Postgastrectomy follow-up in the West: evidence base, guidelines, and daily practice

Whether preferences of gastric cancer patients after surgery for follow-up change over time? Analysis based on discrete choice experiment

PURPOSES

The purposes of this discrete choice experiment are as follows: (1) quantify the relevant characteristics that may affect the follow-up selection of gastric cancer patients after surgery and (2) explore the differences in follow-up preferences of gastric cancer patients at different stages and reveal the change trend of preferences over time, thereby providing references for the formulation and optimization of follow-up strategies.

METHODS

A survey instrument that was developed using the design principle of a discrete choice experiment investigated gastric cancer patients on the day of discharge, and at 3 months, 6 months, and 12 months after discharge. In Stata 15.0, a mixed logit model was used to explore the preferences of gastric cancer patients after surgery at different stages, the willingness to pay was calculated, and the NLCOM command was used to simulate the follow-up uptake rates of different attribute levels at different stages.

RESULTS

On the day of discharge, and 3 months, 6 months, and 12 months after discharge, the most important attribute levels of gastric cancer patients after surgery were "thoroughness-very thorough," "method-face-to-face," "thoroughness-very thorough," and "provider-specialist nurse," respectively, and patients were willing to pay more for these services. Patients' preference for the attribute level "very thorough" decreased over time, while their preferences for "specialist doctors" as follow-up providers remained relatively stable. Furthermore, the attribute levels with the greatest effect on receiving the baseline follow-up program varied across stages.

CONCLUSION

The gastric cancer patients' preferences for follow-up change over time, and the time factor should be considered when developing follow-up strategies.

International Delphi consensus guidelines for follow-up after prophylactic total gastrectomy: the Life after Prophylactic Total Gastrectomy (LAP-TG) study

BACKGROUND

Prophylactic total gastrectomy (PTG) remains the only means of preventing gastric cancer for people with genetic mutations predisposing to Hereditary Diffuse Gastric Cancer (HDGC), mainly in the CDH1 gene. The small but growing cohort of people undergoing PTG at a young age are expected to have a life-expectancy close to the general population, however, knowledge of the long-term effects of, and monitoring requirements after, PTG is limited. This study aims to define the standard of care for follow-up after PTG.

METHODS

Through a combination of literature review and two-round Delphi consensus of major HDGC/PTG units and physicians, and patient advocates, we produced a set of recommendations for follow-up after PTG.

RESULTS

There were 42 first round, and 62 second round, responses from clinicians, allied health professionals and patient advocates. The guidelines include recommendations for timing of assessments and specialties involved in providing follow-up, micronutrient supplementation and monitoring, bone health and the provision of written information.

CONCLUSION

While the evidence supporting the guidelines is limited, expert consensus provides a framework to best manage people following PTG, and could support the collection of information on the long-term effects of PTG.

Extragastric recurrence in patients who underwent surgical resection of stage I gastric cancer: Incidence, risk factors, and value of abdominal computed tomography as a postoperative surveillance method

Extragastric recurrence after radical resection of stage I gastric cancer is very rare. We investigated the incidence of extragastric recurrence and risk factors in patients who underwent surgical resection of stage I gastric cancer and evaluated the value of abdominal CT as a surveillance tool. This retrospective study enrolled 914 patients with stage I gastric cancer who underwent surgical resection at a single tertiary hospital. We investigated extragastric recurrence during the follow-up period, and disease-free survival (DFS) was assessed. Over a median follow-up period of 39 months, the overall incidence of extragastric recurrence was 2.2% (20/914). Risk factors for extragastric recurrence included deep submucosal invasion (SM2-3), muscularis propria invasion, and lymph node metastasis (hazard ratio [HR]=10.37, 28.101, and 6.843; P = .028, .002, and .001, respectively). Based on the number of risk factors, patients were stratified into 3 subgroups: low-risk (pT1aN0, pT1b(SM1)N0, 496/914), moderate-risk (pT1aN1, pT1b(SM1)N1, pT1b(SM2-3)N0, pT2N0, 369/914), and high-risk (pT1b(SM2-3)N1, 49/914). DFS was significantly longer in the low-risk group, followed by the moderate-risk and high-risk groups. We propose that postoperative CT surveillance should be omitted for stage 1A cases involving the mucosa and SM1 because of the extreme rarity of extragastric recurrence.

