Struma ovarii: An NCDB retrospective study of demographic and socioeconomic factors.

Abstract

e17590 Background: Struma ovarii malignant cancer (SOMC) is an extremely rare ovarian teratoma originating from aberrant thyroid tissue that can mimic thyroid carcinoma. Despite a high preoperative misdiagnosis rate of 98%, SOMC carries a favorable 25-year survival rate of 79%. Given the paucity of literature on SOMC, analyzing its demographic and prognostic trends could improve patient outcomes. Methods: A retrospective cohort analysis is conducted using the 2004-2020 National Cancer Database (NCDB) to analyze patients with a confirmed diagnosis of SOMC. The study examined demographic factors such as age, race, Hispanic ethnicity, insurance type, distance from the treatment facility, facility type, and Charleson-Deyo score using descriptive statistics and regression analysis to evaluate incidence trends. Results: Patients with a confirmed diagnosis of SOMC (n = 224) were identified in the NCDB, with incidence rates remaining stable over time (R² = 0.012). The majority of patients diagnosed were a median age of 49 years old (SD = 14.5, range = 13 - 87), White (77%), of non-Hispanic descent (83%), privately insured (66%) and belonging to high-income households (43%). A significant proportion of patients lived outside of large metropolitan areas (37%) and sought treatment at research programs (41%) or community cancer programs (30%). Surgery was the primary treatment modality (96%), with a significant proportion of cases demonstrating non-evaluable margins or unknown outcomes (27%). The predominant surgical procedures were total abdominal hysterectomy with bilateral salpingo-oophorectomy and lymphadenectomy (23%), unilateral salpingo-oophorectomy (18%), and total abdominal hysterectomy with bilateral salpingo-oophorectomy and omentectomy (15%). A significant proportion of patients received radiation therapy (20%), while few received chemotherapy, either as primary (2%) or adjuvant (1%) treatment, with the primary SOMC site located in an unspecified ovary (99%). Conclusions: This study is the first NCDB analysis on demographic and socioeconomic factors of patients diagnosed with SOMC. According to the National Comprehensive Cancer Network guidelines, surgery alone is curative for stage I, grade I cases, while chemotherapy is recommended for higher stages and grades. However, despite 17% of cases being stage II-IV, our retrospective analysis found chemotherapy was infrequently prescribed. While fertility preservation is emphasized in SOMC management, the most common intervention (23%) was total abdominal hysterectomy with bilateral salpingo-oophorectomy and lymphadenectomy. As most Americans live in metropolitan areas, SOMC may be over-represented in rural populations. Building on this study, future studies should examine the relationship between patient age demographics and the selection of non-fertility-preserving surgical interventions in SOMC management.