Soft Tissue Sarcomas

Abstract

Soft tissue sarcomas are uncommon in children, accounting for about 6% of all childhood malignancies. The majority of these are rhabdomyosarcomas (RMS), and a smaller proportion consists of non-rhabdomyosarcoma soft tissue sarcomas (NRSTS). Most RMS have a bimodal age distribution, with most being in children <6 years of age and a second peak in adolescents. The most common pathology is embryonal RMS, which have a better prognosis than the less common alveolar histology. The common sites of involvement are the head and neck and genitourinary regions, while the extremities and trunk are also involved. Biologically, some sites like the orbit, paratesticular, vagina, and uterus have very good outcomes and are called favorable sites, while others are the unfavorable sites (parameningeal, bladder and prostate, extremities and trunk). Work-up requires a biopsy (open or core needle) for histological diagnosis and cross-sectional imaging (CT scan or MRI) for extent of disease. The Children Oncology Groups’s (COG) clinical grouping (CG) and TNM systems are used for staging these tumors. The treatment is multimodality utilizing chemotherapy, surgery, and radiotherapy and depends on the risk categorization. The chemotherapy protocol commonly used is VAC (vincristine, actinomycin D, and cyclophosphamide). Surgical resection is much more conservative, with organ and limb preserving intent. Low-risk tumors have excellent prognosis (5-year EFS > 85%), while high-risk tumors have poorer prognosis (5-year EFS < 35%). One-fifth of patients have metastatic disease at presentation, and these have the worst outcome. Currently, local control is achieved in 80–90% of RMS patients, and approximately 70% of the patients survive for 5 years or more and are probably cured.