Evaluation of post-operative surveillance strategies for esophageal and gastric cancers: a systematic review and meta-analysis

BACKGROUND

There is no consensus or guidelines internationally to inform clinicians of how patients should be monitored for recurrence after esophagogastric resections.

AIM

This systematic review and meta-analysis summarizes the latest evidence investigating the usefulness of surveillance protocols in patients who underwent esophagectomy or gastrectomy.

METHODS

A systematic review of the literature was performed using MEDLINE, EMBASE, the Cochrane Review and Scopus databases. Articles were evaluated for the use of surveillance strategies including history-taking, physical examination, imaging modalities and endoscopy for monitoring patients post-gastrectomy or esophagectomy. Studies that compared surveillance strategies and reported detection of recurrence and post-recurrence survival were also included in the meta-analysis.

RESULTS

Fifteen studies that described a surveillance protocol for post-operative patients were included in the review. Seven studies were used in the meta-analysis. Random-effects analysis demonstrated a statistically significant higher post-recurrence survival (standardized mean difference [SMD] 14.15, 95% CI 1.40-27.26, p = 0.03) with imaging-based planned surveillance post-esophagectomy. However, the detection of recurrence (OR 1.76, 95% CI 0.78-3.97, p = 0.17) for esophageal cancers as well as detection of recurrence (OR 0.73, 95% CI 0.11-5.12, p = 0.76) and post-recurrence survival (SMD 6.42, 95% CI -2.16-18.42, p = 0.14) for gastric cancers were not significantly different with planned surveillance.

CONCLUSION

There is no consensus on whether surveillance carries prognostic survival benefit or how surveillance should be carried out. Surveillance may carry prognostic benefit for patients who underwent surgery for esophageal cancer. Randomized controlled trials are required to evaluate the survival benefits of intensive surveillance strategies, determine the ideal surveillance protocol and tailor it to the appropriate population.

Development of a predictive model for extragastric recurrence after curative resection for early gastric cancer

BACKGROUND

Stratification of patients who undergo curative resection for early gastric cancer (EGC) is warranted due to the heterogeneity in the risk of developing extragastric recurrence (EGR). Therefore, we aimed to stratify the need for postoperative surveillance for EGR detection in patients with EGC by developing a model for predicting EGR-free survival.

METHODS

This retrospective cohort study included patients who underwent postoperative surveillance after curative resection of EGC (n = 4149). Cox proportional hazard models were used to identify predictors to build a model for predicting EGR-free survival. Bootstrap-corrected c-index and calibration plots were used for internal and external (n = 2148) validations.

RESULTS

A risk-scoring system was constructed using variables significantly associated with EGR-free survival: pathologic T stage (pT1b[sm1], hazard ratio [HR] 4.928; pT1b[sm2], HR 5.235; pT1b[sm3], HR 7.748) and N stage (pN1, HR 4.056; pN2, HR 9.075; pN3, HR 30.659). Patients were dichotomized into a very-low-risk group or a low-or-greater-risk group. The 5-year EGR-free survival rates differed between the two groups (99.9 vs. 97.3%). The discriminative performance of the model was 0.851 (Uno's c-index) and 0.751 in the internal and external cohorts, respectively. The calibration slope was 0.916 and 1.131 in the internal and external cohorts, respectively.

CONCLUSIONS

Our model for predicting EGR-free survival based on the pathologic T and N stages may be useful for stratifying patients who have undergone curative surgery for EGC. The results suggest that patients in the very-low-risk group may be spared from postoperative surveillance considering their extremely high EGR-free survival rate.

Prospective multicentre randomised clinical trial comparing survival rates, quality of life and nutritional status between advanced gastric cancer patients with different follow-up intensities: study protocol for the STOFOLUP trial

INTRODUCTION

Patients who underwent curative gastrectomy for gastric cancer are regularly followed-up for the early detection of recurrence and postoperative symptom management. However, there is a lack of evidence with regard to proper surveillance intervals and diagnostic tools. This study aims to evaluate whether frequent surveillance tests have a survival benefit or improve the quality of life in patients who underwent curative resection for advanced gastric cancer.

