Clinical Behavior and Treatment Response of Epstein-Barr Virus-Positive Metastatic Gastric Cancer: Implications for the Development of Future Trials

Background. Epstein-Barr virus (EBV)-positive gastric can cers (GCs) have been recently identified as a molecular sub group showing excellent outcomes after surgery for early stage disease and responsiveness to immune checkpoint
inhibitors (ICIs) for metastatic stage. No data are available
on the prevalence, clinical characteristics, and prognosis of
this subgroup of GCs in the metastatic setting.
Materials and Methods. In this cohort study, we assessed
the impact of EBV status in patients with metastatic GC
treated with chemotherapy at two Italian institutions.
Results. Among the 175 cases analyzed, only 7 (4%) were
EBV positive and all showed long-lasting and even complete
responses to first-line chemotherapy with fluorouracil and
platinum and a significantly better survival compared with
EBV-negative patients (3-year overall survival: 80%
vs. 20.1%; hazard ratio: 0.12).
Conclusion. If confirmed in larger data sets, our results may
give a strong rationale for investigating the addition of ICIs
to chemotherapy, in order to maximize the chance of
achieving durable and complete responses in this uncom mon subtype of GC. T