Association between education level and prognosis after esophageal cancer surgery: a Swedish population-based cohort study

Community Engagement to Inform Multilevel Analyses of the Role of Neighborhood Factors in Cancer Control Behaviors in African Americans

BACKGROUND

Although community engagement has had a substantial presence in public health research, community input to inform geospatial and health analyses remains underutilized and novel. This article reports on community engagement activities to solicit stakeholder perspectives on the role of neighborhood conditions in health and cancer. We discuss how this community input refined an a priori conceptual model to be tested in the larger Families, Friends, and Neighborhoods Study.

METHODS

We conducted semistructured virtual interviews with 82 stakeholders (e.g., community and faith leaders, educators, and healthcare workers) across four states (Maryland, Connecticut, Alabama, and Missouri). Participants discussed the impact where a person lives can have on their health and cancer risk. We subsequently convened a virtual group discussion with 17 randomly selected interviewees. Our study team individually reviewed discussion notes, which were synthesized into a consensus document.

RESULTS

In addition to constructs from the original conceptual model, participants identified neighborhood-level factors not present in the original model, including K-12 educational quality, local property investment, homelessness, public transportation infrastructure, proximity to healthcare facilities, environmental toxin exposures, access to healthy foods, and cost of living. These factors will be incorporated into the Families, Friends, and Neighborhoods Study analytic models.

CONCLUSIONS

Although geospatial analyses in health research have not traditionally employed community engagement techniques, this study illustrates the value of informing multilevel analytic models with the lived experiences of those negatively affected by neighborhood conditions that underlie the risk, prevention, and screening behaviors driving cancer incidence and mortality.

IMPACT

Future social epidemiology research can be enriched through community engagement.

Development and Validation of a Nomogram Model for the Risk of Cardiac Death in Patients Treated with Chemotherapy for Esophageal Cancer

The primary cause of mortality in esophageal cancer survivors is cardiac death. Early identification of cardiac mortality risk during chemotherapy for esophageal cancer is crucial for improving the prognosis. We developed and validated a nomogram model to identify patients with high cardiac mortality risk after chemotherapy for esophageal cancer for early screening and clinical decision-making. We randomly allocated 37,994 patients with chemotherapy-treated esophageal cancer into two groups using a 7:3 split ratio: model training (n = 26,598) and validation (n = 11,396). 5- and 10-year survival rates were used as endpoints for model training and validation. Decision curve analysis and the consistency index (C-index) were used to evaluate the model's net clinical advantage. Model performance was evaluated using receiver operating characteristic curves and computing the area under the curve (AUC). Kaplan-Meier survival analysis based on the prognostic index was performed. Patient risk was stratified according to the death probability. Age, surgery, sex, and year were most closely related to cardiac death and used to plot the nomograms. The C-index for the training and validation datasets were 0.669 and 0.698, respectively, indicating the nomogram's net clinical advantage in predicting cardiac death risk at 5 and 10 years. The 5- and 10-year AUCs were 0.753 and 0.772 for the training dataset and 0.778 and 0.789 for the validation dataset, respectively. The accuracy of the model in predicting cardiac death risk was moderate. This nomogram can identify patients at risk of cardiac death after chemotherapy for esophageal cancer at an early stage.

After Anterior Cruciate Ligament Injury, Patients With Medicaid Insurance Experience Delayed Care and Worse Clinical Outcomes Than Patients With Non-Medicaid Insurance

Purpose

To evaluate the effects of socioeconomic factors on the operative treatment of anterior cruciate ligament injuries and outcomes following surgical reconstruction.

Methods

A retrospective cohort study of primary anterior cruciate ligament reconstruction surgeries at a single institution performed from 2011 to 2015 with minimum 2-year follow-up was conducted. Patient demographics, insurance type, workers' compensation status, surgical variables, International Knee Documentation Committee score, and failure were recorded from chart review. Education level and income were obtained via phone interview. Differences between functional outcome were compared between Medicaid and non-Medicaid groups.

