Geographic difference in safety and efficacy of systemicchemotherapy for advanced gastric or gastroesophagealcarcinoma: a meta-analysis and meta-regression

A comparison between triplet and doublet chemotherapy in improving the survival of patients with advanced gastric cancer: a systematic review and meta-analysis

BACKGROUND

Chemotherapy can improve the survival of patients with advanced gastric cancer. However, whether triplet chemotherapy can further improve the survival of patients with advanced gastric cancer compared with doublet chemotherapy remains controversial. This study reviewed and updated all published and eligible randomized controlled trials (RCTs) to compare the efficacy, prognosis, and toxicity of triplet chemotherapy with doublet chemotherapy in patients with advanced gastric cancer.

METHODS

RCTs on first-line chemotherapy in advanced gastric cancer on PubMed, Embase, and the Cochrane Register of Controlled Trials and all abstracts from the annual meetings of the European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology conferences up to October 2018 were searched. The primary outcome was overall survival, while the secondary outcomes were progression-free survival (PFS), time to progress (TTP), objective response rate (ORR), and toxicity.

RESULTS

Our analysis included 23 RCTs involving 4540 patients and 8 types of triplet and doublet chemotherapy regimens, and systematic review and meta-analysis revealed that triplet chemotherapy was superior compared with doublet chemotherapy in terms of improving median OS (HR = 0.92; 95% CI, 0.86-0.98; P = 0.02) and PFS (HR = 0.82; 95% CI, 0.69-0.97; P = 0.02) and TTP (HR = 0.92; 95% CI, 0.86-0.98; P = 0.02) and ORR (OR = 1.21; 95% CI, 1.12-1.31; P < 0.0001) among overall populations. Compared with doublet chemotherapy, subgroup analysis indicated that OS improved with fluoropyrimidine-based (HR = 0.80; 95% CI, 0.66-0.96; P = 0.02), platinum-based (HR = 0.75; 95% CI, 0.57-0.99; P = 0.04), and other drug-based triplet (HR = 0.79; 95% CI, 0.69-0.90; P = 0.0006) chemotherapies while not with anthracycline-based (HR = 0.70; 95% CI, 0.42-1.15; P = 0.16), mitomycin-based (HR = 0.81; 95% CI, 0.47-1.39; P = 0.44), taxane-based (HR = 0.91; 95% CI, 0.81-1.01; P = 0.07), and irinotecan-based triplet (HR = 1.01; 95% CI, 0.82-1.24; P = 0.94) chemotherapies. For different patients, compared with doublet chemotherapy, triplet chemotherapy improved OS (HR = 0.89; 95% CI, 0.81-0.99; P = 0.03) among Western patients but did not improve (HR = 0.96; 95% CI, 0.86-1.07; P = 0.47) that among Asian patients.

CONCLUSIONS

Compared with doublet chemotherapy, triplet chemotherapy improved OS, PFS, TTP, and ORR in patients with advanced gastric cancer in the population overall, and improved OS in Western but not in Asian patients.

The Use of (Network) Meta-Analysis in Clinical Oncology

Meta-analysis is important in oncological research to provide a more reliable answer to a clinical research question that was assessed in multiple studies but with inconsistent results. Pair-wise meta-analysis can be applied when comparing two treatments at once, whereas it is possible to compare multiple treatments at once with network meta-analysis (NMA). After careful systematic review of the literature and quality assessment of the identified studies, there are several assumptions in the use of meta-analysis. First, the added value of meta-analysis should be evaluated by examining the comparability of study populations. Second, the appropriate comparator in meta-analysis should be chosen according to the types of comparisons made in individual studies: (1) Experimental and comparator arms are different treatments (A vs. B); (2) Substitution of a conventional treatment by an experimental treatment (A+B vs. A+C); or (3) Addition of an experimental treatment (A+B vs. B). Ideally there is one common comparator treatment, but when there are multiple common comparators, the most efficacious comparator is preferable. Third, treatments can only be adequately pooled in meta-analysis or merged into one treatment node in NMA when considering likewise mechanism of action and similar setting in which treatment is indicated. Fourth, for both pair-wise meta-analysis and NMA, adequate assessment of heterogeneity should be performed and sub-analysis and sensitivity analysis can be applied to objectify a possible confounding factor. Network inconsistency, as statistical manifestation of violating the transitivity assumption, can best be evaluated by node-split modeling. NMA has advantages over pair-wise meta-analysis, such as clarification of inconsistent outcomes from multiple studies including multiple common comparators and indirect effect calculation of missing direct comparisons between important treatments. Also, NMA can provide increased statistical power and cross-validation of the observed treatment effect of weak connections with reasonable network connectivity and sufficient sample-sizes. However, inappropriate use of NMA can cause misleading results, and may emerge when there is low network connectivity, and therefore low statistical power. Furthermore, indirect evidence is still observational and should be interpreted with caution. NMA should therefore preferably be conducted and interpreted by both expert clinicians in the field and an experienced statistician. Finally, the use of meta-analysis can be extended to other areas, for example the identification of prognostic and predictive factors. Also, the integration of evidence from both meta-analysis and expert opinion can improve the construction of prognostic models in real-world databases.

