Soft tissue sarcoma as a second malignant neoplasm in the pediatric age group.

BACKGROUND. Survivors of childhood malignancies have an increased risk of developing second malignant neoplasms (SMN) due to their prior treatment and/or genetic susceptibility. A small proportion of SMNs are soft tissue sarcomas (STS), whose prognosis is generally thought to be poor, though publications on such patients’ treatment and outcome is limited. METHODS. The authors analyzed 25 patients who were registered for the Italian Cooperative Group protocols for pediatric STS from 1979 to 2000. The primary tumor was STS in five patients; Hodgkin disease in five patients; leukemia in four patients; retinoblastoma, neuroblastoma, and Wilms tumor in two patients each; and other tumor types in five patients. SMNs occurred after a median of 8 years (range, 1.9 –15.0 years) and included rhabdomyosarcoma (RMS) in 4 patients, malignant peripheral nerve sheath tumor in 4 patients, extraosseous Ewing family tumor (EFT) in 4 patients, leiomyosarcoma in 3 patients, fibrosarcoma in 2 patients, synovial sarcoma in 2 patients, and other tumor types in 6 patients. Treatment generally was administered according to the guidelines for primary STS. RESULTS. Seven non-RMS patients with STS underwent surgery alone, whereas 18 patients received chemotherapy and 8 patients received radiotherapy. Retreatment was feasible with acceptable toxicity. Fifteen patients were alive in complete remission of their SMN at the time of last follow-up. Responses to chemotherapy and survival were satisfactory for patients with tumors such as RMS and EFT. Complete tumor resection was correlated with a favorable prognosis in patients with other types of STS and in patients with postirradiation sarcoma. Two patients developed a third malignancy. CONCLUSIONS. Although prior treatment may hinder the management of these patients, pediatric STS second malignancies can be cured using the same strategies used for de novo pediatric sarcomas. Long-term follow-up is mandatory given the risks of further malignancies and more severe, treatment-related side effects. Cancer 2004;100:1758–65. © 2004 American Cancer Society. KEYWORDS: soft tissue sarcoma, second malignancy, rhabdomyosarcoma, malignant peripheral nerve sheath tumor, leiomyosarcoma, children.