Incidence patterns and temporal trends of chordoma: A population-based analysis of over 6000 cases in the United States

Background: Chordoma is a rare malignant bone tumor arising from notochordal remnants, with largely unknown etiology and limited descriptive characterization. Methods: Data from the North American Association of Central Cancer Registries, covering 93% of the U.S. population, were used to estimate age-standardized incidence rates and trends from 2003-2022 by demographic and clinical factors. Period trends were quantified using Joinpoint regression, and birth-cohort trends were assessed using age-period-cohort modeling. Data from 21 Surveillance, Epidemiology, and End Results (SEER) registries were used to estimate relative survival for cases diagnosed from 2003-2021. Results: A total of 6,260 chordoma cases were diagnosed during 2003-2022. Cranial tumors were most frequent (38.7%), followed by sacral (32.7%) and spinal (25.4%) sites. The age-standardized incidence rate was 0.097 per 100,000, increasing with age and peaking at 80-84 years. Males had higher incidence than females after age 35. Incidence was lowest among Black individuals and highest in the Northeast and metropolitan areas. From 2003-2022, incidence rose 1.47% annually (95% CI = 0.61-2.39), with steeper increases among younger individuals, women, and localized and cranial tumors. Successive birth cohorts showed increasing risk, with those born near 1998 having approximately twice the rate of those born near 1958 (95% CI = 1.28-3.16). Among 2,181 SEER cases, 5-year relative survival was 83.4%, varying by race/ethnicity and region, and for distant-stage disease ranged from 68.6% (cranial) to 38.3% (sacral). Conclusions: Chordoma incidence and survival vary by demographic and clinical factors, suggesting potential differences in detection, healthcare access, and underlying etiology.