Diagnostic Delay and Mortality Risk in Gastric Cancer During the COVID-19 Pandemic: A Retrospective Tertiary-Center Study

<b>Background/Objectives:</b> The COVID-19 pandemic disrupted healthcare delivery worldwide, potentially delaying the diagnosis and treatment of oncologic diseases. This study aimed to evaluate the impact of the pandemic on stage at diagnosis, treatment allocation, and survival outcomes among patients with gastric cancer. <b>Methods</b>: We retrospectively analyzed 419 consecutive patients diagnosed with gastric cancer between January 2018 and December 2021 at a tertiary oncology-surgical center. Patients were divided into pre-pandemic (2018-2019) and pandemic (2020-2021) cohorts. Demographic, clinical, and treatment variables were compared using <i>t</i>-tests and χ² tests. Multivariate logistics and Cox regression models were applied to identify independent predictors of metastatic presentation and mortality. Overall survival (OS) was calculated from diagnosis to death or last contact (OS_days), with same-day events censored at time zero. <b>Results</b>: Baseline characteristics were comparable between cohorts (age, <i>p</i> = 0.098; sex, <i>p</i> = 0.137; residence, <i>p</i> = 0.345). The proportion of metastatic cases (M1) increased from 42.8% in 2018-2019 to 64.4% in 2020-2021 (χ²<i>p</i> < 0.001). Surgical rates remained stable (55.1% vs. 47.7%, <i>p</i> = 0.161). Diagnosis during the pandemic independently predicted metastatic presentation (OR = 2.63, 95% CI 1.68-4.11, <i>p</i> < 0.001) and higher mortality (HR = 1.72, 95% CI 1.41-2.03, <i>p</i> < 0.001). Kaplan-Meier analysis confirmed significantly reduced OS in the pandemic cohort (log-rank χ² = 81.29, <i>p</i> < 0.001). <b>Conclusions</b>: The pandemic was associated with delayed diagnosis, stage migration toward advanced disease, and inferior survival in gastric cancer, despite comparable demographics and treatment capacity. These findings emphasize the need to safeguard diagnostic pathways-particularly endoscopy-during healthcare crises to prevent avoidable oncologic deterioration.