Results

In total, 268 patients were included in the analysis (43 patients in the Medicaid group and 225 patients in the non-Medicaid group, overall mean follow-up of 3.1 ± 0.8 years). The Medicaid group demonstrated lower annual income (P < .001) and a lower level of completed education compared with the non-Medicaid group (P < .001). Patients who received Medicaid had a greater duration between time of initial knee injury and surgery compared with the those in non-Medicaid group (11.8 ± 16.3 months vs 6.1 ± 16.5 months, P < .001). At the time of follow-up, patients in the non-Medicaid group had a significantly greater International Knee Documentation Committee score compared with patients who received Medicaid (82.5 ± 13.8 vs 75.3 ± 20.8, P = .036).

Conclusions

Patients with Medicaid insurance were seen in the clinic significantly later after initial injury and had worse outcomes compared with patients with other insurance types. Also, patients in higher annual income brackets had significantly better clinical outcomes scores at a minimum of 2 years postoperatively.

Level of Evidence

Level III, retrospective cohort study.

Cardiac Dose Predicts the Response to Concurrent Chemoradiotherapy in Esophageal Squamous Cell Carcinoma

Definitive concurrent chemoradiation (CCRT) is the standard treatment for cervical esophageal cancer and non-surgical candidates. Initial treatment response affects survival; however, few validated markers are available for prediction. This study evaluated the clinical variables and chemoradiation parameters associated with treatment response. Between May 2010 and April 2016, 86 completed CCRT patients' clinical, dosimetric, and laboratory data at baseline and during treatment were collected. Cox regression analysis assessed the risk factors for overall survival (OS). A receiver operating characteristic curve with Youden's index was chosen to obtain the optimal cut-off value of each parameter. Treatment response was defined per Response Evaluation Criteria in Solid Tumors v.1.1 at the first post-CCRT computed tomography scan. Responders had complete and partial responses; non-responders had stable and progressive diseases. Logistic regression (LR) was used to evaluate the variables associated with responders. The Cox regression model confirmed the presence of responders (n = 50) vs. non-responders (n = 36) with a significant difference in OS. In multivariate LR, cardiac dose-volume received ≥10 Gy; the baseline hemoglobin level, highest neutrophil to lymphocyte ratio during CCRT, and cumulative cisplatin dose were significantly associated with the responders. The initial clinical treatment response significantly determines disease outcome. Cardiac irradiation may affect the treatment response.

Sex differences in treatment allocation and survival of potentially curable gastroesophageal cancer: A population-based study

BACKGROUND

Although curative treatment options are identical for male and female gastroesophageal cancer patients, access to care and survival may vary. This study aimed to compare treatment allocation and survival between male and female patients with potentially curable gastroesophageal cancer.

METHODS

Nationwide cohort study including all patients with potentially curable gastroesophageal squamous cell or adenocarcinoma diagnosed between 2006 and 2018 registered in the Netherlands Cancer Registry. The main outcome, treatment allocation, was compared between male and female patients with oesophageal adenocarcinoma (EAC), oesophageal squamous cell carcinoma (ESCC), and gastric adenocarcinoma (GAC). Additionally, 5-year relative survival with relative excess risk (RER), that is, adjusted for the normal life expectancy, was compared.

RESULTS

Among 27,496 patients (68.8% men), most were allocated to curative treatment (62.8%), although rates dropped to 45.6%>70 years. Curative treatment rates were comparable among younger male and female patients (≤70 years) with gastroesophageal adenocarcinoma, while older females with EAC were less frequently allocated to curative treatment than males (OR = 0.85, 95% confidence interval [CI] 0.73-0.99). For those allocated to curative treatment, relative survival was superior for female patients with EAC (RER = 0.88, 95% CI 0.80-0.96) and ESCC (RER = 0.82, 95% CI 0.75-0.91), and comparable for males and females with GAC (RER = 1.02, 95% CI 0.94-1.11).

CONCLUSIONS

While curative treatment rates were comparable between younger male and female patients with gastroesophageal adenocarcinoma, treatment disparities were present between older patients. When treated, the survival of females with EAC and ESCC was superior to males. The treatment and survival gaps between male and female patients with gastroesophageal cancer warrant further exploration and could potentially improve treatment strategies and survival.

Factors associated with follow-up attendance of patients with oral squamous cell carcinoma: A retrospective cohort study

BACKGROUND

This study examined the postoperative follow-up attendance of oral squamous cell carcinoma (OSCC) patients, evaluated some of the factors associated with it, and assessed its relationship with early detection of postoperative disease progression.

