Relation of number of positive lymph nodes to the prognosis of patients with primary gastric adenocarcinoma

Clinical implications of micro lymph node metastasis for patients with gastric cancer

BACKGROUND

Lymph node size is considered as a criterion for possible lymph node metastasis in imageology. Micro lymph nodes are easily overlooked by surgeons and pathologists. This study investigated the influencing factors and prognosis of micro lymph node metastasis in gastric cancer.

METHODS

191 eligible gastric cancer patients who underwent D2 lymphadenectomy from June 2016 to June 2017 in the Third Surgery Department at the Fourth Hospital of Hebei Medical University were retrospectively analyzed. Specimens were resected en bloc and the postoperative retrieval of micro lymph nodes was carried out by the operating surgeon for each lymph node station. Micro lymph nodes were submitted for pathological examination separately. According to the results of pathological results, patients were divided into the "micro-LNM (micro lymph node metastasis)" group (N = 85) and the "non micro-LNM" group (N = 106).

RESULTS

The total number of lymph nodes retrieved was 10,954, of which 2998 (27.37%) were micro lymph nodes. A total of 85 (44.50%) gastric cancer patients had been proven to have micro lymph node metastasis. The mean number of micro lymph nodes retrieved was 15.7. The rate of micro lymph node metastasis was 8.1% (242/2998). Undifferentiated carcinoma (90.6% vs. 56.6%, P = 0.034) and more advanced Pathological N category (P < 0.001) were significantly related to micro lymph node metastasis. The patients with micro lymph node metastasis had a poor prognosis (HR for OS of 2.199, 95% CI = 1.335-3.622, P = 0.002). For the stage III patients, micro lymph node metastasis was associated with shorter 5-year OS (15.6% vs. 43.6%, P = 0.0004).

CONCLUSIONS

Micro lymph node metastasis is an independent risk factor for poor prognosis in gastric cancer patients. Micro lymph node metastasis appears to be a supplement to N category in order to obtain more accurate pathological staging.

Log odds of positive lymph nodes as a novel prognostic predictor for gastric cancer: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis to summarize the predictive and prognostic ability of the log odds of positive lymph nodes (LODDS) staging system and compare it with pathological N (pN) classification and the ratio-based lymph node system (rN) for the overall survival (OS) of gastric cancer (GC).

METHODS

Through a systematic review till March 7, 2022, we identified population-based studies that reported the prognostic effects of LODDS in patients with GC. We compare the predictive effectiveness of the LODDS staging system with that of the rN and pN classification systems for the OS of GC.

RESULTS

Twelve studies comprising 20,312 patients were included in this systematic review and meta-analysis. The results showed that LODDS1, LODDS2, LODDS3, and LODDS4 in GC patients were correlated with poor OS compared with LODDS0 (LODDS1 vs. LODDS0: HR = 1.62, 95% CI (1.42, 1.85); LODDS2 vs. LODDS0: HR = 2.47, 95% CI (2.02, 3.03); LODDS3 vs. LODDS0: HR = 3.15, 95% CI (2.50, 3.97); LODDS4 vs. LODDS0: HR = 4.55, 95% CI (3.29, 6.29)). Additionally, significant differences in survival were observed among patients with different LODDS classifications (all P-values were < 0.001) with the same rN and pN classifications. Meanwhile, for patients with different pN or rN classifications with the same LODDS classification, prognosis was highly similar.

CONCLUSION

The findings show that LODDS is correlated with the prognosis of GC patients and is superior to the pN and rN classifications for prognostic assessment.

Assessment of Carbon Nanoparticle Suspension Lymphography-Guided Distal Gastrectomy for Gastric Cancer

IMPORTANCE

Carbon nanoparticle suspension injection (CNSI) can be used to visualize lymph node (LN) drainage in gastric cancer. The tracing and diagnostic value of carbon nanoparticle suspension lymphography-guided distal gastrectomy for gastric cancer has not been thoroughly reported.

OBJECTIVE

To compare the number of lymph nodes identified in patients with gastric cancer receiving a CNSI vs no injection.

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective cohort study including patients with clinical T1 to T4 disease who underwent laparoscopic or robotic distal gastrectomy. Data from a cohort of 1225 patients at the Fourth Hospital of Hebei Medical University (Shijiazhuang, China) from November 2019 to February 2021 were analyzed. Patients were divided into the CNSI group and conventional group after 1:1 propensity matching analysis. The mean number of LNs detected was compared between groups, and the diagnostic role of CNSI was analyzed in the CNSI group. Statistical analysis was performed from May to July 2021.

EXPOSURE

CNSI was peritumorally injected under an endoscope 1 day before surgery in the CNSI group, and the conventional group did not receive any treatment before surgery.

MAIN OUTCOMES AND MEASURES

The main outcome was the number of LNs detected. Gastrectomy with systematic D1+ (ie, stations 1, 3, 4sb, 4d, 5, 6, and 7) or D2 (ie, all D1 stations, plus 8a, 9, 11p, and 12a) lymphadenectomy was performed. Black-stained LNs and nonblack-stained LNs were examined separately in the CNSI group.

RESULTS

A total of 312 consecutive patients (mean [SD] age, 56.7 [10.4] years; 216 [69.2%] men) who underwent distal gastrectomy were enrolled, including 78 patients in the CNSI group, and another 78 patients determined from 1:1 propensity score matching, making an overall cohort size of 156 patients. The mean (SD) number of LNs detected in the CNSI group was 59.6 (21.4), which was significantly higher than that in the conventional group (30.0 [11.3] LNs; P < .001). In the CNSI group, the mean (SD) number of LNs detected at black-stained LN stations was significantly higher than that at nonstained LN stations (9.2 [6.1] LNs per station vs 3.5 [3.2] LNs per station; P < .001). For black-stained LN stations, the sensitivity was 97.8% (95% CI, 91.6%-99.6%), specificity was 38.1% (95% CI, 34.2%-42.3%), positive predictive value was 20.1% (95% CI, 16.6%-24.2%), and negative predictive value was 99.1% (95% CI, 96.4%-99.8%); for the black-stained LNs, sensitivity was 97.6% (95% CI, 95.3%-98.8%), specificity was 35.4% (95% CI, 33.9%-36.8%), positive predictive value was 11.6% (95% CI, 10.5%-12.8%), and negative predictive value was 99.4% (95% CI, 98.8%-99.7%).

CONCLUSIONS AND RELEVANCE

These findings suggest that CNSI was associated with facilitating the dissection of all positive LNs, which could improve surgical quality. Carbon nanoparticle suspension-guided lymphography may be an alternative to conventional systematic lymphadenectomy for distal gastrectomy.

Clinical Application of Indocyanine Green Fluorescence Technology in Laparoscopic Radical Gastrectomy

Background

This study aimed to observe the application and evaluate the feasibility and safety of indocyanine green (ICG) fluorescence technology in laparoscopic radical gastrectomy (LRG).

Methods

Patients who underwent LRG & D2 lymphadenectomy at Qilu Hospital of Shandong University were included between January 2018 and August 2019. According to whether endoscopic injection of ICG was performed, patients were assigned to the ICG group (n=107) and the control group (n=88). The clinicopathologic features, retrieved lymph nodes, postoperative recovery, and follow-up data were compared between the two groups.

Results

Baseline characteristics are comparable. The ICG group had a significantly larger number of lymph nodes retrieved (49.55 ± 12.72 vs. 44.44 ± 10.20, P<0.05), shorter total operation time (min) (198.22 ± 13.14 vs. 202.50 ± 9.91, P<0.05), shorter dissection time (min) (90.90 ± 5.34 vs. 93.74 ± 5.35, P<0.05) and less blood loss (ml) (27.51 ± 12.83 vs. 32.02 ± 17.99, P<0.05). The median follow-up time was 29.0 months (range 1.5-43.8 months), and there was no significant difference between the ICG group and the control group in 2-year OS (87.8% vs. 82.9%, P>0.05) or DFS (86.0% vs. 80.7%, P>0.05).

Conclusions

ICG fluorescence technology in laparoscopic radical gastrectomy has advantages in LN dissection, operation time, and intraoperative blood loss. The 2-year OS and 2-year DFS rates between the two groups were comparable. In conclusion, ICG fluorescence technology is feasible and safe.

