also recorded: 1) total lymph node count, 2) metastatic node count, 3) negative node count, and 4) lymph node ratio. Eighty-three patients underwent pathologic reevaluation from a total of 1682 cancer specimens. Mean nodal yields were 7.2 ± 2.6 on the first pathologic review. On reevaluation, 80% of patients had one or more newly identified nodes. On average, 6.9 ± 9.6 more lymph nodes were identified with a metastatic node detected in 4 of 83 patients (4.8%). After pathologic reevaluation, 1 patient (1.2%) had a change in TNM stage from N1 to N2 disease. The lymph node ratio changed in 13 of 15 patients (87% of stage III cancers). Only 4 of these had a change in lymph node quartile. The study was limited by its retrospective nature and small sample size. Few patients have a newly discovered metastatic node or stage change following pathologic reevaluation. The effect of pathologic reevaluation on treatment and outcome should be further investigated.

The prognostic factors for survival after curative resection of distal cholangiocarcinoma: perineural invasion and lymphovascular invasion

The purpose of this study was to elucidate the prognostic factors for distal cholangiocarcinoma after curative resection, and to assess the significance of perineural invasion (PNI) and lymphovascular invasion (LVI) as prognostic factors. A retrospective analysis of 91 patients who underwent radical surgery for distal cholangiocarcinoma between March 2004 and October 2011 was performed. We analyzed the survival rate and prognostic factors affecting the survival. The overall 1-, 3- and 5-year survival rates were 84.1, 49.7 and 38.9 %, respectively. In the univariate analysis, the prognostic factors influencing the survival were the histological differentiation, lymph node (LN) involvement and TNM stage. In the multivariate analysis, LN metastasis was the only independent prognostic factor. Although patients with PNI tended to show poorer survival, it was not a statistically significant factor (3- and 5-year OS; 62.0 and 54.6 % vs. 42.8 and 30.9 %, P = 0.166). In the patients with a total lymph node count (TLNC) of 11 or less, PNI was a significant prognostic factor; however, it was not a significant factor in the patients with a TLNC over 11. Overall, the LVI had no influence on the patient survival. LN metastasis was the only significant prognostic factor after the curative resection of distal cholangiocarcinoma. In cases where adequate dissection was performed, it appeared that the PNI and LVI had no influence on the survival.

Primary breast cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Primary breast cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Ex vivodissection increases lymph node yield in oesophagogastric cancer

Retrieval and analysis of an adequate number of lymph nodes is critical for accurate staging of oesophageal and gastric cancer. Higher total node counts reported by pathologists are associated with improved survival. A prospective study was undertaken to understand the factors contributing to variability in lymph node counts after oesophagogastric cancer resections and to determine whether a novel strategy of ex vivo dissection of resected specimens into nodal stations improves node counts reported by pathologists. The study involved 88 patients with potentially curable oesophagogastric cancer undergoing radical resection. Lymph node counts were obtained from pathology reports and analysed in relation to multiple variables including the introduction of ex vivo dissection of nodal stations in theatre. Higher lymph node counts were obtained with ex vivo dissection of nodal stations (median 19 versus 8, P < 0.01). Node counts also varied significantly with the reporting pathologist (median range 4 to 48, P = 0.02) which was independent of the level of experience of the pathologist (P = 0.67). Node counts were not affected by patient age (P = 0.26), gender (P = 0.50), operative approach (P = 0.50) or neoadjuvant therapy (P = 0.83). Specimen handling is a significant factor in determining lymph node yield following radical oesophageal and gastric cancer resections. Ex vivo dissection of resected specimens into nodal stations improves node counts without alterations to surgical techniques. Ex vivo dissection should be considered routine.

Response to editorial titled 'Intrapulmonary lymph node retrieval: unclear benefit for aggressive pathologic dissection'.

Response to editorial titled 'Intrapulmonary lymph node retrieval: unclear benefit for aggressive pathologic dissection'.

Effect of body mass index in patients undergoing resection for gastric cancer: A single-center U.S. experience.

