Early-onset gastric cancer: A comparison of metastatic and locoregional disease.

e16036 Background: The incidence of metastatic gastric cancer among young adults is rising and has a dismal prognosis with 5-year survival of only 4%. Little is known about the clinicopathologic features and symptoms associated with locoregional vs metastatic disease. Methods: This retrospective study evaluated patients treated for early-onset (age < 50 years) gastric cancer at the USC Norris Comprehensive Cancer Center and LA General Hospital from 2000-2022. Data from medical records (sociodemographic characteristics, tumor features, cancer predisposition risk factors and patterns of symptom presentation) were compared by extent of disease at presentation. Results: 275 patients were evaluable (104 locoregional, 142 metastatic, 29 unknown stage). There was no difference in stage at presentation by sex or insurance type. Racial/ethnic minorities were more likely to present with metastases (Table 1). There was no difference in BMI for locoregional or metastatic patients (p = 0.10); primary location of tumor, histologic characteristics (diffuse vs intestinal; adenocarcinoma with or without signet ring cell features). Of 163 patients with HER2 status, there was no association between HER2+ status and locoregional vs metastatic disease (p = 0.23) or race/ethnicity (p = 0.06). Locoregional patients were not more likely to have a known genetic cancer predisposition syndrome (p = 0.06) or a family history of cancer (p = 0.15). Patients with metastatic disease were more likely to have more symptoms (4 vs 3, p = 0.001) compared to locoregional, specifically ascites (OR 6.14 p = 0.001), fatigue (OR 3.16, p = 0.016), abdominal pain (OR 2.63, p < 0.001), and weight loss (OR 2.36, p = 0.001). Metastatic patients were less likely to have heartburn or indigestion (OR 0.50, p = 0.02). Patients with a negative endoscopy prior to diagnosis (n = 48, 17%) were equally likely to present with locoregional or metastatic disease (p = 0.21), even in those whose negative endoscopy was within 4 months prior to diagnosis (p = 0.15). Conclusions: Early detection of gastric cancer, especially in minoritized communities is crucial as these patients are more likely to present with metastatic disease. Although patients with metastatic disease had more symptoms, the type of symptoms, cancer predisposition risk and workup prior to diagnosis do not clearly identify an opportunity for early intervention. Further evaluation, including molecular characterization of metastatic vs locoregional patients may identify other factors contributing to poor outcomes. Race/Ethnicity LocoregionalN (%) MetastaticN (%) Missing StageN (%) TotalN (%) p-value Hispanic 62 (32.8) 102 (54.0) 25 (13.2) 189 (100) 0.034 Non-Hispanic Asian 13 (37.1) 21 (60.0) 1 (2.9) 35 (100) Non-Hispanic Black 3 (75.0) 1 (25.0) 4 (100) Non-Hispanic White 26 (55.3) 18 (38.3) 3 (6.4) 47 (100)