Significance of Lymph Node Metastasis in the Treatment of Gastric Cancer and Current Challenges in Determining the Extent of Metastasis

The stomach exhibits abundant lymphatic flow, and metastasis to lymph nodes is common. In the case of gastric cancer, there is a regularity to the spread of lymph node metastasis, and it does not easily metastasize outside the regional nodes. Furthermore, when its extent is limited, nodal metastasis of gastric cancer can be cured by appropriate lymph node dissection. Therefore, identifying and determining the extent of lymph node metastasis is important for ensuring accurate diagnosis and appropriate surgical treatment in patients with gastric cancer. However, precise detection of lymph node metastasis remains difficult. Most nodal metastases in gastric cancer are microscopic metastases, which often occur in small-sized lymph nodes, and are thus difficult to diagnose both preoperatively and intraoperatively. Preoperative nodal diagnoses are mainly made using computed tomography, although the specificity of this method is low because it is mainly based on the size of the lymph node. Furthermore, peripheral nodal metastases cannot be palpated intraoperatively, nodal harvesting of resected specimens remains difficult, and the number of lymph nodes detected vary greatly depending on the skill of the technician. Based on these findings, gastrectomy with prophylactic lymph node dissection is considered the standard surgical procedure for gastric cancer. In contrast, several groups have examined the value of sentinel node biopsy for accurately evaluating nodal metastasis in patients with early gastric cancer, reporting high sensitivity and accuracy. Sentinel node biopsy is also important for individualizing and optimizing the extent of uniform prophylactic lymph node dissection and determining whether patients are indicated for function-preserving curative gastrectomy, which is superior in preventing post-gastrectomy symptoms and maintaining dietary habits. Notably, advancements in surgical treatment for early gastric cancer are expected to result in individualized surgical strategies with sentinel node biopsy. Chemotherapy for advanced gastric cancer has also progressed, and conversion gastrectomy can now be performed after downstaging, even in cases previously regarded as inoperable. In this review, we discuss the importance of determining lymph node metastasis in the treatment of gastric cancer, the associated difficulties, and the need to investigate strategies that can improve the diagnosis of lymph node metastasis.

Recent Advances in the Diagnosis, Staging, Treatment, and Prognosis of Advanced Gastric Cancer: A Literature Review

Gastric cancer is one of the most common cause of cancer related deaths worldwide which results in malignant tumors in the digestive tract. The only radical treatment option available is surgical resection. Recently, the implementation of neoadjuvant chemotherapy resulted in 5-year survival rates of 95% for early gastric cancer. The main reason of treatment failure is that early diagnosis is minimal, with many patients presenting advanced stages. Hence, the greatest benefit of radical resection is missed. Consequently, the main therapeutic approach for advanced gastric cancer is combined surgery with neoadjuvant chemotherapy, targeted therapy, or immunotherapy. In this review, we will discuss the various treatment options for advanced gastric cancer. Clinical practice and clinical research is the most practical way of reaching new advents in terms of patients' characteristics, optimum drug choice, and better prognosis. With the recent advances in gastric cancer diagnosis, staging, treatment, and prognosis, we are evident that the improvement of survival in this patient population is just a matter of time.

Evaluation of dual-energy CT derived radiomics signatures in predicting outcomes in patients with advanced gastric cancer after neoadjuvant chemotherapy

BACKGROUND

To investigate the prognostic value of dual-energy CT (DECT) based radiomics to predict disease-free survival (DFS) and overall survival (OS) for patients with advanced gastric cancer (AGC) after neoadjuvant chemotherapy (NAC).

METHODS

From January 2014 to December 2018, a total of 156 AGC patients were enrolled and randomly allocated into a training cohort and a testing cohort at a ratio of 2:1. Volume of interest of primary tumor was delineated on eight image series. Four feature sets derived from pre-NAC and delta radiomics were generated for each survival arm. Random survival forest was used for generating the optimal radiomics signature (RS). Statistical metrics for model evaluation included Harrell's concordance index (C-index) and the average cumulative/dynamic AUC throughout follow-up. A clinical model and a combined Rad-clinical model were built for comparison.

RESULTS

The pre-IU (derived from iodine uptake images before NAC) RS performed best for DFS and OS in the testing cohort (C-indices, 0.784 and 0.698; the average cumulative/dynamic AUCs, 0.80 and 0.77). When compared with the clinical model, the radiomics model had significantly higher C-index to predict DFS in the testing cohort (0.784 vs. 0.635, p < 0.001), but no statistical difference was found for OS (0.698 vs. 0.680, p = 0.473). The combined Rad-clinical models showed improved performance in the testing cohort, with C-indices of 0.810 and 0.710 for DFS and OS, respectively.

CONCLUSION

DECT-derived radiomics serves as a promising non-invasive biomarker to predict survival for AGC patients after NAC, providing an opportunity for transforming proper treatment.

ICG-NIR-guided lymph node dissection during robotic subtotal gastrectomy for gastric cancer. A single-centre experience

BACKGROUND

Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) allows intraoperative visualisation of the lymph nodes (LNs) draining the tumour.

METHODS

We included in our study 20 patients who underwent robotic subtotal gastrectomy + D2 lymphadenectomy for gastric cancer. In 10 cases, intraoperative ICG-guided lymphography has been used (Group A). We compared the number of LNs retrieved with the use of NIR imaging and the number of LNs retrieved without the use of this technique (Group B, historical group).

RESULTS

No complications related to ICG injection or near-infrared imaging were observed. The mean number of overall LNs retrieved was significantly greater in Group A than in group B (40 vs. 24). No statistically significant difference in operative time was observed.

CONCLUSIONS

ICG-guided fluorescent lymphography can help in performing a more accurate locoregional lymphadenectomy during robotic subtotal gastrectomy for gastric cancer. This technique represents a precious contribution to gastric cancer surgery.

Prognostic significance of pretreatment serum lactate dehydrogenase-to-albumin ratio in gastric cancer

Aim of the study

To investigate the prognostic role of lactate dehydrogenase-to-albumin ratio (LAR) in gastric cancer patients undergoing curative resection.

Material and methods

A retrospective study was conducted including resectable gastric cancer patients. According to the time-dependent receiver operating characteristics (ROC) analysis, the optimal threshold for pretreatment LAR was 5.5. The Kaplan-Meier method, Cox regression univariate and multivariate analyses were used to analyze the prognostic factors for disease-free survival and overall survival (OS).

Results

The study cohort consisted of 81 patients, mean age was 60.2 ±13.8 (range, 29–87) years and 55 (67.9%) were male. The median OS time was 34.8 and 45 months in patients with LAR ≥ 5.5 (n = 50) and LAR < 5.5 (n = 31), respectively. Kaplan-Meier curves showed that with the increase in LAR there was reduced survival, but it was not statistically significant (p = 0.278). Multivariate analyses revealed that the positive lymph node ratio above 20% was an independent predictor in resectable gastric cancer patients (OR = 6.281, 95% CI: 1.135–34.767, p = 0.035).

Conclusions

With the increase in LAR survival in gastric cancer decreased, but it was not statistically significant. Studies involving a large patient series are needed.

Critical number of lymph node involvement in esophageal and gastric cancer and its impact on long-term survival-A single-center 8-year study

BACKGROUND

Nodal disease in esophageal and gastric cancer is associated with poor survival.

OBJECTIVES

To determine the critical level of lymph node involvement where survival becomes significantly compromised.

METHODS

Survival analyses using multivariable Cox regression and receiver operator characteristics (ROC) were undertaken to determine what number of positive lymph nodes were most sensitive and specific in predicting survival.

RESULTS

A total of 317 patients underwent esophagectomy (n = 190, 59.9%) and gastrectomy (n = 127, 40.1%) for adenocarcinoma. At multivariable analyses, four nodes positivity (irrespective of T-category) was associated with nearly a fivefold increased risk of mortality when compared to node-negative patients (hazard ratio [HR], 4.9; interquartile range 2.0-11.5; P < .001). A positive ratio of up to 50.0% was not associated with worse survival than having four nodes positive (HR, 4.6; 95% confidence interval, 2.6-8.1; P < .001). ROC analysis demonstrated four lymph nodes positive to have a sensitivity of 80.5%, a specificity of 60.1%, and an accuracy of 77.8 (P < .001).

CONCLUSION

The absolute number of nodes positive for cancer is more important than the proportion of positive nodes in predicting survival in esophageal/gastric cancer. Four positive lymph nodes are associated with a fivefold increase in mortality. Beyond this, increasing numbers of positive lymph nodes make no appreciable difference to survival.

Prognostic value of a new staging system based on the retrieved number and metastatic rate of LNs in gastric cancer with ≤15 retrieved LNs

OBJECTIVE

To investigate a reasonable lymph node (N) staging system for gastric cancer patients with ≤15 retrieved lymph nodes (LNs).

METHODS

The clinicopathological and follow-up data of patients with ≤15 LNs were obtained from the US Surveillance, Epidemiology, and End Results (SEER) database to analyze the impact of the number of retrieved LNs and metastatic status on the prognosis. In addition, external validation was achieved with data from two medical centers in China.

RESULTS

A total of 18,139 gastric cancer patients with 1-15 retrieved LNs from the SEER database were enrolled and randomly divided into the training group and the internal validation group. A new LN staging system, mNr staging (mNr0-4; 5 stages), was established according to the number of retrieved LNs and the metastatic rate. Compared with the TNM and TNrM staging systems (established by Wang J; misclassification rates of 50.4% and 62.5%, respectively), the mTNrM staging system had a lower misclassification rate (23.4%). Furthermore, there was a significant difference in the 5-year overall survival (OS) rate between the mTNrM staging subgroups (p < 0.05); however, no significant difference was found in the 5-year OS rate of partial adjacent stages in the TNM (8th edition) and TNrM (p > 0.05) staging systems. Similar results were obtained in the external validation cohort.