25 Background: With the rise of obesity in the U.S., the impact of body mass index (BMI) on surgical outcomes and survival in gastric cancer remains undetermined. Methods: An IRB-approved, prospectively-maintained institutional database of patients referred for surgical evaluation of gastric cancer was reviewed. Patients were stratified according to BMI: &lt;18.5 (underweight), 18.5-25 (normal weight), 25.1-30 (overweight), and &gt;30 (obese). Clinicopathologic factors and overall survival (OS) were analyzed using polytomous regression, Pearsons correlation and Kaplan Meier when appropriate. Results: From 1997-2012, 222 patients underwent exploration for gastric adenocarcinoma. Of these, 186 (84%) patients had BMI recorded: 9 (5%) with BMI&lt;18.5, 72 (39%) 18.5-25, 62 (33%) 25.1-30, and 43 (23%) &gt;30. 135 (73%) ultimately underwent resection. Operative factors including American Society of Anesthesiology (ASA) score and blood loss were not significantly associated with BMI. Increased BMI was associated with longer operative time, P=0.02. Pathologic factors including proximal tumor location, perineural invasion (PNI), lymphovascular invasion (LVI), positive surgical margins, and positive lymph nodes (LN+) were all associated with a worse OS. Although increased BMI was associated with a lower total lymph node count, P=0.004, the number of LN+ was not associated with BMI. Tumor location, PNI, LVI, margin status, and final pathologic stage were not significantly associated with BMI. Additionally, the use of neoadjuvant or adjuvant chemotherapy was not associated with BMI. Median OS for the group was 22 months. When stratified by BMI, median OS was improved with increased BMI: 21 months for &lt;18.5, 13 months for 18.5-25, 28 months for 25-30, and 34 months for &gt;30, P=0.02. Similarly, disease free survival (DFS) improved with increasing BMI: 2 months for &lt;18.5, 7 months for 18.5-25, 15 months for 25.1-30, and 15 months for &gt;30, P=0.02. Conclusions: Although BMI may impact the technical difficulty of resection for gastric cancer, increasing BMI is not associated with more aggressive disease. In this experience, increased BMI does not adversely impact OS or DFS.

Anatomic Basis for Lymph Node Counts as Measure of Lymph Node Dissection Extent: A Cadaveric Study

To determine the number, variability, and distribution of pelvic lymph nodes to better understand the utility of the node count as a surrogate for the dissection extent. Although pelvic lymph node dissection (PLND) at radical cystectomy for bladder cancer is critical for disease control and staging, debate regarding the measurement of dissection adequacy remains. Many have proposed minimum node counts, yet an anatomic study assessing the number and variability of lymph nodes in the PLND templates is lacking. Super-extended PLND was performed on 26 human cadavers, and the lymph nodes within each of 12 dissection zones were enumerated by a single pathologist. We calculated the mean, standard deviation, and range of nodal yield within each dissection region. The super-extended and standard dissection templates were compared using the paired t test. Super-extended PLND yielded a mean of 28.5 ± 11.5 lymph nodes, with a total node count range of 10-53 nodes. In contrast, the nodal yield within the standard template was 18.3 ± 6.3 nodes, with a range of 8-28 nodes (P <.001). No significant differences were seen in lymph node counts when stratified by age, sex, or cause of death. Using a cadaveric model and a single pathologist to eliminate many of the factors affecting the nodal yield in surgical series, we found substantial interindividual differences, with counts ranging from 10 to 53 nodes. These results have demonstrated the limited utility of lymph node count as a surrogate for the dissection extent and illustrated the challenges associated with implementing a surgical standard for minimum lymph node counts.

