Survival Analysis with Extended Lymphadenectomy for Gastric Cancer: Removing Stage Migration from the Equation

Impact of Removal of Lymph Nodes on Survival in Stage I-III Gastric Signet-Ring Cell Cancer: The More, the Better?

BACKGROUND

There is an ongoing debate over the prognostic value of the number of examined lymph nodes (ELNs) in cases of gastric signet-ring cell cancer (GSRCC). In this study, we sought to evaluate the correlation between the number of ELNs and the prognosis of GSRCC and identify the optimal number of ELNs.

METHODS

A total of 1020 patients diagnosed with GSRCC between 2011 and 2018 in the National Cancer Center database were identified. Clinicopathological characteristics were retrospectively collected, and optimal cutoff values of ELNs were calculated by using X-tile. The impact of different ELNs on overall survival (OS) was compared by using Kaplan-Meier curves. We used univariate and multivariate Cox and subgroup analyses to explore the relationship between ELNs and OS. Furthermore, nonlinear correlations were investigated by using restricted cubic splines (RCSs).

RESULTS

X-tile showed that the optimal cutoff value of ELNs was 22. The 5-year OS was higher for patients with ELNs > 22 (vs. ELNs ≤ 22, 66.9% vs. 74.9%, P = 0.026). Multivariate Cox analyses showed that high ELNs were associated with superior OS (hazard ratio = 0.56, 95% confidence interval 0.43-0.74, P < 0.001). In subgroup analyses, the significant association between tumor size > 4 cm, and TNM III stage was still observed. The RCS regression model showed a U-shaped dose-response nonlinear relationship between ELNs and OS; the inflection point, as well as the lowest risk points, corresponded to 44-52 ELNs.

CONCLUSIONS

A U-shaped, nonlinear correlation with inflection points of 44-52 ELNs between ELNs and prognosis in GSRCC was identified.

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.

Indocyanine green fluorescence imaging-guided versus conventional laparoscopic lymphadenectomy for gastric cancer: long-term outcomes of a phase 3 randomised clinical trial

Indocyanine green (ICG) fluorescence imaging-guided lymphadenectomy has been demonstrated to be effective in increasing the number of lymph nodes (LNs) retrieved in laparoscopic gastrectomy for gastric cancer (GC). Previously, we reported the primary outcomes and short-term secondary outcomes of a phase 3, open-label, randomized clinical trial (NCT03050879) investigating the use of ICG for image-guided lymphadenectomy in patients with potentially resectable GC. Patients were randomly (1:1 ratio) assigned to either the ICG or non-ICG group. The primary outcome was the number of LNs retrieved and has been reported. Here, we report the primary outcome and long-term secondary outcomes including three-year overall survival (OS), three-year disease-free survival (DFS), and recurrence patterns. The per-protocol analysis set population is used for all analyses (258 patients, ICG [n = 129] vs. non-ICG group [n = 129]). The mean total LNs retrieved in the ICG group significantly exceeds that in the non-ICG group (50.5 ± 15.9 vs 42.0 ± 10.3, P < 0.001). Both OS and DFS in the ICG group are significantly better than that in the non-ICG group (log-rank P = 0.015; log-rank P = 0.012, respectively). There is a difference in the overall recurrence rates between the ICG and non-ICG groups (17.8% vs 31.0%). Compared with conventional lymphadenectomy, ICG guided laparoscopic lymphadenectomy is safe and effective in prolonging survival among patients with resectable GC.

Evaluation of Nationwide Trends in Nodal Sampling Guideline Adherence for Gastric Cancer: 2005-2017

INTRODUCTION

Surgical resection is the primary curative treatment for localized gastric cancer. A multitude of research supports surgical nodal sampling guidelines. Though there are known disparities in adherence to nodal sampling, it is unclear how hospital program-level disparities have changed over time. The purpose of this study is to evaluate trends in program-level disparities in adherence to gastric cancer nodal sampling guidelines.

METHODS

Patients who underwent resection of gastric cancer from 2005 to 2017 were identified in the National Cancer Database. Patients treated at academic programs were compared to those treated at nonacademic programs, and rates and trends of adherence to nodal sampling guidelines (defined as ≥15 lymph nodes) were determined. Adjusted multivariable analysis was used to determine likelihood of nodal sampling adherence while controlling for sociodemographic, clinical, hospital, and travel distance characteristics.

RESULTS

A total of 55,421 patients were included with 27,201 (49.1%) of patients meeting adherence criteria for lymph node sampling. Academic programs treated 44.4% of the total cohort. Overall, lymph node sampling criteria were met in 59.2% of patients treated at high-volume academic programs and 37.0% of patients treated at low-volume nonacademic programs (incidence rate ratios 0.67, 95% confidence interval 0.63-0.72 versus high-volume academic programs). Adherence rates improved from 2005 to 2017 for both low-volume nonacademic programs (27.8% in 2005 to 50.1% in 2017) and high-volume academic programs (46.0% in 2005 to 69.8% in 2017, P < 0.001).