CONCLUSION

mNr and mTNrM staging systems can efficiently distinguish a survival difference in patients who undergo gastrectomy with ≤15 retrieved LNs, with more accurate predictions of the 5-year OS rate of patients compared with the TNM and TNrM staging systems.

Fluorescent Lymphography-Guided Lymphadenectomy During Robotic Radical Gastrectomy for Gastric Cancer

Importance

Fluorescent imaging with indocyanine green can be used to visualize lymphatics. Peritumoral injection of indocyanine green may allow for visualization of every draining lymph node from a primary lesion on near-infrared imaging.

Objectives

To evaluate the role of fluorescent lymphography using near-infrared imaging as an intraoperative tool for achieving complete lymph node dissection and compare the number of lymph nodes retrieved with the use of near-infrared imaging and the number of lymph nodes retrieved without the use of near-infrared imaging.

Design, Setting, and Participants

This prospective single-arm study was conducted among 40 patients who underwent robotic gastrectomy between August 30, 2013, and July 21, 2014, at a single-center, tertiary referral teaching hospital. After propensity score matching, the results of these 40 patients were compared with the results of 40 historical control patients who underwent robotic gastrectomy without indocyanine green injection between January 1, 2012, and August 31, 2013. Statistical analysis was performed from January 1, 2015, to July 31, 2016.

Interventions

Robotic gastrectomy with systemic lymphadenectomy and retrieval of lymph nodes under near-infrared imaging after peritumoral injection of indocyanine green to the submucosal layer 1 day before surgery.

Main Outcomes and Measures

The primary outcome was the number of retrieved lymph nodes in each nodal station.

Results

Among the 40 patients in the study (19 women and 21 men; mean [SD] age, 52.2 [11.7] years), no complications related to indocyanine green injection or near-infrared imaging were observed. On completion of the lymphadenectomy, the absence of fluorescent lymph nodes in the dissected area was confirmed. A mean (SD) total of 23.9 (9.0) fluorescent lymph nodes were recorded among a mean (SD) total of 48.9 (14.6) overall lymph nodes retrieved. The mean number of overall lymph nodes retrieved was larger in the near-infrared group than in the historical controls (48.9 vs 35.2; P < .001), with a significantly greater number of lymph nodes retrieved at stations 2, 6, 7, 8, and 9. In the near-infrared group, 5 patients exhibited lymph node metastases, and all metastatic lymph nodes were fluorescent.

Conclusions and Relevance

This study's findings suggest that fluorescent lymphography may be useful intraoperatively for identifying and retrieving all necessary lymph nodes for a complete and thorough lymphadenectomy.

Ratio-based staging systems are better than the 7th and 8th editions of the TNM in stratifying the prognosis of gastric cancer patients: A multicenter retrospective study

BACKGROUND

The current and the previous editions of the tumor-node-metastasis (TNM) system for gastric cancer (GC; TNM8 and TNM7) have a high risk of stage-migration bias when the node count after gastrectomy is suboptimal. Hence, they are possibly not the optimal staging systems for GC patients. This study aims to compare the TNM with two systems less affected by the stage-migration bias, namely, the lymph nodes ratio (LNR) and the log odds of positive lymph nodes (LODDS), to assess which one is the best in stratifying the prognosis of GC patients.

METHODS

The sample study included 1221 GC patients. Two 7-cluster staging systems based on the combination of pT categories and LNR and LODDS categories (TLNR and TLODDS) were compared with the two last editions of TNM, using the Akaike information criteria, the Bayesian information criteria, and the receiver operating characteristic (ROC) curve graphs. Further validation on an independent sample of 251 patients was carried out.

RESULTS

The univariable and multivariable analyses and the ROC curves detected an advantage of the TLNR and TLODDS systems over the TNM. The TLNR and TLODDS showed the best accuracy both in the subgroup of patients with ≥16 nodes examined. The results were confirmed in the validation analysis.

CONCLUSIONS

TLNR and TLODDS staging systems should be considered a valid implementation of the TNM for the prognostic stratification of GC patients. If these results are confirmed in further studies, the future implementation of the TNM should consider the introduction of the LNR or the LODDS along with the number of metastatic nodes.

Prognostic significance of metastatic lymph node ratio: the lymph node ratio could be a prognostic indicator for patients with gastric cancer

Background

To demonstrate the prognostic significance and value of lymph node ratio (LNR) and evaluate the possibility of becoming a new indicator to enhance the current Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) tumor, lymph node, metastasis (TNM) staging system.

Methods

Our retrospective study included 221 patients who got gastric cancer and underwent curative gastrectomy between 2005 and 2012 at the Fourth Hospital Affiliated of China Medical University. The log-rank test was used to compare the clinicopathological variables. The Kaplan-Meier method and Cox proportional hazard regression model was used to perform the univariate analysis and multivariate statistical survival analysis.

Results

The patients with a better differentiated pathological type; an earlier stage of T staging, N staging, and TNM staging; and a lesser LNR would have a longer survival time according to the univariate analysis. As for the multivariate analysis, the Grade, T stage, N stage, and LNR had the statistical significance. Both in group 1 (the number of lymph nodes examined ≥ 15, namely LN ≥ 15) and group 2 (LN < 15), the LNR had statistical significance and the median survival time would decrease with the increase of the LNR. It was still statistically significant between group LNR1 and group LNR2 which were regrouped by the new cut-off value.

Conclusion

The LNR could estimate the prognosis of patients with curative gastrectomy regardless of the number of lymph nodes examined. Thus LNR could become a new indicator to enhance the current TNM stage system.

Clinicopathology and Survival in Patients with Gastroesophageal Reflux After Radical Surgery of Proximal Gastric Cancer

BACKGROUND

Gastroesophageal reflux (GR) after radical resection of proximal gastric cancer (PGC) may influence survival; however, few studies have investigated survival in PGC patients who develop GR following radical resection. This study aimed to correlate the occurrence of GR after proximal gastrectomy (PG) and total gastrectomy (TG) with clinicopathological factors and long-term survival.

METHODS

The PGC patient cohort was retrospectively grouped as follows: postoperative patients with and without GR (NGR). Clinicopathological characteristics and survival data were compared between the two groups.

RESULTS

A total of 88 patients who underwent PG (53%) experienced postoperative GR; however, only 30 patients who underwent TG (14%) experienced GR (P = 0.000). The incidence of GR was significantly associated with surgical procedure (P < 0.01), tumor size (P < 0.01), infiltration depth (P < 0.01), lymph node metastasis (P = 0.018), postoperative distant metastasis (P < 0.01) and recurrence (P = 0.001). The 5-year overall survival of the GR group was significantly worse than that of the NGR group (39.3 vs. 46.5%, respectively; P = 0.046). The PG and TG groups had significantly different 5-year overall survival (45.2 vs. 50.9%, respectively; P = 0.047), and multivariate analysis revealed GR as an independent risk factor associated with poor overall survival.

CONCLUSIONS

Patients who experienced GR after radical resection for PGC were more likely to develop recurrence and metastasis, leading to shorter survival. TG for PGC was associated with a more favorable 5-year overall survival than was PG. Thus, TG should be performed for PGC patients with tumors larger than 5 cm, T3/T4 disease or lymph node metastasis to improve their long-term survival.

Fibronectin Promotes Tyrosine Phosphorylation of Paxillin and Cell Invasiveness in the Gastric Cancer Cell Line AGS

Aims and Background

Paxillin is a central protein within the focal adhesion and serves as a critical transducer of signals from fibronectin. Although abnormal expression of fibronectin and paxillin is often observed during the development of human malignancies, the relationship between paxillin and cell invasion in gastric cancer is still unclear. The current study was designed to investigate the potential role and mechanisms of fibronectin in tyrosine phosphorylation of paxillin and in the invasiveness of gastric cancer cells.

Methods

Expression of paxillin in human gastric cancer samples was examined by immunohistochemical staining. A gastric cancer cell line, AGS, was stimulated by fibronectin with gradient concentrations, and expression of paxillin and phosphorylation of paxillin tyrosine 118 (tyr118) was detected by immunoprecipitation and Western blotting. The invasiveness of AGS cells was measured by the modified Boyden chamber assay. Small interfering RNA (siRNA) targeting paxillin was used to establish the role of paxillin (tyr118) in the process of cell invasion enhanced by fibronectin. siRNA targeting focal adhesion kinase (FAK) was used to verify the effect of FAK tyrosine 397 (tyr397) on phosphorylation of paxillin(tyr118).

