Lymph node yield following colorectal cancer surgery

Predictors and survival outcomes of having less than 12 harvested lymph nodes in proctectomy for rectal cancer

BACKGROUND

Current recommendations suggest that a minimum of 12 lymph nodes (LNs) should be harvested during curative rectal cancer resection. We aimed to assess predictors and survival outcomes of harvesting < 12 lymph nodes in rectal cancer surgery.

METHODS

A retrospective case-control analysis of factors associated with harvesting < 12 LNs in rectal cancer surgery was conducted. Data were derived from the National Cancer Database 2010-2019. Univariate and multivariate binary logistic regression analyses were performed to determine predictors of harvesting < 12 LNs. Association between harvesting < 12 LNs and 5-year overall survival (OS) was assessed using Cox regression and Kaplan Meier statistics.

RESULTS

67,529 patients (60.8% male; mean age: 61.2 ± 12.5 years) were included. Median number of harvested LNs was 15 (IQR: 11-20); 27.1% of patients had < 12 harvested LNs. Independent predictors of harvesting < 12 LNs were older age (OR: 1.016;p < 0.001), neoadjuvant systemic treatment (OR: 1.522;p < 0.001), neoadjuvant radiation treatment (OR: 1.367;p < 0.001), longer duration of radiation therapy (OR: 1.003;p < 0.001) and abdominoperineal resection (OR: 1.071;p = 0.017). Higher clinical TNM stage and tumor grade, pull-through coloanal anastomosis, and minimally invasive surgery were independently associated with ≥ 12 harvested LNs. < 12 harvested LNs was independently associated with lower 5-year OS (HR: 1.24;p < 0.001) and shorter mean OS (96.7 vs 102.8 months;p < 0.001) than ≥ 12 harvested LNs.

CONCLUSIONS

Older age, open resection, and neoadjuvant therapy were independent predictors of < 12 harvested LNs. Conversely, higher clinical TNM stage and tumor grade, coloanal anastomosis, and minimally invasive surgery were predictive of ≥ 12 harvested LNs. < 12 LNs harvested was associated with lower OS.

Is increasing nodal count associated with improved recurrence-free and overall survival following standard right hemicolectomy for colon cancer?

BACKGROUND AND OBJECTIVES

Increasing lymph node harvest for right-sided colon cancer is associated with improved overall survival (OS), but most relevant studies failed to report the extent of resection. We examined the association between increasing lymph node count with standard right hemicolectomy according to nodal status and prognostic outcomes in right-sided tumors.

METHODS

Retrospective analysis of prospectively collected clinical data from patients with proximal colonic adenocarcinomas (n = 1390) following right hemicolectomy. Associations between lymph node counts (0-12 vs. 13-15, 16-20, and >20) and recurrence-free survival (RFS) and OS were examined using multivariate Cox modeling adjusted for confounders.

RESULTS

We found no association between increasing nodal count and RFS, regardless of nodal status. In the absence of nodal metastases, increasing nodal count (16-20 and >20 vs. 0-12 nodes) was associated with 57% (95% confidence interval [CI]: 0.21-0.89) and 52% (95% CI: 0.24-0.95) improved OS, respectively. In the presence of nodal metastases, increasing nodal count was not associated with OS. Adjuvant chemotherapy did not modify this effect.

CONCLUSION

Increasing nodal count (>15 nodes) with right hemicolectomy was not associated with improved RFS. Improved OS was only found for node-negative tumors, casting some doubt on the benefits of resecting more lymph nodes in the presence of nodal metastases.

