Background: The primary site of metastasis from extremity sarcomas is the lung. When patients with extremity sarcoma present with the disease in more than one site but not in the lung, the question of whether the disease is multifocal or metastatic is difficult to resolve.
Methods: We reviewed 1423 patients admitted with extremity sarcoma from 1982 through 1996. Patient demographics, primary site, other sites, local recurrence, distant metastasis, and survival were analyzed. Statistics were by Fischer exact test, χ2, Kaplan-Meier method, and log-rank test where appropriate.
Results: Sixteen (1%) patients were identified with multifocal disease out of 1423 patients with extremity sarcoma. There was no difference in sex, age, size, grade, depth, and margins between multifocal and unifocal disease. In a mean follow-up time of 57 months, 50% had local recurrence of primary tumor, 80% had distant metastasis, and only 30% were alive at the time of the analysis. Whereas 21% of all patients with solitary disease develop lung metastasis, 63% of patients with apparent multifocal disease develop lung metastasis. The 5-year disease-specific survival of patients with multifocal disease was not different from that of all patients presenting with metastatic disease to lung.
Conclusion: Whether multifocal disease exists or is merely a form of metastasis is unproven by this analysis, but the outcome is the same. Management algorithms should suggest treating patients with multifocal disease as if it is metastatic disease.