Selective Gastric Cancer Patients with Peritoneal Seeding Benefit from Gastrectomy after Palliative Chemotherapy: A Propensity Score Matching Analysis

Prognostic Significance of PD-L1 Expression in Gastric Cancer Patients with Peritoneal Metastasis

BACKGROUND

Recently, many studies have explored the relationship between the expression of programmed death ligand 1 (PD-L1) and prognosis in gastric cancer, but there is still controversy. Additionally, few studies have specifically investigated the expression of PD-L1 in patients with peritoneal metastasis.

METHODS

Immunohistochemistry was used to analyze the expression of PD-L1 in gastric cancer patients with peritoneal metastasis. The combined positive score (CPS) was calculated to evaluate the expression of PD-L1, and the clinicopathological data were analyzed to explore prognostic significance.

RESULTS

In total, 147 gastric cancer patients with peritoneal metastasis were enrolled. The negative PD-L1 expression was defined as a CPS < 1, and high PD-L1 expression was defined as a CPS ≥ 10. PD-L1 expression with CPS ≥ 1 and CPS-negative was detected in 67 (45.58%) and 80 (54.42%) patients, respectively. High PD-L1 expression at PD-L1 CPS ≥ 10 was detected in 21(14.29%) patients. The median overall survival (OS) was 18.53 months in the CPS < 10 group and 27.00 months in the CPS ≥ 10 group; the OS difference between the two groups was significant (p = 0.015). Multivariate analysis demonstrated that a poor Eastern Cooperative Oncology Group performance score (ECOG PS) (p = 0.002) and severe peritoneal metastasis (p = 0.033) were significantly associated with poor survival, while palliative chemotherapy (p = 0.002) and high PD-L1 expression (p = 0.008) were independent and significantly favorable prognostic factors.

CONCLUSIONS

Our study demonstrated that PD-L1 expression was widely presented in gastric cancer patients with peritoneal metastasis, while a CPS no less than 10 predicted better prognosis.

Palliative Gastrectomy versus Gastrojejunostomy for advanced Gastric cancer with outlet obstruction: a propensity score matching analysis

Background

Gastric outlet obstruction (GOO) is a late complication of advanced gastric cancer, and it is controversial how to select the therapeutic strategies: gastrojejunostomy and palliative gastrectomy? Therefore, this study was to compare the surgical and survival outcomes of gastrojejunostomy and palliative gastrectomy.

Methods

In total, 199 gastric cancer patients with outlet obstruction treated by surgery between January 2000 and December 2015 at Sun Yat-sen University Cancer Center were retrospectively reviewed. Patients were divided into gastrojejunostomy group and palliative gastrectomy group. Propensity score matching (PSM) was performed to balance the selection bias.

Results

After 1:1 PSM, a total of 104 patients were included for final analysis. The median overall survival (OS) times in the gastrojejunostomy group and palliative gastrectomy group were 8.50 and 11.87 months, respectively (P = 0.243). The postoperative complication rates in the gastrojejunostomy group and palliative gastrectomy group were 19.23% (10/52) and 17.31% (9/52), respectively (P = 0.800), and no treatment-related death was observed. Multivariate analysis showed that periton0eal seeding (P = 0.014) and chemotherapy (P < 0.001) were independent prognostic factors. Among them, peritoneal seeding was a risk factor and postoperative chemotherapy was a protective factor.

Conclusions

Our results indicated that although the surgical complications of palliative gastrectomy were manageable, it showed no survival benefit. Therefore, relieving obstruction symptom, improving patients’ quality of life and creating better conditions for chemotherapy appear to be the main therapeutic strategies for advanced gastric cancer with GOO.

PDCD4 regulates apoptosis in human peritoneal mesothelial cells and promotes gastric cancer peritoneal metastasis

OBJECTIVE

Programmed cell death 4 (PDCD4) is a tumor suppressor gene, however, the function and regulatory mechanism remain to be discovered. The connection between tumorigenesis and apoptosis is one of the most important foci of cancer research. Our study aimed to explore the connections between PDCD4-mediated apoptosis of human peritoneal mesothelial cells (HPMC) and peritoneal metastasis in gastric cancer.

METHODS

The PDCD4 expression in 31 pairs of HPMC and tumor tissues was assessed by immunohistochemistry and RT-PCR. In cell experiments, we monitored gastric cancer cell migration with a Transwell chamber assay when PDCD4 was silenced in HPMC. Subsequently, apoptosis of HPMC was detected by a flow cytometric assay and western blotting. After analyzing cytokines in culture supernatants from gastric cancer with enzyme-linked immunosorbent assays (ELISAs), transforming growth factor-beta 1 (TGF-β1) was abundant in the culture supernatants of gastric cancer. Then, PDCD4 expression in HMrSV5 cells was analyzed by western blotting after retreatment with different concentrations of TGF-β1. Moreover, apoptosis of peritoneal mesothelial cells treated with TGF-β1 was detected according to the above methods.