METHODS

An exploratory retrospective cohort study of 430 OSCC patients was conducted. We examined associations of follow-up attendance within the first year after surgery with selected demographic and clinical factors, and with early detection of disease progression.

RESULTS

The mean number of follow-up visits within the first year after surgery was 3.9 out of the 12 recommended at our center; few patients were fully adherent. Age ≥70 years, unmarried status, high education level, and negative history of surgery for premalignant or malignant lesions from oral cavity or other sites were significantly associated with lower follow-up attendance. Greater follow-up attendance was significantly associated with early detection of disease progression during the first year after surgery (p = 0.025).

CONCLUSIONS

Adherence to follow-up visits was poor. Several sociodemographic and clinical factors were related to follow-up attendance, greater follow-up attendance was significantly associated with early detection of disease progression, and these should be further explored in future research.

Risk factors associated with esophageal cancers, diagnosed at tertiary level in Afghanistan: a descriptive cross-sectional study

Background:

Worldwide, esophageal cancer (EC) is a common cancer in term of incidence and mortality and is the 4th common cancer in Afghanistan. Current study aimed to evaluate the profile of risk factors for EC among patients diagnosed at tertiary level in Afghanistan.

Methodology:

A descriptive cross-sectional study was carried out between January 2019 up to February 2021 including all esophageal cancers diagnosed at pathology department of French Medical Institute for Mothers and Children, Afghanistan.

Result:

240 diagnosed cases were analyzed, in which 59.40% of squamous cell carcinoma and 41.07% Adenocarcinoma. Both histopathological type of were predominantly diagnosed in males. The majority of the patients were residents of rural areas. More than 80% of the patients were illiterate with only less than 2% completing higher education. Majority of the patients were laborers and farmers while less than 10% were employed. According to income assessment, more than 80% were from low-income household, the rest from middle-income and none from high-income family. Oral snuff consumption was noted in 33.9% of squamous cell carcinoma patients and 40% adenocarcinoma patients whereas, family history of esophageal cancer was observed in 37.8% and 36.7% in both types of carcinomas, respectively. More than 60% of both types of carcinomas patients were hot tea drinkers.

Conclusion:

Current study demonstrated that most patients diagnosed with esophageal cancers were male, uneducated, belongs to low-income groups, lives in rural areas. These findings suggest distribution of esophageal cancer in specific socioeconomic groups, clearly demonstrating the need further analytical study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10228-9.

Effect of Marital Status on the Survival of Patients With Adenocarcinoma of the Esophagogastric Junction: A Population-Based, Propensity-Matched Study

Background

Marital status has been reported as an independent prognostic factor in various types of malignancies. However, the association between marital status and outcomes of patients with adenocarcinoma of the esophagogastric junction (AEG) has not been fully explored. To this end, we aimed to investigate the effect of marital status on survival of AGE patients.

Methods

The Surveillance Epidemiology and End Results (SEER) database (2010–2015) was used to extract eligible patients with Siewert type II AEG. Meanwhile, propensity score matching was performed to match 1576 unmarried patients with 1576 married patients. Kaplan–Meier method with log-rank test was used to plot survival curves, univariate and multivariate Cox regression analyses were adopted to investigate the association of marital status with overall survival (OS) and cancer-specific survival (CSS) in AEG patients before and after matching.

Results

Multivariate analysis in the unmatched cohort revealed that marital status was an independent prognostic factor in patients with Siewert type II AEG. Unmarried patients had poorer OS (hazard ratio [HR]: 1.22, 95% confidence interval [CI]: 1.12–1.29, P < .001) and poorer CSS (HR: 1.19, 95% CI: 1.10–1.29, P < .001) than married patients before matching. Additionally, widowed patients had the poorest OS (HR: 1.26, 95% CI: 1.11–1.44, P < .001) and CSS (HR: 1.29, 95% CI: 1.12–1.48, P < .001) compared with married patients. Furthermore, unmarried status remained as an independent prognostic for both OS (HR: 1.20, 95% CI: 1.10–1.31, P < .001) and CSS (HR: 1.18, 95% CI: 1.08–1.30, P < .001) in 1:1 propensity score-matched analysis. Subgroup analysis further revealed that OS and CSS rates were significantly higher in married patients than unmarried ones in most subgroups stratified by different variables.

