Single and multiple metachronous osteosarcoma tumors after therapy.

BACKGROUND: The objective of the current study was to determine the incidence, clinical and pathologic characteristics, and outcome of patients with conventional osteosarcoma who developed metachronous tumors after treatment for the primary tumor and prevention of pulmonary metastases.

METHODS: The medical records of 270 pediatric patients (younger than age 18 years) were reviewed. The prevention and absence of pulmonary metastases was confirmed by chest radiographs and computerized scans of the lungs. Radionuclide bone scans were used to confirm the absence of skeletal metastases.

RESULTS: Eleven patients with metachronous tumors were identified. Index primary tumors involved the femur (n = 8), the tibia (n = 2), and the radius (n = 1). Single metachronous tumors developed in the femur (n = 6), in the humerus (n = 1), and multifocal in multiple bones (n = 4). Two patients later developed second metachronous tumors. The interval between identification of the primary tumor to development of the single metachronous tumors varied from 11 months to 78 months and from 12 months to 42 months for synchronous multifocal tumors. Metachronous tumors were treated with single-agent cisplatin or ifosfamide. Only 1 patient experienced > 90% tumor necrosis. Pulmonary metastases were not detected in 10 of 11 patients at the time metachronous tumors were discovered. In the 11th patient, synchronous pulmonary metastasis with the metachronous tumor was noted. Three patients had a prior history of bilateral retinoblastoma. The Li-Fraumeni syndrome may have been present in another patient. Six patients died. Five patients have survived for 20+ to 50+ months after the appearance, treatment, and resection of metachronous tumors.

CONCLUSIONS: With improvement in the cure rate, metachronous osteosarcoma should be recognized as an important sequela in long-term survivors. The etiology of this disease is unknown. Speculation rests on a skeletal multicentric origin, which includes an inherited predisposition to develop osteosarcoma in retinoblastoma and in the Li-Fraumeni syndrome. Meticulous follow-up is required to permit early detection and successful therapeutic intervention.