How many lymph nodes are enough?-defining the extent of lymph node dissection in stage I-III gastric cancer using the National Cancer Database

Oncologic Outcome of the Extent of Pelvic Lymph Node Dissection During Radical Prostatectomy: A Systematic Review, Meta-analysis, and Network Analysis

CONTEXT

Some authors propose extended pelvic lymph node dissection (ePLND) to enhance diagnostic and therapeutic outcomes in patients with localized prostate cancer. However, recent evidence found no difference in biochemical recurrence (BCR).

OBJECTIVE

To stratify and analyze available evidence on ePLND and its impact on BCR in patients with localized prostate cancer.

EVIDENCE ACQUISITION

We systematically reviewed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to identify studies up to November 2023. We identified original articles that presented statistical comparisons through Cox regressions reported as hazard ratio (HR) or survival curve data reported as Kaplan-Meier curve differences in BCR in patients undergoing radical prostatectomy and stratified by the extent of lymph node dissection for localized prostate cancer.

EVIDENCE SYNTHESIS

We identified 12 studies, with two being randomized controlled trials (RCTs). The RCTs showed no benefit of ePLND with an HR of 1.03 ([0.92, 1.14], p = 0.61). A combined analysis with the ten retrospective studies revealed a notable reduction in BCR with an HR of 0.68 ([0.52, 0.88], p = 0.003). A subgroup analysis based on the extent of dissection demonstrated that studies focusing on the more conservative extended template of dissection did not show significant BCR benefit (HR 0.97 [0.72, 1.32], p = 0.86). In contrast, dissections that expanded the anatomical extent showed decreased BCR (HR 0.56 [0.41, 0.75], p < 0.0001). A Bayesian network analysis highlights significant differences in BCR reduction between different dissection approaches, indicating the potential benefits of specific dissection templates.

CONCLUSIONS

Available literature on the extent of pelvic lymph node dissection needs to be improved in quality and varying definitions of the ePLND template. Dissection of the common iliac nodes may be beneficial.

PATIENT SUMMARY

There is a potential benefit in removing more lymph nodes during radical prostatectomy. However, more research is needed to determine whether this strategy benefits certain patient groups.

A 3 M Evaluation Protocol for Examining Lymph Nodes in Cancer Patients: Multi-Modal, Multi-Omics, Multi-Stage Approach

Through meticulous examination of lymph nodes, the stage and severity of cancer can be determined. This information is invaluable for doctors to select the most appropriate treatment plan and predict patient prognosis; however, any oversight in the examination of lymph nodes may lead to cancer metastasis and poor prognosis. In this review, we summarize a significant number of articles supported by statistical data and clinical experience, proposing a standardized evaluation protocol for lymph nodes. This protocol begins with preoperative imaging to assess the presence of lymph node metastasis. Radiomics has replaced the single-modality approach, and deep learning models have been constructed to assist in image analysis with superior performance to that of the human eye. The focus of this review lies in intraoperative lymphadenectomy. Multiple international authorities have recommended specific numbers for lymphadenectomy in various cancers, providing surgeons with clear guidelines. These numbers are calculated by applying various statistical methods and real-world data. In the third chapter, we mention the growing concern about immune impairment caused by lymph node dissection, as the lack of CD8 memory T cells may have a negative impact on postoperative immunotherapy. Both excessive and less lymph node dissection have led to conflicting findings on postoperative immunotherapy. In conclusion, we propose a protocol that can be referenced by surgeons. With the systematic management of lymph nodes, we can control tumor progression with the greatest possible likelihood, optimize the preoperative examination process, reduce intraoperative risks, and improve postoperative quality of life.

Prognostic role of the number of resected and negative lymph nodes in Spanish patients with gastric cancer

INTRODUCTION

Lymph node (LN) involvement is one of the most critical prognostic factors in resected gastric cancer (GC). Some analyses, mainly conducted in Asian populations, have found that patients with a higher number of total lymph nodes (NTLN) and/or negative lymph nodes (NNLN) have a better prognosis, although other authors have failed to confirm these results.

MATERIALS AND METHODS

Retrospective study including all patients with GC resected in a tertiary hospital in Spain between 2001 and 2019 (n = 315). Clinicopathological features were collected and patients were categorized according to the NTLN and the NNLN. Statistical analyses were performed.

RESULTS

Mean NNLN was 17. The NNLN was significantly related to multiple clinicopathological variables, including recurrence and tumor-related death. The classification based on the NNLN (N1: ≥16, N2: 8-15, N3: ≤7) effectively stratified the entire cohort into three distinct prognostic groups and maintained its prognostic value within both the pN0 and pN+ patient subsets. Furthermore, it was an independent prognostic indicator for both overall and disease-free survival. Conversely, the mean NTLN was 21.9. Patients with ≤16 LN retrieved exhibited distinct clinicopathological features compared to those with >16 LN, but no significant differences were observed in terms of recurrence or disease-associated death. The application of alternative cut-off points for NTLN (10, 20, 25, 30, and 40) showed no prognostic significance.

