Navigating Nodal Metrics for Node-Positive Gastric Cancer in the United States: An NCDB-Based Study and Validation of AJCC Guidelines

The minimum number of examined lymph nodes was 24 for optimal survival of pathological T2-4 gastric cancer: a multi-center, hospital-based study covering 20 years of data

INTRODUCTION

The current National Comprehensive Cancer Network (NCCN) guidelines recommend that at least 16 lymph nodes should be examined for gastric cancer patients to reduce staging migration. However, there is still debate regarding the optimal management of examined lymph nodes (ELNs) for gastric cancer patients. In this study, we aimed to develop and test the minimum number of ELNs that should be retrieved during gastrectomy for optimal survival in patients with gastric cancer.

METHODS

We used the restricted cubic spline (RCS) to identify the optimal threshold of ELNs that should be retrieved during gastrectomy based on the China National Cancer Center Gastric Cancer (NCCGC) database. Northwest cohort, which sourced from the highest gastric cancer incidence areas in China, was used to verify the optimal cutoff value. Survival analysis was performed via Kaplan-Meier estimates and Cox proportional hazards models.

RESULTS

In this study, 12,670 gastrectomy patients were included in the NCCGC cohort and 4941 patients in the Northwest cohort. During 1999-2019, the average number of ELNs increased from 17.88 to 34.45 nodes in the NCCGC cohort, while the number of positive lymph nodes remained stable (5-6 nodes). The RCS model showed a U-curved association between ELNs and the risk of all-cause mortality, and the optimal threshold of ELNs was 24 [Hazard ratio (HR) = 1.00]. The ELN ≥ 24 group had a better overall survival (OS) than the ELN < 24 group clearly (P = 0.003), however, with respect to the threshold of 16 ELNs, there was no significantly difference between the two groups (P = 0.101). In the multivariate analysis, ELN ≥ 24 group was associated with improved survival outcomes in total gastrectomy patients [HR = 0.787, 95% confidence interval (CI): 0.711-0.870, P < 0.001], as well as the subgroup analysis of T2 patients (HR = 0.621, 95%CI: 0.399-0.966, P = 0.035), T3 patients (HR = 0.787, 95%CI: 0.659-0.940, P = 0.008) and T4 patients (HR = 0.775, 95%CI: 0.675-0.888, P < 0.001).

CONCLUSION

In conclusion, the minimum number of ELNs for optimal survival of gastric cancer with pathological T2-4 was 24.

Gastric Cancer Surgery in the US: a Contemporary Trend Analysis of Lymphadenectomy and the Impact of Minimally Invasive Approaches

BACKGROUND

The National Comprehensive Cancer Network guidelines recommend harvesting 16 or more lymph nodes for the adequate staging of gastric adenocarcinoma. This study examines the rate of adequate lymphadenectomy over recent years, its predictors, and its impact on overall survival(OS).

STUDY DESIGN

The National Cancer Database was utilized to identify patients who underwent surgical treatment for gastric adenocarcinoma between 2006-2019. Trend analysis was performed for lymphadenectomy rates during the study period. Logistic regression, Kaplan-Meier survival plots, and Cox proportional hazard regression were utilized.

RESULTS

A total of 57,039 patients who underwent surgical treatment for gastric adenocarcinoma were identified. Only 50.5% of the patients underwent a lymphadenectomy of ≥ 16 nodes. Trend analysis showed that this rate significantly improved over the years, from 35.1% in 2006 to 63.3% in 2019 (p < .0001). The main independent predictors of adequate lymphadenectomy included high-volume facility with ≥ 31 gastrectomies/year (OR: 2.71; 95%CI:2.46-2.99), surgery between 2015-2019 (OR: 1.68; 95%CI: 1.60-1.75), and preoperative chemotherapy (OR:1.49; 95%CI:1.41-1.58). Patients with adequate lymphadenectomy had better OS than patients who did not: median survival: 59 versus 43 months (Log-Rank: p < .0001). Adequate lymphadenectomy was independently associated with improved OS (HR:0.79; 95%CI:0.77-0.81). Laparoscopic and robotic gastrectomies were independently associated with adequate lymphadenectomy compared to open, OR: 1.11, 95%CI:1.05-1.18 and OR: 1.24, 95%CI:1.13-1.35, respectively.

CONCLUSION

Although the rate of adequate lymphadenectomy improved over the study period, a large number of patients still lacked adequate lymph node dissection, negatively impacting their OS despite multimodality therapy. Laparoscopic and robotic surgeries were associated with a significantly higher rate of lymphadenectomy ≥ 16 nodes.

Pattern of Distribution of Lymph Node Metastases in Individual Stations in Middle and Lower Gastric Carcinoma

(1) Background: Lymph node (LN) dissection is the cornerstone of curative treatment of GC. The pattern of distribution of LN metastases is closely related to several factors. The aim of this study is to evaluate the factors determining the distribution of nodal metastases in a population of N+ distal GC patients undergoing gastrectomy and D2 lymphadenectomy. (2) Methods: The medical charts of 162 N+ GC patients who underwent surgical resection over a 15-year period were retrospectively analyzed. Clinical, pathological and anatomical characteristics were evaluated to identify the factors affecting the patterns and prevalence of metastases in individual LN stations. (3) Results: LN metastasis is correlated with the depth of the tumor and to diffuse-type tumors. A higher number of metastatic nodes was documented in patients with middle-third tumors (8.2 ± 7.3 vs. 4.5 ± 5.0 in lower-third tumors, p = 0.0001) and in patients with tumors located on the lesser curve. Station 4 showed the highest rate of metastases (53.1%). Concerning stations 7 to 12, station 8 showed the highest metastasis rate (28.4%). Metastases at stations 1, 2, 4 and 7 to 11 were dominant in middle-third cancer, whereas stations 5 and 6 were dominant in lower-third cancers. Station 4, 5, 6, 10 and 11 metastases were dominant when the cancer was located on the greater curve, whereas stations 1, 2, 7, 8 and 12 were dominant in lesser-curve cancers. (4) Conclusions: The study documented that in patients with distal GC, the distribution of nodal metastases at individual stations is closely related to primary tumor location.