CONCLUSIONS

Though adherence rates have improved from 2005 to 2017, high-volume academic programs were more likely to adhere to lymph node sampling guidelines for gastric cancer.

Impact of the Deep Neuromuscular Block on Oncologic Quality of Laparoscopic Surgery in Obese Gastric Cancer Patients: A Randomized Clinical Trial

BACKGROUND

Obesity can hinder laparoscopic procedures and impede oncological safety during laparoscopic cancer surgery. Deep neuromuscular block (NMB) reportedly improves laparoscopic surgical conditions, but its oncological benefits are unclear. We aimed to evaluate whether deep NMB improves the oncologic quality of laparoscopic cancer surgery in obese patients.

STUDY DESIGN

We conducted a double-blinded, parallel-group, randomized, phase 3 trial at 9 institutions in Korea. Clinical stage I and II gastric cancer patients with a BMI at or above 25 kg m -2 were eligible and randomized 1:1 ratio to the deep or moderate NMB groups, with continuous infusion of rocuronium (0.5-1.0 and 0.1-0.5 mg kg -1 h -1, respectively). The primary endpoint was the number of retrieved lymph nodes (LNs). The secondary endpoints included the surgeon's surgical rating score (SRS) and interrupted events.

RESULTS

Between August 2017 and July 2020, 196 patients were enrolled. Fifteen patients were excluded, and 181 patients were finally included in the study. There was no significant difference in the number of retrieved LNs between the deep (N = 88) and moderate NMB groups (N = 93; 44.6 ± 17.5 vs 41.5 ± 16.9, p = 0.239). However, deep NMB enabled retrieving more LNs in patients with a BMI at or above 28 kg/m2 than moderate NMB (49.2 ± 18.6 vs 39.2 ± 13.3, p = 0.026). Interrupted events during surgery were lower in the deep NMB group than in the moderate NMB group (21.6% vs 36.6%; p = 0.034). The SRS was not influenced by NMB depth.

CONCLUSION

Deep NMB provides potential oncologic benefits by retrieving more LNs in patients with BMI at or above 28 kg/m2 during laparoscopic gastrectomy.

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

BACKGROUND

The optimal number of examined lymph nodes (ELNs) and the positive lymph node ratio (LNR) for potentially curable gastric cancer are not established. We sought to determine clinical benchmarks for these values using a large national database.

METHODS

Demographic, clinicopathologic, and treatment-related data from patients treated using an R0, curative-intent gastrectomy registered in the National Cancer Database during 2004 to 2016 were evaluated. Patients with node-positive (pTxN+M0) disease were considered for analysis.

RESULTS

A total of 22,018 patients met the inclusion criteria, with a median follow-up of 2.2 years. Mean age at diagnosis was 65.6 years, 66% were male, 68% were White, 33% of tumors were located near the gastroesophageal junction, and 29% of patients had undergone preoperative therapy. Most primary tumors (62%) were category pT3-4, 67% had a poor or anaplastic grade, and 19% had signet features. Clinical nodal staging was inaccurate compared with staging at final pathology. The mean [SD] number of nodes examined was 19 [11]. On multivariable analysis, the pN category, ELNs, and LNR were independently associated with survival (all P<.0001). Using receiver operating characteristic (ROC) analysis, an optimal ELN threshold of ≥30 was established for patients with pN3b disease and was applied to the entire cohort. Node positivity and LNR had minimal change beyond 30 examined nodes. Stage-specific LNR thresholds calculated by ROC analysis were 11% for pN1, 28% for pN2, 58% for pN3a, 64% for pN3b, 30% for total combined. By using an ELN threshold of ≥30, prognostically advantageous stage-specific LNR values could be determined for 96% of evaluated patients.

CONCLUSIONS

Using a large national cancer registry, we determined that an ELN threshold of ≥30 allowed for prognostically advantageous LNRs to be achieved in 96% of patients. Therefore, ≥30 examined nodes should be considered a clinical benchmark for practice in the United States.

Retrieval of 30 Lymph Nodes Is Mandatory for Selected Stage II Gastric Cancer Patients

Background

According to the 8th edition AJCC staging manual, a least of 16 lymph nodes retrieval (LNRs) is the minimal requirement for lymph nodes (LNs) dissection of gastric cancer surgery. Previous studies have shown that increasing the number of LNRs (≥30) prolongs survival for selected patients. However, the necessity of retrieving 30 or more LN for stage II gastric cancer patients is still under debate.

Aim

This study aims to explore the impact of retrieving 30 or more lymph nodes on the survival of stage II cancer patients.

