Salvage systemic therapy for advanced gastric and oesophago-gastric junction adenocarcinoma

BACKGROUND

Salvage systemic therapy has become the new standard of care in patients with advanced gastric and oesophago-gastric junction (OGJ) adenocarcinoma, following disease progression on first-line fluoropyrimidine and platinum-containing chemotherapy. Pharmacological agents proven to be effective in this setting include both chemotherapy and biological therapy, however, the consensus on the best salvage systemic therapy has not been reached.

OBJECTIVES

To assess the effects of systemic chemotherapy and biological therapy, either alone or in combination, on overall survival (OS) and progression-free survival (PFS) in patients with advanced gastric and OGJ adenocarcinoma, whose disease has progressed on, or relapsed after first-line fluoropyrimidine and platinum-containing chemotherapy. Adverse events (AEs), tumour response rate (TRR) and quality of life (QoL) associated with systemic chemotherapy and/or biological therapy were additionally assessed.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, trial registries and proceedings of the major oncology conferences up to October 2020. We additionally handsearched the reference lists of studies. No language restriction was applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing salvage systemic therapy (chemotherapy and/or biological therapy) and either another type of salvage systemic therapy, placebo, best supportive care (BSC) or no treatment in patients with gastric and OGJ adenocarcinoma refractory to first-line fluoropyrimidine and platinum-containing chemotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed selection of eligible studies and the primary author extracted study characteristics and outcome data from included studies. We assessed the quality and risk of bias of eligible studies according to the Cochrane Handbook for Systematic Reviews of Interventions. We expressed pooled estimates of effect using hazard ratio (HR) calculated using an inverse variance random-effects model for time-to-event data, and risk ratio (RR) calculated using Mantel-Haenszel random-effects model for binary data. The certainty of evidence was graded using GRADEpro.

MAIN RESULTS

We identified 17 RCTs with 5110 participants for inclusion in this review. Tweenty-nine studies are ongoing and twenty studies are awaiting classification. No studies examined the following comparisons: chemotherapy combined with biological therapy versus placebo, BSC or no treatment, chemotherapy combined with biological therapy versus biological therapy, biological therapy versus biological therapy and chemotherapy combined with biological therapy versus chemotherapy combined with biological therapy. Chemotherapy versus placebo, best supportive care or no treatment Chemotherapy probably improves OS (HR = 0.66, 95% CI 0.52 to 0.83, moderate-certainty evidence) based on two studies involving 547 participants and improves PFS (HR = 0.57, 95% CI 0.47 to 0.69, high-certainty evidence) based on one study involving 507 participants over placebo and BSC. Chemotherapy probably increases serious AEs (SAEs) (RR = 1.38, 95% CI 1.20 to 1.59, moderate-certainty evidence) based on one study involving 503 participants. Biological therapy versus placebo, best supportive care or no treatment Biological therapy improves OS (HR = 0.55, 95% CI 0.41 to 0.73, high-certainty evidence) and probably improves PFS (HR = 0.33, 95% CI 0.19 to 0.57, moderate-certainty evidence) over placebo based on three studies involving 781 participants. There is currently insufficient evidence for increased SAEs from biological therapy (RR = 1.14, 95% CI 0.95 to 1.37, low-certainty evidence) based on two studies involving 638 participants. Chemotherapy versus biological therapy This comparison only considered immunotherapy. There is probably no evidence of a difference for OS (HR = 0.82, 95% CI 0.66 to 1.02, moderate-certainty evidence) between chemotherapy and immunotherapy, and immunotherapy probably reduces PFS (HR = 1.27, 95% CI 1.03 to 1.57, moderate-certainty evidence) based on one study involving 395 participants. SAEs may be less frequent with immunotherapy compared to chemotherapy (RR = 0.41, 95% CI 0.30 to 0.57, low-certainty evidence). Chemotherapy combined with biological therapy versus chemotherapy Addition of biological therapy to chemotherapy probably does not improve OS (HR = 0.93, 95% CI 0.83 to 1.04, moderate-certainty evidence) and we are uncertain whether it improves PFS (HR = 0.87, 95% CI 0.74 to 1.02, very low-certainty evidence) based on seven studies involving 2743 participants. We are similarly uncertain whether combined chemotherapy and biological therapy increases SAEs (RR = 1.17, 95% CI 0.95 to 1.44, very low-certainty evidence) based on four studies involving 1618 participants. Chemotherapy versus chemotherapy There is no evidence of a difference for OS and PFS between irinotecan and paclitaxel (HR = 1.13, 95% CI 0.86 to 1.48, low-certainty evidence for OS; HR = 1.14, 95% CI 0.88 to 1.48, low-certainty evidence for PFS) based on one study involving 219 participants. Similarly, there is no evidence to indicate improved OS and PFS from addition of another chemotherapy to docetaxel (HR = 1.05, 95% CI 0.72 to 1.54, low-certainty evidence for OS; HR = 0.75, 95% CI 0.52 to 1.09, low-certainty evidence for PFS) based on two studies involving 121 participants. Grade ≥ 3 neutropenia occurred commonly with both mono- and poly-chemotherapy except for docetaxel-S1 and EOX chemotherapy.