RESULTS

In human metastatic peritoneal tissues, the expression of PDCD4 was significantly lower than that in normal tissues. At the same time, decreased expression of PDCD4 in HPMC was associated with increased migration capacity of gastric cancer cells. Moreover, suppressing the expression of PDCD4 promoted apoptosis in mesothelial cells which may be regulated by TGF-β secreted from gastric cancer cells.

CONCLUSIONS

These data suggested that decreased expression of PDCD4 significantly promoted apoptosis in human peritoneal mesothelial cells, thus inducing peritoneal metastasis, and that TGF-β1 secreted from gastric cancer cells may have played a crucial role.

Estimating the treatment effect in patients with gastric cancer in the presence of noncompliance

AIM

In this study, these methods were used to estimate the treatment effect in patients with gastric cancer in the presence of noncompliance.

BACKGROUND

In medical sciences, simple and advanced methods are used to estimate treatment effects in the presence of noncompliance.

METHODS

This historical cohort study surveyed 178 patients with gastric cancer underwent chemotherapy alone (chemotherapy alone group) and 193 patients underwent surgery and chemotherapy (surgery plus chemotherapy group) from 2003 to 2007 at the Cancer Institute of Imam Khomeini Hospital (Tehran). Demographic and clinical characteristics were extracted from patients' hospital records. The survival of patients was calculated as being from diagnosis to death or to the end of the study. The treatment effect was estimated using three methods: treatment as a time-dependent covariate, IPCW, and Structural Nested Models using STATA and R software.

RESULTS

Fifty-six patients (31.5%) who underwent chemotherapy and 69 patients (35.8%) who underwent surgery and chemotherapy died by the end of the study. The hazard ratio in group I compared to group II was estimated between 1.5 to 2.07 times based on the simple analysis method. The modified hazard ratio was estimated to be 1.21 (95% CI: 1.11-1.32) based on the SNM method. Surgery plus chemotherapy is superior to chemotherapy alone, and it improves the overall survival (OS) rate of gastric cancer patients.

CONCLUSION

Survival was improved in patients undergoing chemotherapy and surgery together compared to those undergoing chemotherapy alone. The results of the current study suggest that treatment effect can be estimated unbiasedly using the appropriate method.

Peri-operative Outcomes and Survival Following Palliative Gastrectomy for Gastric Cancer: a Systematic Review and Meta-analysis

BACKGROUND

Many patients with gastric cancer present with late stage disease. Palliative gastrectomy remains a contentious intervention aiming to debulk tumour and prevent or treat complications such as gastric outlet obstruction, perforation and bleeding.

METHODS

We conducted a systematic review of the literature for all papers describing palliative resections for gastric cancer and reporting peri-operative or survival outcomes. Data from peri-operative and survival outcomes were meta-analysed using random effects modelling. Survival data from patients undergoing palliative resections, non-resective surgery and palliative chemotherapy were also combined. This study was registered with the PROSPERO database (CRD42019159136).

RESULTS

One hundred and twenty-eight papers which included 58,675 patients contributed data. At 1 year, there was a significantly improved survival in patients who underwent palliative gastrectomy when compared to non-resectional surgery and no treatment. At 2 years following treatment, palliative gastrectomy was associated with significantly improved survival compared to chemotherapy only; however, there was no significant improvement in survival compared to patients who underwent non-resectional surgery after 1 year. Palliative resections were associated with higher rates of overall complications versus non-resectional surgery (OR 2.14; 95% CI, 1.34, 3.46; p < 0.001). However, palliative resections were associated with similar peri-operative mortality rates to non-resectional surgery.

CONCLUSION

Palliative gastrectomy is associated with a small improvement in survival at 1 year when compared to non-resectional surgery and chemotherapy. However, at 2 and 3 years following treatment, survival benefits are less clear. Any survival benefits come at the expense of increased major and overall complications.

Conversion Surgery in Metastatic Gastric Cancer and Cancer Dormancy as a Prognostic Biomarker

The role of conversion surgery in metastatic gastric cancer remains unclear. Cancer dormancy markers might have a role in predicting the survival in patients with conversion surgery. We identified 26 patients who went through conversion surgery, i.e., a curative-intent gastrectomy with metastasectomy after chemotherapy in initially metastatic gastric cancer. As controls, 114 potential candidates for conversion surgery who only received chemotherapy were included for the propensity score matching. Conversion surgery showed a significantly longer overall survival (OS) compared with only palliative chemotherapy (median-43.6 vs. 14.0 months, respectively, p < 0.001). This better survival in the conversion surgery group persisted even after propensity matching (p < 0.001), and also when compared to patients with tumor response over 5.1 months in the chemotherapy only group (p = 0.005). In the conversion surgery group, OS was longer in patients with R0 resection (22/26, 84.6%) than without R0 resection (4/26, 15.4%) (median-not reached vs 22.1 months, respectively, p = 0.005). Although it should be interpreted with caution due to the primitive analysis in a small population, the positive expression of NR2F1 showed a longer duration of disease-free survival (DFS) after conversion surgery (p = 0.016). In conclusion, conversion surgery showed a durable OS even in patients with initially metastatic gastric cancer when R0 resection was achieved after chemotherapy.

