Surgical management of unknown primary tumors metastatic to the spine

Patients presenting with spinal metastases from unknown primary tumors (UPTs) are rare. The authors reviewed their surgical experience to evaluate outcomes and identify predictors of survival in these patients.

This study is a retrospective analysis of patients undergoing surgery for metastatic spine disease from UPTs between June 1993 and February 2007 at The University of Texas M. D. Anderson Cancer Center.

Fifty-one patients undergoing 52 surgical procedures were identified. The median age at spine surgery was 60 years. The median survival from time of diagnosis was 15.8 months (95% CI 8.1-23.6) and it was 8.1 months (95% CI 1.6-14.7) from time of spine surgery. Postoperative neurological function (Frankel score) was the same or improved in 94% of patients. At presentation, 77% had extraspinal disease, which was associated with poorer survival (6.4 vs 18.1 months; p = 0.041). Multiple sites (vs a single site) of spine disease did not impact survival (12.7 vs 8.7 months; p = 0.50). Patients with noncervical spinal disease survived longer than those with cervical disease (11.8 vs 6.4 months, respectively; p = 0.029). Complete versus incomplete resection at index surgery had no impact on survival duration (p > 0.5) or local recurrence (p = 1.0). Identification of a primary cancer was achieved in 31% of patients.

This is the first reported surgical series of patients with an unknown source of spinal metastases. The authors found that multiple sites of spinal disease did not influence survival; however, the presence of extraspinal disease had a negative impact. The extent of resection had no effect on survival duration or local recurrence. With an overall median survival of 8.1 months following surgery, aggressive evaluation and treatment of patients with metastatic disease of the spine from an unknown primary source is warranted.