Treatment of Newly Diagnosed Childhood Soft Tissue Sarcoma
Chondro-osseous tumors include the following tumor subtypes:
- Extraskeletal chondrosarcoma (mesenchymal and other variants).
- Extraskeletal osteosarcoma.
Extraskeletal chondrosarcoma (mesenchymal and other variants)
Mesenchymal chondrosarcoma is a highly malignant tumor with a propensity to spread to the lungs. A review of 15 patients younger than 26 years from the German Cooperative Soft Tissue Sarcoma Study Group (11 with soft-tissue lesions) and the German-Austrian-Swiss Cooperative Osteosarcoma Study Group (four with primary bone lesions) protocols suggests that complete surgical removal, or incomplete resection followed by radiation therapy, is necessary for local control.[Level of evidence: 3iiA]
Multiagent chemotherapy may decrease the likelihood of lung metastases: OS at 10 years was 67%, compared with approximately 20% in an earlier series of young patients.
Extraskeletal osteosarcoma is extremely rare in the pediatric and adolescent age range. A 2003 review identified only ten case reports in the medical literature.
Extraskeletal osteosarcoma is associated with a high risk of local recurrence and pulmonary metastasis.
The primary therapy for extraskeletal osteosarcoma is surgical resection of the primary tumor. Chemotherapy for extraskeletal osteosarcoma has not been well studied. It has been recommended that the treatment for extraskeletal osteosarcoma abide by the soft tissue sarcoma (STS) guidelines, rather than the guidelines for osteosarcoma of bone. A report of a series of adult patients with extraskeletal osteosarcoma suggested that adjuvant chemotherapy reduced the risk of recurrence. Extraskeletal osteosarcoma may be more chemosensitive in young patients than in adults. A retrospective analysis of the German Cooperative Osteosarcoma Study identified a favorable outcome for extraskeletal osteosarcoma treated with surgery and conventional osteosarcoma chemotherapy. (Refer to the PDQ summary on Osteosarcoma and Malignant Fibrous Histiocytoma of Bone Treatment for more information.)
Fibroblastic/myofibroblastic tumors include the following tumor subtypes:
- Desmoid tumor.a
- Infant fibrosarcoma.
- Adult-type fibrosarcoma.
- Inflammatory myofibroblastic tumor.a
- Low-grade fibromyxoid sarcoma.
- Sclerosing epithelioid fibrosarcoma.
a Not a high-grade tumor.
Desmoid tumors are also known as aggressive fibromatoses.
Desmoid tumors are low-grade malignancies with extremely low potential to metastasize. The tumors are locally infiltrating, and surgical control can be difficult because of the need to preserve normal structures. These tumors also have a high potential for local recurrence. Desmoid tumors have a highly variable natural history, including well documented examples of spontaneous regression. Mutations in exon 3 of the beta-catenin gene are seen in over 80% of desmoid tumors and the mutation 45F has been associated with an increased risk of disease recurrence. Repeated surgical resection can sometimes bring recurrent lesions under control.