Results

Positivity for paxillin staining in human gastric cancer was associated with tumor stage. AGS cell showed dose dependence on fibronectin for invasiveness and phosphorylation of paxillin (tyr118). Invasiveness and phosphorylation of paxillin(tyr118) in AGS cells reached their peak when the concentration of fibronectin reached 100 nmol/L. siRNA targeting paxillin decreased the phosphorylation of paxillin(tyr118) and the invasiveness of AGS cells significantly as compared with controls. Blockage of FAK(tyr397) can inhibit phosphorylation of paxillin(tyr118) stimulated by fibronectin.

Conclusions

Fibronectin promotes paxillin(tyr118) phosphorylation and invasiveness of AGS cells. Paxillin silencing by RNA interference inhibits the cell invasiveness stimulated by fibronectin. Paxillin is a key factor in the fibronectin-stimulated invasiveness of AGS cells.

Differential expression of matrix metalloproteinase-13 in association with invasion of breast cancer

Matrix metalloproteinase-13 (MMP-13) has a potential role in tumour invasion and metastasis. However, its relevance to the prognosis of human breast cancer is poorly understood. The aim of this study is to investigate the expression patterns of MMP-13 protein and to determine its prognostic value in breast cancer, and to define its relation to the clinicopathological features. Immunohistochemistry analysis of MMP-13 was performed on formalin-fixed, paraffin-embedded sections of cancerous breast tissue (n = 76) and normal breast tissue (n = 20), all of which had clinicopathological information available. Based on the principle of immunoreactivity, the detection of MMP-13 on breast tissue was conducted using monoclonal antibodies against MMP-13. A semi-quantitative scoring system was used to assess the presence of, as well as the cellular localisation of MMP-13. MMP-13 expression was significantly greater in the cancerous breast tissues in comparison to those of normal breast tissues. In addition, high levels of MMP-13 expression were also found to be related to the positive detection of breast cancer cells in lymph nodes-amongst breast cancer patients. The results of this study showed that MMP-13 was frequently present in breast tumours, especially when tumours were accompanied by positive breast cancer cell detection in lymph nodes. This suggests that MMP-13 plays a potentially significant role in breast cancer invasion and metastasis.

Prognostic Impact of the Signet Ring Cell Type in Node-Negative Gastric Cancer

Little is known regarding the prognostic impact of the signet ring cell (SRC) histotype on negative lymph nodes (LNs) in gastric cancer (GC). In this study, we aimed to investigate the differences between SRC and non-SRC GC patients without LN metastasis. The medical records of patients with GC who underwent gastrectomy at Sun Yat-Sen University Cancer Centre from 1996 to 2012 were reviewed to analyse the clinicopathologic characteristics associated with survival. A total of 480 cases of GC patients without LN metastasis were identified, which included 90 SRC GC patients and 390 non-SRC GC patients. Between the two groups, there were a host of significant differences in the American Joint Committee on Cancer, 7th edition (AJCC) stage. We found that SRC histology was correlated with a poor prognosis in terms of recurrence in node-negative GC patients and that SRC histologic analysis combined with AJCC staging maybe an effectual method for prediction of the recurrence rate. Additionally, we found that SRC GC presents a more dismal overall prognosis in patients with perineural or vascular invasion.

Whole genome gene copy number profiling of gastric cancer identifies PAK1 and KRAS gene amplification as therapy targets

Gastric cancer is the second leading cause of death from cancer worldwide, with an approximately 20% 5-year survival rate. To identify molecular subtypes associated with the clinical prognosis, in addition to genetic aberrations for potential targeted therapeutics, we conducted a comprehensive whole-genome analysis of 131 Chinese gastric cancer tissue specimens using whole-genome array comparative genomic hybridization. The analyses revealed gene focal amplifications, including CTSB, PRKCI, PAK1, STARD13, KRAS, and ABCC4, in addition to ERBB2, FGFR2, and MET. The growth of PAK1-amplified gastric cancer cells in vitro and in vivo was inhibited when the corresponding mRNA was knocked down. Furthermore, both KRAS amplification and KRAS mutation were identified in the gastric cancer specimens. KRAS amplification was associated with worse clinical outcomes, and the KRAS gene mutation predicted sensitivity to the MEK1/2 inhibitor AZD6244 in gastric cancer cell lines. In summary, amplified PAK1, as well as KRAS amplification/mutation, may represent unique opportunities for developing targeted therapeutics for the treatment of gastric cancer.

The prognostic value of lymph nodes dissection number on survival of patients with lymph node-negative gastric cancer

Objective. The study was designed to explore the prognostic value of examined lymph node (LN) number on survival of gastric cancer patients without LN metastasis. Methods. Between August 1995 and January 2011, 300 patients who underwent gastrectomy with D2 lymphadenectomy for LN-negative gastric cancer were reviewed. Patients were assigned to various groups according to LN dissection number or tumor invasion depth. Some clinical outcomes, such as overall survival, operation time, length of stay, and postoperative complications, were compared among all groups. Results. The overall survival time of LN-negative GC patients was 50.2 ± 30.5 months. Multivariate analysis indicated that LN dissection number (P < 0.001) and tumor invasion depth (P < 0.001) were independent prognostic factors of survival. The number of examined LNs was positively correlated with survival time (P < 0.05) in patients with same tumor invasion depth but not correlated with T1 stage or examined LNs >30. Besides, it was not correlated with operation time, transfusion volume, length of postoperative stay, or postoperative complication incidence (P > 0.05). Conclusions. The number of examined lymph nodes is an independent prognostic factor of survival for patients with lymph node-negative gastric cancer. Sufficient dissection of lymph nodes is recommended during surgery for such population.

N stages of the seventh edition of TNM Classification are the most intensive variables for predictions of the overall survival of gastric cancer patients who underwent limited lymphadenectomy

The objective of this study was to explore the prognostic prediction rationality of the seventh edition N stage for gastric cancer (GC) patients who underwent the limited lymphadenectomy. Clinicopathological data of 769 GC patients who underwent the curative resection between 1997 and 2006 were analyzed for demonstration that the seventh edition N stage had the significant superiorities of prognostic prediction to the patients who underwent the limited lymphadenectomy. Although the extent of lymphadenectomy was associated with the overall survival (OS) of gastric cancer (GC) patients, the N stages of the seventh edition of the TNM Classification were identified as the most intensively independent predictors of GC prognosis. Using stratum analysis, the 5-year survival rate of patients who underwent limited lymphadenectomy was observed to be significantly different from that of patients who underwent extended lymphadenectomy, regardless of the extent of lymph node metastasis. Multinomial logistic regression analysis revealed that combining the extents of lymph node metastasis and lymphadenectomy could improve the prediction accuracy of patient survival status. Case control analysis showed that regardless of the extent of lymphadenectomy, the seventh edition N stages featured significant superiority for OS evaluation of GC patients. The seventh edition N stage had the prediction rationality for the OS of GC patients who underwent the limited lymphadenectomy.

Anatomic extent of metastatic lymph nodes: still important for gastric cancer prognosis

BACKGROUND

Currently, gastric cancer staging systems do not consider the anatomic extent of metastatic lymph nodes (mLNs) as a prognostic factor. We therefore investigated the prognostic impact of the anatomic extent of mLNs on gastric cancer.

METHODS

The prognoses of 4,043 gastric cancer patients who underwent curative resection were analyzed. Patients with mLNs in lymph node (LN) stations 1-6 (n = 1,980) comprised the perigastric LN-positive (PLN) group, and patients with mLNs in LN stations 7-12 and 14 (n = 2,063) were assigned to the extraperigastric LN-positive (ELN) group. Overall survival was estimated using the Kaplan-Meier method, and hazard ratios (HRs) were calculated by the Cox proportional hazard model.

RESULTS

The ELN group exhibited worse survival than the PLN group (p < 0.001), although there were differences in their clinicopathological features. When patients were stratified according to tumor-node-metastasis stage, the ELN groups had unfavorable prognoses compared with the PLN groups (p < 0.05). There were significant differences in long-term survival when the nodal stage of the current staging systems were subdivided according to anatomic nodal extent (p < 0.05), although there was a strong association between the probability of having extraperigastric mLNs and N classification. In multivariate analysis using age, gender, tumor size, tumor location, histology, T classification, and the extent of mLNs as covariates, presence of extraperigastric mLNs was an independent prognostic factor (HR 1.89, 95 % CI 1.73-2.07), along with age, tumor size, tumor location, and T classification.

CONCLUSIONS

The anatomic extent of mLNs significantly affects patient prognosis. Including the anatomic extent of mLNs in the current staging system may predict gastric cancer prognosis more accurately in patients with the same stage of cancer.

Clinical implication of an insufficient number of examined lymph nodes after curative resection for gastric cancer

BACKGROUND

The seventh edition of the tumor, lymph node (LN), metastasis (TNM) staging system increased the required number of examined LNs in gastric cancer from 15 to 16. However, the same staging system defines lymph node-negative gastric cancer regardless of the number of examined LNs. In this study, the authors evaluated whether gastric cancer can be staged properly with fewer than 15 examined LNs.