Radical lymph node dissection and assessment: Impact on gallbladder cancer prognosis

To investigate the lymph node metastasis patterns of gallbladder cancer (GBC) and evaluate the optimal categorization of nodal status as a critical prognostic factor. From May 1995 to December 2010, a total of 78 consecutive patients with GBC underwent a radical resection at Liaocheng People's Hospital. A radical resection was defined as removing both the primary tumor and the regional lymph nodes of the gallbladder. Demographic, operative and pathologic data were recorded. The lymph nodes retrieved were examined histologically for metastases routinely from each node. The positive lymph node count (PLNC) as well as the total lymph node count (TLNC) was recorded for each patient. Then the metastatic to examined lymph nodes ratio (LNR) was calculated. Disease-specific survival (DSS) and predictors of outcome were analyzed. With a median follow-up time of 26.50 mo (range, 2-132 mo), median DSS was 29.00 ± 3.92 mo (5-year survival rate, 20.51%). Nodal disease was found in 37 patients (47.44%). DSS of node-negative patients was significantly better than that of node-positive patients (median DSS, 40 mo vs 17 mo, χ² = 14.814, P < 0.001), while there was no significant difference between N1 patients and N2 patients (median DSS, 18 mo vs 13 mo, χ² = 0.741, P = 0.389). Optimal TLNC was determined to be four. When node-negative patients were divided according to TLNC, there was no difference in DSS between TLNC < 4 subgroup and TLNC ≥ 4 subgroup (median DSS, 37 mo vs 54 mo, χ² = 0.715, P = 0.398). For node-positive patients, DSS of TLNC < 4 subgroup was worse than that of TLNC ≥ 4 subgroup (median DSS, 13 mo vs 21 mo, χ² = 11.035, P < 0.001). Moreover, for node-positive patients, a new cut-off value of six nodes was identified for the number of TLNC that clearly stratified them into 2 separate survival groups (< 6 or ≥ 6, respectively; median DSS, 15 mo vs 33 mo, χ² = 11.820, P < 0.001). DSS progressively worsened with increasing PLNC and LNR, but no definite cut-off value could be identified. Multivariate analysis revealed histological grade, tumor node metastasis staging, TNLC and LNR to be independent predictors of DSS. Neither location of positive lymph nodes nor PNLC were identified as an independent variable by multivariate analysis. Both TLNC and LNR are strong predictors of outcome after curative resection for GBC. The retrieval and examination of at least 6 nodes can influence staging quality and DSS, especially in node-positive patients.

Influence of Microsatellite Instability and KRAS and BRAF Mutations on Lymph Node Harvest in Stage I–III Colon Cancers

Lymph node (LN) harvest is influenced by several factors, including tumor genetics. Microsatellite instability (MSI) is associated with improved node harvest, but the association to other genetic factors is largely unknown. Research methods included a prospective series of stage I-III colon cancer patients undergoing ex vivo sentinel-node sampling. The presence of MSI, KRAS mutations in codons 12 and 13, and BRAF V600E mutations was analyzed. Uni- and multivariate regression models for node sampling were adjusted for clinical, pathological and molecular features. Of 204 patients, 67% had an adequate harvest (≥ 12 nodes). Adequate harvest was highest in patients whose tumors exhibited MSI (79%; odds ratio [OR] 2.5, 95% confidence interval [CI] 1.2-4.9; P = 0.007) or were located in the proximal colon (73%; 2.8, 1.5-5.3; P = 0.002). In multiple linear regression, MSI was a significant predictor of the total LN count (P = 0.02). Total node count was highest for cancers with MSI and no KRAS/BRAF mutations. The independent association between MSI and a high LN count persisted for stage I and II cancers (P = 0.04). Tumor location in the proximal colon was the only significant predictor of an adequate LN harvest (adjusted OR 2.4, 95% CI 1.2-4.9; P = 0.01). An increase in the total number of nodes harvested was not associated with an increase in nodal metastasis. In conclusion, number of nodes harvested is highest for cancers of the proximal colon and with MSI. The nodal harvest associated with MSI is influenced by BRAF and KRAS genotypes, even for cancers of proximal location. Mechanisms behind the molecular diversity and node yield should be further explored.

