A nationwide epidemiological study of newly diagnosed spine metastasis in the adult Korean population

Background Context Metastatic spine tumor has become clinically important because of the availability of improved diagnostic tools and increases in survival periods in cancer patients. In spite of this interest, the burden of metastatic spine tumor on the general population has not been extensively reported. Purpose The aim of this 2009–2011 nationwide study of adult Koreans was to describe characteristics, medical use, and survival rate of patients with newly diagnosed metastatic spine tumors according to the primary tumor. Design/Setting This is a retrospective cohort study. Patient Sample A national health insurance database was used to identify a cohort of patients with newly diagnosed metastatic spine tumors. Outcome Measures This study aimed to analyze characteristics, medical use, and survival rate of patients with newly diagnosed metastatic spine tumors according to the primary tumor. Methods Data for patients with metastatic spine tumors were extracted from the Korean Health Insurance Review and Assessment Service database. Data included patient age, sex, health insurance type, comorbidities, medical cost, and hospital stay duration. Hospital stay duration and medical costs per person during 1 calendar year were evaluated. In addition, survival rates of patients with metastatic spine tumor according to primary tumor sites were evaluated. Results The incidence rate of spine metastasis increased with age, year of diagnosis, and the number of comorbidities (p≤.0001). The 6 most prevalent primary tumor sites were lung, liver and biliary tract, breast, colon, stomach, and prostate. Of patients with the 6 most prevalent primary tumors, total average annual medical costs, including inpatient and outpatient services, ranged from 12,734USD (prostate origin) to 15,556 USD (lung origin). Of patients with the 6 most prevalent primary tumors, total average annual hospital stay duration, including inpatient and outpatient services, ranged from 70.8 days (stomach origin) to 78.7 days (colon origin). Median overall survival duration in patients with metastatic spine tumor was 191 days. In addition to age, sex, and comorbidities, primary tumor sites (lung, liver and biliary tract, breast, stomach, and prostate) significantly affected survival rate. Conclusions This nationwide study was able to depict the burden of metastatic spine tumor in Korea. The metastatic spine tumor incidence rate is highest in the group of 70- to 79-year-old men. Average annual medical costs ranged from 12,734 USD to 15,556 USD. The mean annual hospital stay duration was from 70.8 days to 78.7 days. In addition to age, sex, and comorbidities, primary tumor sites significantly affected the survival rate in patients with metastatic spine tumor.