Solitary skeletal osteosarcoma recurrence. Findings from the Cooperative Osteosarcoma Study Group.

Background: Solitary skeletal osteosarcoma (OS) manifestations distant from the site of the primary tumor rarely arise as only sign of disease recurrence.

Methods: This report reviews 38 patients with high-grade central OS of the limbs or axial skeleton and initial complete surgical remission (CR) who developed first recurrences as solitary osseous lesions distant from the primary tumor. The Cooperative Osteosarcoma Study Group (COSS) database was used to evaluate patient-, tumor-, and treatment-related variables and outcomes.

Results: Thirty-eight patients (27 males and 11 females; 36 limb and 2 axial primaries) developed solitary osseous recurrences a median of 2.1 years (range: 0.5-14.3) from primary diagnosis. Relapses involved axial (24), extremity (10), or craniofacial bones (4). Treatment for recurrence included surgery (28), radiotherapy (10), and chemotherapy (27). After a median follow-up of 1.9 years (range: 0.1-21.2) from first recurrence for all 38 patients and 5.5 years (0.3-21.2) for 16 survivors (10 in continuous second CR), 2- and 5-year overall and event-free survival (EFS) probabilities were 55% and 34% and 34% and 27%, respectively. A long interval to recurrence (>1.5 years) predicted for better overall (P < 0.001) and EFS (P = 0.005). For 21 patients achieving a second CR, 2- and 5-year overall and EFS probabilities were 81% and 61% and 52% and 49%, respectively, while only 1/17 others survived beyond 5 years (P < 0.001). Survivors (14/16) had also received second-line chemotherapy.

Conclusion: First solitary skeletal recurrences of OS should be treated with curative intent. Some presumed bone metastases may represent second primary OSs.