Evidence for a Better Nodal Staging System for Melanoma: The Clinical Relevance of Metastatic Disease Confined to the Sentinel Lymph Nodes

The hypothesis tested in this study was whether patients with stage III metastatic melanoma confined to their sentinel lymph nodes (SLNs) had a more favorable prognosis than patients who had SLN and non-SLN (NSLN) metastases. Patients were identified who were clinically negative in their regional basins but with lymphatic mapping were found to have positive SLNs (331 patients). All patients subsequently underwent a complete lymph node dissection of the lymphatic basin involved, and the total number of metastatic SLNs and NSLNs were documented. As the regional metastatic disease involves NSLNs, disease-free survival (DFS) and overall survival (OS) decreases. For patients with a total of 2 nodes positive, those with disease confined to the SLNs had a significant better prognosis (DFS and OS: P < .00001) than those in whom 1 SLN and 1 non-SLN was involved. This difference was apparent for those patients with N2 and N3 disease (2 or more nodes positive in their regional basin). A multivariate regression analysis that included Breslow thickness, ulceration, number of positive nodes, and NSLN positivity showed that NSLN positivity (P = .0019) was the most powerful predictor of DFS and OS. When metastatic melanoma overwhelms the SLN and involves NSLNs, the biologic behavior changes to portend a worse survival, regardless of the total node count positive. These data make the argument that the current N staging system should be changed to incorporate SLN vs NSLN involvement.

Predictors of Lymph Node Count in Colorectal Cancer Resections

To identify factors that influence the total and negative lymph node counts in colorectal cancer resection specimens independent of pathologists and surgeons. We used multivariate negative binomial regression. Covariates included age, sex, body mass index, family history of colorectal carcinoma, year of diagnosis, hospital setting, tumor location, resected colorectal length (specimen length), tumor size, circumferential growth, TNM stage, lymphocytic reactions and other pathological features, and tumor molecular features (microsatellite instability, CpG island methylator phenotype, long interspersed nucleotide element 1 [LINE-1] methylation, and BRAF, KRAS, and PIK3CA mutations). Two US nationwide prospective cohort studies. Patients with rectal and colon cancer (N=918). The negative and total node counts (continuous). Specimen length, tumor size, ascending colon location, T3N0M0 stage, and year of diagnosis were positively associated with the negative node count (all P.002). Mutation of KRAS might also be positively associated with the negative node count (P=.03; borderline significance considering multiple hypothesis testing). Among node-negative (stages I and II) cases, specimen length, tumor size, and ascending colon location remained significantly associated with the node count (all P.002), and PIK3CA and KRAS mutations might also be positively associated (P=.03 and P=.049, respectively, with borderline significance). This molecular pathological epidemiology study shows that specimen length, tumor size, tumor location, TNM stage, and year of diagnosis are operator-independent predictors of the lymph node count. These crucial variables should be examined in any future evaluation of the adequacy of lymph node harvest and nodal staging when devising individualized treatment plans for patients with colorectal cancer.

National Comprehensive Cancer Network Practice Guidelines 2011: Need for More Accurate Recommendations for Pelvic Lymph Node Dissection in Prostate Cancer

The 2011 NCCN (National Comprehensive Cancer Network) guidelines for prostate cancer recommend pelvic lymph node dissection at radical prostatectomy in all individuals with a nomogram predicted lymph node invasion probability of 2% or greater. We examined the ability of these guidelines to correctly predict lymph node invasion in patients treated with extended pelvic lymph node dissection. We examined 3,064 consecutive patients treated with radical prostatectomy and extended pelvic lymph node dissection between 2000 and 2010. We formally validated the NCCN guideline nomogram using discrimination, calibration and decision curve analysis as benchmarks. Moreover the performance characteristics of the 2% nomogram cutoff as well as other cutoff values (range 1% to 10%) were tested. Overall 10.0% of patients had lymph node invasion. The discrimination accuracy of the NCCN guideline nomogram was 79.8%, with a maximum underestimation of the lymph node invasion risk of 41.2%. On decision curve analysis the NCCN nomogram fared better than not performing pelvic lymph node dissection in all patients. However, in the prediction range between 0% and 9% the nomogram did not fare better than performing pelvic lymph node dissection in all patients. The use of the 2% cutoff would allow the avoidance of 49.3% of pelvic lymph node dissections, at the cost of missing 20.3% of patients with lymph node invasion. The NCCN nomogram tends to significantly underestimate the real lymph node invasion rate. Moreover the use of the currently recommended cutoff of 2% to trigger pelvic lymph node dissection might not be appropriate.