A real-world evidence of efficacy of palliative gastrectomy plus chemotherapy in metastatic gastric cancer patients

Background: The benefit of palliative gastrectomy for patients with metastatic gastric cancer (mGC) is controversial, and suitable candidates for surgery and treatment strategies remain unclear. The present study aimed to investigate the efficacy of palliative gastrectomy plus chemotherapy among patients with mGC and to identify the potential patients for such treatment using real-world data.

Methods: A dataset of 236 patients with mGC diagnosed at the Sun Yat-Sen University Cancer Center from January 1, 2006 to December 31, 2012 were analyzed retrospectively. The cohort comprised 80 patients who had palliative gastrectomy plus chemotherapy (SC) and 156 patients who had chemotherapy only (CO). Propensity score matching (PSM) was employed to minimize the influence of confounders.

Results: The median overall survival of the SC group was significantly better than that of the CO group (Before PSM: 17.0 months vs 12.0 months, P=0.038; after PSM: 17.0 months vs 13.0 months, P=0.017). In the multivariate analysis, SC (Before PSM: hazard ratio (HR) =0.68, P=0.023; after PSM: HR =0.64, P=0.021) was favored for better survival after adjustment for sex, age, year of diagnosis, primary tumor location, and tumor grade. Total gastrectomy (P=0.026) was associated with worse survival for the SC group. The significant survival advantage of SC over CO was retained in patients with single organ metastasis (P=0.016), peritoneal seedings (P=0.039), and those receiving taxane-based chemotherapy (P=0.011).

Conclusion: SC could improve the overall survival of patients with mGC as compared with CO. The chemotherapy regimen and type of resection were proven to influence efficacy. Patients who received taxane-based regimens might be suitable for palliative gastrectomy.

Risk-stratification model to select conversion surgery for advanced gastric cancer patients

Objective

Conversion surgery is a surgery with a purpose of R0 resection in primary advanced gastric cancer (GC) that responded well to systemic chemotherapy. This study aimed to explore the efficacy of conversion surgery for advanced GC.

Methods

A total of 618 advanced GC patients receiving systemic chemotherapy were stratified into low-, moderate- and high-risk groups based on a nomogram-predicted probability of overall survival. The survival of conversion surgery and chemotherapy alone groups was compared using the log-rank test and Cox regression analysis after propensity score matching (PSM).

Results

A nomogram with good discrimination (concordance index: 0.65) and accurate calibration was constructed. After PSM, the median survival time (MST) of conversion surgery was 26.80 months, compared with 16.60 months of chemotherapy alone (P<0.001). Conversion surgery was associated with a longer MST for patients in the low-risk group (30.40 monthsvs. 20.90 months, P=0.013), whereas it was not associated with prolonged survival in the moderate- and high-risk groups (P=0.221 and P=0.131, respectively).

Conclusions

Conversion surgery was associated with longer survival, especially for low-risk population.

Palliative gastrectomy plus chemotherapy versus chemotherapy alone for incurable advanced gastric cancer: a meta-analysis

BACKGROUND

Whether palliative gastrectomy combined with chemotherapy can improve the survival of patients with advanced gastric cancer remains controversial. We performed a meta-analysis to clarify whether palliative gastrectomy plus chemotherapy can benefit patients with incurable advanced gastric cancer and to explore the best candidates in this patient population.

METHODS

We searched the literature systematically using electronic databases including PubMed, EMBASE, and the Cochrane Library. And HRs and their 95% CIs were used to express the results for overall survival (OS) and progression-free survival (PFS).

RESULTS

One randomized controlled trial with 175 patients and 12 cohort studies with 2,193 patients were analyzed. The pooled HR for OS (HR=0.43, 95% CI=0.29-0.65, P<0.001), subgroup analysis of stage M1 (HR=0.53, 95% CI=0.40-0.72, P<0.001), peritoneal dissemination (HR=0.46, 95% CI=0.28-0.73, P=0.001), and liver metastasis (HR=0.46, 95% CI=0.33-0.65, P<0.001) all indicated the superiority of palliative gastrectomy plus chemotherapy. However, the pooled HR for PFS (HR=0.61, 95% CI=0.33-1.13, P=0.110) got separate outcome.

CONCLUSION

The results of this meta-analysis indicated that palliative gastrectomy plus chemotherapy can improve OS for incurable advanced gastric cancer. In addition, analyses based on liver metastasis and peritoneal dissemination demonstrated the advantages of palliative gastrectomy plus chemotherapy. However, the PFS of incurable advanced gastric cancer with palliative gastrectomy plus chemotherapy was no better than that under chemotherapy alone.