The impact of complete surgical resection of spinal metastases on the survival of patients with thyroid cancer

Spinal metastases (SMs) from thyroid cancers significantly reduce the quality of life by causing pain and neurological deficits and increase mortality. Complete surgical resection of isolated thyroid SMs is a promising treatment option; however, the postoperative outcome is unknown. This study aimed to compare the postoperative courses of patients undergoing complete resection of thyroid SMs with those of patients undergoing incomplete resection, with a minimum 4-year follow-up. We performed a retrospective analysis of 32 patients who underwent tumor excision surgery for thyroid SMs at our medical center during a 28-year period. Twenty patients underwent complete excision, and 12 underwent incomplete excision. Survival was defined as the time from the first spinal surgery to death or last follow-up. Kaplan-Meier analysis with the long-rank test was used to compare the overall survival rates between the groups. For all patients, the overall 5- and 10-year survival rates were 71% and 31%, respectively. The median overall survival time was 6.4 years. The patients undergoing complete excision survived longer than those undergoing incomplete excision (5-year survival: 84% vs. 50%; 10-year survival: 52% vs. 8%; P < 0.01). Only one patient undergoing complete excision experienced local tumor recurrence in the operated spine, whereas all long-term survivors (>18 months after surgery) in the incomplete excision group experienced local tumor recurrence and a consequent deterioration in performance status. Complete surgical resection of thyroid SMs, if achievable, has the potential not only to maintain performance status, but also to prolong survival.