Dedifferentiated chordoma: Socioeconomic factors and treatment outcomes.
Authors: Chin Kat , Tade Yanick , Gutierrez Reyna , Choe Sharon , Sachs Anton , Ng Sandy , Shin Won , Silberstein Peter T. , Lee Daniel , Demangone Michael , Rossi Anthony , Heise Craig , Hsia Beau 
Published: June 2024

e23507 Background: Dedifferentiated chordoma (DC) is a rare and aggressive chordoma that arises in the spine and skull base characterized by frequent metastasis. Comparatively common in children, these rare tumors arise from the remnants of the fetal notochord. Though surgery and radiation therapy are common treatments, definitive therapeutic guidelines are poorly characterized due to DC’s rarity. Examining the diagnostic trends of DC may yield valuable information about its epidemiology. Thus, the National Cancer Database (NCDB) was analyzed to explore the demographics of patients diagnosed with this rare condition. Methods: The 2004–2020 NCDB recorded 53 patients histologically diagnosed with DC (ICD-O-3 code 9372). Diagnostic trends were analyzed with linear regression and demographic factors such as age, sex, race, and Charles/Deyo score were quantified descriptively. Results: Of the 53 NCDB cases, the most frequently diagnosed group were white (94%), non-Hispanic (85%) women (57%) in the top income quartile (36%) with no comorbidities (87%) living in metropolitan areas with a population of 1 million or more (51%). They often received treatment at academic/research programs (36%) or integrated network cancer programs (21%). In the years 2004-2020, rates of diagnosis remained constant (R2 = 0.0235). Nearly all (98%) of patients were insured, most commonly with Medicare or privately (42% each). The average age at diagnosis was 51 ± 26 years. Over half (55%) of DC cases originated in the pelvic bones, sacrum, or coccyx. Most (74%) patients received surgery, with the most common procedure being wide excision of the primary site (32%), eliminating the tumor (30%). Radiation therapy (55%) was another common treatment. Ninety days post-surgery, 94% of patients were still alive. However, the survivorship (58%) plummets after two years, with an overall survival time of just 5.8 years. Conclusions: This review is the first to explore the demographic and diagnostic factors of DC on the NCDB. Though rare, DC is an aggressive cancer that half of patients succumb to in around 2 years. It commonly originates in the pelvis, sacrum, or coccyx, contrary to prior literature that suggests it affects the skull base or spine. White, non-Hispanic women in the top income bracket were the most frequently diagnosed group. With patient ages ranging from 1 to 86, it affects children and adults alike. Despite this, prior literature mainly explores childhood cases, highlighting a gap in current scientific understanding of DC, a significant barrier to effective treatment. Intriguingly, 51% of DC cases occurred in cities, but 83% of all Americans live in metropolises. This discrepancy suggests that lower-income urban populations may face greater challenges obtaining diagnosis or treatment. Thus, further research into the effects of sociodemographic factors on the prognosis of adult-onset DC is critical to treatment equity for this poorly understood disease.