Nationwide comparative study of synchronous and metachronous spine metastasis in the adult Korean population

•Metachronous was defined when primary tumor was diagnosed before spine metastasis.•The incidence rate of the metachronous group was significantly higher than that of the synchronous group.•Patients in the synchronous group survived significantly longer than those in the metachronous group.•Among combination treatment modalities, surgery combined with RT was the most common treatment. This nationwide study of the adult Korean population aimed to compare the survival period between synchronous and metachronous group and to determine recent treatment trends in newly diagnosed spine metastasis patients. Data were extracted from the Korean Health Insurance Review and Assessment Service database. Patients in this study were newly diagnosed with metastatic spine tumors between July 1, 2011 and June 31, 2014. The metachronous group was defined when the primary tumor was diagnosed prior to the diagnosis of spine metastasis, otherwise patients were considered to be the part of the synchronous group. The survival period was calculated from the date of first diagnosis of spine metastasis. In a multivariate analysis, patients in the synchronous group survived significantly longer than those in the metachronous group (P