Önder BAĞCI, Levent KORKMAZ, Mehmet Zahid KOÇAK
Eurasian Journal of Medical Investigation - 2026;10(2):118-123
Objectives: To assess the effect of prior SARS-CoV-2 infection and COVID-19 vaccination on overall survival (OS) in patients with metastatic solid tumors and to examine potential variation in this association across major cancer subtypes. Methods: This retrospective observational study included 62 patients with histologically confirmed metastatic solid tumors. Patients were categorized into four groups according to vaccination and infection status: vaccinated and previously infected, vaccinated only, infected only, and unvaccinated/uninfected controls. Results: OS was longer in vaccinated or previously infected patients than in double-negative controls (51.4 months vs. 33.8 months) (p=0.324). Among patients in remission, survival was markedly longer in those with prior vaccination or COVID-19 infection than in individuals negative for both factors (90 vs. 36 months), although this difference did not reach statistical significance (p=0.302). The most pronounced benefit occurred within the breast cancer subgroup, where prior infection or vaccination was strongly associated with extended remission survival (106 months). Conclusion: Prior COVID-19 infection and vaccination were associated with improved long-term survival in patients with metastatic solid tumors. These observations raise the possibility that immune activation triggered by viral exposure or vaccination may enhance tumor immunosurveillance and strengthen host resilience.
