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Osteosarcoma and Ewing sarcoma are the 2 most common malignant bone tumors of pediatrics, with peak incidence during the adolescent years.
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Rhabdomyosarcoma is the most common soft-tissue sarcoma of childhood, with a bimodal age distribution of 2 to 6 years and 15 to 19 years of age.
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Sarcomas are best treated with multimodality treatment that often includes chemotherapy, surgery, and/or radiation therapy.
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Children with localized sarcoma fare well with multimodality treatment, whereas those with
Sarcomas
Section snippets
Key points
Osteosarcoma
OS is a malignancy that derives its origin from mesenchymal cells. The pathologic hallmark is the production of malignant osteoid by pleomorphic malignant cells within a connective tissue matrix. OS can be divided into several subsets defined by location (appendicular vs axial, central vs surface), histologic grade (low, intermediate, or high), and the predominant matrix type.1 Most OS tumors are conventional OS, a high-grade OS made up of 3 major subtypes based on the predominant mix of
Epidemiology
OS is the most common malignant bone tumor in pediatrics, with an incidence of approximately 4.5 cases per 1 million children in the developed world.17 EWS is the second most common malignant bone tumor in pediatrics, with an incidence of nearly 3 cases per 1 million children, a slight predilection for males over females, and a markedly lower incidence in individuals of African descent.17, 18 Both OS and EWS peak in the second decade of life, but whereas OS is very rare in young children, EWS
Clinical features
Both OS and EWS, when they occur as primary bone tumors, most commonly present with locoregional pain and swelling, which often last for weeks to months before presentation. In the appendicular skeleton, the pain can be followed by a palpable mass. In the case of OS, fevers, weight loss, and other systemic complaints are uncommon. In EWS, where there may be bone marrow involvement in advanced disease, systemic symptoms may be present. Because these symptoms can be nonspecific and occur most
Diagnostic workup
Although the initial evaluation of a child or adolescent with a suspected bone or soft-tissue tumor often starts with radiography in the primary care setting, the importance of referral to a pediatric tertiary care center must be emphasized. A multidisciplinary team including pediatric general and orthopedic surgery, oncology, radiology, and pathology is critical for accurate diagnosis, staging, and initial therapy (Figs. 6 and 7).
Plain radiographs are often helpful for discriminating OS or EWS
Staging
For both EWS and OS, conventional TNM (Tumor, Lymph Node, Metastases) staging is not used. Patients with OS and EWS rarely metastasize to the lymph nodes. Instead, tumors are considered either localized or metastatic. In OS, although patients are generally considered to have either localized or metastatic disease, the Enneking staging system exists, which incorporates tumor grade in addition to the presence or absence of metastatic disease to account for those rare low-grade OS tumors such as
Osteosarcoma and Ewing Sarcoma
The most important adverse prognostic factor in OS and EWS is the presence or absence of metastatic disease. Patients with localized disease at diagnosis have a 5-year overall survival of about 75% compared with patients with metastatic disease at diagnosis, who have a 5-year overall survival of approximately 20% to 25%.26, 28 Since complete surgical resection of macroscopic disease is essential for cure in OS, surgical resectability is also an important prognostic factor; therefore, tumors
Management goals
The care of a child or adolescent with a malignant bone or soft-tissue sarcoma requires a multidisciplinary approach to achieve successful multimodality care. The overarching goals are to achieve local disease control with wide surgical resection and/or radiation therapy and distant disease control, typically through the use of systemic chemotherapy. Surgical approaches, the use of radiation therapy, and specific chemotherapy regimens are unique to the sarcoma subtypes, as outlined next.
Summary
The outcome for patients with localized sarcoma has improved dramatically with the addition of systemic, combination chemotherapy in conjunction with local control using surgery and/or radiation. Improvements in surgical technique and the ability to salvage functional limbs have led to greater use of surgery for local control with satisfactory function. However, patients with metastatic and recurrent disease continue to have dismal outcomes despite the use of intensive chemotherapy, surgery,
References (58)
- et al.
Cytogenetics and molecular biology of osteosarcoma
Lab Invest
(2002) - et al.
Myogenesis and rhabdomyosarcoma the Jekyll and Hyde of skeletal muscle
Curr Top Dev Biol
(2011) - et al.
Targeting oxidative stress in embryonal rhabdomyosarcoma
Cancer Cell
(2013) - et al.
Non-metastatic unresected paediatric non-rhabdomyosarcoma soft tissue sarcomas: results of a pooled analysis from United States and European groups
Eur J Cancer
(2011) - et al.
Neurofibromatosis in children with Rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma study IV
J Pediatr
(2004) - et al.
Soft tissue sarcomas of childhood
Cancer Treat Rev
(2004) - et al.
Survival from high-grade localised extremity osteosarcoma: combined results and prognostic factors from three European Osteosarcoma Intergroup randomised controlled trials
Ann Oncol
(2012) Osteosarcoma
Eur J Cancer
(1997)- et al.
The role of surgical margins in treatment of Ewing's sarcoma family tumors: experience of a single institution with 512 patients treated with adjuvant and neoadjuvant chemotherapy
Int J Radiat Oncol Biol Phys
(2006) - et al.
Osteosarcoma: anatomic and histologic variants
Am J Clin Pathol
(2006)