Anti-angiogenic Therapy in Patients with Advanced Gastric and Gastroesophageal Junction Cancer: A Systematic Review

Despite advancements in therapy for advanced gastric and gastroesophageal junction cancers, their prognosis remains dismal. Tumor angiogenesis plays a key role in cancer growth and metastasis, and recent studies indicate that pharmacologic blockade of angiogenesis is a promising approach to therapy. In this systematic review, we summarize current literature on the clinical benefit of anti-angiogenic agents in advanced gastric cancer. We conducted a systematic search of PubMed and conference proceedings including the American Society of Clinical Oncology, the European Society for Medical Oncology, and the European Cancer Congress. Included studies aimed to prospectively evaluate the efficacy and safety of anti-angiogenic agents in advanced gastric or gastroesophageal junction cancer. Each trial investigated at least one of the following endpoints: overall survival, progression-free survival/time to progression, and/or objective response rate. Our search yielded 139 publications. Forty-two met the predefined inclusion criteria. Included studies reported outcomes with apatinib, axitinib, bevacizumab, orantinib, pazopanib, ramucirumab, regorafenib, sorafenib, sunitinib, telatinib, and vandetanib. Second-line therapy with ramucirumab and third-line therapy with apatinib are the only anti-angiogenic agents so far shown to significantly improve survival of patients with advanced gastric cancer. Overall, agents that specifically target the vascular endothelial growth factor ligand or receptor have better safety profile compared to multi-target tyrosine kinase inhibitors.

Positioning of second-line treatment for advanced gastric and gastroesophageal junction adenocarcinoma

Tumors of the upper gastrointestinal tract are increasing in incidence; yet, approaches to the treatment of advanced gastric and/or gastroesophageal junction cancer vary widely, with no internationally agreed first‐line regimens. Recent clinical trials have shown that second‐line treatment is now possible for selected patients with advanced disease, and current data suggest that the combination of ramucirumab plus paclitaxel may become a standard of care in the second‐line setting for metastatic gastric cancer. Several prognostic factors have been identified for overall survival in the second‐line setting; this emphasizes the need for careful sequencing of all treatments to ensure that individual patients receive optimum care. This article reviews published data on the treatment of advanced gastric cancer, with a particular emphasis on second‐line chemotherapy, and suggests treatment sequences based on current understanding.

Postoperative chemoradiotherapy versus chemotherapy for R0 resected gastric cancer with D2 lymph node dissection: an up-to-date meta-analysis

BACKGROUND

This meta-analysis aims to provide more evidence on the role of postoperative chemoradiotherapy (CRT) for gastric cancer (GC) patients in Asian countries where D2 lymphadenectomy is prevalent.

METHODS

We conducted a systematic review of randomized controlled trials (RCTs), extracted data of survival and toxicities, and pooled data to evaluate the efficacy and toxicities of CRT compared with chemotherapy (CT) after D2 lymphadenectomy.

RESULTS

A total of 960 patients from four RCTs were selected. The results showed that postoperative CRT significantly reduced loco-regional recurrence rate (LRRR: RR = 0.50, 95 % CI = 0.34-0.74, P = 0.0005) and improved disease-free survival (DFS: HR = 0.73, 95 % CI = 0.60-0.89, P = 0.002). However, CRT did not affect distant metastasis rate (DMR: RR = 0.81, 95 % CI = 0.60-1.08, P = 0.15) and overall survival (OS: HR = 0.91, 95 % CI = 0.74-1.11, P = 0.34). The main grade 3-4 toxicities manifested no significant differences between the two groups.

CONCLUSIONS

Overall, CRT after D2 lymphadenectomy may reduce LRRR and prolong DFS. The role of postoperative CRT should be further investigated in the population with high risk of loco-regional recurrence.

