Abstract
BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic disrupted cancer care, resulting in significant diagnostic delays. OBJECTIVES: While prior studies have examined shifts in clinical stage, limited data exist on the pandemic's effect on histopathological features and long-term survival in gastric cancer (GC). We aimed to address this gap through a comprehensive comparative analysis. DESIGN: Retrospective cohort study. SETTING: Tertiary-care center. PATIENTS AND METHODS: This single-center study included 317 participants newly diagnosed with GC, divided into pre-pandemic (March 2018-March 2020) and pandemic (March 2020-March 2022) groups. Demographic, clinical, and detailed histopathological characteristics and 1- and 3-year overall survival (OS) rates were compared between groups. MAIN OUTCOME MEASURES: Comparison of clinical stage, treatment modality, histopathological features, and 1- and 3-year overall survival between GC patients diagnosed before and during the COVID-19 pandemic. SAMPLE SIZE: 317 patients. RESULTS: The pandemic group exhibited a significantly higher rate of metastasis at diagnosis (38.0% vs. 26.9%; P=.035), lower rate of surgical resection (54.0% vs. 65.3%; P=.041), and higher rate of palliative therapy (44.0% vs. 31.1%; P=.018). Histopathologically, this cohort had a greater proportion of high-grade (G3) tumors (P=.014), lower median number of dissected lymph nodes (P=.002), and poorer response to neoadjuvant therapy (P=.025). Both 1- and 3-year OS were significantly lower in the pandemic group (P=.009 and .045, respectively). CONCLUSIONS: The COVID-19 pandemic was associated with more advanced disease at diagnosis and significantly worse long-term survival for patients with GC. These outcomes appear to result from diagnostic and treatment delays rather than substantial changes in tumor biology. These findings underscore the need to establish resilient cancer care systems to reduce vulnerability during health crises. LIMITATIONS: Single-center retrospective design and selection bias due to histopathological analyses being limited to surgically treated patients.