Conclusions

This population-based study identified that marital status was an independent prognostic indicator for AEG patients. Married AEG patients had better prognosis than their unmarried counterparts.

Prediction Model of Long-term Survival After Esophageal Cancer Surgery

OBJECTIVE

We aimed to develop prediction models for estimating the long-term survival in patients who have undergone surgery for esophageal cancer.

BACKGROUND

Few prediction models have been developed for the long-term survival in esophageal cancer patients.

METHODS

This nationwide Swedish population-based cohort study included 1542 patients who survived for ≥90 days after esophageal cancer surgery between 1987 and 2010, with follow-up until 2016. Risk prediction models for 1-, 3-, and 5-year all-cause mortality and 3- and 5-year disease-specific mortality were developed using logistic regression. Candidate predictors were established and readily identifiable prognostic factors. The performance of the models was assessed by the area under receiver-operating characteristic curve (AUC) with interquartile range (IQR) using bootstrap cross-validation and risk calibration.

RESULTS

Predictors included in all models were age, sex, pathological tumor stage, tumor histology, and resection margin status. The models also included various additional predictors depending on the outcome, that is, education level, neoadjuvant therapy, reoperation (within 30 d of primary surgery) and comorbidity (Charlson comorbidity index). The AUC statistics after cross-validation were 0.71 (IQR 0.69-0.74) for 1-year, 0.77 (IQR 0.75-0.80) for 3-year, and 0.78 (IQR 0.76-0.81) for 5-year all-cause mortality. The corresponding values were 0.76 (IQR 0.74-0.79) for 3-year and 0.77 (IQR 0.71-0.83) for 5-year disease-specific mortality. All models showed good agreement between the observed and predicted risks.

CONCLUSIONS

These models showed good performance for predicting long-term survival after esophageal cancer surgery and may thus be useful for patients in planning their lives and to guide the postoperative treatment and follow-up.

Meta-analysis of prognostic factors of overall survival in patients undergoing oesophagectomy for oesophageal cancer

INTRODUCTION

Currently, the American Joint Commission on Cancer (AJCC) staging system is used for prognostication for oesophageal cancer. However, several prognostically important factors have been reported but not incorporated. This meta-analysis aimed to characterize the impact of preoperative, operative, and oncological factors on the prognosis of patients undergoing curative resection for oesophageal cancer.

METHODS

This systematic review was performed according to PRISMA guidelines and eligible studies were identified through a search of PubMed, Scopus, and Cochrane CENTRAL databases up to 31 December 2018. A meta-analysis was conducted with the use of random-effects modeling to determine pooled univariable hazard ratios (HRs). The study was prospectively registered with the PROSPERO database (Registration: CRD42018157966).

RESULTS

One-hundred and seventy-one articles including 73,629 patients were assessed quantitatively. Of the 122 factors associated with survival, 39 were significant on pooled analysis. Of these. the strongly associated prognostic factors were 'pathological' T stage (HR: 2.07, CI95%: 1.77-2.43, P < 0.001), 'pathological' N stage (HR: 2.24, CI95%: 1.95-2.59, P < 0.001), perineural invasion (HR: 1.54, CI95%: 1.36-1.74, P < 0.001), circumferential resection margin (HR: 2.17, CI95%: 1.82-2.59, P < 0.001), poor tumor grade (HR: 1.53, CI95%: 1.34-1.74, P < 0.001), and high neutrophil:lymphocyte ratio (HR: 1.47, CI95%: 1.30-1.66, P < 0.001).

CONCLUSION

Several tumor biological variables not included in the AJCC 8th edition classification can impact on overall survival. Incorporation and validation of these factors into prognostic models and next edition of the AJCC system will enable personalized approach to prognostication and treatment.

Standardizing Health Outcomes for Lung Cancer. Adaptation of the International Consortium for Health Outcomes Measurement Set to the Spanish Setting

Purpose: Lung cancer (LC) and its treatment impose a significant burden on patients' life. However, patient-centered outcomes are rarely collected during patient follow-up. Filling this gap, the International Consortium for Health Outcomes Measurement (ICHOM) developed a standard set of variables for newly diagnosed LC patients. In order to facilitate the use of this standard set, the project aims to adapt it to the Spanish setting.