METHODS AND ANALYSIS

The STOFOLUP trial is an investigator-initiated, parallel-assigned, multicentre randomised controlled trial involving 16 hospitals in the Republic of Korea. Patients (n=886) diagnosed with pathological stage II or III gastric adenocarcinoma will be randomised to either the 3-month or the 6-month group at a 1:1 ratio, stratified by trial site and tumour stage. Patients allocated to the 3-month group will undergo an abdominal CT scan every 3 months postoperatively and those allocated to the 6-month group will undergo CT every 6 months. The primary endpoint is 3-year overall survival and the secondary endpoints are quality of life, as assessed using KOrean QUality of life in Stomach cancer patients Study group-40, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and the stomach cancer-specific module (STO22), and nutritional outcomes. Other survival data including data concerning 3-year disease-free survival, recurrence-free survival, gastric cancer-specific survival and postrecurrence survival will also be estimated. The first patient was enrolled on July 2021 and active patient enrolment is currently underway.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board of eight of the participating hospitals (NCC 2021-0085, KBSMC2021-01-059, SMC 2021-01-140, KC21OEDE0082, 4-2021-0281, AJIRB-MED-INT-20-608, 2021-0515 and H-2102-093-1198). This study will be disseminated through peer-reviewed publications, national or international conferences.

TRIAL REGISTRATION NUMBER

NCT04740346.

Eliciting gastric cancer survivors' preferences for follow-up services: a discrete choice experiment protocol

INTRODUCTION

Follow-up care is important for gastric cancer survivors, but follow-up strategies for gastric cancer survivors remain inconsistent, and compliance of gastric cancer survivors with follow-up care is very low. Understanding the needs and preferences of gastric cancer survivors is conducive to developing appropriate and acceptable follow-up strategies, thereby improving patient compliance. Discrete choice experiments can quantify individual needs and preferences. However, to date, there is no discrete choice experiment on the preferences of gastric cancer survivors, and no studies have examined how gastric cancer survivors make choices based on different characteristics of follow-up. This paper outlines an ongoing discrete choice experiment that aims to (1) explore follow-up service-related characteristics that may affect gastric cancer survivors' choices about their follow-up, (2) elicit how gastric cancer survivors consider the trade-offs among different follow-up service options using discrete choice experiment, (3) determine whether gastric cancer survivors' needs and preferences for follow-up vary due to the economy, politics, technology and culture in different regions.

METHODS AND ANALYSIS

Six attributes were developed through a literature review, semistructured interviews and experts and focus group discussions. A fractional factorial design was used to evaluate the interaction between attributes. A multiple logit model will be used to understand the trade-off between the follow-up characteristics of gastric cancer survivors. A mixed logit model will be used to explore the willingness to pay and uptake rate of gastric cancer survivors for follow-up attributes and further explore the preferences of different groups.

ETHICS AND DISSEMINATION

This study was approved by the ethics committee of the School of Nursing, Jilin University. The results of this study will be shared through online blogs, policy briefs, seminars and peer-reviewed journal articles and will be used to modify the current strategy of gastric cancer survivors' follow-up services according to economic development and regional culture.

Preferences of gastric cancer survivors for follow-up care-a multicenter discrete choice experiment study

PURPOSES

The purposes of this discrete choice experiment are as follows: (1) to investigate the preferences of gastric cancer survivors for follow-up care, and (2) to quantify the importance of follow-up care-related characteristics that may affect the gastric cancer survivors' choices of their follow-up, so as to provide references for the development of the follow-up strategy of gastric cancer survivors.

METHODS

Discrete choice experimental design principle was applied to develop the survey instrument. All questionnaires were filled out by the respondents and collected on site. A mixed logit model was used to estimate gastric cancer survivors' preferences. Willingness to pay estimates and simulations of follow-up uptake rates were calculated.

RESULTS

All six attributes are significantly important for the follow-up care of gastric cancer survivors (p < 0.05). Achieving very thorough follow-up contents was the most valued attribute level (coefficient = 1.995). Specialist doctors are the most preferred providers followed by specialist nurses, and gastric cancer survivors were willing to pay more for these attribute levels. Changes in attribute levels affected uptake rate of follow-up. When the multiple attribute levels were changed at the same time, a very thorough follow-up content was provided by the same specialist doctor (specialist nurse), and the probability of receiving follow-up increases by 95.82% (94.90%).

