Contemporary Trends in the Incidence and Timing of Spinal Metastases: A Population-Based Study

Spinal metastases are a significant complication of advanced cancer. In this study we assess temporal trends in the incidence and timing of spinal metastases and examine underlying patient demographics and primary cancer associations. In this population-based retrospective cohort study, health data from 2007 to 2019 in Ontario, Canada were analyzed (n = 37, 375 patients identified with spine metastases). Primary outcomes were annual incidence of spinal metastasis, and time to metastasis after primary diagnosis. The age-standardized incidence of spinal metastases increased from 229 to 302 cases per million over the 13-year study period. The average annual percent change (AAPC) in incidence was 2.2% (95% CI 1.4 to 3.0%) with patients aged ≥85 years demonstrating the largest increase (AAPC 5.2%; 95% CI 2.3 to 8.3%). Lung cancer had the greatest annual incidence, while prostate cancer had the greatest increase in annual incidence (AAPC 6.5; 95% CI 4.1 to 9.0%). Lung cancer patients were found to have the highest risk of spine metastasis with 10.3% (95% CI 10.1 to 10.5%) of patients being diagnosed at 10-years. Gastrointestinal cancer patients were found to have the lowest risk of spine metastasis with 1.0% (95% CI 0.9 to 1.0%) of patients being diagnosed at 10-years. The incidence of spinal metastases has increased in recent years particularly among older patients. The incidence and timing vary substantially among different primary cancer types. These findings contribute to the understanding of disease trends and emphasize a growing population of patients that require subspecialty care.