METHODS

The survival rates of 10,010 patients who underwent curative gastrectomy from 1987 to 2007 were analyzed. The patients were divided into 2 groups according to the number of examined LNs, termed the "insufficient" group (≤15 examined LNs) and the "sufficient" group (≥16 examined LNs). The survival curves of patients from both groups were compared according to the seventh edition of the TNM classification.

RESULTS

Three hundred sixteen patients (3.2%) had ≤15 examined LNs for staging after they underwent standard, curative lymphadenectomy. Patients who had T1 tumor classification, N0 lymph node status, and stage I disease with an insufficient number of examined LNs after curative gastrectomy had a significantly worse prognosis than patients who had ≥16 examined LNs. Moreover, having an insufficient number of examined LNs was an independent prognostic factor for patients who had T1, N0, and stage I disease.

CONCLUSIONS

Lymph node-negative cancers in which ≤15 LNs were examined, classified as N0 in the new TNM staging system, could not adequately predict patient survival after curative gastrectomy, especially in patients with early stage gastric cancer.

Validation of seventh edition AJCC gastric cancer staging modifications

BACKGROUND AND OBJECTIVES

The seventh edition of the AJCC has more detailed staging categories for gastric cancer than does the sixth edition. The aim of our study was to compare the prognostic accuracies of the sixth and seventh AJCC editions for gastric cancer patients.

METHODS

We analyzed survival rates by category using the sixth and seventh editions of the AJCC in 10,060 patients with gastric cancer who had undergone gastrectomy between 1994 and 2007 at Samsung Medical Center.

RESULTS

Significant differences in prognosis were seen when comparing the new stages of the seventh edition of the AJCC that are subgroups of stages IB, II, IIIA, and IV in the sixth edition. In particular, stage IV of the AJCC sixth edition is divided into stages IIB, IIIA, IIIB, IIIC and IV in the seventh edition, and the 5-year survival rates of these respective stages were 80.2%, 45.3%, 23.5%, 17.2%, and 10.1% (P < 0.001).

CONCLUSIONS

Each category of the AJCC sixth edition has been divided into multiple stages in the AJCC seventh edition, each with a different prognosis. The newly divided subgroups from AJCC sixth edition stage IV showed more accurate outcome classification based on AJCC seventh edition staging stratification.

Transverse mesocolon invasion in advanced gastric cancer: should we reconsider current T staging?

BACKGROUND

According to the AJCC/UICC TNM classification, T mesocolon invasion in AGC is classified as T2b or T3 according to the presence or the absence of serosa invasion. However, many authors have considered T mesocolon invasion in AGC as T4. This study was performed to evaluate the appropriate T stage for T mesocolon invasion in AGC.

MATERIALS AND METHODS

From 1996 to 2008, 90 patients underwent curative gastrectomy with T mesocolon excision at the authors' institute under the suspicion of T mesocolon invasion based on surgical findings and without pathologic invasion to any other organ. Histopathologic findings were reviewed to determine whether tumors had invaded the T mesocolon. Survival data of AGC patients registered in the SNUH database (N = 9998, from 1986 to 2007) was used as reference data for comparative purposes.

RESULTS

A total of 27 patients (30%) had proven histopathological invasion of the T mesocolon, and a significant difference in survival rates was found between these 27 and the remaining 63 (P = .012). As compared with the SNUH database population, the survival rate of T mesocolon invasion patients differed from those of T2b (P < .001) and T3 (P = .043) patients, but was similar to that of T4 patients (P = .218). Furthermore, for N1 stage patients, the survival rate differed from those of T2b (P = .001) and T3 (P = .046) patients, but was similar to that of T4 patients (P = .744).

CONCLUSIONS

The T stage of T mesocolon invasion in AGC should be revised to AJCC/UICC stage T4, because the survival rate of T mesocolon invasion AGC is lower than that of stage T2b or T3.

Investigation of the recurrence patterns of gastric cancer following a curative resection

PURPOSE

The goal of this study was to investigate the recurrence patterns of gastric cancer and determine the predictive information of recurrence patterns of gastric cancer following a curative resection.

METHODS

This study retrospectively analyzed the data of 308 gastric cancer patients who underwent a curative resection, to identify the factors associated with the recurrence patterns.

RESULTS

One hundred and sixty-nine gastric cancer patients had recurrence following curative resection. One hundred and twenty-six patients were observed for 3 years after the operation. Locoregional recurrence formed part of the recurrence pattern in 107 patients, peritoneal dissemination was observed in 98 patients, and distant metastasis occurred in 22 patients. A multivariate analysis revealed that locoregional recurrence was only associated with the Lauren classification (P = 0.003); peritoneal dissemination was only associated with N stage (P < 0.001); and distant metastasis was only associated with the Lauren classification (P = 0.016).

CONCLUSIONS

Locoregional recurrence, peritoneal dissemination, and distant metastasis were the most common recurrence patterns of gastric cancer following a curative resection. Each recurrence pattern is associated with specific clinicopathological factors.

Comparison of 6th and 7th AJCC TNM staging classification for carcinoma of the stomach in China

BACKGROUND

The 7th edition of American Joint Committee on Cancer tumor-node-metastasis (AJCC TNM) staging system was put into use recently. The study aimed to evaluate its predictive ability on survival and compare the difference between the 6th and 7th editions of AJCC TNM system in gastric carcinoma.

MATERIALS AND METHODS

A total of 1000 gastric carcinoma patients receiving treatment in our center were selected for the analysis. Patients were staged using both the 6th and 7th editions AJCC TNM staging system. Survival analysis was performed with a Cox regression model.

RESULTS

Of previous stage IV patients, 39.9% (112 of 281) migrated to a lower tier in the 7th edition. By setting the cutoff of positive lymph nodes as 0, 2, 6, and 15, the 7th edition strengthens the role of positive lymph nodes. Multivariable regression analysis showed that both 6th and 7th TNM stage systems were independent factors for overall survival. For lymph nodes negative patients, the 5-year overall survival for patients with fewer than 15 resected lymph nodes was significantly lower than those with more than 15.

CONCLUSIONS

AJCC 7th is not superior to AJCC 6th in predicting the 5-year overall survival rates of gastric adenocarcinoma patients. The definition of stage IV and the selection of cutoffs for MLNC in the AJCC 7th system is much more reasonable compared with the AJCC 6th system.

Comparison of the 6th and 7th editions of the UICC TNM staging system for gastric cancer: results of a Chinese single-institution study of 1,503 patients

AIM

To evaluate the prognostic efficacy of the 7th edition tumor-node-metastasis (TNM) classification compared with the 6th edition in gastric cancer patients.

METHODS

A total of 1,503 gastric cancer patients undergoing surgical resection were staged using the 6th and 7th edition staging systems. Homogeneity, discriminatory ability, and monotonicity of gradients of the two systems were compared using linear trend χ(2), likelihood ratio χ(2) statistics, and Akaike information criterion (AIC) calculations.

RESULTS

Significant differences in 5-year survival rates were observed for the T, N, and M subgroups using the 7th edition system, except for stage N2 and N3 patients in the 6th edition system. There were no significant differences in survival between IB and IIA in the 7th edition system. Patients with stage IV disease due to T4/N3 in the 6th edition system who were downstaged to stage III in the 7th edition system had significantly better survival than those who remained at stage IV. The 7th edition system had higher linear trend and likelihood ratio χ(2) scores, and smaller AIC values compared with those for the 6th edition, which represented the optimum prognostic stratification.

CONCLUSIONS

Our study suggests that the 7th edition system performs better than the 6th edition in several aspects.

Prognostic impact of metastatic lymph node ratio on gastric cancer after curative distal gastrectomy

AIM: To investigate the prognostic impact of metastatic lymph node ratio (rN) on gastric cancer after curative distal gastrectomy.

METHODS: A total of 634 gastric cancer patients who underwent curative resection (R0) of lymph nodes at distal gastrectomy in 1995-2004. Correlations between positive nodes and retrieved nodes, between rN and retrieved nodes, and between rN and negative lymph node (LN) count were analyzed respectively. Prognostic factors were identified by univariate and multivariate analyses. Staging accuracy of the pN category (5th UICC/TNM system) and the rN category was compared according to the survival rates of patients. A linear regression model was used to identify the relation between rN and 5-year survival rate of the patients.

RESULTS: The number of dissected LNs was related with metastatic LNs but not related with rN. Cox regression analysis showed that depth of invasion, pN and rN category were the independent predictors of survival (P < 0.05). There was a significant difference in survival between LN stages classified by the rN category or by the pN category (P < 0.05). However, no significant difference was found in survival rate between LN stages classified by the pN category or by the rN category (P > 0.05). Linear regression model showed a significant linear correlation between rN and the 5-year survival rate of gastric cancer patients (β = 0.862, P < 0.001). Pearson’s correlation test revealed that negative LN count was negatively correlated with rN (P < 0.001).