AUTHORS' CONCLUSIONS

Survival outcome of patients with advanced gastric and OGJ adenocarcinoma whose disease progressed on first-line fluoropyrimidine and platinum-containing chemotherapy can be improved by chemotherapy and biological therapy. Biological therapy, in particular, achieves this without clear increase in SAEs or QoL impairment. Whether biological therapy is preferred over chemotherapy is still unclear and there is no evidence of a difference for OS outcome, although immunotherapy may be associated with less SAEs. Addition of biological therapy to chemotherapy and poly-chemotherapy are associated with frequent treatment-related toxicity without clear survival benefit.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer is the fifth most common cancer worldwide. In "Western" countries, most people are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. In people with advanced disease, significant benefits from targeted therapies are currently limited to HER-2 positive disease treated with trastuzumab, in combination with chemotherapy, in first-line. In second-line, ramucirumab, alone or in combination with paclitaxel, demonstrated significant survival benefits. Thus, systemic chemotherapy remains the mainstay of treatment for advanced gastric cancer. Uncertainty remains regarding the choice of the regimen.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care (BSC), combination versus single-agent chemotherapy and different chemotherapy combinations in advanced gastric cancer.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and Embase up to June 2016, reference lists of studies, and contacted pharmaceutical companies and experts to identify randomised controlled trials (RCTs).

SELECTION CRITERIA

We considered only RCTs on systemic, intravenous or oral chemotherapy versus BSC, combination versus single-agent chemotherapy and different chemotherapy regimens in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified studies and extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

We included 64 RCTs, of which 60 RCTs (11,698 participants) provided data for the meta-analysis of overall survival. We found chemotherapy extends overall survival (OS) by approximately 6.7 months more than BSC (hazard ratio (HR) 0.3, 95% confidence intervals (CI) 0.24 to 0.55, 184 participants, three studies, moderate-quality evidence). Combination chemotherapy extends OS slightly (by an additional month) versus single-agent chemotherapy (HR 0.84, 95% CI 0.79 to 0.89, 4447 participants, 23 studies, moderate-quality evidence), which is partly counterbalanced by increased toxicity. The benefit of epirubicin in three-drug combinations, in which cisplatin is replaced by oxaliplatin and 5-FU is replaced by capecitabine is unknown.Irinotecan extends OS slightly (by an additional 1.6 months) versus non-irinotecan-containing regimens (HR 0.87, 95% CI 0.80 to 0.95, 2135 participants, 10 studies, high-quality evidence).Docetaxel extends OS slightly (just over one month) compared to non-docetaxel-containing regimens (HR 0.86, 95% CI 0.78 to 0.95, 2001 participants, eight studies, high-quality evidence). However, due to subgroup analyses, we are uncertain whether docetaxel-containing combinations (docetaxel added to a single-agent or two-drug combination) extends OS due to moderate-quality evidence (HR 0.80, 95% CI 0.71 to 0.91, 1466 participants, four studies, moderate-quality evidence). When another chemotherapy was replaced by docetaxel, there is probably little or no difference in OS (HR 1.05; 0.87 to 1.27, 479 participants, three studies, moderate-quality evidence). We found there is probably little or no difference in OS when comparing capecitabine versus 5-FU-containing regimens (HR 0.94, 95% CI 0.79 to 1.11, 732 participants, five studies, moderate-quality evidence) .Oxaliplatin may extend (by less than one month) OS versus cisplatin-containing regimens (HR 0.81, 95% CI 0.67 to 0.98, 1105 participants, five studies, low-quality evidence). We are uncertain whether taxane-platinum combinations with (versus without) fluoropyrimidines extend OS due to very low-quality evidence (HR 0.86, 95% CI 0.71 to 1.06, 482 participants, three studies, very low-quality evidence). S-1 regimens improve OS slightly (by less than an additional month) versus 5-FU-containing regimens (HR 0.91, 95% CI 0.83 to 1.00, 1793 participants, four studies, high-quality evidence), however since S-1 is used in different doses and schedules between Asian and non-Asian population, the applicability of this finding to individual populations is uncertain.