CONCLUSIONS

The characteristics of follow-up care in our study reflect the health management services' expectations of gastric cancer survivors. A dedicated specialist nurse involved in follow-up care should be developed to contribute to solve the complex and multifaceted personal needs of gastric cancer survivors.

Bone Metastases from Gastric Cancer: What We Know and How to Deal with Them

Gastric cancer (GC) is the third cause of cancer-related death worldwide; the prognosis is poor especially in the case of metastatic disease. Liver, lymph nodes, peritoneum, and lung are the most frequent sites of metastases from GC; however, bone metastases from GC have been reported in the literature. Nevertheless, it is unclear how the metastatic sites may affect the prognosis. In particular, knowledge about the impact of bone metastases on GC patients’ outcome is scant, and this may be related to the rarity of bone lesions and/or their underestimation at the time of diagnosis. In fact, there is still a lack of specific recommendation for their detection at the diagnosis. Then, the majority of the evidences in this field came from retrospective analysis on very heterogeneous study populations. In this context, the aim of this narrative review is to delineate an overview about the evidences existing about bone metastases in GC patients, focusing on their incidence and biology, the prognostic role of bone involvement, and their possible implication in the treatment choice.

Predictive Role of Endoscopic Surveillance after Total Gastrectomy with R0 Resection for Gastric Cancer

BACKGROUND

Endoscopic surveillance after total gastrectomy (TG) for gastric cancer is routinely performed to detect tumor recurrence and postoperative adverse events. However, the reports on the clinical benefits of endoscopic surveillance are ambiguous. We investigated the clinical benefit of endoscopic surveillance after TG for gastric cancer.

METHODS

We analyzed 848 patients who underwent TG with R0 resection for gastric cancer between 2011 and 2012 (380 early gastric cancer and 468 advanced gastric cancer) and underwent regular postoperative surveillance with endoscopy and abdominopelvic computed tomography (CT) with contrast.

RESULTS

Median follow-up periods were 58 months for both endoscopy (range, 3-96) and abdominopelvic CT (range, 1-96). Tumor recurrence occurred in 167 patients (19.7%), of whom seven (4.2%) were locoregional recurrences in the peri-anastomotic area (n = 5) or regional gastric lymph nodes (n = 2). Whereas the peri-anastomotic recurrences were detected by both endoscopy and abdominopelvic CT, regional lymph node recurrences were only detected by abdominopelvic CT. Out of the 23 events of postoperative adverse events, the majority (87%) were detected by radiologic examinations; three events of benign strictures in the anastomotic site were detected only by endoscopy.

CONCLUSION

Endoscopic surveillance did not have a significant role in detecting locoregional tumor recurrence and postoperative adverse events after TG with R0 resection for gastric cancer. Routine endoscopic surveillance after TG may be considered optional and performed according to the capacities of each clinical setting.

Substantial risk of recurrence even after 5 recurrence-free years in early-stage hepatocellular carcinoma patients

Background/Aims

Although hepatocellular carcinoma (HCC) is notorious for its high recurrence rate, some patients do not experience recurrence for more than 5 years after resection or radiofrequency ablation for early-stage HCC. For those with five recurrence-free period, the risk of HCC recurrence within the next 5 years remains unknown.

Methods

A total of 1,451 consecutive patients (median, 55 years old; males, 79.0%; hepatitis B virus-related, 79.3%) with good liver function (Child-Pugh class A) diagnosed with early-stage HCC by Barcelona Clinic Liver Cancer Staging and received radiofrequency ablation or resection as an initial treatment between 2005 and 2010 were analyzed.

Results

During a median follow-up period of 8.1 years, 961 patients (66.2%) experienced HCC recurrence. The cumulative recurrence rates increased to 39.7%, 60.3%, and 71.0% at 2, 5, and 10 years, respectively, and did not reach a plateau. Five years after HCC diagnosis, 487 patients were alive without experiencing a recurrence. Among them, during a median of 3.9 additional years of follow-up (range, 0.1–9.0 years), 127 patients (26.1%) experienced recurrence. The next 5-year cumulative recurrence rate (5–10 years from initial diagnosis) was 27.0%. Male sex, higher fibrosis-4 scores, and alpha-fetoprotein levels at 5 years were associated with later HCC recurrence among patients who did not experience recurrence for more than 5 years.