Can S-1 replace fluorouracil for advanced gastric cancer? A PRISMA-compliant systematic review and meta-analysis

It remains to be seen whether S-1 can be a replacement for infusional fluorouracil (5-FU) for advanced gastric cancer (AGC). The aim of this study was to compare the efficacy and safety of S-1 with 5-FU in AGC.PubMed and Cochrane Library were searched. Randomized controlled trials and meta-analyses comparing S-1 with 5-FU for AGC were eligible. Meta-analysis was performed using RevMan 5.2.Seven trials involving 2443 patients were included. Compared with 5-FU, S-1 showed no significant prolongation of overall survival (OS) (hazard ratio [HR] = 0.91, 95% confidence interval [CI] [0.83-1.01], P = 0.07) and progression-free survival (HR = 0.89, 95% CI [0.70-1.13], P = 0.35), but longer time to treatment failure (HR = 0.74, 95% CI [0.56-0.97], P = 0.03). The objective response rates were comparable (risk ratio [RR] = 1.36, 95% CI [0.95, 1.96], P = 0.10). Regarding treatment-related deaths and hematological toxicities, there was significant heterogeneity between Asian and non-Asian trials, and subgroup analysis was applied. In Asian patients, there was a significant increase in hematological toxicities such as leukopenia (grade 1-4: RR = 1.22, 95% CI [1.08, 1.37], P = 0.001; grade 3-4: RR = 2.21, 95% CI [1.52, 3.21], P < 0.0001), neutropenia (grade 1-4: RR = 1.29, 95% CI [1.11, 1.48], P = 0.0005; grade 3-4: RR = 1.87, 95% CI [1.11, 3.17], P = 0.02), and thrombocytopenia (grade 1-4: RR = 1.71, 95% CI [1.22, 2.41], P = 0.002) in S-1-containing regimens compared with 5-FU-containing regimens, but without significant difference in treatment-related mortality rate (risk difference [RD] = 0.00, 95% CI [-0.01, 0.01], P = 0.68). In non-Asian patients, S-1-containing regimens were, however, associated with significantly fewer treatment-related deaths (RD = -0.02, 95% CI [-0.05, -0.00], P = 0.04), as well as less all grade 1-4 and grade 3-4 hematological toxicities except anemia. There was no significant heterogeneity in nonhematologic toxicities between Asian and non-Asian trials. Lower incidence of grade 1-4 nausea, diarrhea, mucositis, grade 3-4 mucositis, increased creatinine, and decreased calculated creatinine clearance was observed in S-1-containing regimens.S-1 could not improve OS, but increase some hematological toxicities in Asian patients. Therefore, special attention on hematological toxicities should be paid to Asian patients because S-1 is administered on an outpatient basis.

The survival difference between gastric cancer patients from the UK and Japan remains after weighted propensity score analysis considering all background factors

BACKGROUND

Previous studies comparing survival between gastric cancer (GC) patients from the West and the East were based on the assumption that background factors and prognostic factors were identical. The aim of the current study was to compare the survival of GC patients from the UK and Japan using weighted propensity score analysis after identifying all different background factors.

METHODS

Data from 464 patients from the Leeds Teaching Hospital NHS Trust, Leeds, UK (LTHT), and 465 patients from the Kanagawa Cancer Center Hospital, Yokohama, Japan (KCCH), who had surgery for GC were analyzed. Prognostic factors for overall survival (OS) and cancer-specific survival (CSS) were identified by univariate and multivariate analyses. Survival was compared by propensity score weighting after adjusting for all significantly different background factors.

RESULTS

Most background factors were different between LTHT and KCCH patients. Unadjusted stage-specific OS and CSS were significantly better in KCCH. Independent prognostic factors for unadjusted OS and CSS were pT and pN in KCCH and in addition tumor location, pancreatectomy, resection margin status and number of examined lymph nodes in LTHT. Even after adjusting for all background characteristics, survival remained better in KCCH.

CONCLUSIONS

These results suggest that differences in background factors are unable to fully explain the survival difference of GC patients between UK and Japan. Comprehensive studies into the biology of GC and/or host factors are needed to fully understand the survival difference.

Multimodality management of resectable gastric cancer: A review

Adenocarcinoma of the stomach carries a poor prognosis and is the second most common cause of cancer death worldwide. It is recommended that surgical resection with a D1 or a modified D2 gastrectomy (with at least 15 lymph nodes removed for examination) be performed in the United States, though D2 lymphadenectomies should be performed at experienced centers. A D2 lymphadenectomy is the recommended procedure in Asia. Although surgical resection is considered the definitive treatment, rates of recurrences are high, necessitating the need for neoadjuvant or adjuvant therapy. This review article aims to outline and summarize some of the pivotal trials that have defined optimal treatment options for non-metastatic non-cardia gastric cancer. Some of the most notable trials include the INT-0116 trial, which established a benefit in concurrent chemoradiation and adjuvant chemotherapy. This was again confirmed in the ARTIST trial, especially in patients with nodal involvement. Later, the Medical Research Council Adjuvant Gastric Infusional Chemotherapy trial provided evidence for the use of perioperative chemotherapy. Targeted agents such as ramucirumab and trastuzumab are also being investigated for use in locally advanced gastric cancers after demonstrating a benefit in the metastatic setting. Given the poor response rate of this difficult disease to various treatment modalities, numerous studies are currently ongoing in an attempt to define a more effective therapy, some of which are briefly introduced in this review as well.

