Clinical significance of skip lymph node metastasis in gastric cancer patients

Defining Optimal Lymph Node Yield in Gastrectomy: A Real-World Cohort Analysis

BACKGROUND

Gastric cancer (GC) has a high global mortality and incidence rate. Lymph node (LN) invasion is crucial in TNM staging, and an accurate LN staging system is vital for treatment decisions. However, the appropriate number of examined LNs remains uncertain.

METHODS

We retrospectively analyzed consecutive GC patients who underwent gastrectomy at the First Medical Center of the Chinese PLA General Hospital from January 2010 to December 2023. A new statistical model based on the β-binomial distribution and maximum likelihood method in R software was employed to calculate false-negative probabilities.

RESULTS

A total of 6463 GC patients were included. For cT1 patients, even with only five LNs excised, the likelihood of encountering occult positive LNs remained below 5%. For cT2 patients, 17 nodes were needed to rule out occult nodal disease with 90% confidence. While for cT3 and cT4 patients, even after the removal of 35 LNs, the likelihood of overlooking a positive node was still above 20%. Considering surgical extent, 25 nodes were required for patients who underwent proximal gastrectomy or distal gastrectomy to rule out occult nodal disease with 90% confidence, whereas those who received entire gastrectomy needed 59 nodes to achieve the same level of confidence.

CONCLUSION

Our study establishes a novel quantitative framework linking LN harvest thresholds to false-negative metastasis risk in GC, derived from real-world clinicopathological data.

Value of Computed Tomography Scan for Detecting Lymph Node Metastasis in Early Esophageal Squamous Cell Carcinoma

BACKGROUND

The necessity of computed tomography (CT) scan for detecting potential lymph node metastasis (LNM) in early esophageal squamous cell carcinoma (ESCC) before endoscopic and surgical treatments is under debate.

METHODS

Patients with histologically proven ESCC limited to the mucosa or submucosa were examined retrospectively. Diagnostic performance of CT for detecting LNM was analyzed by comparing original CT reports with pathology reports. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

A total of 625 patients from three tertiary referral hospitals were included. The rate of pathologically confirmed LNM was 12.5%. Based on original CT reports, the sensitivity, specificity, accuracy, PPV, and NPV of CT to determine LNM in T1 ESCC were 41.0%, 83.2%, 77.9%, 25.8%, and 90.8% respectively. For mucosal cancers (T1a), these parameters were 50.0%, 81.7%, 80.9%, 6.8%, and 98.4%, respectively. For submucosal cancers (T1b), they were 40.0%, 85.0%, 75.0%, 43.0%, and 83.3%, respectively. Additionally, the diagnostic performance of CT for LNM was relatively better for ESCC in the lower esophagus. Pathologically, 69.2% of patients with LNM did not exhibit lymphovascular invasion (LVI), and the sensitivity of CT for recognizing LNM in these patients (33.3%) was lower than those with LVI (58.3%).

CONCLUSIONS

Computed tomography can detect nearly half of the LNM cases in early ESCC with high specificity. The performance of CT further improved in LNM cases with LVI. Therefore, we conclude that routine preoperative CT for the assessment of potential LNM risk in patients with early ESCC is necessary.

Clinical characteristics and prognostic impact of direct distant organ metastasis in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most common type of cancer worldwide, and distant metastasis is frequently noted at diagnosis or follow-up. Notably, some patients with CRC can present with distant organ metastasis without any nodal involvement, which was defined as direct distant organ metastasis (DDOM). In this study, we evaluated the prognostic significance of DDOM for patients with CRC.

METHODS

This study included 325 patients who had undergone primary colorectal cancer resection between August 2008 and December 2021. The patients with and without DDOM were compared (Kaplan-Meier analysis) in terms of overall survival (OS) and time to recurrence. Furthermore, the patients' clinicopathological risk factors and protective factors were analyzed (multivariate Cox proportional hazards model).