Conclusions

The HCC recurrence rate following 5 recurrence-free years after HCC treatment was high, indicating that HCC patients warrant continued HCC surveillance, even after 5 recurrence-free years.

Consensus statement of the Hellenic and Cypriot Gastric Cancer Study Group on the diagnosis, staging and management of gastric cancer

Gastric Cancer epidemics have changed over recent decades, declining in incidence, shifting from distal to proximal location, transforming from intestinal to diffuse histology. Novel chemotherapeutic agents combined with modern surgical operations hardly changed overall disease related survival. This may be attributed to a substantial inherent geographical variation of disease genetics, but also to a failure to standardize and implement treatment protocols in clinical practice. To overcome these drawbacks in Greece and Cyprus, a Gastric Cancer Study Group under the auspices of the Hellenic Society of Medical Oncology (HeSMO) and Gastrointestinal Cancer Study Group (GIC-SG) merged their efforts to produce a consensus considering ethnic parameters of healthcare system and the international proposals as well. Utilizing structured meetings of experts, a consensus was reached. To achieve further consensus, statements were subjected to the Delphi methodology by invited multidisciplinary national and international experts. Sentences were considered of high or low consensus if they were voted by ≥ 80%, or < 80%, respectively; those obtaining a low consensus level after both voting rounds were rejected. Forty-five statements were developed and voted by 71 experts. The median rate of abstention per statement was 9.9% (range: 0-53.5%). At the end of the process, one statement was rejected, another revised, and all the remaining achieved a high consensus. Forty-four recommendations covering all aspects of the management of gastric cancer and concise treatment algorithms are proposed by the Hellenic and Cypriot Gastric Cancer Study Group. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and individualization are emphasized.

A Proposal of a Personalized Surveillance Strategy for Gastric Cancer: A Retrospective Analysis of 9191 Patients

Background

In gastric cancer, various surveillance strategies are suggested in international guidelines. The current study is intended to evaluate the current strategies and provide more personalized proposals for personalized cancer medicine.

Materials and Methods

In the aggregate, 9191 patients with gastric cancer after gastrectomy from 1998 to 2009 were selected from the Surveillance, Epidemiology, and End Results database. Disease-specific survival was analyzed by Kaplan-Meier method and the log-rank test. Cox proportional hazards regression analyses were used to confirm the independent prognostic factors. As well, hazard ratio (HR) curves were used to compare the risk of death over time. Conditional survival (CS) was applied to dynamically assess the prognosis after each follow-up.

Results

Comparisons from HR curves on different stages showed that earlier stages had distinctly lower HR than advanced stages. The curve of stage IIA was flat and more likely the same as that of stage I while that of stage IIB is like that of stage III with an obvious peak. After estimating CS at intervals of three months, six months, and 12 months in different periods, stages I and IIA had high levels of CS all along, while there were visible differences among CS levels of stages IIB and III.

Conclusions

The frequency of follow-up for early stages, like stages I and IIA, could be every six months or longer in the first three years and annually thereafter. And those with unfavorable conditions, such as stages IIB and III, could be followed up much more frequently and sufficiently than usual.

Postoperative follow-up programs improve survival in curatively resected gastric and junctional cancer patients: a propensity score matched analysis

BACKGROUND

To date there is no evidence that more intensive follow-up after surgery for esophagogastric adenocarcinoma translates into improved survival. This study aimed to evaluate the impact of standardized surveillance by a specialized center after resection on survival.

METHODS

Data of 587 patients were analyzed who underwent curative surgery for esophagogastric adenocarcinoma in our institution. Based on their postoperative surveillance, patients were assigned to either standardized follow-up (SFU) by the National Center for Tumor Diseases (SFU group) or individual follow-up by other physicians (non-SFU group). Propensity score matching (PSM) was performed to compensate for heterogeneity between groups. Groups were compared regarding clinicopathological findings, recurrence, and impact on survival before and after PSM.