Indirect comparison showed survival benefit from adjuvant chemoradiotherapy in completely resected gastric cancer with d2 lymphadenectomy

Background. Little data on directly comparing chemoradiotherapy with observation has yet been published in the setting of adjuvant therapy for resected gastric cancer who underwent D2 lymphadenectomy. The present indirect comparison aims to provide more evidence on comparing the two approaches. Methods. We conducted a systematic review of randomized controlled trials, extracted time-to-event data using Tierney methods (when not reported), and performed indirect comparison to obtain the relative hazards of adjuvant chemoradiotherapy to observation on overall and disease-free survival. Results. seven randomized controlled trials were identified. Three trials compared adjuvant chemoradiotherapy with adjuvant chemotherapy, and 4 trials compared adjuvant chemotherapy with observation. Using indirect comparison, the relative hazards of adjuvant chemoradiotherapy to observation were 0.43 (95% CI: 0.33-0.55) in disease-free survival and 0.52 (95% CI: 0.38-0.71) in overall survival for completely resected gastric cancer with D2 lymphadenectomy. Conclusions. Postoperative chemoradiotherapy can prolong survival and decrease recurrence in patients with resected gastric cancer who underwent D2 gastrectomy. Molecular biomarker might be a promising direction in the prediction of clinical outcome to postoperative chemoradiotherapy, which warranted further study.

Measuring patient-reported outcomes in advanced gastric cancer

Background

Gastric cancer (GC), one of the most common cancers in the world, is often diagnosed at an advanced stage and associated with a poor prognosis. Quality of life and patient-reported outcomes (PROs) are important considerations when treating GC patients. The aim of this study was to identify existing PRO instruments that would be appropriate for use in GC trials.

Methods

Data were obtained from a systematic literature review and interviews with clinical experts. A literature search was conducted using OVID (EMBASE and MEDLINE) and yielded 1,008 abstracts; 92 assessed PROs in an advanced GC.

Results

Key symptoms and functional impacts identified through the literature and expert input included abdominal pain or pain at the site of distant metastases, dysphagia and other symptoms related to eating, and digestive symptoms. The liver and lungs were the most frequent locations of metastases, leading to dyspnea, abdominal fullness, and jaundice. Symptoms related to changes in bowel habits appeared to be more frequent and pronounced in Asian patients, possibly due to the higher prevalence of GC in the body of the stomach in this population. The five most commonly used PRO instruments were identified, but their validity in advanced-stage GC patients remains unclear.

Conclusions

The symptoms and functional impacts identified here should be confirmed with robust input from advanced-stage GC patients. Optimal measurement of PROs in GC should account for patient burden and possible differences between Asian and non-Asian patients.

Postoperative chemoradiotherapy versus postoperative chemotherapy for completely resected gastric cancer with D2 Lymphadenectomy: a meta-analysis

Background

Both chemoradiotherapy and chemotherapy are used in postoperative adjuvant therapy for resected gastric cancer. However, it is controversial whether chemoradiotherapy or chemotherapy is the optimal strategy for patients with gastric cancer after D2 lymphadenectomy. The present meta-analysis aims to provide more evidence on the relative benefits of adjuvant therapies in this setting.

Methods

We conducted a systematic review of randomized controlled trials, extracted time-to-event data using Tierney methods (when not reported), and performed meta-analysis to obtain the relative hazards of adjuvant chemoradiotherapy to chemotherapy on efficacy and toxicities.

Results

A total of 895 patients from 3 randomized controlled trials were identified for this meta-analysis. All patients were from Asian countries. Our results showed that postoperative chemoradiotherapy significantly improved locoregional recurrence-free survival [LRRFS: hazard ratio (HR) = 0.53, 95% CI = 0.32–0.87, p = 0.01] and disease-free survival (DFS: HR = 0.72, 95% CI = 0.59–0.89, p = 0.002); however, the improvement of distant metastasis recurrence-free survival (DMRFS: HR = 0.86; 95% CI = 0.66–1.11, p = 0.25) and overall survival (OS: HR = 0.79, 95% CI = 0.61–1.03, p = 0.08) were non-significant. The main grade 3 or 4 toxicities were equivalent between the two groups.

Conclusion

In non-selected Asian patients with resected gastric cancer who underwent D2 lymphadenectomy, postoperative chemoradiotherapy improved LRRFS and DFS but might not improve OS compared to postoperative chemotherapy.