Soft tissue sarcomas in children

Tumours arising from the soft tissues are uncommon in children, accounting for about 6% of all childhood malignancies. More than half (53%) of these originate from the striated muscles and are called rhabdomy-osarcomas (RMS) the remaining are non-rhabdomyosarcoma soft tissue sarcomas (NRSTS). Almost two-thirds of cases of RMS are diagnosed in children less than 6 years of age. They can arise at varied locations like the head and neck region, genitourinary tract, extremities, trunk and retroperito-neum. Pathologically RMS is now classified as superior, intermediate and poor outcome histologies. For stratification of treatment and also comparison of results the RMS are now staged both by the clinical grouping and the TNM staging systems. The ultimate outcome depends on site, extent of disease and histology. Currently approximately 70% of the patients survive for 5 years or more and are probably cured. This is credited to the use of multi-modal, risk adapted therapy, refinements in tumour grouping and better supportive care which has emerged out of cooperative studies like Intergroup Rhabdomyosarcoma Study (IRS) and the International Society of Pediatric Oncology studies (SIOP). The treatment involves chemotherapy, radiotherapy and organ/function preserving surgery. The gold standard chemotherapy is still VAC regime (vincristine, actinomycin D and cyclophos-phamide).

The NRSTS are rare and of heterogenous histologies and so it has been difficult to arrive at a treatment strategy for these. What is definitely understood is that these are usually immature and poorly differentiated tumours that respond poorly to chemotherapy and so surgical resection forms the mainstay of treatment with adjuvant radiotherapy and chemotherapy to prevent local recurrences.

In all likelihood, the molecular analysis of RMS will further refine current classification schemes, and knowledge of genetic features of the tumours will significantly improve the ability of investigators to identify patients at lower or higher risk of treatment failures, thus paving the way for advances in risk-based therapy.