Postoperative survival after lumbar instrumented surgery for metastatic spinal tumors: a nationwide population-based cohort analysis

Background It is difficult to predict the expected survival after lumbar instrumented surgery for metastases owing to the difference among different cancer origins and the relatively short survival after surgery. Aims The aim of this study is to analyze the postoperative survival period of lumbar spinal metastasis patients who underwent lumbar instrumented surgery. Methods Data were collected from the Korean National Health Insurance Review and Assessment Service database. Patients who underwent lumbar spinal surgery with instrumentation between January 2011 and December 2015 for metastatic lumbar diseases were reviewed. The mean postoperative survival period of patients with metastatic lumbar cancer according to each primary cancer type was evaluated. Results A total of 628 patients were enrolled and categorized according to primary cancer type. The overall median survival rate was 1.11±1.30 years. The three most prevalent primary cancer groups were lung, hepatobiliary, and colorectal cancers, presenting relatively short postoperative survival rates (0.93±1.25, 0.74±0.75 and 0.74±0.88 years, respectively). The best postoperative survival period was observed in breast cancer (2.23±1.83 years), while urinary tract cancer showed the shortest postoperative survival period (0.59±0.69 years). Conclusion The postoperative survival period of patients with lumbar metastatic spinal tumors according to different primary cancers after instrumented fusion was ˃1 year overall, with differences according to different primary origins. This result may provide information regarding the expected postoperative survival after instrumented surgery for lumbar spinal metastases.