Impact of Lymph Node Count versus Lymph Node Ratio (LNR) on Survival Analysis in UICC Stage III Colorectal Cancer

Background: Lymph node status is an important prognostic factor in curative oncologic colorectal surgery. An inadequate number of lymph nodes may result in under-staging with consequences on therapeutic and prognostic effects. The aim of our study was to evaluate the impact of total lymph node count (LNC) in comparison to the lymph node ratio (LNR) on overall (OAS) and disease specific survival (DSS) in UICC stage III colorectal cancer.

Editorial Comment: Cancer of the oesophagus and gastrooesophageal junction: neoadjuvant therapy should not be a surrogate for suboptimal lymphadenectomy

In preparation for the 7th edition of the UICC/AJCC cancer staging manual for cancers of the oesophagus and gastrooesophageal junction [1], data were collected from centres world-wide, creating the World-Wide Esophageal Cancer Collaboration (WECC) in 2006 [2]. Thirteen institutions from five countries and three continents submitted 7884 desindentified patient files; within this dataset, 4625 patients who had undergone primary oesophagectomy without neoadjuvant or adjuvant therapy were identified [3]. This database compilation permitted a data-driven proposal for the 7th edition of the AJCC cancer staging manual, and additionally permitted a characterization of the relationship between survival and extent of lymphadenectomy. This effort has resulted in a definition of the optimum extent of lymphadenectomy in patients treated by primary surgery [4]. In this issue of the journal, Stiles et al .[ 5] hypothesized that optimal lymphadenectomy, as defined by the WECC, may also be relevant to cases of surgery following neoadjuvant therapy in patients with cancer of the oesophagus and gastro-oesophageal junction. They conclude that the WECC definitions for lymphadenectomy are especially relevant in cases where induction therapy results in persistent nodal disease, or a lack of tumour downstaging by T-stage classification. The survival figures in their series are impressive, with the overall 5-year survival of 47.8%; a 3-year survival of 50.8% in ypT3 patients who were not downstaged; and 55.4% survival at 3 years in patients with persistent nodal disease. Although a comparison with suboptimal lymphadenectomy did not reach statistical significance due to small patient numbers, these figures underline the value of an optimal lymphadenectomy after neoadjuvant therapy. That is a very important message. Besides this statistical limitation, a few other caveats may be noted: these excellent outcome figures are somewhat skewed by the selection process employed to define the study cohort. Indeed, patients with R1 and R2 resections, as well as patients with seven or more positive nodes at final pathological examination were excluded from the study, given their poor survival and the inability to demonstrate a benefit from extended lymphadenectomy. Furthermore, it is unclear why 41 patients (representing 48% of ypT3/T4 patients) appeared to have a suboptimal lymphadenectomy. Does this represent technical difficulty in achieving optimal lymph node clearance intraoperatively, or is it related to concerns of an increased risk of morbidity with an extensive lymphadenectomy in frail or elderly patients? The WECC guidelines for optimum lymphadenectomy are based on the data obtained after primary surgery. In the vast majority of these patients, lymphadenectomy was limited to a standard two-field lymphadenectomy, with the upper border of the lymph node dissection being the aortic arch. However, in this study, as many as 94 patients underwent a three-field lymphadenectomy, which includes dissection along both recurrent nerves above the level of the aortic arch, a bilateral lymphadenectomy along the remainder of both recurrent nerves in the neck and the removal of the lower deep cervical nodes located posterior and lateral to the carotid sheath [6]. Lymphadenectomy performed in this manner typically adds another 10–15 nodes to the total node count. That is to say, this subset of patients may have had an inadequate thoracic and abdominal lymph node dissection, according to WECC guidelines for lymphadenectomy. The question arises therefore, whether the claimed survival benefit is related to the addition of the third field, rather than the total number of dissected lymph nodes and as such satisfies the definition of optimum lymphadenectomy. As stated by the authors, the most important drawback of the study is the rather limited number of patients within each group (in particular the group with suboptimal lymphadenectomy). Differences in therapeutic modalities may further confound the study outcomes, such as the presence or the absence of radiotherapy in the induction protocol, variations in radiation doses over the study period and the use of different combinations of chemotherapeutic agents, all of which have a potential to modulate the treatment effect. Additionally, outcomes could potentially be ascribed to differences in histological tumour subtypes, the anatomic location of the primary tumour, the preinduction burden of nodal disease, the location of nodal basins within anatomic compartments (single versus multiple compartments) and extracapsular lymph node involvement. Patient factors relating to