RESULTS

Of the 325 patients, 65 (20%) had DDOM (Direct+ group) and 260 (80%) did not (Direct- group). The Kaplan-Meier analysis revealed that OS was significantly better in the Direct+ group than in the Direct- group (p < 0.01). A subgroup analysis by CRC stage was performed; for the patients with non-stage-IV CRC, the rate of OS was significantly higher in the Direct+ group than in the Direct- group (p = 0.02). However, DDOM did not affect the OS of the patients with stage IV CRC. The multivariate analysis indicated DDOM, left colon tumor location, and postoperative adjuvant chemotherapy were significant protective factors for disease-related mortality in the patients with non-stage-IV CRC; by contrast, body mass index, curative resection, and postoperative adjuvant chemotherapy were identified to be significant protective factors in the patients with stage IV CRC.

CONCLUSIONS

DDOM appears to be significantly associated with improved OS in patients with non-stage-IV CRC but not in those with stage IV CRC. Furthermore, the time to cancer recurrence may not vary significantly between patients with DDOM and those without it.

Oncological risk of proximal gastrectomy for proximal advanced gastric cancer after neoadjuvant chemotherapy

PURPOSE

This study assesses the metastasis rate of the key distal lymph nodes (KDLN) that are not routinely dissected in proximal gastrectomy, aiming to explore the oncological safety of proximal gastrectomy for upper gastric cancer who underwent neoadjuvant chemotherapy.

METHODS

We analyzed a cohort of 150 patients with proximal locally advanced gastric cancer (cT3/4 before chemotherapy) from two high-volume cancer centers in China who received preoperative neoadjuvant chemotherapy (NAC) and total gastrectomy with lymph node dissection. Metastasis rate of the KDLN (No.5/6/12a) and the risk factors were analyzed.

RESULTS

Key distal lymph node metastasis was detected in 10% (15/150) of patients, with a metastasis rate of 6% (9/150) in No. 5 lymph nodes, 6.7% (10/150) in No. 6 lymph nodes, and 2.7% (2/75) in No. 12a lymph nodes. The therapeutic value index of KDLN as one entity is 5.8. Tumor length showed no correlation with KDLN metastasis, while tumor regression grade (TRG) emerged as an independent risk factor (OR: 1.47; p-value: 0.04). Of those with TRG3 (no response to NAC), 80% (12/15) was found with KDLN metastasis.

CONCLUSION

For cT3/4 proximal locally advanced gastric cancer patients, the risk of KDLN metastasis remains notably high even after NAC. Therefore, proximal gastrectomy is not recommended; instead, total gastrectomy with thorough distal lymphadenectomy is the preferred surgical approach.

Long-Term Impact of D2 Lymphadenectomy during Gastrectomy for Cancer: Individual Patient Data Meta-Analysis and Restricted Mean Survival Time Estimation

BACKGROUND

Debate exists concerning the impact of D2 vs. D1 lymphadenectomy on long-term oncological outcomes after gastrectomy for cancer.

METHODS

PubMed, MEDLINE, Scopus, and Web of Science were searched and randomized controlled trials (RCTs) analyzing the effect of D2 vs. D1 on survival were included. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were assessed. Restricted mean survival time difference (RMSTD) and 95% confidence intervals (CI) were used as effect size measures.

RESULTS

Five RCTs (1653 patients) were included. Overall, 805 (48.7%) underwent D2 lymphadenectomy. The RMSTD OS analysis shows that at 60-month follow-up, D2 patients lived 1.8 months (95% CI -4.2, 0.7; p = 0.14) longer on average compared to D1 patients. Similarly, 60-month CSS (1.2 months, 95% CI -3.9, 5.7; p = 0.72) and DFS (0.8 months, 95% CI -1.7, 3.4; p = 0.53) tended to be improved for D2 vs. D1 lymphadenectomy.

CONCLUSIONS

Compared to D1, D2 lymphadenectomy is associated with a clinical trend toward improved OS, CSS, and DFS at 60-month follow-up.