Retrospective Cohort Analysis of the Effect of Age on Lymph Node Harvest, Positivity, and Ratio in Colorectal Cancer

Introduction: Colon cancer among young patients has increased in incidence and mortality over the past decade. Our objective was to determine if age-related differences exist for total positive nodes (TPN), total lymph node harvest (TLH), and lymph node ratio (LNR). Material and Methods: A retrospective review of stage III surgically resected colorectal cancer patient data in the National Cancer Database (2004−2016) was performed, reviewing TPN, TLH, and LNR (TPN/TLH). Results: Unadjusted analyses suggested significantly higher levels of TLH and TPN (p < 0.0001) in younger patients, while LNR did not differ by age group. On adjusted analysis, TLH remained higher in younger patients (<35 years 1.56 (CI 95 1.54, 1.59)). The age-related effect was less pronounced for LNR (<35 years 1.16 (CI 95 1.13, 1.2)). Conclusion: Younger patients have increased TLH, even after adjusting for known confounders, while age does not have a strong independent impact on LNR.

The Value of Federated Data Networks in Oncology: What Research Questions Do They Answer? Outcomes From a Systematic Literature Review

OBJECTIVES

Real-world evidence (RWE) plays an important role in addressing key research questions of interest to healthcare decision makers. Federated data networks (FDNs) apply novel technology to enable the conduct of RWE studies with multiple partners, without the need to share the individual partner's data set. A systematic review of the published literature was performed to determine which types of research questions can best be addressed through FDNs, specifically in the field of oncology.

METHODS

Systematic searches of MEDLINE and Embase were undertaken to identify the types of research questions that had been addressed in studies using FDNs. Additional information was retrieved about study characteristics, statistical methods, and the FDN itself.

RESULTS

In total, 40 publications were included where research questions on the following had been addressed (multiple categories possible): disease natural history (58%), safety surveillance (18%), treatment pathways (15%), comparative effectiveness (10%), and cost/resource use studies (3%)-13% of studies had to be left uncategorized. A total of 50% of the studies were run with data partners in networks of ≤5. The size of the networks ranged from 227 patients to >5 million patients. Statistical methods used included distributed learning and distributed regression methods.

CONCLUSIONS

Further work is needed to raise awareness of the important role that FDNs can play in leveraging readily available RWE to address key research questions of interest in cancer and the benefits to the research community in engaging in federated data initiatives with a long-term perspective.

The quality of lymph node harvests in extralevator abdominoperineal excisions

Background

Lymph node (LN) harvest in colorectal cancer resections is a well-recognised prognostic factor for disease staging and determining survival, particularly for node-negative (N0) diseases. Extralevator abdominoperineal excisions (ELAPE) aim to prevent “waisting” that occurs during conventional abdominoperineal resections (APR) for low rectal cancers, and reducing circumferential resection margin (CRM) infiltration rate. Our study investigates whether ELAPE may also improve the quality of LN harvests, addressing gaps in the literature.

Methods

This retrospective observational study reviewed 2 sets of 30 consecutive APRs before and after the adoption of ELAPE in our unit. The primary outcomes are the total LN counts and rates of meeting the standard of 12-minimum, particularly for those with node-negative disease. The secondary outcomes are the CRM involvement rates. Baseline characteristics including age, sex, laparoscopic or open surgery and the use of neoadjuvant chemoradiotherapy were accounted for in our analyses.

Results

Median LN counts were slightly higher in the ELAPE group (16.5 vs. 15). Specimens failing the minimum 12-LN requirements were almost significantly fewer in the ELAPE group (OR 0.456, P = 0.085). Among node-negative rectal cancers, significantly fewer resections failed the 12-LN standard in the ELAPE group than APR group (OR 0.211, P = 0.044). ELAPE led to a near-significant decrease in CRM involvement (OR 0.365, P = 0.088). These improvements were persistently observed after taking into account baselines and potential confounders in regression analyses.

Conclusion

ELAPE provides higher quality of LN harvests that meet the 12-minimal requirements than conventional APR, particularly in node-negative rectal cancers. The superiority is independent of potential confounding factors, and may implicate better clinical outcomes.