Three dimensional finite element analysis of partial slip contacts subjected to combined loading

In this study, partial slip contacts are analyzed employing three dimensional finite element analysis to investigate the effects of edge fillet and bulk stress on the specimen. Geometries selected for analysis are cylinder with and without an edge fillet contacting flat specimen and both the contacting members having same thickness/depth. Meshing techniques adopted ensure that the element dimension near the free edge of the contact interface is minimum, while keeping the total node count within manageable limits. Analyses are carried out using regular solid elements with reduced integration and full integration schemes. In addition to normal and tangential loads on pad, bulk stress is applied to the specimen. For cylindrical pad without fillet contacting flat specimen, fine mesh with full integration scheme is required for convergence in longitudinal stress which has steep gradients. For cylindrical pad with edge fillet contacting flat specimen, very fine mesh along with sub-modeling is necessary to achieve convergence and usage of full integration elements is essential to get accurate results. Contact tractions are found to be maximum at the mid-surface for the cylindrical pad without fillet. For the filleted pad, maximum contact tractions are near the free surface, close to the fillet and are higher than that in cylindrical pad without fillet. Slip is found to increase significantly with addition of bulk stress and is found to be maximum closer to the free surface in both cases. Damage parameters calculated with the resulting stress/strain indicate that the maximum likelihood of damage is at the mid-section for the case of cylinder without fillet and near the filleted edge for cylinder with fillet.

Microsatellite instability status does not predict total lymph node or negative lymph node retrieval in stage III colon cancer

The relationship between higher total lymph node resection number in colorectal cancer resection specimens and improved overall survival is well known. Recent studies describe an association between a high rate of microsatellite instability and a high total lymph node count in colorectal cancer. Higher lymph node retrieval may potentially explain the improved survival seen in cancers with microsatellite instability. We investigate whether these associations can be validated in a cohort of American Joint Committee on Cancer stage III colon cancers. Medical records from 200 cases of stage III colon cancer resection specimens were reviewed, and sufficient tissue was available for 168. Expression of DNA mismatch repair proteins was determined by immunohistochemistry, and microsatellite status, by polymerase chain reaction. The mean total lymph node count in cases with microsatellite instability versus microsatellite stable tumors (15.9 versus 16.9; P = .664) and the mean number of negative lymph nodes in each respective category (12.2 versus 13.6; P = .522) were not significantly different. There was no difference between microsatellite stable cases and cases with microsatellite instability when total lymph node counts (P = .953) or negative lymph node counts (P = .381) were analyzed with respect to percentage of cases above and below the medians. This cohort of stage III colon cancers does not support a significant relationship between microsatellite status and a higher retrieval of total or negative lymph nodes. Although microsatellite instability is associated with improved overall survival in our cohort (P = .026), the reason for this does not appear to be related to higher numbers of retrieved lymph nodes.

Lymph node harvest in colon and rectal cancer: Current considerations.