Methods: The variables (instrument and periodicity) to be included in Spanish standard set were selected through consensus during 4 nominal groups (13 oncologists, 14 hospital pharmacists, 4 hospital managers and 3 LC patients), under the supervision of a Scientific Committee (1 oncologist, 3 hospital pharmacists, 2 LC patients advocates).

Results: The variables agreed upon included: (1) case-mix: demographic [age, sex, education and social-family support], clinical [weight loss, smoking status, comorbidities (Charlson index), pulmonary function (FEV-1)], tumor [histology, clinical, and pathological stage (TNM), EGFR, ALK, ROS-1, PD-L1] and treatment factors [intent and completion] and (2) outcomes: degree of health [performance status (ECOG) and quality-of-life (EQ-5D, LCSS)], survival [overall survival and cause of death], quality of death [place of death, end-of-life care and palliative care, death aligned with living will], treatment complications, and others [date of diagnosis and treatment initiation, productivity loss (sick leave)].

Conclusion: The adaptation of ICHOM standard set to the Spanish setting pave the way to standardize the collection of variables in LC.

Patient Age and Survival After Surgery for Esophageal Cancer

Background

Esophagectomy for esophageal cancer is associated with a substantial risk of life-threatening complications and a limited long-term survival. This study aimed to clarify the controversial questions of how age influences short-term and long-term survival.

Methods

This population-based cohort study included almost all patients who underwent curatively intended esophagectomy for esophageal cancer in Sweden in 1987–2010, with follow-up through 2016. The exposure was age, analyzed both as a continuous and categorical variable. The probability of mortality was computed using a novel flexible parametric model approach. The reported probabilities are proper measures of the risk of dying, and the related odds ratios (OR) are therefore more suitable measures of association than hazard ratios. The outcomes were 90-day all-cause mortality, 5-year all-cause mortality, and 5-year disease-specific mortality. A novel flexible parametric model was used to derive the instantaneous probability of dying and the related OR along with 95% confidence intervals (CIs), adjusted for sex, education, comorbidity, tumor histology, pathological tumor stage, and resection margin status.

Results

Among 1737 included patients, the median age was 65.6 years. When analyzed as a continuous variable, older age was associated with slightly higher odds of 90-day all-cause mortality (OR 1.05, 95% CI 1.02–1.07), 5-year all-cause mortality (OR 1.02, 95% CI 1.01–1.03), and 5-year disease-specific mortality (OR 1.01, 95% CI 1.01–1.02). Compared with patients aged < 70 years, those aged 70–74 years had no increased risk of any mortality outcome, while patients aged ≥ 75 years had higher odds of 90-day mortality (OR 2.85, 95% CI 1.68–4.84), 5-year all-cause mortality (OR 1.56, 95% CI 1.27–1.92), and 5-year disease-specific mortality (OR 1.38, 95% CI 1.09–1.76).

Conclusions

Patient age 75 years or older at esophagectomy for esophageal cancer appears to be an independent risk factor for higher short-term mortality and lower long-term survival.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08653-w) contains supplementary material, which is available to authorized users.

Surgeon Volume and Surgeon Age in Relation to Proficiency Gain Curves for Prognosis Following Surgery for Esophageal Cancer

Background

Surgery proficiency gain curves must be shortened to reduce patient harm during esophagectomy learning.

Objective

This study aimed to test whether surgeon volume and surgeon age influenced the length of period of surgical proficiency gain.

Methods

This population-based cohort study included 1384 patients with esophageal cancer who underwent esophagectomy by any of the 36 highest-volume surgeons in Sweden between 1987 and 2010, with follow-up until 2016. Annual surgeon volume was dichotomized by the median values into ‘higher-volume surgeons’ (≥ 4 cases per year) and ‘lower-volume surgeons’ (< 4 cases per year), and surgeon age at the start of practicing esophagectomies into ‘younger surgeons’ (aged < 45 years) and ‘older surgeons’ (aged ≥ 45 years). Proficiency gain curves were constructed using risk-adjusted cumulative sum analysis for 1- to 5-year mortality (main outcome) and secondary outcomes (presented below). The results were adjusted for all established prognostic factors.

Results

For 1- to 5-year mortality, the change point was at 14 cases among ‘higher-volume surgeons’, while ‘lower-volume surgeons’ had a later change point at 31 cases. The corresponding change points were at 13 cases among ‘younger surgeons’ and at 48 cases among ‘older surgeons’. Similar patterns of differences in the proficiency gain curves were seen for the secondary outcomes of 30-day mortality and resection margin status (tumor involvement).