The microprotein encoded by exosomal lncAKR1C2 promotes gastric cancer lymph node metastasis by regulating fatty acid metabolism

Lymph node metastasis (LNM) is the prominent route of gastric cancer dissemination, and usually leads to tumor progression and a dismal prognosis of gastric cancer. Although exosomal lncRNAs have been reported to be involved in tumor development, whether secreted lncRNAs can encode peptides in recipient cells remains unknown. Here, we identified an exosomal lncRNA (lncAKR1C2) that was clinically correlated with lymph node metastasis in gastric cancer in a VEGFC-independent manner. Exo-lncAKR1C2 secreted from gastric cancer cells was demonstrated to enhance tube formation and migration of lymphatic endothelial cells, and facilitate lymphangiogenesis and lymphatic metastasis in vivo. By comparing the metabolic characteristics of LN metastases and primary focuses, we found that LN metastases of gastric cancer displayed higher lipid metabolic activity. Moreover, exo-lncAKR1C2 encodes a microprotein (pep-AKR1C2) in lymphatic endothelial cells and promotes CPT1A expression by regulating YAP phosphorylation, leading to enhanced fatty acid oxidation (FAO) and ATP production. These findings highlight a novel mechanism of LNM and suggest that the microprotein encoded by exosomal lncAKR1C2 serves as a therapeutic target for advanced gastric cancer.

Degenerative Changes in Aging Human Pelvic Lymph Nodes-A Reason to Rethink Staging and Therapy of Regional Malignancies?

Lymph node metastases are common in pelvic urological tumors, and the age-related remodeling process of the pelvic lymph nodes influences metastatic behavior. The aim of this work is to characterize age-related degenerative changes in the pelvic lymph nodes with respect to their occurrence and extent. A total of 5173 pelvic lymph nodes of 390 patients aged 44 to 79 years (median 68 years, IQR 62-71 years) were histologically examined for degenerative structural changes. Lymph node size, lipomatous atrophy, capsular fibrosis, framework fibrosis, and calcifications were recorded semi-quantitatively and evaluated by age group. Significantly more lymph nodes <10 mm were found in older patients (p = 0.001). The incidence of framework fibrosis, capsular fibrosis, and calcifications increased significantly with increasing patient age (p < 0.001). In lipomatous atrophy, an increase in mild to moderate lipomatous atrophy was observed with increasing age (p < 0.001). In this, the largest study to date on this topic, age-related degenerative changes in pelvic lymph nodes were proven. Due to the consecutive decrease in hte filtration function of pelvic lymph nodes with increasing age, staging and therapy of metastatic pelvic urologic carcinomas should be reconsidered.

Incremental value of PET primary lesion-based radiomics signature to conventional metabolic parameters and traditional risk factors for preoperative prediction of lymph node metastases in gastric cancer

BACKGROUND

Precise preoperative prediction of lymph node metastasis (LNM) is crucial for optimal diagnosis and treatment in patients with gastric cancer (GC), in which existing imaging methods have certain limitations. We hypothesized that PET primary lesion-based radiomics signature could provide incremental value to conventional metabolic parameters and traditional risk indicators in predicting LNM in patients with GC.

METHODS

This retrospective study was performed in 127 patients with GC who underwent preoperative PET/CT. Basic clinical data and PET conventional metabolic parameters were collected. Radiomics signature was constructed by the least absolute shrinkage and selection operator algorithm (LASSO) logistic regression. Based on the postoperative histological results, the patients were divided into LNM group and non-lymph node metastasis (NLNM) group. Receiver-operating characteristic (ROC) was used to evaluate the discriminatory ability of Radiomics score (Rad-score) for predicting LNM and determine whether adding Rad-score to PET conventional metabolic parameters and traditional risk factors could improve the predictive value in LNM. The Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were calculated to further confirm the incremental value of Rad-score for predicting LNM in GC.