CONCLUSION: rN category is a better prognostic tool than the 5th UICC pN category for gastric cancer patients after curative distal gastrectomy. Increased negative LN count can reduce rN and improve the survival rate of gastric cancer patients.

Factors affecting recurrence in node-negative advanced gastric cancer

BACKGROUND AND AIM

Prognostic factors of lymph node-negative gastric adenocarcinoma after curative resection have been discussed. Recurrent pattern of advanced lymph node-negative gastric cancer after curative resection has rarely been described.

METHODS

Recurrent sites and correlated clinicopathological factors of 372 patients with lymph node-negative advanced gastric adenocarcinoma that underwent R0 resection from 1988 to 2005 were analyzed.

RESULTS

Recurrence was noted in 51 (13.7%) patients. Recurrent rates according to site of recurrence were 26 peritoneal seeding (51.0%), 26 locoregional (51.0%), 17 hematogenous (33.3%), and 4 lymph node metastasis (7.8%). Clinicopathological factors to predict peritoneal seeding were serosal exposure, lymphovascular invasion, Lauren's diffuse type differentiation and scirrhous stromal reaction. Serosal exposure, tumor size, microscopic infiltrating growth type predicts locoregional recurrence. Tumor had only lymphovascular invasion predict hematogenous spreading.

CONCLUSION

Node-negative advanced gastric cancer has more peritoneal seeding and locoregional recurrence. Aggressive cell behavior predicted the route of tumor cell spreading.

Prognostic impact of dissected lymph node count on patients with node-negative gastric cancer

AIM: To investigate the long-term effect of the number of resected lymph nodes (LNs) on the prognosis of patients with node-negative gastric cancer.

METHODS: Clinical data of 211 patients with gastric cancer, without nodal involvement, were analyzed retrospectively after D2 radical operation. We analyzed the relationship between the number of resected LNs with the 5-year survival, the recurrence rate and the post-operative complication rate.

RESULTS: The 5-year survival of the entire cohort was 82.2%. The total number of dissected LNs was one of the independent prognostic factors. Among patients with comparable depth of invasion, the larger the number of resected LNs, the better the survival (P < 0.05). A cut-point analysis provided the possibility to detect a significant survival difference among subgroups. Patients had a better long-term survival outcomes with LN counts ≥ 15 for pT1-2, ≥ 20 for pT3-4, and ≥ 15 for the entire cohort. The overall recurrence rate was 29.4% within 5 years after surgery. There was a statistically significant, negative correlation between the number of resected LNs and the recurrence rate (P < 0.01). The post-operative complication rate was 10.9% and was not significantly correlated with the number of dissected LNs (P > 0.05).

CONCLUSION: For node-negative gastric cancer, sufficient number of dissected LNs is recommended during D2 lymphadenectomy, to improve the long-term survival and reduce the recurrence. Suitable increments of the dissected LN count would not increase the post-operative complication rate.

Sentinel Lymph Node Mapping for Gastric Adenocarcinoma

The optimal extent of regional lymphadenectomy for gastric adenocarcinoma remains a controversial topic. Traditional approaches have focused on various anatomical nodal stations to define the extent of resection. In this prospective trial, we update our experience with sentinel lymph node (SLN) mapping and biopsy to augment resection of nodal metastasis in gastric carcinoma. Twenty-seven patients with gastric cancer were enrolled. SLNs were identified with isosulfan blue, resected, and sent fresh to pathology for staining and evaluation. The procedure then continued with radical gastrectomy and celiac node dissection. SLNs were identified in all cases. The average patient age was 65 years, with 12 women and 15 men. Eighteen patients had pathology-confirmed nodal metastasis. Positive SLN were found in 15 (83%); three patients had a false negative SLN mapping procedure (17%). Accuracy rate was 88.9 per cent. SLN mapping and biopsy for gastric carcinoma is feasible. However, the negative predictive value is 75 per cent, and therefore caution should be considered in using lymphatic mapping to determine extent of regional lymphadenectomy. Additionally, our study shows no utility in identifying micro-metastatic disease with immunohistochemical techniques. Although a promising modality, we do not recommend the clinical use of SLN mapping for gastric cancer.

Ratio of metastatic to resected lymph nodes for prediction of survival in patients with inadequately staged gastric cancer

Background

Staging is inadequate in up to 70 per cent of patients with gastric cancer in Western countries owing to the small number of lymph nodes dissected during surgery. The aim was to determine whether using the ratio of metastatic to resected lymph nodes (LNR) might improve accuracy.

Methods

Data were analysed from patients with gastric cancer who had gastrectomy in several centres between 1986 and 1998, with dissection of 15 or fewer lymph nodes. LNRs and other prognostic factors were evaluated.

Results

From a total of 738 patients, the median number of resected nodes was 8 (range 1–15) and median LNR was 42·8 per cent. The number of metastatic nodes significantly affected survival only in univariable analysis. In a Cox proportional hazards model, patient age, depth of tumour infiltration, tumour location, and LNR were identified as independent prognostic factors. Compared with node-negative patients, the hazard ratio for an LNR of 0·1–40·0 per cent was 1·85 (P &lt; 0·001), increasing to 2·93 (P &lt; 0·001) when the LNR exceeded 40·0 per cent.

Conclusion

The LNR cannot be used as a substitute for staging with adequate lymphadenectomy. It may help to stratify patients in terms of prognosis when the number of resected lymph nodes is limited.

The most appropriate category of metastatic lymph nodes to evaluate overall survival of gastric cancer following curative resection

AIMS

The purpose of this study was to provide a nodal grouping category based on metastatic lymph nodes to evaluate overall survival in gastric cancer patients following curative resection (R0).

PATIENTS AND METHODS

We reviewed data of 308 gastric cancer patients following curative resection to evaluate significantly survival differences in different categories of the number of metastatic lymph nodes.

RESULTS

In 308 evaluable patients, 5-year survival rate (YSR) was 52.9% (median follow-up, 84 months; range, 6-144 months). A total of 6309 lymph nodes were harvested and examined from all 308 patients, and the average number of lymph nodes harvested for per patient was 20.5 (range, 15-49). The average number of metastatic lymph nodes was 5.4 (range, 0-37) per patient. The initial metastatic node cutoffs were designed as 0, 1-4, 5-8, 9-11, 12-16, and >or=17. According to this new category of the number of metastatic lymph nodes, the 5-YSR of various patient groups were 85.7%, 62.8%, 34.3%, 0%, 0%, and 3.4%, respectively. However, we found that there were not significant prognostic differences between patients with 9 metastatic lymph nodes and patients with more than 9 metastatic lymph nodes (P > 0.05). So we redesigned the later cutoffs of number of metastatic lymph nodes. They were as follows: 0, 1-4, 5-8, and >or=9 of metastatic lymph nodes. We demonstrated this new category of the number of metastatic lymph nodes was more appropriate to evaluate overall survival of gastric cancer patients following curative resection than anyone of the current metastatic lymph nodal stagings (such as N stag in UICC, location of metastatic lymph nodes in JCGC, or ratio of metastatic lymph nodes) by using the case-control matched fashion.

CONCLUSIONS

Our new category of the number of metastatic lymph nodes was an important prognostic factor of gastric cancer patients following curative resection. There were significant overall survival differences in gastric cancer patient groups with various numbers of metastatic lymph nodes following curative resection.

Prognostic impact of metastatic lymph node ratio in advanced gastric cancer from cardia and fundus

AIM: To investigate the prognostic impact of the metastatic lymph node ratio (MLR) in advanced gastric cancer from the cardia and fundus.

METHODS: Two hundred and thirty-six patients with gastric cancer from the cardia and fundus who underwent D2 curative resection were analyzed retrospectively. The correlations between MLR and the total lymph nodes, positive nodes and the total lymph nodes were analyzed respectively. The influence of MLR on the survival time of patients was determined with univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. And the multiple linear regression was used to identify the relation between MLR and the 5-year survival rate of the patients.

RESULTS: The MLR did not correlate with the total lymph nodes resected (r = -0.093, P = 0.057). The 5-year overall survival rate of the whole cohort was 37.5%. Kaplan-Meier survival analysis identified that the following eight factors influenced the survival time of the patients postoperatively: gender (χ² = 4.26, P = 0.0389), tumor size (χ² = 18.48, P < 0.001), Borrmann type (χ² = 7.41, P = 0.0065), histological grade (χ² = 5.07, P = 0.0243), pT category (χ² = 49.42, P < 0.001), pN category (χ² = 87.7, P < 0.001), total number of retrieved lymph nodes (χ² = 8.22, P = 0.0042) and MLR (χ² = 34.3, P < 0.001). Cox proportional hazard model showed that tumor size (χ² = 7.985, P = 0.018), pT category (χ² = 30.82, P < 0.001) and MLR (χ² = 69.39, P < 0.001) independently influenced the prognosis. A linear correlation between MLR and the 5-year survival was statistically significant based on the multiple linear regression (β = -0.63, P < 0.001). Hypothetically, the 5-year survival would surpass 50% when MLR was lower than 10%.

