Carcinoma with osteoclast-like giant cells.

e16392 Background: Carcinoma with osteoclast-like giant cells (COGC) is a rare, undifferentiated malignancy composed of atypical epithelial cells and reactive multinucleated giant cells resembling osteoclasts. Although most tumors arise in the pancreas, COGC has been reported at other anatomic sites and can share features with hepatocellular and other giant-cell rich neoplasms, complicating diagnosis. Current understanding is largely limited to case reports and small institutional series, leaving its epidemiology poorly defined. We therefore analyzed the National Cancer Database (NCDB) to characterize the demographic and socioeconomic features of patients with COGC. Methods: A retrospective analysis of the 2004–2020 NCDB identified 333 cases of histologically confirmed COGC (8035). Demographic, socioeconomic, and clinical variables, including age, sex, race, ethnicity, insurance type, facility characteristics, residential setting, income, Charlson–Deyo score, and short-term mortality, were summarized using descriptive statistics. Incidence trends were analyzed using regression analysis, additional variables analyzed include survival outcomes, treatment modalities, and primary site. Results: The mean age at diagnosis was 64.9 ± 12.8 years; most patients were female (60.4%), White (85.6%), and non-Hispanic (88.9%). Tumors most commonly arose in the pancreatic head (32.7%). Patients were most often treated at academic (51.1%) or comprehensive community programs (24.6%); approximately half were insured through Medicare (50.2%). Most resided in metropolitan areas (87.0%), and 44.3% were in the highest income quartile (≥$74,063). The largest proportion presented with Stage II disease (36.6%), though 20.7% had Stage IV disease. Surgery was performed in 64.0% of cases, with margin-negative resection achieved in 53.8%. Radiation and chemotherapy were administered in 28.8% and 49.8% of patients, respectively. Overall survival was 87.3% at two years, 79.9% at five years, and 45.8% at ten years, with a mean survival of 78.8 months. Conclusions: To our knowledge, this is the first NCDB analysis of COGC. Patients were predominantly older, non-Hispanic White females, with tumors most commonly arising in the pancreatic head. Despite frequent early-stage presentation, one in five patients were diagnosed at Stage IV, indicating a substantial burden of advanced disease. Surgical resection was common, but margin-negative removal occurred in only half of cases, underscoring challenges in local control. Radiation and chemotherapy were frequently used, suggesting reliance on multimodal therapy. Although early mortality was low, long-term survival declined markedly. These findings highlight the need for improved diagnostic strategies, more effective treatments, and refined prognostic tools for this rare tumor.