RESULTS

The LNM group had higher Rad-score than NLNM group [(0.35 (-0.13-0.85) vs. -0.61 (-1.92-0.18), P < 0 .001)]. After adjusted for gender, age, BMI, and FBG, multivariable logistic regression analysis illustrated that Rad-score (OR: 6.38, 95% CI: 2.73-14.91, P < 0.0001) was independent risk factors for LNM in GC. Adding PET conventional parameters to traditional risk factors increased the predictive value of LNM in GC (AUC 0.751 vs 0.651, P = 0.02). Additional inclusion of Rad-score to conventional metabolic parameters and traditional risk indicators significantly improved the AUC (0.882 vs 0.751; P = 0.006). Bootstrap resampling (times = 500) was used for internal verification, 95% confidence interval (CI) was 0.802-0.948, with the sensitivity equaled to 89.5%, and positive predictive value (PPV) was 93.5%. When Rad-score was added to conventional metabolic parameters and traditional risk indicators, net reclassification improvement (NRI) was 0.293 (P = 0.0040) and integrated discrimination improvement (IDI) was 0.293 (P = 0.0045).

CONCLUSION

In GC patients, PET Radiomics signature of the primary lesion-based was significantly associated with LNM and could improve the prediction of LNM above PET conventional metabolic parameters and traditional risk factors, which could provide incremental value for individual diagnosis and treatment of GC.

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.

Extragastric Metastasis of Early Gastric Cancer After Endoscopic Submucosal Dissection With Lymphovascular Invasion and Negative Resected Margins

Purpose

Lymphovascular invasion is a criterion for non-curative resection in patients who have undergone endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). We aimed to determine the rate of extragastric metastasis (EGM) and identify the predictors of EGM in patients with negative resection margins (R0 resection) and lymphovascular invasion in post-ESD pathology.

Materials and Methods

A total of 2,983 patients underwent ESD for EGC. Among them, 110 had a pathology of R0 resection and positive lymphovascular invasion. Patients underwent additional gastrectomy (n=63) or further follow-up without gastrectomy (n=47).

Results

The 110 patients were assigned to one of the 3 groups according to ESD indications based on post-ESD pathology. The first group satisfied the absolute indication for ESD (n=18), the second group satisfied the expanded indications for ESD (n=34), and the last group satisfied the beyond indication (n=58). The number of occurrences of EGM in each group was 1 (5.6%), 3 (8.8%), and 3 (5.2%), respectively. The logistic regression analysis adjusted for age, sex, tumor size, and indication for ESD, showed that larger tumor size was associated with EGM (odds ratio, 1.76; 95% confidence interval, 1.00–3.10; P=0.048). In contrast, ESD indication criteria did not affect EGM (P=0.349).

Conclusions

Tumor size was the only predictive indicator for EGM in patients who underwent R0 resection and lymphovascular invasion on post-ESD pathology. Even patients with pathology corresponding to the absolute indication criteria of ESD had lymphovascular invasion, which means that they require additional gastrectomy due to the risk of EGM.

The risk of lymph node metastasis in gastric cancer conforming to indications of endoscopic resection and pylorus-preserving gastrectomy: a single-center retrospective study

Background

Lymph node metastasis (LNM) status is an important prognostic factor that strongly influences the treatment decision of early gastric cancer (EGC). This study aimed to evaluate the pattern and clinical significance of LNM in EGC.

Methods

A total of 354 patients with carcinoma in situ (n = 42), EGC (n = 312) who underwent radical gastrectomy were enrolled. Their clinicopathological features, pathological reports, and prognostic data were collected and analyzed.

Results

The incidence of LNM in all patients was 18.36% (65/354). The rates of D1 and D2 station metastases were 12.10% (43/354) and 6.21% (22/354), respectively. The rates of LNM in absolute indication of endoscopic resection and expanded indication were 3.27% (2/61) and 28.55% (4/14), respectively. Skip LNM was observed in 3.67% (13/354) of patients. For those with middle-third tumor, the metastasis rate of the No. 5 lymph node was 3.05% (5/164). The independent risk factors for LNM were tumors measuring > 30 mm, poorly differentiated tumors, and lymphovascular invasion (all P < 0.05; area under the curve, 0.783). The 5-year disease-free survival rates of patients with and without LNM were 96.26 and 79.17%, respectively (P = 0.011). Tumors measuring > 20 mm and LNM were independent predictive factors for poor survival outcome in all patients.