A Review of Current Challenges in Colorectal Cancer Reporting

Context.—

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

Objective.—

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

Data Sources.—

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

Conclusions.—

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Mesocolic Lymph Node Number, Size, and Density: An Anatomical Study

BACKGROUND

Lymph nodes play a critical role in the staging, treatment, and prognosis of colon cancer. However, the normal number and morphology of lymph nodes in the normal mesocolon is unknown.

OBJECTIVE

This study aimed to investigate the number and size of lymph nodes in the ascending and sigmoid mesocolons.

DESIGN

This is a descriptive anatomical cadaver study of 10 sigmoid mesocolons and 5 ascending mesocolons, resected in a standardized manner and examined systematically after serial histological sectioning. The number, maximum length, and appearance of lymph nodes were analyzed, and the 2 mesocolons were compared by using the Mann-Whitney U test, the Wilcoxon signed rank test, and the χ test.

PATIENTS

Ten cadavers (mean age, 82.9 years; 5 male) with no evidence of colorectal disease were examined.

MAIN OUTCOME MEASURE

The number, maximum length, and appearance of lymph nodes and fat-associated lymphoid clusters were the primary outcomes measured.

RESULTS

The median number of lymph nodes in the sigmoid and ascending mesocolons was 71 (range, 24-116) and 61 (range, 33-71). More than 90% of lymph nodes were less than 5 mm in maximum length. Sigmoid mesocolic nodes were significantly smaller than ascending mesocolic nodes (median maximum lymph nodes length, 1.6 mm vs 2.1 mm; p < 0.001), but there was no statistically significant difference in the density of lymph nodes between the sigmoid and ascending mesocolon. Fatty replacement was seen in almost 30% of lymph nodes. A few fat-associated lymphoid clusters were observed in both mesocolons.

LIMITATIONS

Only 15 mesocolic specimens could be examined because of the detailed labor-intensive methodology, and younger cadavers were not available for analysis.

CONCLUSIONS

In this descriptive anatomical study, the median number of lymph nodes in the sigmoid and ascending mesocolon was 71 and 61. Ascending mesocolic nodes were significantly larger than sigmoid mesocolic nodes. These anatomical findings are relevant to the interpretation of lymph node yields after the surgical resection of colon cancer.

The effect of colonoscopic tattooing on lymph node retrieval and sentinel lymph node mapping

BACKGROUND

In colorectal cancer (CRC), colonoscopic tattooing is performed to mark the tumor site before laparoscopic surgery.

OBJECTIVE

To determine whether colonoscopic tattooing can be used to refine staging accuracy by increasing the lymph node (LN) yield per specimen and to determine its accuracy as a sentinel LN procedure.

DESIGN

Retrospective, case-control study. All LNs were microscopically examined for the presence of carbon particles.

SETTING

A university hospital and a teaching hospital.

PATIENTS

A consecutive series of 95 tattooed patients who had surgery for CRC between 2005 and 2009. A series of 210 non-tattooed patients who had surgery in the same time period served as controls.

MAIN OUTCOME MEASUREMENTS

Total number of LNs retrieved, detection rate, and sensitivity of tattooing as a sentinel node procedure.

RESULTS

A higher LN yield was observed in patients with preoperative tattooing, median (interquartile range) 15 (10-20) versus 12 (9-16), (P = .014). In multivariable analysis, the presence of carbon-containing LNs was an independent predictive factor for a higher LN yield (P = .002). The detection rate was 71%, with a median of 5 carbon-containing LNs per specimen. If preoperative tattooing was used for sentinel node mapping, the overall accuracy of predicting LN status was 94%. In the 24 N1 cases, there were 4 false-negative procedures (sensitivity 83%).

LIMITATIONS

Retrospective series.

CONCLUSION

After tattooing of CRC, the LN yield was higher than in a control group, and it could be used as a sentinel node procedure with acceptable accuracy rates. Because LN yield and sentinel node mapping are associated with improved diagnostic accuracy of LN involvement, preoperative tattooing can refine staging.