CONCLUSION: The MLR is an independent prognostic factor for patients with advanced gastric cancer from the cardia and fundus. The decrease of MLR due to adequate number of total resected lymph nodes can improve the survival.

Prognostic significance of the ratio between metastatic and dissected lymph nodes (n ratio) in patients with advanced gastric cancer

BACKGROUND AND OBJECTIVES

To determine the prognostic significance of the ratio between metastatic and dissected lymph nodes (n ratio) in gastric cancer patients.

METHODS

We retrospectively reviewed 777 advanced gastric cancer patients who had undergone curative gastrectomy at our hospital.

RESULTS

The n ratio was significantly greater in cases with a large tumor, undifferentiated tumor, lymphatic vessel invasion, or blood vessel invasion. Furthermore, the n ratio was significantly correlated with the depth of invasion, level of lymph node metastasis, and number of lymph node metastases. The prognosis for gastric cancer patients correlated well with the n ratio. Multivariate analysis indicated that the n ratio, but not the number of lymph node metastases, was an independent prognostic indicator. Moreover, the n ratio was an independent prognostic factor in N1, N2, and N3 patients defined by the Japanese Classification of Gastric Cancer (JCGC).

CONCLUSIONS

The n ratio is useful for evaluating the status of lymph node metastasis in gastric cancer. Therefore, the addition of the n ratio to the N (nodal) category defined by the JCGC may be a useful strategy in the N-staging classification of gastric cancer.

Solitary lymph node metastasis in gastric cancer

The feasibility and diagnostic reliability of sentinel node (SN) biopsy for gastric cancer are still controversial. We studied the clinicopathological features and localization of solitary lymph node metastasis (SLM) in gastric cancer to provide useful information for use of the SN concept in gastric cancer. From 2000 to 2004, 3,267 patients with gastric cancer underwent D2 radical gastrectomy. The clinicopathological features of 195 patients with histologically proven SLM and the distribution of metastasized nodes were assessed. The incidence of SLM was 6.0% in all cases. Compared with the node-negative patients, significant differences were observed in age, tumor size, depth of invasion, and surgical type. The cumulative 5-year survival rate of patients with SLM was 80.5%, which was significantly lower than 90.2% for node-negative patients (P<0.001). Of patients with SLM, 82.6% had it in the perigastric node area (N1), and the other 17.4% patients had skip metastasis in the N2-N3 nodes. Perigastric nodes were the most common first sites of drainage from the tumor, making them the main targets of the operative SN mapping procedure. Due to the higher than expected incidence of skip metastasis in gastric cancer, D2 lymphadenectomy should be performed until the reliability of SN navigation surgery is validated in multicenter prospective clinical trials.

Clinical implications of metastatic lymph node ratio in gastric cancer

Background

The 5-year survival rate in patients with gastric cancer is still poor, and lymph node metastasis is considered one of the most important prognostic factors. However, there are controversies in the classification of lymph node metastasis in gastric cancer. This study was carried out to investigate whether the metastatic lymph node ratio is a reliable classification of lymph node metastasis in gastric cancer in Chinese.

Methods

224 cases with gastric cancer with more than D1 dissection were retrospectively reviewed. The association between the total number of resected lymph nodes and the number of metastatic lymph nodes was determined. The prognostic value of the metastastic node ratio, defined as the ratio of the number of metastatic lymph nodes over the total number of resected lymph nodes, and the pN classification was assessed.

Results

The number of metastatic lymph node increased with the number of total resected lymph nodes. A Cox regression revealed that the metastatic node ratio, the number of metastatic nodes, histological type, and histological growth pattern independently influenced prognosis. The 5-year survival rates were 78%, 61%, 25%, 0% in cases with a metastastic node ratio of 0%, > 0% but < 40%, 40–80%, > 80%, respectively (P < 0.001), and were 78%, 62%, 38%, 0% in cases with gastric cancer histologically classified as pN0, pN1, pN2, pN3, respectively (P < 0.001).

Conclusion

The metastatic lymph node ratio is a simple and useful independent prognostic factor. It may obviate possible confounding factors that are related to stage migration, and should be considered as an important component in the lymph node category.

Survival predictors in patients with node-negative gastric carcinoma

BACKGROUND

Presence or absence of nodal metastasis influences outcome of gastric cancer patients. This study gives insight into survival predictors and clinicopathological features of node-negative gastric adenocarcinoma.

METHODS

Between 1988 and 1999, 689 gastric cancer patients without other cancer or gastrectomy for benign disease who underwent curative resection were enrolled in this study. Clinicopathological data in patients with node metastasis were compared with those without.

RESULTS

The survival rate at 5 and 10 years for node-negative cases was 91.7% and 89.7%, respectively. On univariate analysis, node-negative patients were characterized by frequent location in the lower two-thirds of the stomach (84.9%), tumor size less than 4 cm (63.5%), grossly superficial type (71.6%), more medullary stromal reaction (50.5%) and intestinal type (67.7%), tumor invasion confined to serosa (78.4%), less poorly differentiated cell type (43.2%), and less lymphovascular invasion (33.4%). Multivariate analysis demonstrated that lymphovascular invasion (relative risk: 5.036) and depth of cancer invasion (relative risk: 4.404) were independent poor prognostic factors. However, lymphovascular invasion and serosal invasion were also correlated (P < 0.001).

CONCLUSION

Patients with node-negative gastric adenocarcinoma had less disease progression and a favorable survival. Lymphovascular invasion and depth of cancer invasion were two independent but correlated survival predictors.

Prognostic significance of level and number of lymph node metastases in patients with gastric cancer

BACKGROUND

To present data that provide some insight into the appropriateness of a nodal grouping category and its relation to survival in patients with gastric cancer.

METHODS

We reviewed data of 777 patients with advanced gastric cancer who had undergone curative gastrectomy to investigate the prognostic significance of level and number of lymph node metastases.

RESULTS

The prognosis of patients with gastric cancer was well correlated with the level and number of lymph node metastases. Multivariate analysis indicated that the level and number of lymph node metastases were independent prognostic indicators. Moreover, the number of lymph node metastases was an independent prognostic factor in N1, N2, and N3 patients. The most statistically significant difference in disease-specific survival was observed at a threshold of 11 lymph node metastases, yielding a chi2 value of 42.88, a hazard ratio of 2.523, at a 95% confidence interval of 1.913, 3.329 (P < .0001) by Cox proportional hazard model. On the basis of this result, patients were divided into two groups as follows: marked lymph node metastasis group (number of positive nodes > or =11) and slight lymph node metastasis group (number of positive nodes < or =10). The prognosis of patients with marked lymph node metastasis was statistically significantly worse than that with slight lymph node metastasis in N1, N2, and N3 patients.

CONCLUSIONS

Both level and number were indispensable for evaluating lymph node metastasis. Therefore, addition of the number of positive nodes to the N category defined by the Japanese Classification of Gastric Carcinoma may be a useful strategy in the N staging classification in gastric cancer.

Stage migration influences on stage-specific survival comparison between D1 and D3 gastric cancer surgeries

AIMS

We evaluate the influency stage migration in a randomised trial comparing D1 (N 1 lymphadenectomy) and D3 (N 1, 2 and 3 lymphadenectomy) dissections.

METHODS

Two hundred and thirteen curatively resected patients were analysed, with this TNM data.

RESULTS

After applying D3 patients' data according to simulated D1 staging, D3 resections were associated with up-staging to N2-3 levels in 8% of patients according to the N stage. The likelihood of N-status migration increased with increasing depth of invasion into the gastric wall. The increases in the calculated survival rate after stage migration on known 5-year survival rates were: 2% in stage IB, 1% in stage II, 4% in stage IIIA, and 1% in stage IIIB.

CONCLUSIONS

Stage migration secondary to meticulous lymph node dissection affects stage-specific survival rates. True therapeutic survival benefit of D3 resection can only be assessed in this context.

Metastatic lymph node ratio as a prognostic factor in gastric cancer

BACKGROUND

There is an association between the number of resected lymph node and the number of metastatic lymph nodes in gastric cancer, suggesting that pN category could be influenced by the extension of the lymphadenectomy. This study evaluates this association and proposes a comprehensive use of the ratio as prognostic factor.

METHOD

Review of 183 consecutive patients with gastric adenocarcinoma. The association between the number of resected lymph nodes and the number of metastatic lymph nodes was analysed and evaluated with other prognostic factors.

RESULTS

The number of lymph node metastases increased with the number of resected lymph nodes. The lymph node ratio was a better prognostic factor than the number of metastatic lymph nodes.

