Prognostic Factors in the Operative Management of Sacral Chordomas

Surgical resection of sacral chordomas offers the best long-term prognosis but has high rates of local recurrence, metastases, and mortality. Most prognostic studies are limited by low patient numbers, variation in treatment, follow-up, and prognostic variables studied. The objective of this study was to identify factors associated with recurrence, metastasis, and survival.

Retrospective review of 58 patients undergoing sacrectomy for chordoma with a mean age of 63 years (range: 41-80 years) and a mean follow-up of 45.3 months (range: 2-144 months). Data on prognostic variables and outcomes were collected. Forty-two patients underwent a combined anterior and posterior approach and 16 underwent a posterior-only approach.

Twenty-six patients (44.8%) died during follow-up. Kaplan-Meier estimates for 5- and 10-year survival were 62% and 26%, respectively. Local recurrence occurred in 32 patients (51.7%) and metastases in 19 (32.7%). Adequacy of resection margins was the most important predictor of disease recurrence, metastases, and survival. Tumors >8 cm were associated with significantly increased risk of metastases and reduced survival (P < 0.05). Dedifferentiated disease and infiltration of the sacroiliac joints and/or adjacent musculature were also associated with reduced survival. Median survival was 23 months for patients with gluteus maximus invasion, 66 months for gluteus maximus and piriformis invasion, 67 months for piriformis invasion, and 90 months for patients with no muscle invasion.

Patients with inadequate resection margins, tumors >8 cm, sacroiliac joint and/or musculature infiltration, and dedifferentiated disease have significantly worse oncologic outcomes. Involvement of gluteus maximus alone confers a higher risk of metastases and local recurrence than involvement of piriformis and gluteus maximus, or piriformis alone.