Conclusion

Higher-volume- and younger surgeons seem to have a substantially shorter period of proficiency gain for long-term mortality and other outcomes following surgery for esophageal cancer. This indicates a value of intensified training of younger surgeons for these complex operations.

Electronic supplementary material

The online version of this article (10.1245/s10434-018-6869-8) contains supplementary material, which is available to authorized users.

Sociodemographic variation in the use of chemotherapy and radiotherapy in patients with stage IV lung, oesophageal, stomach and pancreatic cancer: evidence from population-based data in England during 2013-2014

BACKGROUND

Sociodemographic inequalities in cancer treatment have been generally described, but there is little evidence regarding patients with advanced cancer. Understanding variation in the management of these patients may provide insights into likely mechanisms leading to inequalities in survival.

METHODS

We identified 50,232 patients with stage IV lung, oesophageal, pancreatic and stomach cancer from the English national cancer registry. A generalised linear model with a Poisson error structure was used to explore variation in radiotherapy and chemotherapy within 6 months from diagnosis by age, sex, deprivation, ethnicity, cancer site, comorbidity and, additionally, performance status.

RESULTS

There was substantial variation by cancer site, large gradients by age, and non-trivial associations with comorbidity and deprivation. After full adjustment, more deprived patients were consistently least likely to be treated with chemotherapy alone or chemotherapy and radiotherapy combined compared with less deprived patients with equally advanced disease stage (treatment rate ratio: 0.82 95% CI (0.78, 0.87) for CT, 0.78 95% CI (0.71, 0.85) for CTRT p < 0.0001).

CONCLUSIONS

There was marked variation in the management of patients with stage IV cancer. Routinely collected data could be used for surveillance across all cancers to help reduce treatment variation and optimise outcomes among patients with advanced cancer.

Oesophageal cancer

Oesophageal cancer is the sixth most common cause of cancer-related death worldwide and is therefore a major global health challenge. The two major subtypes of oesophageal cancer are oesophageal squamous cell carcinoma (OSCC) and oesophageal adenocarcinoma (OAC), which are epidemiologically and biologically distinct. OSCC accounts for 90% of all cases of oesophageal cancer globally and is highly prevalent in the East, East Africa and South America. OAC is more common in developed countries than in developing countries. Preneoplastic lesions are identifiable for both OSCC and OAC; these are frequently amenable to endoscopic ablative therapies. Most patients with oesophageal cancer require extensive treatment, including chemotherapy, chemoradiotherapy and/or surgical resection. Patients with advanced or metastatic oesophageal cancer are treated with palliative chemotherapy; those who are human epidermal growth factor receptor 2 (HER2)-positive may also benefit from trastuzumab treatment. Immuno-oncology therapies have also shown promising early results in OSCC and OAC. In this Primer, we review state-of-the-art knowledge on the biology and treatment of oesophageal cancer, including screening, endoscopic ablative therapies and emerging molecular targets, and we discuss best practices in chemotherapy, chemoradiotherapy, surgery and the maintenance of patient quality of life.

Weekday of Surgery Affects Postoperative Complications and Long-Term Survival of Chinese Gastric Cancer Patients after Curative Gastrectomy

Many factors have been reported to affect the long-term survival of gastric carcinoma patients after gastrectomy; the present study took the first attempt to find out the potential role of weekday carried out surgery in the postoperative prognosis of gastric cancer patients. 463 gastric cancer patients have been followed up successfully. Pearson χ² test was used for univariate analyses. Survival curves were constructed by using Kaplan-Meier method and evaluated by using the log-rank test. The Cox proportional hazard regression model was used to find out the risk factors, and subgroup analysis was conducted to rule out confounding factors. We found that the patients who underwent gastrectomy on the later weekday (Wednesday–Friday) more easily suffered from a higher postoperative morbidity. Weekday of surgery was one of the independent indicators for the prognosis of patients after gastric cancer surgery. However, the role of weekday of surgery was significantly weakened in the complications group. In conclusion, surgery performed in the later weekday was more likely to lead to increased postoperative complications and an unfavorable role in prognosis of Chinese gastric cancer patients after curative gastrectomy.