The prognostic significance of identifying lymph node (LN) metastases following surgical resection for colon and rectal cancer is well recognized and is reflected in accurate staging of the disease. An established body of evidence exists, demonstrating an association between a higher total LN count and improved survival, particularly for node negative colon cancer. In node positive disease, however, the lymph node ratios may represent a better prognostic indicator, although the impact of this on clinical treatment has yet to be universally established. By extension, strategies to increase surgical node harvest and/or laboratory methods to increase LN yield seem logical and might improve cancer staging. However, debate prevails as to whether or not these extrapolations are clinically relevant, particularly when very high LN counts are sought. Current guidelines recommend a minimum of 12 nodes harvested as the standard of care, yet the evidence for such is questionable as it is unclear whether an increasing the LN count results in improved survival. Findings from modern treatments, including down-staging in rectal cancer using pre-operative chemoradiotherapy, paradoxically suggest that lower LN count, or indeed complete absence of LNs, are associated with improved survival; implying that using a specific number of LNs harvested as a measure of surgical quality is not always appropriate. The pursuit of a sufficient LN harvest represents good clinical practice; however, recent evidence shows that the exhaustive searching for very high LN yields may be unnecessary and has little influence on modern approaches to treatment.

Body Mass Index Is Associated With Higher Lymph Node Counts During Retroperitoneal Lymph Node Dissection

To determine whether body mass index (BMI) is associated with lymph node counts in patients treated with a primary retroperitoneal lymph node dissection (RPLND). Lymph node counts are a proposed measure of quality assurance for numerous malignancies. Investigation of patient factors associated with lymph node counts are lacking. Using the Memorial Sloan-Kettering Testis Cancer Database, we identified 255 patients treated with a primary RPLND for nonseminomatous germ cell tumors (NSGCT) from 1999-2008. The associations between BMI and node counts were evaluated using linear regression models in univariate and multivariable models adjusting for features reported to predict higher node counts (year of surgery, stage, and surgeon volume). Median BMI (IQR) was 26.1 (23.4-28.7) and median (IQR) total node count was 38 (27-53). Median total node count for patients with a BMI<25, 25 to 29, and ≥30 was 35, 42, and 44 nodes, respectively. In a univariate analysis, higher BMI was significantly associated with higher total node counts (coefficient 0.7 nodes for each 1-U increase in BMI; P=.026). Features associated with higher node count on multivariate analysis included high-volume surgeon (P=.047), pathologic stage (P=.017), more recent year of surgery (P<.001), and higher BMI (P=.009). Our results suggest for the first time that BMI is independently associated with higher lymph node counts during a lymph node dissection. If confirmed by others, these results may be important when using lymph node counts as a surrogate for adequacy of a lymph node dissection.

Comparative analysis of various prognostic nodal factors, adjuvant chemotherapy and survival among stage III colon cancer patients over 65 years: an analysis using Surveillance, Epidemiology and End Results (SEER)‐Medicare data

The prognostic effects of chemotherapy and various lymph node measures [positive nodes, total node count and the positive lymph node ratio (PLNR)] have been established. It is unknown whether the cancer-specific survival benefit of chemotherapy differs across these nodal prognostic categories. This retrospective analysis of linked Surveillance, Epidemiology and End Results (SEER) data and Medicare data (SEER-Medicare)included patients ≥ 65 years of age with a diagnosis of stage III colon cancer between 1997 and 2002. We grouped patients according to the number of positive nodes (N1 and N2), total node count (≥ 12 and < 12 total nodes) and PLNR (below the 75th percentile and at least at the 75th percentile of the PLNR). The end point was colon cancer-specific mortality. Fifty-one per cent (3701) of the 7263 patients received adjuvant therapy during the time period 1997-2002. The mean (standard deviation) number of total nodes examined was 13 (9) and the number of positive nodes identified was 3 (3). Patients with N2 disease, < 12 total nodes examined and a high PLNR had a worse survival at 2, 3 and 5 years following colectomy. Utilization of chemotherapy demonstrated a colon cancer-specific survival benefit (hazard ratio at median follow up = 0.7; P < 0.001) that was consistent and statistically significant across the three nodal prognostic categories examined. The benefit of chemotherapy did not vary based on N stage, total node count or PLNR. The results favour a broad-based approach towards increasing the chemotherapy treatment rates in stage III patients of ≥ 65 years of age, rather than an approach that targets clinical subgroups.