Methods

A total of 1,177 patients diagnosed with stage II gastric cancer were enrolled in this study. The clinicopathological parameters and the impact of different LNRs (<30 or ≥30) and positive lymph node ratio (NR) on overall survival (OS) were retrospectively analyzed.

Results

The mean number of LNRs was 34 ± 15. A total of 44% (518/1,177) of patients had an LNRs <30, while 56% (659/1,177) of patients had an LNRs ≥30. The 5-year survival rate was 81% for all patients, 76% for the LNRs <30 group, and 86% for LNRs ≥30 group, respectively (P = 0.003). The survival benefit of retrieving 30 lymph nodes was significant in certain subgroups: age >60 years/male/underwent total gastrectomy/stage IIB. For N+ patients, higher NR was significantly correlated with poor survival.

Conclusion

The survival benefit of retrieving 30 LNs varies in different subgroups. An LNRs of 30 is mandatory for selected stage II gastric cancer patients.

"D2 plus" lymphadenectomy is associated with improved survival in distal gastric cancer with clinical serosa invasion: a propensity score analysis

The aim of this study was to elucidate the potential impact of “D2 plus” lymphadenectomy on the long-term survival of distal gastric cancer (GC) patients with clinical serosa invasion. A total of 394 distal GC patients with clinical serosa invasion who underwent at least standard D2 lymphadenectomy were enrolled. Patients were categorized into two groups according to the extent of lymphadenectomy: D2 group and “D2 plus” group. Propensity score matching was used to adjust for the differences in baseline characteristics. In the multivariate analysis for the whole study series, extent of lymphadenectomy was an independent prognostic factor for GC patients (P = 0.011). With the strata analysis, the significant prognostic differences between the two groups were only observed in patients at the IIIa-b or N1-3a stages. After matching, patients in “D2 plus” group still demonstrated a significantly higher 5-year overall survival rate than those in D2 group (55.3% versus 43.9%, P = 0.042). The common therapeutic value index of No. 12b, No. 12p, No. 14v and No. 13 LNs was 4.6, which was close to that of No. 5 LN station. In conclusion, “D2 plus” lymphadenectomy may be associated with improved overall survival in distal GC with clinical serosa invasion.

Overweight or Obesity is an Unfavorable Long-Term Prognostic Factor for Patients who Underwent Gastrectomy for Stage II/III Gastric Cancer

BACKGROUND

Obesity has been reported to be a prognostic factor for many diseases in epidemiological studies; however, the results of studies examining the relationship between obesity and gastric cancer (GC) prognosis are inconsistent.

METHODS

A total of 460 patients with Stage II and III GC who underwent open R0 gastrectomy were included. Age, sex, body mass index (BMI classified into < 18.5, 18.5-25, and ≥ 25 kg/m²), stage, and postoperative adjuvant chemotherapy were analyzed to investigate the correlation with relapse-free survival (RFS).

RESULTS

Five-year RFS was 51% for the study patients. Five-year RFS values were 47.6%, 54.3%, and 40.1% for patients with BMI < 18.5, 18.5-25, and ≥ 25 kg/m², respectively. The forest plot for relapse risk according to BMI showed a U shape. Multivariate analysis for RFS showed significant differences in stage and BMI; the hazard ratio for recurrence in patients with BMI ≥ 25 kg/m² was 1.42 (95% confidence interval: 1.01-2.02, p = 0.0423) with reference to patients with BMI < 25 kg/m². BMI ≥ 25.0 was associated with longer operation times, more blood loss, fewer lymph nodes dissected, more frequent postoperative surgical site infection, and intra-abdominal abscesses.

CONCLUSIONS

BMI ≥ 25 kg/m² is an unfavorable prognostic factor for patients who underwent gastrectomy for Stage II and III GC.

Anatomical analysis of gastric lymph nodes in cancer-free individuals

Lymphadenectomy is a crucial part of the surgical therapy for gastric cancer. The number of normal lymph nodes could indicate the number of nodes that need to be retrieved during the procedure. The aim of this study is to analyze the number of lymph nodes in cadavers without gastric cancer according to the Japanese Gastric Cancer Association guidelines. Twenty fresh adult cadavers (14 males, mean age 55, range 24-93 years) were used. Abdominal lymph nodes were dissected and classified according to the Japanese Gastric Cancer Association. For total gastrectomy, the median number of lymph nodes that comprised D1 + dissection was 27 (range 15-42). The median and mean number of lymph nodes that comprised D2 dissection was 33, ranging from 18 to 50. For distal gastrectomy, the D1 + level comprised a median of 21 lymph nodes (range 11-38), and the D2 level 22 lymph nodes (range 11-39). In conclusion, considering gastrectomy + D2 lymphadenectomy as the standard treatment for gastric cancer, our results show that adequate lymphadenectomy must encompass around 30 lymph nodes. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc.