Prognostic factors for advanced gastric cancer: stage-stratified analysis of patients who underwent curative resection

Establishment and evaluation of a prognostic model for patients with unresectable gastric cancer liver metastases

BACKGROUND

Liver metastases (LM) is the primary factor contributing to unfavorable outcomes in patients diagnosed with gastric cancer (GC). The objective of this study is to analyze significant prognostic risk factors for patients with GCLM and develop a reliable nomogram model that can accurately predict individualized prognosis, thereby enhancing the ability to evaluate patient outcomes.

AIM

To analyze prognostic risk factors for GCLM and develop a reliable nomogram model to accurately predict individualized prognosis, thereby enhancing patient outcome assessment.

METHODS

Retrospective analysis was conducted on clinical data pertaining to GCLM (type III), admitted to the Department of General Surgery across multiple centers of the Chinese PLA General Hospital from January 2010 to January 2018. The dataset was divided into a development cohort and validation cohort in a ratio of 2:1. In the development cohort, we utilized univariate and multivariate Cox regression analyses to identify independent risk factors associated with overall survival in GCLM patients. Subsequently, we established a prediction model based on these findings and evaluated its performance using receiver operator characteristic curve analysis, calibration curves, and clinical decision curves. A nomogram was created to visually represent the prediction model, which was then externally validated using the validation cohort.

RESULTS

A total of 372 patients were included in this study, comprising 248 individuals in the development cohort and 124 individuals in the validation cohort. Based on Cox analysis results, our final prediction model incorporated five independent risk factors including albumin levels, primary tumor size, presence of extrahepatic metastases, surgical treatment status, and chemotherapy administration. The 1-, 3-, and 5-years Area Under the Curve values in the development cohort are 0.753, 0.859, and 0.909, respectively; whereas in the validation cohort, they are observed to be 0.772, 0.848, and 0.923. Furthermore, the calibration curves demonstrated excellent consistency between observed values and actual values. Finally, the decision curve analysis curve indicated substantial net clinical benefit.

CONCLUSION

Our study identified significant prognostic risk factors for GCLM and developed a reliable nomogram model, demonstrating promising predictive accuracy and potential clinical benefit in evaluating patient outcomes.

Association between Environmental Temperature and Survival in Gastroesophageal Cancers: A Population Based Study

BACKGROUND

Cold stress suppresses antitumor response in animal models, leading to tumor growth. Recent studies have also shown a negative correlation between the average annual temperature (AAT) and cancer incidence. We hypothesized that esophageal cancer (EC) and gastric cancer (GC) patients living in warmer climates have improved survival outcomes than those living in colder climates.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database from 1996 to 2015. We retrieved the National Centers for Environmental Information data to calculate the county-level AAT. Cox multivariate regression models were performed to measure the association between temperature (measured continuously at diagnosis and in 5-degree increments) and OS/DSS, adjusting for variables. All associations were compared at a significance level of 0.05. The OS and DSS were summarized using Kaplan-Meier methods. All statistics were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA).

RESULTS

A total of 17,408 EC patients were analyzed. The average age of the cohort was 65 years, 79% of which were males and 21% were females. Of them, 61.6% had adenocarcinoma, and 37.6% were squamous. After adjusting for covariates, patients in regions with an AAT > 53.5 °F had an 11% improvement in OS [HR 0.89 (95% CI 0.86-0.92), p < 0.0001] and 13% in DSS [HR 0.87 (95% CI 0.84-0.90), p < 0.0001]. When the temperature was analyzed in 5 °F increments, with each increment, there was a 3% improvement in OS [HR 0.97 (95% CI 0.96-0.98), p < 0.0001] and 4% in DSS [HR 0.96 (95% CI 0.95-0.97), p < 0.0001]. Subgroup analysis of squamous and adenocarcinoma showed similar results. These findings were validated in 20,553 GC patients. After adjusting for covariates, patients in regions with an AAT > 53.5 had a 13% improvement in OS [HR 0.87 (95% CI 0.85-0.90), p < 0.0001] and 14% in DSS [HR 0.86 (95% CI 0.83-0.89), p < 0.0001]. When analyzed in 5 °F increments, with each increment, there was a 4% improvement in OS [HR 0.96 (95% CI 0.952-0.971), p < 0.0001] and 4% in DSS [HR 0.96 (95% CI 0.945-0.965), p < 0.0001].

CONCLUSION

We showed for the first time that higher environmental temperatures are associated with significant improvements in OS and DSS in patients with gastro-esophageal cancers, notwithstanding the limitations of a retrospective database analysis. Further confirmatory and mechanistic studies are required to implement specific interventional strategies.

Separating lymph node stations by the surgeon from the gastric cancer specimen improves the quality of nodal status evaluation

BACKGROUND

In gastric cancer (GC), the pN-stage is an important prognostic factor influencing treatment. Along with the depth of invasion of the tumor, the presence of nodal metastases is one of the most important prognostic factors guiding treatment strategies in gastric cancer. Examining a small number of lymph nodes may lead to understaging of the disease; hence, it is essential for the nodal status to be precisely assessed. In this study, we explored whether dissecting lymph node stations into separate samples by the surgeon from the gastric cancer surgical specimen affects the quality of nodal status evaluation and patient outcome.

METHODS

The clinical data of 130 GC patients treated at the Helsinki University Hospital between 2016 and 2019 was reviewed. The performed operations included 59 total and 71 subtotal gastrectomies. The processing of the surgical specimen before the pathological examination was assessed from the operation records and pathology reports. The association of the number of examined lymph nodes with other variables was assessed, and multivariate survival analysis was performed to explore the independent prognostic factors in disease-specific survival.

RESULTS

Dissecting lymph node stations into separate specimens before pathological evaluation yielded a significantly greater number of examined lymph nodes compared with a specimen without intervention (median 34.5 vs 21.0, p < 0.001). The pT-stage, the pN-stage, and the extent of lymphadenectomy were identified as independent prognostic factors, whereas dissecting the specimen's lymph node stations did not associate with survival.

CONCLUSIONS

Dissecting lymph node stations into separate specimens results in a greater number of examined lymph nodes, which has the potential to lead to a more reliable pN-stage assessment.

Survival of gastric cancer patients in Iran: a systematic review and meta-analysis

Aim

This study aimed to estimate the survival rates among Iranian gastric cancer patients and to evaluate if the survival has improved during the last three decades.

Background

Gastric cancer is one of the most common cancers in Iran with high mortality.

Methods

A systematic review and meta-analysis of all published studies addressing gastric cancer survival in Iran was performed. International databases of Scopus, Web of Science, PubMed, and Iranian databases were included in the study. The study included databases from their inception till February 2022. Due to the inherent heterogeneity, we used a random effect model to pool the survivals in three categories of one, three, and five-year survivals.

Results

Thirty-three studies with total cases of 17,207 were included in the study. The overall (pooled) one, three, and five-year survivals were estimated as 58.9% (95% CI: 0.52, 0.66), 29.9% (95% CI: 0.25, 0.35), and 18.2% (95% CI: 0.15, 0.23), respectively. Results of subgroup analysis for the calendar years of study showed that the one, three, and five-year survival rates increased during the last three decades but the results were not statistically significant. There was the disparity in survival based on geographic distribution.

Conclusion

The results of our study which has pooled many studies for a long period of time clearly indicate that the survival rates of gastric cancer patients have improved. As the improvement of survival may be due to many factors, more studies is needed to understand the dynamic behind this improvement.

Dynamic gene screening enabled identification of a 10-gene panel for early detection and progression assessment of gastric cancer

Early diagnosis and progression assessment are critical for the timely detection and treatment of gastric cancer (GC) patients. Identification of diagnostic biomarkers for early detection of GC represents an unmet clinical need, and how these markers further influence GC progression is explored rarely. We performed dynamic gene screening based on high-throughput data analysis from patients with precancerous lesions and early gastric cancer (EGC) and identified a 10-gene panel by the lasso regression model. This panel demonstrated good diagnostic performance in TCGA (AUC = 0.95, sensitivity = 86.67 %, specificity = 90.63 %) and GEO (AUC = 0.84, sensitivity = 91.67 %, specificity = 78.13 %) cohorts. Moreover, three GC subtypes were clustered based on this panel, in which cluster 2 (C2) demonstrated the highest tumor progression level with a high expression of 10 genes, showing a decreased tumor mutation burden, significantly enriched epithelial-mesenchymal transition hallmark and increased immune exclusion/exhausted features. Finally, the cell localization of these panel genes was explored in scRNA-seq data based on more than 40,000 cells. The 10-gene panel is expected to be a new clinical early detection signature for GC and may aid in progression assessment and personalized treatment of patients.

Factors Associated With Geographic Disparities in Gastrointestinal Cancer Mortality in the United States

BACKGROUND & AIMS

Significant geographic variability in gastrointestinal (GI) cancer-related death has been reported in the United States. We aimed to evaluate both modifiable and nonmodifiable factors associated with intercounty differences in mortality due to GI cancer.

METHODS

Data from the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research platform were used to calculate county-level mortality from esophageal, gastric, pancreatic, and colorectal cancers. Multivariable linear regression models were fit to adjust for county-level covariables, considering both patient (eg, sex, race, obesity, diabetes, alcohol, and smoking) and structural factors (eg, specialist density, poverty, insurance prevalence, and colon cancer screening prevalence). Intercounty variability in GI cancer-related mortality explained by these covariables was expressed as the multivariable model R².

RESULTS

There were significant geographic disparities in GI cancer-related county-level mortality across the US from 2010-2019 with the ratio of mortality between 90th and 10th percentile counties ranging from 1.5 (pancreatic) to 2.1 (gastric cancer). Counties with the highest 5% mortality rates for gastric, pancreatic, and colorectal cancer were primarily in the Southeastern United States. Multivariable models explained 43%, 61%, 14%, and 39% of the intercounty variability in mortality rates for esophageal, gastric, pancreatic, and colorectal cancer, respectively. Cigarette smoking and rural residence (independent of specialist density) were most strongly associated with GI cancer-related mortality.

CONCLUSIONS

Both patient and structural factors contribute to significant geographic differences in mortality from GI cancers. Our findings support continued public health efforts to reduce smoking use and improve care for rural patients, which may contribute to a reduction in disparities in GI cancer-related death.

Characterization of the Prognostic Values of CXCL Family in Epstein-Barr Virus Associated Gastric Cancer

Background

CXCL family is a class of secreted growth factors signaling through G-protein-coupled receptors, and abnormal expression is associated with the growth and progression of many tumors. However, their prognostic value has been poorly studied in Epstein-Barr virus- (EBV-) associated gastric cancer (EBVaGC). Therefore, it is of great significance to explore the prognostic value of the CXCL family in EBVaGC.

Methods

CXCL family mRNA expression was analyzed in STAD data from The Cancer Genome Atlas (TCGA). Kaplan-Meier Plotter was used to assess the prognostic value of the CXCL family. Transcription factors (TFs) and miRNAs associated with the CXCL family were identified by TFCheckpoint, miRWalk, and ViRBase databases. The prognostic model was evaluated using the EBVaGC patient cohort GSE51575.

Results

The mRNA expression of CXCL1/3/5/6/8/9/10/11/16 was significantly upregulated, while the expression of CXCL12/14 was downregulated in EBVaGC compared with normal tissues from TCGA-STAD. The mRNA expressions of CXCL9, CXCL10, CXCL11, and CXCL17 in EBVaGCs were higher than those in EBVnGCs, but the mRNA expressions of CXCL6, CXCL12, and CXCL17 were lower than those in EBVnGCs. The mRNA expression levels of CXCL9, CXCL10, and CXCL11 in EBVaGCs were higher than those in EBVnGCs regardless of the tumor stage. High mRNA expression of CXCL8 was associated with better OS in patients with EBVaGC, while high expression of CXCL9 was associated with better OS in patients with EBVnGC. We obtained 10 candidate potential transcription factors (TFs) associated with CXCLs: OTOP3, NKX6-2, NKX2-2, FEV, SMYD1, TRIMSO, TBX10, CDX1, SLC26A3, and ARC. 576 miRNA-mRNA interactions were obtained. Among them, 65 miRNAs were predicted to be correlated with CXCL6, CXCL9, CXCL10, and CXCL11. Similar to the results of TCGA-STAD, the GSE51575 dataset also showed that the mRNA expression levels of CXCL1/3/9/10/11/16 were markedly enhanced in EBVaGC tissues compared with corresponding normal gastric mucosa tissues, while the mRNA expression levels of CXCL12/14 were significantly reduced. The mRNA expression levels of CXCL3/9/10/11/13/17 were increased in EBVaGC compared with EBVnGC tissues.

Conclusions

The expression differences of CXCL family members are closely associated with the progression of EBVaGC. Expression of CXCL9/10/11/17 mRNA may be a promising prognostic indicator for EBVaGC patients.

Quantification of the Landscape for Revealing the Underlying Mechanism of Intestinal-Type Gastric Cancer

Gastric cancer is a daunting disease with a tragic impact on global health. It is the fourth most common cancer and has become the second most frequent cause of cancer death in recent times. According to the Lauren classification, gastric cancer can be classified into two types: intestinal and diffuse. Intestinal-type gastric cancer (IGC) is more common in elderly people, and atrophic gastritis (AG) and intestinal metaplasia (IM) have been proven to be the main premalignant causes of intestinal-type gastric cancer. In turn, Helicobacter pylori infection has been identified as the most significant cause of AG and IM. In this study, we determine the mechanism of IGC progression and how H. pylori infection induces IGC. Through researching the relevant literature, we identified the key genes associated with gastric cancer and the specific genes associated with IGC. We then use hese genes to build up a gene regulatory network for IGC. Based on this gene regulatory network, we quantify the IGC landscape. Within this landscape, there are three stable states, which are classified as the normal, AG, and gastric cancer states. Through landscape topography, we can determine the biological features and progression process of IGC. To investigate the influence of H. pylori infection on IGC, we simulated different degrees of H. pylori infection. As the H. pylori infection becomes more serious, the landscape topography changes accordingly. A fourth state, named the intestinal metaplasia (IM) state, emerges on the landscape and is associated with a very high risk of developing gastric cancer. The emergence of this state is due to the interactions/regulations among genes. Through variations in the landscape topography, we can determine the influence of H. pylori infection on IGC. Finally, we use global sensitivity analysis to research the regulations most sensitive to IGC prevention or therapies. This study presents a new approach and a novel model with which to explore the mechanism of IGC. The simulations of different degrees of H. pylori infection can provide us with a systematic view of IGC progression. The key regulations found can give us some insight and guidance for clinical trials and experimental studies.

Systemic Immune-Inflammation Index as a Prognostic Marker of Late Recurrence in Operable Gastric Cancer: a Dual-Center Study

AIM

To evaluate the prognostic role of the systemic immune-inflammation index (SII) in patients with operable gastric cancer.

METHODS

We assessed 354 patients with operable gastric cancer from tertiary centers in Turkey. SII was calculated by following formula: [neutrophil (cells × 10⁹/L) × platelet (cells × 10⁹/L)]/lymphocyte (cells × 10⁹/L). The best cut-off value for SII was determined by using "receiver operating characteristics (ROC)" analysis. We used log-rank and Cox-regression analysis for survival analyses.

RESULTS

One hundred twenty patients were in the late recurrence group (recurrences have developed 36 months after the surgery). SII was not a prognostic factor in the early recurrence group. However, relapse-free survival (RFS) was longer in SII-low patients than SII-high patients in the late recurrence group. In multivariable analysis, SII was the only independent prognostic factor for RFS in the late recurrence group (hazard ratio (HR): 5.42, 95% CI: 1.18-24.82, p = 0.03).

CONCLUSION

SII was an independent prognostic factor for RFS in GC patients with late recurrence. Late recurrence risk was higher in SII-high patients than SII-low patients. Inflammation contributes to tumor progression, invasion, and metastasis. Prolonged exposure to chronic inflammation could explain the results of this study.

Early Weight Loss as a Prognostic Factor in Patients with Advanced Gastric Cancer: Analyses from REGARD, RAINBOW, and RAINFALL Phase III Studies

BACKGROUND

Weight loss is common in advanced gastric and gastroesophageal junction adenocarcinoma (G/GEA); however, the prognostic implications of weight loss during the first cycle (C1) of chemotherapy remain poorly characterized. In this study, we investigated the impact of early weight loss during systemic treatment as a potential prognostic factor for overall survival (OS) in patients with advanced G/GEA.

MATERIALS AND METHODS

We performed a post hoc analysis of three phase III studies of ramucirumab. Patients were categorized into two groups: weight loss of ≥3% and <3% based on weight change during C1 (3-4 weeks) of treatment. OS by weight groups was assessed for each study and as a pooled meta-analysis. The effect of C1 weight change on patient survival was evaluated using univariate and multivariate Cox models.

RESULTS

A total of 1,464 patients with weight data at the end of C1 were analyzed: REGARD (n = 311), RAINBOW (n = 591), and RAINFALL (n = 562). For all three studies, there were fewer patients in the weight loss ≥3% than <3% group. OS was numerically shorter for patients with weight loss of ≥3% than for patients with weight loss of <3% during C1 irrespective of treatment arm. Similar treatment independent effects of early weight loss on OS were observed in the meta-analysis. Overall, early weight loss ≥3% was associated with shorter survival in patients receiving active drug as well as placebo/best supportive care.

CONCLUSION

This large post hoc analysis demonstrated that weight loss of ≥3% during C1 was a negative prognostic factor for OS in patients with advanced G/GEA.

IMPLICATIONS FOR PRACTICE

This comprehensive analysis examining early weight loss during systemic treatment as a predictor of survival outcomes in patients with advanced gastric and gastroesophageal junction adenocarcinoma (G/GEA) includes a large sample size, reliable on-treatment data reported in well-conducted phase III clinical trials, and global representation of cancer patients with advanced G/GEA. Understanding the impact of on-treatment weight loss is clinically relevant and may represent an opportunity for targeted interventions.

Lymph Node Involvement in Advanced Gastric Cancer in the Era of Multimodal Treatment-Oncological and Surgical Perspective

Simple Summary

Gastric cancer (GC) continues to be one of the major oncological challenges on a global scale. The role of neoadjuvant chemotherapy (NAC) in GC is to downstage primary tumour, eliminate potential micrometastases, and increase the chance for radical resection. Although systemic treatment prolongs the survival in advanced GC, persistent lymph node (LN) metastases indicate poor prognosis. Therefore, further identification of prognostic factors after NAC is urgent and could positively influence clinical outcomes. This article aimed to review the actual trends and future perspectives in multimodal therapy of advanced GC, with a particular interest in the post-neoadjuvant pathological nodal stage. Since downstaged and primarily node-negative patients show a similar prognosis, the main target for NAC in advanced GC should be nodal clearance. Adequate staging and personalised perioperative therapy seem to be of great importance in the multimodal treatment of GC.

Abstract

Gastric cancer (GC) continues to be one of the major oncological challenges on a global scale. The role of neoadjuvant chemotherapy (NAC) in GC is to downstage primary tumour, eliminate potential micrometastases, and increase the chance for radical resection. Although systemic treatment prolongs the survival in advanced GC, persistent lymph node (LN) metastases indicate poor prognosis. Further identification of prognostic factors after NAC is urgent and could positively influence clinical outcomes. This article aimed to review the actual trends and future perspectives in multimodal therapy of advanced GC, with a particular interest in the post-neoadjuvant pathological nodal stage. A favourable prognostic impact for ypN0 patients is observed, either due to truly negative LN before the start of therapy or because preoperative therapy achieved a pathologically complete nodal response. Ongoing trials investigating the extent of lymphadenectomy after neoadjuvant therapy will standardise the LN dissection from the multimodal therapy perspective. Since downstaged and primarily node-negative patients show a similar prognosis, the main target for NAC in advanced GC should be nodal clearance. Adequate staging and personalised perioperative therapy seem to be of great importance in the multimodal treatment of GC.

Tubular gastric adenocarcinoma: machine learning-based CT texture analysis for predicting lymphovascular and perineural invasion

PURPOSE

Lymphovascular invasion (LVI) and perineural invasion (PNI) are associated with poor prognosis in gastric cancers. In this work, we aimed to investigate the potential role of computed tomography (CT) texture analysis in predicting LVI and PNI in patients with tubular gastric adenocarcinoma (GAC) using a machine learning (ML) approach.

METHODS

Sixty-eight patients who underwent total gastrectomy with curative (R0) resection and D2-lymphadenectomy were included in this retrospective study. Texture features were extracted from the portal venous phase CT images. Dimension reduction was first done with a reproducibility analysis by two radiologists. Then, a feature selection algorithm was used to further reduce the high-dimensionality of the radiomic data. Training and test splits were created with 100 random samplings. ML-based classifications were done using adaptive boosting, k-nearest neighbors, Naive Bayes, neural network, random forest, stochastic gradient descent, support vector machine, and decision tree. Predictive performance of the ML algorithms was mainly evaluated using the mean area under the curve (AUC) metric.

RESULTS

Among 271 texture features, 150 features had excellent reproducibility, which were included in the further feature selection process. Dimension reduction steps yielded five texture features for LVI and five for PNI. Considering all eight ML algorithms, mean AUC and accuracy ranges for predicting LVI were 0.777-0.894 and 76%-81.5%, respectively. For predicting PNI, mean AUC and accuracy ranges were 0.482-0.754 and 54%-68.2%, respectively. The best performances for predicting LVI and PNI were achieved with the random forest and Naive Bayes algorithms, respectively.

CONCLUSION

ML-based CT texture analysis has a potential for predicting LVI and PNI of the tubular GACs. Overall, the method was more successful in predicting LVI than PNI.

Immunohistochemical and genetic features of mucinous and signet-ring cell carcinomas of the stomach, colon and rectum: a comparative study

Gastric and colorectal cancers are prevalent and fatal cancers worldwide. Although mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC) are relatively uncommon, they are of critical importance because of poor prognosis. In Turkey, studies on MSI and other molecular characteristics in mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC) of stomach and colon have not been conducted. The present study aimed to investigate the similarities and differences between gastric/colorectal MACs and SRCCs. A total of 590 patients with gastric carcinoma and 1075 patients with colorectal carcinoma, in whom pathologic diagnosis was made within a period of 8 years in our hospital, were retrospectively evaluated. Tissue blocks and slides obtained from the pathology archive were used for immunohistochemical and genetic studies and for microscopic re-evaluation according to the WHO criteria. Data from a total of 135 patients, of whom 78 had been diagnosed with MAC and 57 had been diagnosed with SRCC, were analyzed. MAC patients were significantly older than those with SRCCs. While colorectal localization was more common among MACs, SRCC patients mostly showed gastric localization. Macroscopically, ulceroinfiltrative type was the most prevalent in both groups followed by fungating type in MAC and infiltrative type in SRCC. When compared with SRCC group, MAC group was associated with higher tumor invasion stage, lower rate of patients with infiltrative growth pattern and perineural invasion, and less frequent lymph node invasion. More effective approaches will be developed in the treatment and prevention of cancer along with more data about the incidence, pathogenesis, prognostic factors, and clinical course of cancers.

Should All Stage N3b Patients with Advanced Gastric Cancer Be Considered Equivalent? A 30-Year Single Center Study

PURPOSE

To investigate the survival of stage N3b patients with advanced gastric cancer (AGC) after radical surgery and to evaluate the TNM staging of subgroups of stage N3b patients.

METHODS

We reviewed the data of 222 stage N3b patients with AGC who underwent D2/D3 radical surgery. Depending on the number of metastatic lymph nodes (MLNs), we divided N3b patients into several groups and compared the survival differences among them. We found that survival of patients with 16-20 MLNs was better than that of patients with ≥ 21 MLNs. Therefore, we divided the N3b patients into two subgroups and defined patients with 16-21 MLNs as N3b1 and patients with ≥ 21 MLNs as N3b2. Then, we compared survival differences between the two groups and their subgroups. Patients who underwent palliative surgery served as the reference group. In addition, we selected stage IIIB, IIIC, and IV patients from the same database to properly re-classify the N3b subgroups in the TNM staging system.

RESULTS

Survival differed significantly between the new N3b1and N3b2 groups and between the new N3b1 group and the palliative group. However, the survival of the new N3b2 group was similar to that of the palliative group. Comparisons of survival according to T staging revealed similarities between the following groups: (1) stages T2-3N3b1 and IIIB, (2) stages T4N3b1 and IIIC, and (3) stages T2-4N3b2 and IV.

CONCLUSIONS

All stage N3b patients with AGC should not be considered equivalent. A significant difference in survival was observed between stage N3b1 and N3b2 patients after radical surgery, while the survival of stage N3b2 patients was similar to that of patients who undergo palliative surgery. We recommend re-classifying stage T2-3N3b1 as TNM stage IIIB, stage T4N3b1 as stage IIIC, and T2-4N3b2 as stage IV.

Computational Drug Repositioning for Gastric Cancer using Reversal Gene Expression Profiles

Treatment of gastric cancer (GC) often produces poor outcomes. Moreover, predicting which GC treatments will be effective remains challenging. Computational drug repositioning using public databases is a promising and efficient tool for discovering new uses for existing drugs. Here we used a computational reversal of gene expression approach based on effects on gene expression signatures by GC disease and drugs to explore new GC drug candidates. Gene expression profiles for individual GC tumoral and normal gastric tissue samples were downloaded from the Gene Expression Omnibus (GEO) and differentially expressed genes (DEGs) in GC were determined with a meta-signature analysis. Profiles drug activity and drug-induced gene expression were downloaded from the ChEMBL and the LINCS databases, respectively. Candidate drugs to treat GC were predicted using reversal gene expression score (RGES). Drug candidates including sorafenib, olaparib, elesclomol, tanespimycin, selumetinib, and ponatinib were predicted to be active for treatment of GC. Meanwhile, GC-related genes such as PLOD3, COL4A1, UBE2C, MIF, and PRPF5 were identified as having gene expression profiles that can be reversed by drugs. These findings support the use of a computational reversal gene expression approach to identify new drug candidates that can be used to treat GC.

Gene expression signature for detection of gastric cancer in peripheral blood

Gastric cancer (stomach cancer) is the fifth most common malignancy and the third leading cause of cancer-associated mortality worldwide. Identifying gastric cancer patients at an early and curable stage of the disease is essential if mortality rates for this disease are to decrease. A non-invasive blood-based test that is an indicator of gastric cancer risk would likely be of benefit in identifying gastric cancer patients at an early stage, and such a test may enhance clinical decision making. This study identified a four-gene expression signature in peripheral blood samples associated with gastric cancer. A total of 216 blood samples were collected, including those from 36 gastric cancer patients, 55 healthy controls and 125 patients with other carcinomas, and gene expression profiles were examined using an Affymetrix Gene Profiling microarray. Blood gene expression profiles were compared between patients with stomach cancer, healthy controls and patients affected with other malignancies. A four-gene panel was identified comprising purine-rich element binding protein B, structural maintenance of chromosomes 1A, DENN/MADD domain containing 1B and programmed cell death 4. The four-gene panel discriminated gastric cancer with an area under the receiver-operating-characteristic curve of 0.99, an accuracy of 95%, sensitivity of 92% and specificity of 96%. The non-invasive nature of the blood test, together with the relatively high accuracy of the four-gene panel may assist physicians in gastric cancer screening decision making.

Genetic host factors in Helicobacter pylori-induced carcinogenesis: Emerging new paradigms

Helicobacter Pylori is a gram negative rod shaped microaerophilic bacterium that colonizes the stomach of approximately half the world's population. Infection with c may cause chronic gastritis which via a quite well described process known as Correas cascade can progress through sequential development of atrophic gastritis, intestinal metaplasia and dysplasia to gastric cancer. H. pylori is currently the only bacterium that is classified as a class 1 carcinogen by the WHO, although the exact mechanisms by which this bacterium contributes to gastric carcinogenesis are still poorly understood. Only a minority of H. pylori-infected patients will eventually develop gastric cancer, suggesting that host factors may be important in determining the outcome of H. pylori infection. This is supported by a growing body of evidence suggesting that the host genetic background contributes to risk of H. pylori infection and gastric carcinogenesis. In particular single nucleotide polymorphisms in genes that influence bacterial handling via pattern recognition receptors appear to be involved, further strengthening the link between host risk factors, H. pylori incidence and cancer. Many of these genes influence cellular pathways leading to inflammatory signaling, inflammasome formation and autophagy. In this review we summarize known carcinogenic effects of H. pylori, and discuss recent findings that implicate host genetic pattern recognition pathways in the development of gastric cancer and their relation with H. pylori.

Comparison of capecitabine and oxaliplatin with S-1 as adjuvant chemotherapy in stage III gastric cancer after D2 gastrectomy

Aim

To compare capecitabine and oxaliplatin (XELOX) with S-1 as adjuvant chemotherapy in stage III gastric cancer after D2 gastrectomy.

Methods

Clinical data from 206 patients who received XELOX or S-1 regimens as adjuvant chemotherapy in stage III gastric cancer were collected. Patients were divided into 2 groups according to regimen; the groups were XELOX (n = 114) and S-1 monotherapy (n = 92).

Results

3-year disease-free survival (DFS) was higher in the S-1 group than in the XELOX group (66.6% vs 59.1%; p = 0.636). 3-year overall survival (OS) was 75.6% in the S-1 group and 69.6% in the XELOX group (p = 0.495). But, the difference was not statistically significant. Especially, for patients with stage IIIC disease, 3-year overall survival was 55.2% in the XELOX group and 39.0% in the S-1 group (hazard ratio, HR 0.50, 95% confidence interval, CI 0.23–1.10; p = 0.075). In multivariate analysis, N stage (HR, 5.639; 95% CI, 1.297–24.522; p = 0.021) and cycle completion as planned (HR, 5.734; 95% CI, 3.007–10.936; p<0.001) were independent predictors of overall survival.

Conclusion

Adjuvant XELOX and S-1 regimen did not prove anything superior for stage III gastric cancer in this study. But, XELOX had a tendency to be superior to S-1 in stage IIIC gastric cancer after D2 gastrectomy although the difference was not statistically significant. N stage and cycle completion as planned were prognostic factors.

Clinicopathological and molecular stability and methylation analyses of gastric papillary adenocarcinoma

The molecular alterations and pathological features of gastric papillary adenocarcinoma (GPA) remain unknown. We examined GPA samples and compared their molecular and pathological characteristics with those of gastric tubular adenocarcinoma (GTA). Additionally, we identified pathological and molecular features of GPA that vary with microsatellite stability. In the present study, samples from 63 GPA patients and 47 GTA patients were examined using a combination of polymerase chain reaction (PCR)-microsatellite assays and PCR-pyrosequencing in order to detect microsatellite instability (microsatellite instability, MSI; microsatellite stable, MSS), methylation status (low methylation, intermediate methylation and high methylation level), and chromosomal AI in multiple cancer-related loci. Additionally, the expression levels of TP53 and Her2 were evaluated using immunohistochemistry. GTA and GPA are statistically different in their frequency of pathological features, including mucinous, poorly differentiated and invasive micropapillary components. Clear genetic patterns differentiating GPA and GTA could not be identified with a hierarchical cluster analysis, but microsatellite stability was linked with TP53 and Her2 overexpression. Methylation status in GPA was also associated with the development of high microsatellite instability. However, no pathological differences were associated with microsatellite stability. We suggest that although molecular alterations in a subset of GPAs are closely associated with microsatellite stability, they play a minor role in GPA carcinogenesis.

Early postoperative tumor marker responses provide a robust prognostic indicator for N3 stage gastric cancer

The clinical significance of tumor markers after radical gastrectomy has not been well characterized. The purpose of this study is to evaluate the prognostic value of early postoperative tumor marker normalization in N3 stage gastric cancer (GC) patients. A total of 259 N3 stage GC patients with preoperatively elevated carcinoembryonic antigen (CEA, >5 ng/mL) or carbohydrate antigen 19-9 (CA19-9, >37 U/mL) levels underwent radical gastrectomy were analyzed retrospectively. Early postoperative tumor marker response was considered as a normalization of CEA or CA19-9 levels 4 weeks after surgery. The disease-free survival (DFS) and overall survival (OS) were analyzed. N3 stage GC patients were divided into N3a (n = 157) and N3b (n = 102) groups according to the 8th TNM stage system. Early tumor marker response was identified in 96 of 157 N3a patients (61.15%) and 57 of 102 N3b patients (55.88%). In N3 stage GC patients with a tumor marker response, significant increase was observed in both DFS (25.2 months vs 12.5 months, P < .001) and OS (32.5 months vs 18.5 months, P < .001) compared with those without tumor marker response. N3b patients with a tumor marker response showed more favorable DFS (19.2 months vs 13.6 months, P = .019) and OS (25.8 months vs 19.0 months, P = .013) compared with N3a patients lacking a tumor marker response. Multivariate analysis revealed that early tumor marker response was an independent factor for DFS and OS in N3 stage GC, as well as for depth of invasion and metastatic lymph node rate (P < .05). Early postoperative CEA or CA19-9 normalization serves as a strong prognostic indicator in N3 stage GC. Both N3a and N3b patients with increased early postoperative tumor marker levels showed poor outcomes.

Impact of the Surveillance Interval on the Survival of Patients Who Undergo Curative Surgery for Gastric Cancer

BACKGROUND

For patients who undergo gastrectomy for gastric cancer, systematic follow-up evaluation to detect recurrent lesions is recommended, although the benefits of a surveillance program using short-term imaging studies have not been evaluated.

METHODS

This study reviewed the clinical data of patients who underwent curative surgery for gastric cancer using a prospective database. Patients with recurrence were classified according to surveillance interval as follows: ≤3, 3-6, and 6-12 months.

RESULTS

Of the 2785 patients who underwent curative surgery for gastric cancer, 376 (13.5 %) had intraabdominal recurrences, excluding the stomach. Multivariable analysis showed that a short surveillance interval did not increase the post-recurrence survival duration (with 6-12 months as the reference: ≤3 months: hazard ratio [HR] 0.954; 95 % confidence interval [CI] 0.689-1.323; 3-6 months: HR 0.994, 95 % CI 0.743-1.330). In addition, short surveillance intervals did not increase overall survival (with 6-12 months as the reference: ≤3 months: HR 0.969; 95 % CI 0.699-1.342; 3-6 months: HR 0.955; 95 % CI 0.711-1.285). In contrast to the surveillance interval, age, cancer stage, symptoms at recurrence, and recurrence time after gastrectomy were factors associated with both post-recurrence survival and overall survival.

CONCLUSIONS

Although the detection of recurrence before symptoms helped to prolong both post-recurrence survival and overall survival, shortening the surveillance interval to less than 6 months did not improve either the patient's post-recurrence survival or overall survival. Hence, it is not recommended that asymptomatic patients undergo surveillance involving imaging studies more often than once a year.

Review of atrophic gastritis and intestinal metaplasia as a premalignant lesion of gastric cancer

Atrophic gastritis (AG) and intestinal metaplasia (IM) are the main precursor lesions of gastric cancer as the incidence of gastric cancer increases in the gastric mucosa involved with AG and IM. The prevalence of AG and IM vary depending on countries, even it represents diverse results in the same nation. Usually AG is antecedent of IM but the etiologies of AG and IM are not always the same. The sensitivity and specificity of diagnostic methods to detect AG and IM are different. Furthermore, the management strategy of AG and IM has not been established, yet. Helicobacter pylori infection has been proved as the most important cause of AG and IM. Thus the eradication of H. pylori is very important to prevent the progression to gastric cancer which is still placed in the high rank in morbidity and mortality among cancers. However, the reversibility of AG and IM by eradication of H. pylori which was assumed to be certain by meta-analysis is; however, controversial now. Therefore, the understanding and early diagnosis of AG and IM are very important, especially, in high incidence area of gastric cancer such as Republic of Korea.

Comparison of five staging systems of lymph node metastasis in the gastric carcinoma

BACKGROUND

The presence of metastatic lymph nodes is the most important prognostic factor for gastric carcinoma; however, the optimal system for the accurate staging of lymph node metastasis for patients with gastric cancer remains controversial. This study was designed to compare five systems in relation to the N classification of gastric carcinoma.

MATERIALS AND METHODS

This multicentric historical cohort study was conducted on 148 patients with M0 gastric adenocarcinoma who underwent gastrectomy in, five referral hospitals in Iran. Lymph nodes were sectioned, stained with hematoxyl in and eosin. The lymph node status was classified according to the five systems which are: The number of involved lymph nodes (TNM staging), metastatic lymph node ratio (N ratio), and the largest involved lymph node size, largest metastatic nest size and largest metastatic nest to lymph node size ratio.

RESULTS

Patients were classified into significant prognostic groups by the five N classification method including the TNM method, N ratio (0, ≤0.15, 0.15-0.4, >0.4), largest involved lymph node size (0, ≤5, 5-11, >11 mm), Largest metastatic nest size (≤1, 1-7.5, >7.5 mm) and largest metastatic nest to lymph node size ratio (≤0.3, 0.3-0.9, >0.9). All of the above systems remained as independently significant prognostic factors in terms of overall and disease free survival time.

CONCLUSION

Among the N staging systems we recommend the metastatic lymph node ratio and largest metastatic nest to lymph node size systems, since they are reproducible, simple, have good survival applicability, have prognostic value and include less stage migration especially in patients whom fewer than 15 lymph nodes are dissected.

Disappearance of Serum Methylated p16 Indicates Longer Survival in Patients with Gastric Cancer

Purpose

The aim of this study was to assess clinical correlations with postoperative alteration of p16 DNA methylation, and to clarify whether postoperative changes in the serum DNA methylation status of p16 could be used as a reliable prognostic factor for gastric cancer.

Materials and Methods

Fifty-three consecutive gastric adenocarcinoma patients who underwent gastric resection (Chung-Ang University Hospital, Seoul, Korea) were included. DNA methylation of p16 was evaluated by methylation-specific polymerase chain reaction using serum DNA preoperatively and at the 10th postoperative day. The correlation between changes in methylation status and patients' prognosis was analyzed.

Results

p16 was methylated in 79.2% of preoperative serum DNA and in 54.7% of postoperative serum DNA, respectively. Methylation in p16 disappeared more frequently in patients who underwent standard D2 lymphadenectomy compared to those who underwent modified D1+ lymphadenectomy (P=0.016). Whereas methylation of preoperative serum DNA was not correlated with survival, patients with postoperative disappearance of p16 methylation showed longer survival than those without postoperative disappearance of p16 methylation in the patients who had gastric cancer with lymph node metastasis (P=0.042).

Conclusions

Postoperative disappearance of p16 methylation could be an available prognostic factor for node-positive gastric cancer.

Prevalence and risk factors of atrophic gastritis and intestinal metaplasia: a nationwide multicenter prospective study in Korea

Background/Aims

Atrophic gastritis (AG) and intestinal metaplasia (IM) are premalignant gastric lesions. The aims of this study were to evaluate the prevalence of endoscopic AG and IM and to document the risk factors for these lesions.

Methods

In total, 4,023 subjects were enrolled at eight hospitals in Korea. AG and IM were diagnosed by endoscopy. Helicobacter pylori immunoglobulin G antibodies were measured.

Results

The prevalences of endoscopic AG and IM were 40.7% and 12.5%. In a multivariate analysis, the risk factors for AG were age groups of 40 to 59 years and >60 years, male sex, positive H. pylori serology, IM, and education below the college level (odds ratio [OR], 2.55, 5.00, 1.38, 1.41, 4.29, and 1.35, respectively). The risk factors for IM were age groups of 40 to 59 years and >60 years, male sex, positive H. pylori serology, AG, having relatives with gastric cancer, education below the college level and consumption of dairy products (OR, 3.16, 3.25, 1.88, 2.17, 3.68, 1.48, 1.47, and 1.40, respectively).

Conclusions

A nationwide survey regarding the prevalence of endoscopic AG and IM and their risk factors in Korea supports the hypothesis that endoscopic diagnosis of these premalignant lesions could be helpful to describe a group at high risk for gastric cancer.

High mobility group-box 3 overexpression is associated with poor prognosis of resected gastric adenocarcinoma

AIM: To elucidate high mobility group-box 3 (HMGB3) protein expression in gastric adenocarcinoma, its potential prognostic relevance, and possible mechanism of action.

METHODS: Ninety-two patients with gastric adenocarcinomas surgically removed entered the study. HMGB3 expression was determined by immunohistochemistry through a tissue microarray procedure. The clinicopathologic characteristics of all patients were recorded, and regular follow-up was made for all patients. The inter-relationship of HMGB3 expression with histological and clinical factors was analyzed using nonparametric tests. Survival analysis was carried out by Kaplan-Meier (log-rank) and multivariate Cox (Forward LR) analyses between the group with overexpression of HMGB3 and the group with low or no HMGB3 expression to determine the prognosis value of HMGB3 expression on overall survival. Further, HMGB3 expression was knocked down by small hairpin RNAs (shRNAs) in the human gastric cancer cell line BGC823 to observe its influence on cell biological characteristics. The MTT method was utilized to detect gastric cancer cell proliferation changes, and cell cycle distribution was analyzed by flow cytometry.

RESULTS: Among 92 patients with gastric adenocarcinomas surgically removed in this study, high HMGB3 protein expression was detected in the gastric adenocarcinoma tissues vs peritumoral tissues (P < 0.001). Further correlation analysis with patients’ clinical and histology variables revealed that HMGB3 overexpression was obviously associated with extensive wall penetration (P = 0.005), a positive nodal status (P = 0.004), and advanced tumor-node-metastasis (TNM) stage (P = 0.001). But there was no correlation between HMGB3 overexpression and the age and gender of the patient, tumor localization or histologic grade. Statistical Kaplan-Meier survival analysis disclosed significant differences in overall survival between the HMGB3 overexpression group and the HMGB3 no or low expression group (P = 0.006). The expected overall survival time was 31.00 ± 3.773 mo (95%CI = 23.605-38.395) for patients with HMGB3 overexpression and 49.074 ± 3.648 mo (95%CI = 41.925-57.311) for patients with HMGB3 no and low-level expression. Additionally, older age (P = 0.040), extensive wall penetration (P = 0.008), positive lymph node metastasis (P = 0.005), and advanced TNM tumor stage (P = 0.007) showed negative correlation with overall survival. Multivariate Cox regression analysis indicated that HMGB3 overexpression was an independent variable with respect to age, gender, histologic grade, extent of wall penetration, lymph nodal metastasis, and TNM stage for patients with resectable gastric adenocarcinomas with poor prognosis (hazard ratio = 2.791, 95%CI = 1.233-6.319, P = 0.019). In the gene function study, after HMGB3 was knocked down in the gastric cell line BGC823 by shRNA, the cell proliferation rate was reduced at 24 h, 48 h and 72 h. Compared to BGC823 shRNA-negative control (NC) cells, the cell proliferation rate in cells that had HMGB3 shRNA transfected was significantly decreased (P < 0.01). Finally, cell cycle analysis by FACS showed that BGC823 cells that had HMGB3 knocked down were blocked in G1/G0 phase. The percentage of cells in G1/G0 phase in BGC823 cells with shRNA-NC and with shRNA-HMGB3 was 46.84% ± 1.7%, and 73.03% ± 3.51% respectively (P = 0.001), whereas G2/M cells percentage decreased from 26.51% ± 0.83% to 17.8% ± 2.26%.