RESULTS

Of 587 patients, 32.7% were in the SFU and 67.3% in the non-SFU group. Recurrence occurred in 39.4% of patients and 92.6% within the first 3 years; 73.6% were treated, and of those 17.1% underwent resection. In recurrent patients overall and post-recurrence survival (OS/PRS) was influenced by diagnostic tools (p < 0.05), treatment (p ≤ 0.001), and resection of recurrence (p ≤ 0.001). Standardized follow-up significantly improved OS (84.9 vs. 38.4 months, p = 0.040) in matched analysis and was an independent positive predictor of OS before and after PSM (p = 0.034/0.013, respectively).

CONCLUSION

After PSM, standardized follow-up by a specialized center significantly improved OS. Cross-sectional imaging and treatment of recurrence were associated with better outcome. Regular follow-up by cross-sectional imaging especially during the first 3 years should be recommended by national guidelines, since early detection might help select patients for treatment of recurrence and even resection in few designated cases.

Association between PIK3CA alteration and prognosis of gastric cancer patients: a meta-analysis

BACKGROUND

Increasing evidence suggests that dysregulation of phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) plays an important role in carcinogenesis. However, the relationship between PIK3CA expression and gastric cancer (GC) prognosis remains controversial.

METHODS

We searchedPubMed, Embase, Web of Science, and the Cochrane Library databases for relevant studies up to June 30, 2017. Primary outcomes were hazard ratio (HR), odds ratio (OR), and 95% confidence intervals (CI) for association with overall survival and clinicopathological features.

RESULTS

Eleven studies comprising 2481 GC patients were analyzed. Pooled analysis showed that PIK3CA upregulation was significantly associated with worse overall survival (HR = 1.79, 95% CI 1.42-2.27, p< 0.001) at the protein (HR = 1.94, 95% CI 1.52-2.47, p< 0.001) but not the gene (HR = 1.57, 95% CI 0.92-2.69, p= 0.097) level. PIK3CA gene mutation did not correlate with overall survival (HR = 1.05, 95% CI 0.83-1.34, p= 0.666) but was significantly associated with poor tumor differentiation (OR = 0.37, 95% CI 0.17-0.76, p= 0.011).

CONCLUSION

High PIK3CA protein expression predicted poor prognosis in GC, whereas PIK3CA gene amplification or mutation did not. Moreover, PIK3CA mutation was an indicator of poorly differentiated tumors.

Follow-up after curative resection for gastric cancer: Is it time to tailor it?

There is still no consensus on the follow-up frequency and regimen after curative resection for gastric cancer. Moreover, controversy exists regarding the utility of follow-up in improving survival, and the recommendations of experts and societies vary considerably. The main reason to establish surveillance programs is to diagnose tumor recurrence or metachronous cancers early and to thereby provide prompt treatment and prolong survival. In the setting of gastric malignancies, other reasons have been put forth: (1) the detection of adverse effects of a previous surgery, such as malnutrition or digestive sequelae; (2) the collection of data; and (3) the identification of psychological and/or social problems and provision of appropriate support to the patients. No randomized controlled trials on the role of follow-up after curative resection of gastric carcinoma have been published. Herein, the primary retrospective series and systematic reviews on this subject are analyzed and discussed. Furthermore, the guidelines from international and national scientific societies are discussed. Follow-up is recommended by the majority of institutions; however, there is no real evidence that follow-up can improve long-term survival rates. Several studies have demonstrated that it is possible to stratify patients submitted to curative gastrectomy into different classes according to the risk of recurrence. Furthermore, promising studies have identified several molecular markers that are related to the risk of relapse and to prognosis. Based on these premises, a promising strategy will be to tailor follow-up in relation to the patient and tumor characteristics, molecular marker status, and individual risk of recurrence.

Gastric cancer treatment: similarity and difference between China and Korea

Chinese populations have many demographic similarities to Korean populations. However, the long-term survival rates of gastric cancer patients in China are still not satisfactory when compared with Korea, especially for the advanced cases. In this article, we discuss about the similarity and difference of gastric cancer treatment in terms of screening, surgical approach, stomach resection, digestive tract reconstruction, lymphadenectomy, harvested lymph nodes, operative morbidity and mortality, postoperative chemotherapy as well as follow-up between China and Korea. Given that a variety of factors ranging from tumor characteristics to different treatment strategies are seen between the two countries, the reasons accounting for the differences in survival should be focused and the corresponding strategy should be considered and finally promote to improve the prognosis of gastric cancer.