Randomized controlled trial in gastric or gastroesophageal junction adenocarcinoma undergoing systemic therapy over two decades

Introduction: The number of randomized controlled trials (RCTs) investigating the systemic treatment of gastric or gastroesophageal junction adenocarcinoma (GA-RCTs) is increasing. We aimed to describe the characteristics and evaluate the clinical benefit of GA-RCTs over the past 20 years.

Materials and methods: We searched for RCTs of systemic treatment in GA published in eight major journals between 2001 and 2020 in PubMed. From the included studies, the characteristics and results of GA-RCTs were extracted. Clinical benefit was assessed using the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS).

Results: About 93 RCTs with 38365 patients were included. Seventy-one (76.3%) studies received external funding, with an increase from 27.3% (2001-2005) to 94.1% (2016-2020). RCTs on targeted therapy and/or immunotherapy have also increased over time, but only 14 (41.2%) were restricted to specific biomarkers. Forty-four (47.3%) studies met their primary endpoint (defined as positive RCTs), but median overall survival has not improved over time. Moreover, only 16 (36.4%) studies met the ESMO-MCBS threshold. RCTs whose study design and results met the ESMO-MCBS thresholds has not increased over time (p = 0.827 and p = 0.733, respectively).

Conclusions: GA-RCTs are increasingly focused on targeted therapy and/or immunotherapy, and are more likely to receive external funding. However, the effect size has not shown significant improvement in the past 20 years. Only a few RCTs with positive results met ESMO thresholds. Future RCTs should prioritize the clinical benefits and provide direct evidence to optimize and reform GA treatment practices.