Conclusions

Patients with EGC conforming to expanded indications have a relatively high risk of LNM and may not be suitable for endoscopic submucosal dissection. Pylorus-preserving gastrectomy for patients with middle-third EGC remains controversial due to the high metastasis rate of the No. 5 lymph node.

Recent updates and current issues of sentinel node navigation surgery for early gastric cancer

With the increase in the incidence of early gastric cancer (EGC), several endoscopic and laparoscopic approaches, such as endoscopic submucosal dissection and function-preserving gastrectomy, have been accepted as standard treatments. Sentinel node navigation surgery (SNNS) is an ideal surgical option for preservation of most parts of the stomach and consequent maintenance of normal gastric function to improve quality of life in patients with EGC. Although many previous studies and clinical trials have demonstrated the safety and feasibility of the sentinel node concept in gastric cancer, the clinical application of SNNS is debatable. Several issues regarding technical standardization and oncological safety need to be resolved. Recently several studies to resolve these problems are being actively performed, and SNNS might be an important surgical option in the treatment of gastric cancer in the future.

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.

Prognostic impact of anatomical extent of metastatic lymph node on gastric cancer: a propensity score matching study

PURPOSE

Current gastric cancer staging systems overlook the anatomic extent of metastatic lymph nodes (AEMLNs). This study aimed to analyze the prognostic impact of AEMLNs on gastric cancer (GC).

METHODS

GC patients with metastatic lymph nodes (MLNs) undergoing curative surgery were retrospectively reviewed and assigned to perigastric (MLNs in station 1-6, PG) and extraperigastric group (7-12, with or without MLNs in PG area, EPG). Overall survival (OS), disease-free survival (DFS) and recurrence patterns were compared before and after 1:1 propensity score matching (PSM).

RESULTS

662 patients were enrolled, 341 (51.5%) and 321 (48.5%) of whom were in the PG and EPG, respectively. After PSM (n = 195), EPG showed poorer 5-year OS (43.4% vs 54.5%, p = 0.014) and DFS (65.0% vs 73.4%, p = 0.068) than PG. EPG had higher incidence of peritoneal recurrence (PR) than PG (19.4% vs 7.4%, p = 0.002). Multivariate analysis identified AEMLNs as prognostic factor for OS [HR = 1.409, 95% confidence interval (CI) 1.062-1.868), DFS (HR = 1.600, 95% CI 1.059-2.416) and PR (HR = 3.708, 95% CI 1.685-8.160).

CONCLUSIONS

The anatomic extent of metastatic lymph nodes has an independent prognostic role for GC. Including this element may improve the accuracy of current staging systems.

Should the left gastric artery lymph node be considered as the predictive lymph node for extra-gastric lymph node metastases?

BACKGROUND

To validate the prognostic impacts of the left gastric artery lymph node (No. 7 LN) metastasis and investigate whether the No. 7 LN metastasis should be considered as the predictive LN for extra-gastric LN metastases.

METHODS

Between January 2003 and December 2011, a total of 1,586 patients who underwent R0 gastrectomy were retrospected. Patients with LN metastases were divided into three groups: (I) patients with only peri-gastric LN metastases (peri-gastric group); (II) patients with peri-gastric and only No. 7 LN metastases (No. 7 group); and (III) patients with other extra-gastric LN metastases (extra-gastric group). Propensity score matching (PSM) was adopted to accurately evaluate prognoses of all patients after surgery.

RESULTS

Of 1,586 patients, 235 (14.82%) were pathologically identified to present with the No. 7 LN metastases. Patients with the No. 7 LN metastases presented the significantly lower survival rate both before and after adjustment by pTNM stage, compared to those without the No. 7 LN metastases. Patients in the No. 7 group were identified to present the significant lower survival rate than those in the peri-gastric group, and to present the similar median overall survival (OS) to those in the extra-gastric group. In addition, patients with extra-gastric LN except No. 7 LN metastases failed to show any superiority of survival outcomes, compared with those with extra-gastric LN metastases including the No. 7 LN metastasis.

