Prognostic Factors in Patients with Differentiated Thyroid Cancers Metastatic to the Cervical Spine

The spine is the most common site of bone metastases in differentiated thyroid cancer (DTC). The role of surgery in the management of cervical spine (C-spine) metastases (CSpM) has not been adequately explored.

This is a retrospective cohort study at a tertiary referral center from 2002 to 2018. Inclusion criteria were pathologic diagnosis of DTC and imaging/pathologic diagnosis of CSpM. Statistical analysis utilized t tests for continuous variables and χ² tests for categorical variables. Survival analysis was conducted using Kaplan-Meier curves with univariate and multivariate Cox regressions.

Fifty patients with DTC and CSpM were identified. Of those, 16 underwent surgical resection of the C-spine, whereas 34 did not. The most common presenting symptom was neck pain (N = 37, 74%). Patients in the surgery group were more likely to report a subjective improvement of symptoms (P < .01) and to have local (P < .01) and systemic (P = .04) disease control. Five-year overall survival was 44.7% for the surgery group (95% confidence interval [CI]: 17.1-69.3) and 11.1% (95% CI: 2.1-28.8) for the nonsurgery group (P = .01). The strongest risk factor for improved overall survival after C-spine metastasis was local disease control at the C-spine (multivariate hazard ratio [HR] = 0.32, 95% CI: 0.12-0.85, P = .02). Surgical intervention was significantly associated with improved survival on both univariate (HR = 0. 35, 95% CI: 0.15-0.82, P = .02) and multivariate (HR = 0.37, 95% CI: 0.14-0.98, P = .04) analysis.

Surgical management of CSpM in differentiated thyroid cancers is associated with significantly improved local disease control and overall survival. Referral to spine surgeons should be considered after diagnosis.

IV. Laryngoscope, 131:E1741-E1747, 2021.