Survival Outcome of Gastric Signet Ring Cell Carcinoma Based on the Optimal Number of Examined Lymph Nodes: A Nomogram- and Machine-Learning-Based Approach

The optimal number of examined lymph nodes (ELNs) for gastric signet ring cell carcinoma recommended by National Comprehensive Cancer Network guidelines remains unclear. This study aimed to determine the optimal number of ELNs and investigate its prognostic significance. In this study, we included 1723 patients diagnosed with gastric signet ring cell carcinoma in the Surveillance, Epidemiology, and End Results database. X-tile software was used to calculate the cutoff value of ELNs, and the optimal number of ELNs was found to be 32 for adequate nodal staging. In addition, we performed propensity score matching (PSM) analysis to compare the 1-, 3-, and 5-year survival rates; 1-, 3-, and 5-year survival rates for total examined lymph nodes (ELNs < 32 vs. ELNs ≥ 32) were 71.7% vs. 80.1% (p = 0.008), 41.8% vs. 51.2% (p = 0.009), and 27% vs. 30.2% (p = 0.032), respectively. Furthermore, a predictive model based on 32 ELNs was developed and displayed as a nomogram. The model showed good predictive ability performance, and machine learning validated the importance of the optimal number of ELNs in predicting prognosis.

The Comparison of Short- and Long-Term Outcomes for Laparoscopic Versus Open Gastrectomy for Patients With Advanced Gastric Cancer: A Meta-Analysis of Randomized Controlled Trials

Objectives

The effect of laparoscopic gastrectomy (LG) for the treatment of advanced gastric cancer (AGC) is still controversial. The aim of this meta-analysis was to contrast the short- and long-term outcomes of laparoscopic versus conventional open gastrectomy (OG) for patients with AGC.

Methods

Databases including PubMed, Embase, Scopus, and Cochrane Library were systematically searched until December 2021 for randomized controlled trial-enrolled patients undergoing LG or OG for the treatment of AGC. Short-term outcomes were overall postoperative complications, anastomotic leakage, number of retrieved lymph node, surgical time, blood loss, length of hospital stay, and short-term mortality. Long-term outcomes were survival rates at 1, 3, and 5 years.

Results

A total of 12 trials involving 4,101 patients (2,059 in LG group, 2,042 in OG group) were included. No effect on overall postoperative complications (OR 0.84, 95% CI 0.67 to 1.05, p = 0.12, I² = 34%) and anastomotic leakage (OR 1.26, 95% CI 0.82 to 1.95, p = 0.30, I² = 0%) was found. Compared with the open approach, patients receiving LG had fewer blood loss (MD -54.38, 95% CI -78.09 to -30.67, p < 0.00001, I² = 90%) and shorter length of hospital stay (MD -1.25, 95% CI -2.08 to -0.42, p = 0.003, I² = 86%). However, the LG was associated with a lower number of retrieved lymph nodes (MD -1.02, 95% CI -1.77 to -0.27, p = 0.008, I² = 0%) and longer surgical time (MD 40.87, 95% CI 20.37 to 54.44, p < 0.00001, I² = 94%). Furthermore, there were no differences between LG and OG groups in short-term mortality and survival rate at 1, 3, and 5 years.

Conclusions

LG offers improved short-term outcomes including shorter hospital stays and fewer blood loss, with comparable postoperative complications, short-term mortality, and survival rate at 1, 3, and 5 years when compared to the open approach. Our results support the implementation of LG in patients with AGC.

Systematic Review Registration

PROSPERO (CRD 42021297141).

Misclassification of nodal stage in gastric cancer: 16 lymph nodes is not enough

Background

In gastric cancer, nodal stage plays an important role. Insufficient lymph node harvesting or incomplete examination may lead to misclassification and affect postoperative strategy and group survival. This study’s objective was to determine the minimum number of examined lymph nodes needed in gastric cancer and compare this to the minimum lymph node count according to the current Union for International Cancer Control (UICC) classification using real world data.

Methods

Based on anatomical data, expected mean lymph node counts and their 95% confidence intervals for complete D2 lymphadenectomy were calculated. Using stochastic analysis, a threshold for correct classification in 95% of cases was determined. Survival data of nodal negative gastric cancer patients was extracted from the Surveillance, Epidemiology, and End Results (SEER)-Database for 2010–2017. Patients reaching at least the calculated theoretical threshold were compared to the minimum threshold according to the current UICC classification.

Results

The expected lymph node count was 30 (95% CI: 28–32; range 17–52), corresponding to a 27 lymph nodes. In nodal negative patients with exactly 16 and at least 27 examined lymph nodes, relative 5 year survival was 79 and 89% in T1/T2 and 39 and 64% T3/T4 gastric cancer, respectively. Theoretically, when only 16 lymph nodes are analyzed, nodal negative staging may be incorrect in up to 47% of cases.

Conclusions

A minimum threshold of 16 examined lymph nodes cannot be justified. Retrospective analysis confirmed systematic misclassification of patients with insufficient lymphadenectomy in nodal negative gastric cancer patients. Correct lymphadenectomy and thorough examination of the surgical specimen is mandatory.