Loss of local tumor control after index surgery for spinal metastases: a prospective cohort study.

BACKGROUND: As survival after treatment for symptomatic spinal metastases increases, the incidence of local tumor recurrence also may increase. However, data regarding incidence and timing of recurrence or duration of survival after second surgeries are not readily available and may help to inform clinicians when to perform second surgeries. OBJECTIVE: To identify features associated with loss of local control (LLC) at a previously treated or new spinal level. METHODS: Clinical and surgical data were collected from a prospective cohort of 1421 patients who had surgery for symptomatic spinal metastases. Patients undergoing repeat spinal surgery for symptomatic LLC at the same or a different level were identified and analyzed. RESULTS: In total, 3.0% patients underwent repeat surgery for symptomatic LLC after a median interval of 184 days from the first surgery; median survival was 6.1 months after second surgery. Factors associated with second surgery for LLC were the primary tumor type, number of spinal levels, Tomita staging, Tokuhashi and Karnofsky scores, anterior surgical approach, more aggressive surgical resection, and postoperative radiotherapy. In total, 1.5% patients were admitted for surgery for a different spinal level than the index operation after median 338 days from the first operation. CONCLUSIONS: The likelihood for repeat surgery due to LLC cannot be accurately predicted at the time of initial presentation. Factors associated with second surgery for LLC relate to less aggressive tumor biology and better survival. Most patients had a reasonable duration of survival after second surgery.