CONCLUSIONS

In Spanish patients with resected GC the NNLN hold prognostic significance, while the NTLN does not appear to be prognostically significant. Incorporating the NNLN into GC staging may enhance the accuracy of the TNM system.

The Learning Curve for Hand-Assisted Laparoscopic Total Gastrectomy in Gastric Cancer Patients

(1) Background: Hand-assisted laparoscopic total gastrectomy (LTG) for patients with gastric cancer (GC) has been established as the standard surgical treatment at our center. This study aims to quantify the learning curve for surgeons performing minimally invasive total gastrectomy at a high-volume single center. (2) Methods: One hundred and eighteen consecutive patients who underwent minimally invasive total gastrectomy between January 2014 and December 2020 at a single high-volume center were included and reviewed retrospectively. Risk-adjusted cumulative sum analysis (RA-CUSUM) was used to monitor the surgical outcomes for patients with different risks of postoperative mortality using varying-coefficient logistic regression models. Patients were ordered by the sequential number of the procedure performed and divided into two groups according to the degree of surgeon proficiency as determined by RA-CUSUM analysis (group A: 45; group B: 73 patients). Age, gender, body mass index (BMI), tumor location, pathology, and comorbidities were compared while primary endpoints comprised surgical parameters, postoperative course, and survival outcomes. (3) Results: Forty-four cases were required for the completion of the learning curve. During this time, the mean operating time decreased. Hand-assisted laparoscopic total gastrectomy performed after a learning curve was associated with a shorter median operating time (OT) (360 min vs. 289 min, <0.001), and a reduced length of stay (A = 18.0 vs. B = 14.0 days) (p = 0.154), while there was a trend toward less major complications (Clavien−Dindo (CD) 3−5 within 90 days (12 (26.67%) vs. 10 (13.70%) p = 0.079). Our results showed no difference in anastomotic leakage between the two groups (group A vs. group B, 3 (6.67%) vs. 4 (5.48%) p = 0.99). Similarly, 30-day (0 (0%) vs. 1 (1.7%), p = 0.365) and 90-day mortality (1 (2.08%) vs. 2 (3.39%), p = 0.684) were comparable. Following multivariate analysis, the level of surgical proficiency was not a significant prognostic factor for overall survival. (4) Conclusions: A minimum of 44 cases are required for experienced laparoscopic surgeons to achieve technical competence for performing LTG. While operation time decreased after completion of the learning curve, quality criteria such as achievement of R0 resection, anastomotic leakage, and perioperative mortality remained unaltered. Of note, the level of surgical training showed no significant impact on the 2 year OS or DFS.

Clinical significance of the number of retrieved lymph nodes in early gastric cancer with submucosal invasion

The prognosis of early gastric cancer (EGC) with submucosal invasion is favorable; however, several cases of recurrence have been reported even after curative gastrectomy. This study aimed to investigate risk factors and evaluate the clinical significance of the number of retrieved lymph nodes (LNs) in EGC with submucosal invasion. We retrospectively analyzed the data of 443 patients with gastric cancer with submucosal invasion after curative gastrectomy for recurrent risk factors. Recurrence was observed in 22 of the 443 gastric cancer patients with submucosal invasion. In the univariate analysis, the risk factors for recurrence were the number of retrieved LNs ≤ 25 and node metastasis. In the multivariate analysis, retrieved LNs ≤ 25 (hazard ratio [HR] = 5.754, P-value = .001) and node metastasis (HR = 3.031, P-value = .029) were independent risk factors for recurrence after curative gastrectomy. Body mass index was related to retrieved LNs ≤ 25 in univariate and multivariate analyses (HR = .510, P = .002). The number of retrieved LNs and node metastases were independent risk factors for EGC with submucosal invasion. For EGC with submucosal invasion, retrieved LNs > 25 are necessary for appropriate diagnosis and treatment.

Pathologic Lymph Node Staging of Gastric Cancer

OBJECTIVES

The TNM classification is the main tool for lymph node (LN) staging in gastric cancer (GC). However, alternative LN staging systems have been proposed, and the role of features other than the number of metastatic LNs is being investigated. Our aim is to discuss the main challenges of LN assessment in GC.

METHODS

Comprehensive review of the literature on alternative LN staging systems, examined LNs, sentinel LN (SLN) biopsy, LN micrometastases (LNMIs), extracapsular extension (ECE), and tumor deposits (TDs) in GC.

RESULTS

Many controversies exist regarding LN assessment in GC. The TNM classification shows excellent prognostic performance, but alternative prognostic methods such as the LN ratio or log odds of positive LNs have demonstrated to be better than the TNM system in terms of prognostic accuracy. The value of SLN biopsy and LNMIs in GC is still unclear, and several challenges concerning their clinical impact and pathologic analysis must be overcome before their introduction in clinical practice. Most authors have identified ECE and TDs as independent prognostic factors for survival in GC.