AUTHORS' CONCLUSIONS

Chemotherapy improves survival (by an additional 6.7 months) in comparison to BSC, and combination chemotherapy improves survival (by an additional month) compared to single-agent 5-FU. Testing all patients for HER-2 status may help to identify patients with HER-2-positive tumours, for whom, in the absence of contraindications, trastuzumab in combination with capecitabine or 5-FU in combination with cisplatin has been shown to be beneficial. For HER-2 negative people, all different two-and three-drug combinations including irinotecan, docetaxel, oxaliplatin or oral 5-FU prodrugs are valid treatment options for advanced gastric cancer, and consideration of the side effects of each regimen is essential in the treatment decision. Irinotecan-containing combinations and docetaxel-containing combinations (in which docetaxel was added to a single-agent or two-drug (platinum/5-FUcombination) show significant survival benefits in the comparisons studied above. Furthermore, docetaxel-containing three-drug regimens have increased response rates, but the advantages of the docetaxel-containing three-drug combinations (DCF, FLO-T) are counterbalanced by increased toxicity. Additionally, oxaliplatin-containing regimens demonstrated a benefit in OS as compared to the same regimen containing cisplatin, and there is a modest survival improvement of S-1 compared to 5-FU-containing regimens.Whether the survival benefit for three-drug combinations including cisplatin, 5-FU, and epirubicin as compared to the same regimen without epirubicin is still valid when second-line therapy is routinely administered and when cisplatin is replaced by oxaliplatin and 5-FU by capecitabine is questionable. Furthermore, the magnitude of the observed survival benefits for the three-drug regimens is not large enough to be clinically meaningful as defined recently by the American Society for Clinical Oncology (Ellis 2014). In contrast to the comparisons in which a survival benefit was observed by adding a third drug to a two-drug regimen at the cost of increased toxicity, the comparison of regimens in which another chemotherapy was replaced by irinotecan was associated with a survival benefit (of borderline statistical significance), but without increased toxicity. For this reason irinotecan/5-FU-containing combinations are an attractive option for first-line treatment. Although they need to be interpreted with caution, subgroup analyses of one study suggest that elderly people have a greater benefit form oxaliplatin, as compared to cisplatin-based regimens, and that people with locally advanced disease or younger than 65 years might benefit more from a three-drug regimen including 5-FU, docetaxel, and oxaliplatin as compared to a two-drug combination of 5-FU and oxaliplatin, a hypothesis that needs further confirmation. For people with good performance status, the benefit of second-line chemotherapy has been established in several RCTs.

Chemotherapy for advanced gastric cancer: review and update of current practices

No standard adjuvant or palliative chemotherapy regimen has been internationally approved for patients with advanced gastric cancer. Adjuvant chemoradiotherapy is administered prior to surgery and is used in the Unitied States, and intensified chemotherapy is administered prior to and after surgery and is used in Europe. Limited D1 dissections are also frequently performed in the United States and Europe. In Korea, patients undergoing D2 resection appear to benefit from postoperative adjuvant chemotherapy using S-1 or capecitabine plus oxaliplatin. Fluoropyrimidine, platinum, taxane, epirubicin, and irinotecan may be employed alone or in combination as a first-line therapy in a palliative chemotherapy regimen. In Asia, an orally administered fluoropyrimidine, such as capecitabine or S-1, is favored over the continuous infusion of 5-fluorouracil because of its convenience. Trastuzumab has been integrated into the current standard chemotherapy for human epidermal growth factor receptor 2-overexpressing gastric cancers. There is currently no standard regimen for secondary palliative chemotherapy. Clinical studies of several targeted therapies are ongoing.