CONCLUSIONS

The No. 7 LN metastases had the crucial survival implications. Nevertheless, the No. 7 LN failed to be considered as the predictive LN for the extra-gastric LN metastases in gastric cancer (GC).

Sentinel Node Navigation in Gastric Cancer: Where Do We Stand?

BACKGROUND

Early gastric cancer (EGC) is more common nowadays and is related a to low percentage of lymph node metastasis. For this reason, there is enormous interest to implicate minimally invasive approaches. Recently, special efforts have been made towards a potential intraoperative (real-time) lymph node metastasis (LNM) assessment, as nodal disease status could not be identified with precision before or during surgery. In this direction, accurate prediction of the LNM status through sentinel LN mapping has been attempted, as an approach to the intraoperative detection of sentinel lymph nodes (SLNs). A careful literature search was conducted in order to clarify the potential clinical application of SN biopsy in the gastric cancer field.

CONCLUSION

The real clinical application of SN biopsy in gastric cancer treatment has been more than challenging due to the "complicated" nature of gastric lymphatic drainage and the high possibility of "skip" metastasis phenomenon. Notably, sophisticated technical aspects, such as the preferred tracer used and the potential "ideal" method to verify the presence of metastases in the resected SLNs, made SN biopsy application in gastric cancer field extremely demanding. Assessing the potential role of SN navigation for gastric cancer treatment in the era of advanced technology, where the minimally invasive surgical approaches are in the top of the scientific interest, it has to be highlighted that SN navigation for gastric cancer is a topic that remains highly controversial, and the need for future clinical trials on this topic is obvious.

Clinical significance of skip lymph-node metastasis in pN1 gastric-cancer patients after curative surgery

BACKGROUND

In addition to the stepwise manner of lymph-node metastasis from the primary tumour, the skip lymph-node metastasis (SLNM) was identified as a low-incidence metastasis of gastric cancer (GC). So far, both the mechanism and outcome of SLNM have not been elucidated completely. The purpose of this study was to analyse the clinical significance and the potential mechanism of SLNM in GC patients who had lymph-node metastasis.

METHODS

Clinicopathological data and follow-up information of 505 GC patients who had lymph-node metastasis were analysed to demonstrate the significance of SLNM in evaluating the prognostic outcome. According to the pathological results, all GC patients who had lymph-node metastasis were categorized into three groups: patients with the perigastric lymph-node metastasis, patients with the perigastric and extragastric lymph-node metastasis and patients with SLNM.Results: Among the 505 GC patients who had lymph-node metastasis, 24 (4.8%) had pathologically identified SLNM. The location of lymph-node metastasis was not significantly associated with 5-year survival rate and overall survival (OS) (P = 0.194). The stratified survival analysis results showed that the status of SLNM was significantly associated with the OS in patients with pN1 GC (P = 0.001). The median OS was significantly shorter in 19 pN1 GC patients with SLNM than in 100 patients with perigastric lymph-node metastasis (P < 0.001). The case-control matched logistic regression analysis results showed that tumour size (P = 0.002) was the only clinicopathological factor that may predict SLNM in pN1 GC patients undergoing curative surgery. Among the 19 pN1 GC patients with SLNM, 17 (89.5%) had metastatic lymph nodes along the common hepatic artery, around the celiac artery or in the hepatoduodenal ligament.

CONCLUSIONS

SLNM may be considered a potentially practicable indicator for prognosis among various subgroups of pN1 GC patients.