CONCLUSION: HMGB3 is likely to be a useful prognostic marker involved in gastric cancer disease onset and progression by regulating the cell cycle.

Prognostic improvement of reexcision for positive resection margins in patients with advanced gastric cancer

AIM

The aim of this study was to investigate the effect of reexcision for advanced gastric cancer (GC) with positive resection margins on prognosis and to identify the selection criteria for the reexcision of patients with positive margins.

PATIENTS AND METHODS

This was a retrospective study of 122 patients with positive margins who underwent potentially curative resection for locally advanced GC. The clinicopathological factors and survival among 50 patients who were reexcised to a negative resection margin (NR group) and 72 patients who were left with a positive resection margin (PR group) were compared using univariate and multivariate analyses.

RESULTS

Median survival in the PR group was 18 months compared with 23 months in the NR group (p = 0.019). In the ≤ pN2-category subset, the PR group had a significantly worse prognosis compared with the NR group (median survival of 25 months vs. 44 months; p = 0.021). This difference was not observed in the pN3-category subset. In the univariate analysis, variables including pTNM stage, pN-category, and positive resection margin had adverse effects on OS among the entire population of 122 patients. A positive margin was confirmed as an independent prognostic factor for OS in the multivariate analysis.

CONCLUSIONS

The reexcision of a positive margin improves the prognosis of patients with advanced GC, especially in those paitents with ≤ pN2-category disease and in patients undergoing D2 lymphadenectomy. Obtaining routine frozen sections of samples from the resection margin should be mandatory in the treatment of all GC patients undergoing potentially curative surgery.

Advanced gastric cancer in the middle one-third of the stomach: Should surgeons perform total gastrectomy?

BACKGROUND AND OBJECTIVES

To determine which optimal surgical procedure for middle-third advanced gastric cancer (AGC) based on comparative study of the long-term prognosis between total gastrectomy (TG) and distal gastrectomy (DG).

METHODS

Between March 1993 and December 2005, 402 patients with middle-third AGC who underwent gastric resection were enrolled in this study. We analyzed the long-term prognosis according to the length of the proximal resection margin (PRM) and the extent of gastric resection, and determined independent prognostic factors.

RESULTS

TG was performed in 244 patients (60.7%) and DG was performed in 158 patients (39.3%). There were no significant differences in the 5-year survival rates according to the length of PRM. The 5-year survival rates of patients who underwent DG were significantly higher than the rates of the patients who underwent TG in curative cases (67.8% vs. 58.4%, P = 0.037). Nevertheless, there was no significant difference in the stage-stratified survival rates according to the extent of gastric resection. Multivariate analysis revealed that surgical curability, extent of lymphadenectomy, and stage were independent prognostic factors.

CONCLUSION

If curative resection can be performed, the long-term prognosis of patients with middle-third AGC was not affected by the length of PRM or the extent of gastric resection.

STAT3 expression in gastric cancer indicates a poor prognosis

BACKGROUND AND AIM

Signal transducers and activators of transcription (STAT) behave as signal transducers in the cytoplasm and as transcription factors in the nucleus. In the current study, we analyzed the immunohistochemical staining patterns of gastrectomy tissue specimens. We investigated the expression of STAT3 and STAT5 and estimated the relationship between STAT and cancer prognosis.

METHODS

One hundred patients who underwent gastrectomy due to gastric adenocarcinoma at Bundang CHA hospital between January 2000 and May 2005 were studied. Immunohistochemistry was carried out using antibodies against STAT3 and STAT5. The interpretation of the immunohistochemical staining was based on the proportion of stained cells in the field: positive, > 10% stained cells; and negative, < 10% stained cells.

RESULTS

The longest diameter of tumor was 4.67 cm in the positive group and 3.76 cm in the negative group, and these results were not statistically different (P-value = 0.112). Higher T (primary tumor) value (P-value = 0.05), more regional lymph node invasion (P-value = 0.008) and higher TNM staging (P-value = 0.069) were significantly related to STAT3 positivity, but Helicobacter pylori infection or atrophic gastritis were not related. A lower survival rate was observed in the STAT3-positive group (P-value = 0.001). The results of STAT5 were not statistically different with respect to TNM staging and survival (P-value = 0.958). We thus report that the immunohistochemical results of STAT3 revealed a significant association with TNM staging and survival.

CONCLUSION

We anticipate that STAT3 may be used as a molecular staging biomarker predicting poor prognosis of gastric cancer.

Current approaches to gastric cancer in Korea

Gastric cancer remains a significant global health problem and is the most common cancer in Korea. Surgery is the only curative treatment for localized gastric cancer, but most cases present at an advanced stage. The proportion of early gastric cancer and the incidence of gastric cancer located in the upper third of the stomach have increased in Korea. The majority of patients in Korea receive surgery alone or surgery plus chemotherapy. Over 50% of the surgeries have been performed in five major hospitals, with most surgeons performing extended lymph node dissection (D2 or D3). The 5-year survival rate with curative resection is 55.6%-66.0%, with rates of 92.9%-98.0%, 84.2%-92.0%, 69.3%-72.0%, 45.8%-54.0%, 29.6%-36.5%, and 9.2%-23.9% according to TNM stages of Ia, Ib, II, IIIa, IIIb, and IV, respectively. Although convincing phase III data are lacking, postoperative immunochemotherapy with 5-fluorouracil (5-FU) plus mitomycin for 2 months followed by OK-432 plus doxifluridine for 24 months has been widely used in Korea. A phase III trial of adjuvant capecitabine/oxaliplatin is ongoing in curatively resected disease (CLASSIC study). The modified 5-FU/cisplatin regimen has become popular since the mid 90s, and various combinations including taxanes, oral 5-FU prodrugs, oxaliplatin, and irinotecan have been evaluated. Recently, Korean investigators have played pivotal roles in studies initiated by global pharmaceutical companies, and the Korean Cancer Study Group has initiated 14 multicenter trials, including phase III trials in gastric cancer and international cooperative trials. Future international cooperative trials are anticipated.