CONCLUSIONS

Further studies should be performed to evaluate the impact of these features on the TNM classification and patient outcomes, as well as to standardize alternative LN staging systems.

Identifying Outlier Hospitals in Gastric Cancer Lymph Node Yield Using the National Cancer Database

BACKGROUND

Lymph node (LN) yield is a key quality indicator that is associated with improved staging in surgically resected gastric cancer. The National Comprehensive Cancer Network recommends a yield of ≥15 LNs for proper staging, yet most facilities in the United States fail to achieve this number. The present study aimed to identify factors that could affect LN yield on a facility level and identify outlier hospitals.

METHODS

This was a retrospective review of adults (aged ≥18 y) with gastric cancer (Tumor-Node-Metastasis Stages I-III) who underwent gastrectomy. Data were analyzed from the National Cancer Database (2004-2016). Multivariate analysis identified patient and tumor characteristics, whereas an observed-to-expected ratio of identified outlier hospitals. Facility factors were compared between high and low outliers.

RESULTS

A total of 26,590 patients were included in this study. Of these patients, only 50.3% had an LN yield ≥15. The multivariate model of patient and tumor characteristics demonstrated a concordance index was 0.684. A total of 1245 facilities were included. There were 198 low outlier LN yield hospitals and 135 high outlier LN yield hospitals (observed-to-expected ratio of 0.42 ± 0.24 versus 1.38 ± 0.19, P < 0.0001). There was a difference in facility type between low and high outliers (P < 0.0001). High LN yield hospitals had a larger surgical volume than low LN yield hospitals (median 8.4 [4.9, 13.5] versus 3.5 [2.4, 5.2]; P < 0.0001).

CONCLUSIONS

Nearly half of the population exhibited low compliance to National Comprehensive Cancer Network recommendations. Facility-level disparities exist as high yearly surgical volume and academic facility status distinguished high-performing outlier hospitals.

Development and validation of a novel staging system integrating the number and location of lymph nodes for gastric adenocarcinoma

Background

Evidence suggests that the anatomic extent of metastatic lymph nodes (MLNs) affects prognosis, as proposed by alternative staging systems. The aim of this study was to establish a new staging system based on the number of perigastric (PMLN) and extra-perigastric (EMLN) MLNs.

Methods

Data from a Chinese cohort of 1090 patients who had undergone curative gastrectomy with D2 or D2 plus lymphadenectomy for gastric cancer were retrospectively analysed. A Japanese validation cohort (n = 826) was included. Based on the Cox proportional hazards model, the regression coefficients of PMLN and EMLN were used to calculate modified MLN (MMLN). Prognostic performance of the staging systems was evaluated.

Results

PMLN and EMLN were independent prognostic factors in multivariate analysis (coefficients: 0.044, 0.115; all P < 0.001). MMLN was calculated as follows: MMLN = PMLN + 2.6 × EMLN. The MMLN staging system showed superior prognostic performance (C-index: 0.751 in the Chinese cohort; 0.748 in the Japanese cohort) compared with the five published LN staging systems when MMLN numbers were grouped as follows: MMLN0 (0), MMLN1 (1–4), MMLN2 (5–8), MMLN3 (9–20), and MMLN4 (>20).

Discussion

The MMLN staging system is suitable for assessing overall survival among patients undergoing curative gastrectomy with D2 or D2 plus lymphadenectomy.

Gastrectomy case volume and textbook outcome: an analysis of the Population Registry of Esophageal and Stomach Tumours of Ontario (PRESTO)

OBJECTIVE

To determine the association between gastric cancer surgery case-volume and Textbook Outcome, a new composite quality measurement.

BACKGROUND

Textbook Outcome included (a) negative resection margin, (b) greater than 15 lymph nodes sampled, (c) no severe complication, (d) no re-intervention, (e) no unplanned ICU admission, (f) length of stay of 21 days or less, (g) no 30-day readmission and (h) no 30-day mortality following surgery.

METHODS

All patients undergoing gastrectomy for non-metastatic gastric adenocarcinoma registered in the Population Registry of Esophageal and Stomach Tumours of Ontario between 2004 and 2015 were included. We used multivariable generalized estimating equation (GEE) logistic regression modelling to estimate the association between gastrectomy volume (surgeon and hospital annual volumes) and Textbook Outcome. Volumes were considered as continuous variables and quintiles.

RESULTS

Textbook Outcome was achieved in 378 of 1660 patients (22.8%). The quality metrics least often achieved were inadequate lymph node sampling and presence of severe complications, which occurred in 46.1% and 31.7% of patients, respectively. Accounting for covariates and clustering, neither surgeon volume nor hospital volume were significantly associated with Textbook Outcome. However, hospital volume was associated with adequate lymphadenectomy and fewer unplanned ICU admissions.

CONCLUSIONS

Higher case volume can impact certain measures of quality of care but may not address all care structures necessary for ideal Textbook recovery. Future quality improvement strategies should consider using case-mix adjusted Textbook Outcome rates as a surgical quality metric.