Characterization of an orthotopic gastric cancer mouse model with lymph node and organ metastases using bioluminescence imaging

Lymph node (LN) metastasis of gastric cancer (GC) is the strongest prognostic indicator for this disease; however, the majority of the LN metastasis profiles of GC remain unknown, which notably hinders the therapeutic efficacy in clinic. In the present study, an orthotopic model of human GC was established for investigation of time-dependent LN metastasis patterns in mice. Luciferase-expressing NCI-N87 human GC cells were injected into the subserosa of the gastric body, resulting in a tumor formation rate of 100%. LN metastasis at four different anatomical positions in the abdomen were characterized until week 10 after tumor cell injection using sensitive bioluminescence imaging and histopathological analyses. Skip LN metastases were observed at later stages (weeks 8-10) of the experiment. Metastases in other major organs, including liver, spleen and lung, were also examined. Characterization of this orthotopic GC model and metastasis patterns in LNs and major organs should aid in the preclinical GC research regarding the metastatic mechanism and drug development.

Anatomical location of metastatic lymph nodes: an indispensable prognostic factor for gastric cancer patients who underwent curative resection

BACKGROUND

Although the numeric-based lymph node (LN) staging was widely used in the worldwide, it did not represent the anatomical location of metastatic lymph nodes (MLNs) and not reflect extent of LN dissection. Therefore, in the present study, we investigated whether the anatomical location of MLNs was still necessary to evaluate the prognosis of node-positive gastric cancer (GC) patients.

METHODS

We reviewed 1451 GC patients who underwent radical gastrectomy in our institution between January 1986 and January 2008. All patients were reclassified into several groups according to the anatomical location of MLNs and the number of MLNs. The prognostic differences between different patient groups were compared and clinicopathologic features were analyzed.

RESULTS

In the present study, both anatomical location of MLNs and the number of MLNs were identified as the independent prognostic factors (p < .01). The patients with extraperigastric LN involvement showed a poorer prognosis compared with the perigastric-only group (p < .001). For the N1-N2 stage patients, the prognostic discrepancy was still observed among them when the anatomical location of MLNs was considered (p < .05). For the N3-stage patients, although the anatomical location of MLNs had no significant effect on the prognosis of these patients, the higher number of MLNs in the extraperigastric area was correlated with the unfavorable prognosis (p < .05).

CONCLUSION

The anatomical location of MLNs was an important factor influencing the prognostic outcome of GC patients. To provide more accurate prognostic information for GC patients, the anatomical location of MLNs should not be ignored.

The pattern of lymph node metastases in microsatellite unstable gastric cancer

BACKGROUND

Microsatellite instability (MSI) is one of the new groups of molecular divisions of gastric cancer (GC). The aim of this study was to investigate the pattern of lymph node metastasis according to MSI status.

METHODS

MSI analysis of 361 GC patients with information about lymph node stations was performed using 5 quasimonomorphic mononucleotide repeats. The metastasis rates for each lymphatic station was analyzed, combined with clinicopathologic characteristics. Stations were divided into compartments 1-3 on the basis of Japanese Classification. A median number (interquartile range, IQR) of 33 (18-50) lymph nodes were removed and analyzed.

RESULTS

N0 status was observed in 53.7% MSI patients, and in 29.7% microsatellite stable (MSS) (p < 0.001).The median value of involved nodes was 1 in MSI vs. 5 in MSS (p < 0.001). Furthermore, the number of involved node stations was significantly lower in the MSI group (p < 0.001). MSS tumors showed a higher propensity to spread to second and third compartment nodes. In absence of lymphovascular invasion only 3.2% cases demonstrated positive nodes beyond the first compartment. Skip metastases were seen in 6.1% MSS patients and 0% MSI (p = 0.011). No difference in the 10-year cancer related survival among MSI and MSS patients was found, for both those with 1st compartment (p = 0.223) and with 2nd compartment involvement (p = 0.814).

CONCLUSIONS

MSI GC shows a high rate of N0 stage, a lower number of lymph node metastases, and a less extensive spread to lymph node stations than MSS tumors. These data indicate that tailored lymphadenectomy may be investigated for these patients.

Prognostic impact of lymph node skip metastasis in Stage III colorectal cancer

AIM

The aim of this study was to evaluate the prognostic impact of lymph node skip metastasis (LNSM) in patients with Stage III colorectal cancer.