Geographic differences in approach to advanced gastric cancer: Is there a standard approach?

Gastric cancer is one of the leading causes of cancer related deaths worldwide. Regional differences in gastric cancer are evident between Asian and Western societies with respect to etiology, prevalence, clinicopathologic features as well as treatment pattern of the disease. For patients with advanced gastric cancer (AGC), chemotherapy has been found to improve survival and quality of life compared to best supportive care alone. But contrast to other tumors such as colon or pancreatic cancer, there are regional differences in outcome in gastric cancer. Various geographic/ethnic, biology and treatment strategies may contribute to these differences. In the first line setting, cisplatin and fluoropyrimidine based therapies remain the backbone of treatment for advanced gastric cancer in Asian and Western patients, although there is preference for S1 in Asia and 5FU in the West. A third agent may be added in patients with good performance status. Recent trials from Asia and Europe demonstrate an advantage for second line chemotherapy. Irinotecan and taxanes are the most commonly used agents. The introduction of trastuzumab into the frontline therapy of AGC has ushered the age of targeted therapy and personalized medicine in this disease. In this article, we will review the various first and second line chemotherapy regimens in AGC, taking into account regional differences including potential biomarkers.

Treatment strategies for gastric cancer patients with peritoneal metastasis

Although the treatment of gastric cancer improves the clinical outcomes, the survival of gastric cancer patients with peritoneal metastasis is still very poor. Effective drugs against peritoneal metastasis, coupled with new therapeutic modalities, are needed to improve the prognoses of these patients. Paclitaxel and TS-1 are candidate drugs for peritoneal metastasis, and intraperitoneal chemotherapy and targeted therapy are potential new therapeutic modalities. Two phase II studies using TS-1 and intraperitoneal and systemic paclitaxel for gastric cancer patients with peritoneal metastasis showed respectable survival results. In addition, peritoneal metastatic lesions showed high levels of epithelial cellular adhesion molecule (ECAM) and very low levels of human epidermal growth factor receptor 2 (HER2), thus indicating that an anti-ECAM monoclonal antibody, catumaxomab, would be effective against gastric cancer-derived peritoneal metastasis. Although catumaxomab and intraperitoneally administered paclitaxel are not generally used in Japan at present, these treatment strategies might therefore be effectively used in Japan in the near future.

Neoadjuvant chemotherapy for gastric cancer in Japan: a standing position by comparing with adjuvant chemotherapy

Adjuvant chemotherapy aims to eradicate micrometastatic tumor cells before and after curative surgery. Many Phase III trials have been conducted to study the efficacy of postoperative adjuvant chemotherapy; however, most trials have failed to show any survival benefit because of their low statistical power and/or poor patient compliance. Since 2000, two pivotal Phase III trials, the ACTS-GC and the CLASSIC, have demonstrated the efficacy of postoperative adjuvant chemotherapy following D2 gastrectomy. Although treatment with S-1 for 1 year or combination therapy with capecitabine and oxaliplatin for 6 months is effective, more intensive chemotherapy is necessary to further improve the survival rates. In Europe, two Phase III trials, the MAGIC and the FNCLCC/FFCD, have produced results that strongly suggest that neoadjuvant chemotherapy is beneficial. The advantages of neoadjuvant chemotherapy include a high rate of R0 resection, tumor regression, high compliance and the avoidance of unnecessary surgery. The disadvantage of neoadjuvant chemotherapy is over-diagnosis. In Japan, the Japan Clinical Oncology Group has conducted several clinical trials using neoadjuvant chemotherapy to target extensive nodal disease and/or scirrhous carcinomas. The optimal courses and regimens of neoadjuvant chemotherapy should, therefore, be clarified in the future.