A systematic overview of chemotherapy effects in gastric cancer

A systematic review of chemotherapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for the evaluation of the scientific literature are described separately (Acta Oncol 2001; 40: 155-65). This overview of the literature on chemotherapy in the treatment of gastric cancer is based on 153 scientific papers including one meta-analysis, 18 reviews, 60 randomised studies and 57 prospective studies. The trials consist of 12,367 patients. The conclusions reached can be summarized into the following points: A meta-analysis of 21 randomised adjuvant studies revealed a statistically significant survival benefit. The Odds Ratio (OR) is 0.84 (95% confidence interval, 95% CI, 0.74-0.96). However, by analysing Western world and Asian studies separately, a statistically significant difference can be noticed; the Western world studies showed an OR of 0.96 (95% CI 0.83-1.12) and the Asian an OR of 0.58 (95% CI 0.44-0.76). The cause of this difference is not apparent. There is not sufficient evidence to recommend adjuvant chemotherapy as routine treatment in the Western world. Preoperative chemotherapy given to patients with non-resectable tumours or locally advanced potentially resectable tumours has achieved resectability rates of 40-100% and potentially curative resections in 37-80%. One out of two randomised studies showed a significant survival benefit, but reported data are not convincing. Experimental data in favour of preoperative therapy has not yet been confirmed in randomised clinical studies. Therapy is only justified in controlled clinical trials. Published studies on the use of intraperitoneal chemotherapy are few and not conclusive regarding the efficiency and safety. This method of drug administration is, accordingly, justified only in controlled clinical trials. In advanced gastric cancer, phase II studies have indicated better response rates using drug combinations than using single drug regimens, differences that have not, however, been convincingly demonstrated in randomised studies. No firm conclusions can be drawn regarding the superiority for any of the studied drug combinations with respect to response or survival gain. A statistically significant survival benefit has been shown in trials comparing drug combinations with a best supportive care arm in the treatment of advanced gastric cancer. However, the number of included patients is small. The median survival benefit in advanced disease is in the range of three to nine months. The use of chemotherapy in advanced gastric cancer is justified in selected patients, e.g. in younger patients in good performance status, low tumour burden and no other serious medical condition after adequate information of potential gains and risks. The influence of chemotherapy on quality of life in advanced gastric cancer has been reported in only a few studies. It appears that about 50% of the patients have a clinically relevant relief of tumour-related symptoms and thereby improved quality of life. In one study, quality-adjusted survival was estimated to a median of six months in the treated patients compared with two months in the controls. The quality of the literature addressing chemotherapy for gastric cancer is frequently poor with few properly designed randomised trials. In a number of randomised multi-centre adjuvant studies the inclusions rates are remarkably low, which reduces the scientific value of the studies.