A National Cancer Database analysis of hepatoid adenocarcinoma: Epidemiology, socioeconomic, and clinical factors.

e20767 Background: Hepatoid adenocarcinoma (HAC) is a rare extrahepatic neoplasm that displays histologic similarity to hepatocellular carcinoma features. This cancer most commonly occurs in the stomach, pancreas, or lungs. HAC is frequently detected at advanced stages and presents with poor prognoses, demonstrating the need for further epidemiological investigation and comprehension. Accordingly, the National Cancer Database (NCDB) was analyzed to characterize the demographic, clinical, and socioeconomic factors in patients diagnosed with hepatoid adenocarcinoma in the United States. Methods: Utilizing the 2004-2020 National Cancer Database (NCDB), a retrospective cohort study was conducted to identify patients with a histologically confirmed diagnosis of HAC (ICD-O-3 code 8576, N = 584). Descriptive statistics were applied to evaluate patient demographic, socioeconomic, and clinical factors, such as tumor characteristics and treatment options (sex, race, Hispanic status, year of diagnosis, and Charleson-Deyo score), whereas the incidence patterns and survival analysis were assessed using regression analysis and the Kaplan-Meier estimated methodology, respectively. Results: Between 2004 to 2020, the NCDB documented 584 patients with HAC, indicating the incidence rate fluctuated substantially with a non-linear trend (R² = 0.709). The majority of patients were male (60.8%), White (79.6%), and non-Hispanic (89.9%). The mean age at diagnosis is 65.2 (STD ER 0.51). The most common primary sites within the bronchus or lung included the upper lobe (25.3%), lower lobe (9.10%), and NOS (6.50%), with the secondary involvement of the liver (7.40%) and stomach (4.60%). Regarding diagnosis, nearly half of cases (46.9%) were identified as Stage IV, followed by Stage III (9.90%) and Stage II (6.20%). The majority of patients (64.6%) had a low comorbidity burden with a Charlson-Deyo Score of 0. Post-surgical mortality rates were 4.8% at 30 days following surgery, and 11.6% at 90 days following surgery. 35.6% of patients used radiation as their primary form of therapy. 53.3% of patients used chemotherapy, 0.50% used hormone therapy and 5.7% primarily used immunotherapy. The survival rates at 2, 5, and 10 years were 0.227%, 0.128%, and 0.108%, respectively. The mean survival was 30.9 months. Conclusions: This is the first NCDB analysis on hepatoid adenocarcinoma to the best of our knowledge, helping fill a gap in literature on national epidemiological trends. The majority of patients tend to be White males with a primary site of diagnosis being the lung, similar to descriptions in case studies. Most patients use chemotherapy as primary treatment. Further research is needed to understand the gender and racial factors in the diagnosis, treatment, and survival of patients with hepatoid adenocarcinoma.