CONCLUSIONS

The metastatic lymph node ratio seems to be a good prognostic factor, but needs further evaluation.

Overexpression of rho effector rhotekin confers increased survival in gastric adenocarcinoma

Like many epithelial-derived cancers, gastric cancer (GC) results from a multistep tumorigenic process. However, the detailed mechanisms involved in GC formation are poorly characterized. Using an ordered differential display method, we have identified rhotekin (RTKN), the gene coding for the Rho effector, RTKN, as one of the genes differentially expressed in human GC. Northern analysis using human multiple tissue blots showed that RTKN is predominantly expressed in the kidney and spinal cord, and, to a lesser degree, in the thyroid, tongue, liver, brain, prostate, trachea, and stomach. RT-PCR analysis confirmed that RTKN was overexpressed in most (5/7; 71%) GC examined. By analyzing the Stanford Microarray Database for the expression profiles of gastric tissues, we also found a progressional increase in RTKN expression in nonneoplastic mucosa, GC, and then lymph node metastases (p < 0.005 by Jonckheere-Terpstra test), suggesting that RTKN expression correlates with GC progression. The role of RTKN in the pathogenic development of GC was investigated by transfection and expression of RTKN in AGS gastric cells, which express endogenous RTKN at a low basal level. Flow-cytometric analysis showed that RTKN-transfected AGS cells were significantly more resistant than vector-transfected cells to apoptosis upon treatment with sodium butyrate. To explore the mechanisms underlying RTKN-mediated cell survival, a reporter assay was performed. Since the NF-kappaB activation is known to promote cell survival and Rho GTPase may lead to NF-kappaB activation, we transfected AGS cells with the RTKN expression vector along with a pNF-kappaB-Luc reporter plasmid. Our results showed that overexpression of RTKN induced robust activation of NF-kappaB, and RTKN-mediated NF-kappaB activation was suppressed significantly by C3 transferase, an inhibitor of the small GTPase Rho. We conclude that Rho/RTKN-mediated NF-kappaB activation leading to cell survival may play a key role in gastric tumorigenesis. This study provides original documentation for the overrepresentation of the Rho GTPase effector rhotekin in human cancer and its links to cancer formation.

Clinical implications of chromosomal abnormalities in gastric adenocarcinomas

Gastric carcinoma (GC) is one of the most common malignancies worldwide and has a very poor prognosis. Genetic imbalances in 62 primary gastric adenocarcinomas of various histopathologic types and pathologic stages and six gastric cancer-derived cell lines were analyzed by comparative genomic hybridization, and the relationship of genomic abnormalities to clinical features in primary GC was evaluated at a genome-wide level. Eighty-four percent of the tumors and all six cell lines showed DNA copy number changes. The recurrent chromosomal abnormalities including gains at 15 regions and losses at 8 regions were identified. Statistical analyses revealed that gains at 17q24-qter (53%), 20q13-qter (48%), 1p32-p36 (42%), 22q12-qter (27%), 17p13-pter (24%), 16p13-pter (21%), 6p21-pter (19%), 20p12-pter (19%), 7p21-pter (18%), 3q28-qter (8%), and 13q13-q14 (8%), and losses at 18q12-qter (11%), 3p12 (8%), 3p25-pter (8%), 5q14-q23 (8%), and 9p21-p23 (5%), are associated with unique patient or tumor-related features. GCs of differing histopathologic features were shown to be associated with distinct patterns of genetic alterations, supporting the notion that they evolve through distinct genetic pathways. Metastatic tumors were also associated with specific genetic changes. These regions may harbor candidate genes involved in the pathogenesis of this malignancy.

Impact of the latest TNM classification for gastric cancer: retrospective analysis on 94 D2 gastrectomies

The aim of this study was to determine whether the latest edition of tumor-node-metastasis (TNM) classification provides reliable prognostic information. The fifth edition of TNM Classification of Malignant Tumors has introduced for gastric cancer the numeric count of involved lymph nodes whereas their topographic location was considered in earlier editions. For our study, data from 94 patients who underwent D2-gastrectomy were reviewed. The N-factor was scored according to both the Japanese Research Society for Gastric Cancer (JRSGC) classification (n) and, retrospectively, the latest TNM classification (N). Actuarial survival was calculated for both groups. The two staging systems showed similar stratification of actuarial survival with relation to N-stage; in the JRSGC classification no statistical differences were observed between n1 and n2 patients (62.7% vs. 52.5%; p = NS), whereas the 5th TNM classification showed a significant difference between N1 and N2 patients (68.5% vs. 45.0%; p = 0.04), and between N1 and the new category of N3 patients (68.5% vs. 45.0%, p = 0.03). It appears, therefore, that the numeric count of involved nodes may represent a more reliable indicator for single-case prognosis. Reclassification of all node-positive patients in our series caused an overall stage modification in 32.9% (31/94); 22 of those patients were reclassified to a less favorable stage (23.4%). In addition, 11.7% of patients (6/51) who were previously designated n1 were reclassified as N2, shifting from an expected actuarial survival after 72 months of 62.7% to 33.3%.

The superiority of ratio-based lymph node staging in gastric carcinoma

BACKGROUND

The need for a precise lymph node staging without stage migration is of paramount importance when comparing and evaluating international treatment results.

METHODS

We reviewed 1019 patients who underwent R0 resection at Kansai Medical University between 1980 and 1997. The patients were classified according to the 1997 International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) pN classification or the N staging depending on the ratio between the number of excised and the number of involved lymph nodes (pN1, < or = 25%; pN2, < or = 50%; pN3, >50%).

RESULTS

Among the 1997 UICC/AJCC pN subgroups, prognosis worsened with an increase in lymph node ratio. In contrast, the ratio-based classification showed more homogenous survival according to the number of involved lymph nodes. Multiple stepwise regression analysis showed that the ratio-based classification was the most significant prognostic factor, whereas the 1997 UICC/AJCC classification was not found to be an independent predictor of survival. In addition, the ratio-based classification showed a superiority to the 1997 UICC/AJCC classification with respect to stage migration.

CONCLUSIONS

Ratio-based lymph node staging is simple and gives more precise information for prognosis with fewer problems related to stage migration than the 1997 UICC/AJCC staging system.

Nonsteroidal anti-inflammatory drugs for treatment of advanced gastric cancer: cyclooxygenase-2 is involved in hepatocyte growth factor mediated tumor development and progression

Surgical treatment of gastric cancer patients is dismal because advanced tumor is often noted at diagnosis. In order to obtain better adjuvant therapy for gastric cancer patients after operation, it is important to understand the mechanism of invasion and metastasis. It is well known that binding of hepatocyte growth factor (HGF) to its receptor (c-Met) regulates gastric cancer progression and metastasis. Recently, HGF was found to up-regulate the expression of cyclooxygenase-2 (COX-2) gene and increase prostaglandin (PG)synthesis in gastric mucosa cells. Over-expression of COX-2 and increased PG secretion have also been found to be involved in the growth and metastasis of gastric cancer. These results together suggest that the signaling pathway of HGF and c-Met may be mediated through ERK2 activation, up-regulation of COX-2 and increased production of PGE(2)in gastric cancer cells. In view of the fact that c-Met is over-expressed in the majority of gastric cancer patients with poor prognosis, COX-2 specific inhibitors may provide beneficial effects in these patients.

Characterization of early gastric cancer and proposal of the optimal therapeutic strategy

BACKGROUND AND AIMS

The optimal protocol of the treatment for early gastric cancer has not been fully established. The current study was designed to elucidate the relationship between the depth of tumors with or without an ulcer and the presence of lymph node metastasis and to establish the optimal and practical therapeutic strategy for patients with early gastric cancer.

PATIENTS AND METHODS

A retrospective analysis of 1051 patients with early gastric cancer treated by gastrectomy with D1 or D2 lymph node dissection was performed. The patients were divided into those with mucosal (M) tumors and those with submucosal (SM) tumors. These 2 groups were subclassified, depending on the coexistence of ulcer or the degree of submucosal invasion, and were characterized in relation to clinicopathologic factors and 5-year prognosis.

RESULTS

The incidence of lymph node metastases from SM tumors (19.8%, 85 of 430) was more frequent than that from M tumors (2.3%, 14 of 621) (P <.001). All M tumors with lymph node involvement, including tumors smaller than 1.5 cm in diameter, had ulceration or ulceration scar in the lesions. SM tumors that had invaded less than 200 microm in depth (SM1a) had significantly less lymph node involvement than those with deeper invasion. The node metastases were confined to epigastric lymph nodes (N1) in both M tumors with ulceration or ulceration scar and SM1a tumors.

CONCLUSIONS

All macroscopic M tumors without ulceration or ulceration scar should be considered for endoscopic mucosal resection. The need for reoperation for a formal gastrectomy with lymphadenectomy or a limited surgical operation will vary depending on the pathologic analysis of endoscopic mucosal resection specimens (depth of invasion, presence of ulceration).