E478: Exploring the Impacts of the Covid 19 pandemic on Gastric and Esophageal Cancer Severity

Introduction: The COVID-19 pandemic is widely believed to be associated with declined median survival in gastric and esophageal cancer patients. It is not clear if this was related to increased disease severity or delayed diagnosis and management.

Methods: This retrospective study analyzed the National Cancer Database (NCDB 2004-2020) data from 2018 to 2020, focusing on gastric and esophageal cancer patients. We analyzed time from diagnosis to initial treatment and surgical resection in days, AJCC (2017) TNM clinical stage distribution (S0-4), and pathological variables suggestive of tumor aggression between pre-pandemic and pandemic periods and within Covid positive (C19+) and negative (C19-) patients.

Results: For gastric cancer database, 78.4% of patients had adenocarcinoma (AC), while in esophageal database, 65.30% of patients had AC and 27.71% had squamous cell carcinoma (SCC). For gastric cancer, we compared 13,100 pre-pandemic to 11,198 pandemic patients, while in esophageal there were 11,331 pre-pandemic and 10,090 pandemic. Male/female ratio was 64/36% for gastric and 80/20% for esophageal both pre-pandemic and pandemic. During the pandemic, 3.48% gastric and 2.95% of esophageal cancer patients were C19+. Time to definitive surgery increased during the pandemic for gastric cancers (122 vs 116 days, p = 0.003). However, time to initial treatment or surgery did not differ in esophageal cancers due to the pandemic or between C19+ and C19-. During the pandemic, the overall stage distribution differed significantly with higher Stage 4 disease in gastric cancer patients (51.4% Vs 49.56%, P< 0.001), as well as in esophageal adenocarcinoma patients (50.2% Vs 46.5%, P< 0.001) but not in esophageal SCC. During the pandemic, despite a trend for increased stage 4 disease in C19+ patients in both cancers, that difference did not reach statistical significance. Surprisingly, there was a decrease in mean lymphovascular invasion in C19+ vs C19- vs pre-pandemic for stages 1 and 4 in all gastric cancers (S1: 0.32 vs 0.41 vs. 0.69, p < 0.05, S4: 0.375 vs 0.54 vs. 0.92, p < 0.05). There was no difference in lymph nodes positive to nodes harvested ratio in any of the cancers during the pandemic.

Conclusions: The COVID 19 pandemic was associated with significant delays in time to surgery for gastric cancer patients and a significant increase in the incidence of stage 4 disease in both gastric and esophageal cancers. Further data are awaited to better characterize the causes and long-term effects of the pandemic on gastric and esophageal cancer patients.