Efficacy and Safety of Pembrolizumab as Monotherapy and in Combination with Chemotherapy versus Chemotherapy Alone for Advanced Gastric or Gastroesophageal Junction Cancer: A Systematic Review and Meta-Analysis
Zhiqiang Bai, Zujun Ding, Shu Yang, Kaixin Du, Lei Deng, Yechao Qian, Hang LiIntroduction:
This study aimed to assess the effectiveness and safety of pembrolizumab, used either as a monotherapy or in combination with chemotherapy, compared to chemotherapy alone in patients with advanced Gastric Cancer (GC) or Gastroesophageal Junction (GEJ) cancer
Methods:
A comprehensive literature search was conducted in Web of Science, PubMed, and Embase up to October 13, 2025. Included were Randomized Controlled Trials (RCTs) involving adults with pathologically confirmed advanced GC/GEJ cancer that compared pembrolizumab-based regimens to chemotherapy alone. Data were pooled using random-effects models, and study quality was assessed with the Cochrane Risk of Bias Too
Discussion:
This systematic review and meta-analysis provide comprehensive evidence regarding the efficacy and safety of pembrolizumab as monotherapy and in combination with chemotherapy for advanced GC/GEJC. Pooled analysis indicates that combination therapy yields significant survival benefits, particularly in patients with elevated PD-L1 expression. Conversely, monotherapy demonstrated no overall survival advantage and was associated with inferior progression-free survival compared to chemotherapy alone.
Conclusion:
Pembrolizumab combined with chemotherapy is an effective therapeutic strategy for advanced GC/GEJC, whereas monotherapy lacks superior efficacy in the general population and should be interpreted with caution due to observed heterogeneity