METHOD

Between April 2003 and December 2014, a total of 41 patients with lymph node skip metastasis (skip+) were compared with 86 patients with pericolic lymph node metastases [lymph node distribution (LND)1] and 57 patients with intermediate and/or main lymph node metastasis (LND2+3). All patients had radical D3 lymphadenectomy, performed either laparoscopically or as open surgery.

RESULTS

The frequency of pT1-2 stage cancer was significantly higher in the skip+ group than in the LND1 group (26.8% vs 5.8%, P = 0.001). The number of metastatic lymph nodes in the skip+ group was lower than in the LND2+3 group (1.9 ± 1.5 vs 6.5 ± 6.0, P < 0.001). The 3-year disease-free survival (DFS) of the skip+, LND1 and LND2+3 groups was 64.8%, 69.7% and 40.1%, respectively (P = 0.008). The 3-year systemic recurrence rates of the skip+, LND1 and LND2+3 groups were 30.2%, 20.3% and 48.1%, respectively; (P = 0.002). Cox regression analysis revealed that preoperative carcinoembryonic antigen (CEA) of ≥ 5 ng/ml [hazard ratio (HR) = 2.2, P = 0.029], poor differentiation (HR = 3.8, P = 0.001) and skip+ (HR = 0.2, P = 0.021) were independently prognostic factors for DFS.

CONCLUSION

The prognosis for the LND1-negative lymph node skip metastasis group was better than for the LND2+3 group and was comparable with that of the LND1 group after radical D3 lymphadenectomy.

Sentinel node biopsy using blue dye and technetium99 in advanced gastric cancer: anatomical drainage and clinical application

Lymph node metastases are an independent prognosis factor in gastric carcinoma (GC) patients. Radical lymphadenectomy can improve survival but it can also increase surgical morbidity. As a principle, sentinel node (SN) navigation surgery can avoid unnecessary lymphadenectomy without compromising prognosis. In this pilot study, 24 patients with untreated GC were initially screened for SN navigation surgery, of which 12 were eligible. Five patients had T2 tumors, 5 had T3 tumors and 2 had T1 tumors. In 33% of cases, tumor diameter was greater than 5.0 cm. Three hundred and eighty-seven lymph nodes were excised with a median of 32.3 per patient. The SN navigation surgery was feasible in all patients, with a median of 4.5 SNs per patient. The detection success rate was 100%. All the SNs were located in N1 and N2 nodal level. In 70.9% of cases, the SNs were located at lymphatic chains 6 and 7. The SN sensitivity for nodal staging was 91.6%, with 8.3% of false negative. In 4 patients who were initially staged as N0, the SNs were submitted to multisection analyses and immunohistochemistry, confirming the N0 stage, without micrometastases. In one case initially staged as negative for nodal metastases based on SN analyses, metastases in lymph nodes other than SN were found, resulting in a 20% skip metastases incidence. This surgery is a reproducible procedure with 100% detection rate of SN. Tumor size, GC location and obesity were factors that imposed some limitations regarding SN identification. Results from nodal multisection histology and immunohistochemistry analysis did not change initial nodal staging.

Aberrant metastatic behavior and particular features of early gastric cancer

In this paper, we have focused on the metastatic behavior of EGC and its particularities. The main factors that are currently considered as predictors of the metastatic behavior and that are used in the therapeutic decision (endoscopic resection vs surgical removal) are the tumor size (upper or bellow 2 cm), depth of infiltration, angiolymphatic invasion, the presence or absence of ulceration, and histologic type (undifferentiated vs differentiated carcinomas). However, most of the metastatic cases were published as case reports or case series. This is the reason why a proper estimation of metastatic risk in EGC is not well known. To date, 79 cases presenting bone metastases, three reports of brain metastases, and one EGC that was associated with skin metastasis were published. However, occult metastasis, lymph node micrometastasis, and skip metastasis can also occur and should be identified. Making a synthesis of the literature data that is correlated with our experience, we finally proposed the inclusion of the six Japanese subgrouping system, tumor size, angiolymphatic invasion, and micrometastasis as components of the pTNM staging system, which should be particularly adapted for EGC.