Table 5. Radiation Therapy (RT) Dose According to Rhabdomyosarcoma Group, Histology, and Site of Disease (Children's Oncology Group [COG]) continued...
Children who present with tumor cells in the CSF (Stage 4) may or may not have other evidence of diffuse meningeal disease and/or distant metastases. In a review of experience from IRSG Protocols II though IV, eight patients had tumor cells in the CSF at diagnosis; three of four without other distant metastases were alive at 6 to 16 years after diagnosis, as was one of four who had concomitant metastases elsewhere. Patients may also have multiple intraparenchymal brain metastases from a distant primary tumor. They may be treated with central nervous system-directed RT in addition to treatment with chemotherapy/RT for the primary tumor. Spinal RT may also be indicated.[46,47]
For nonparameningeal and nonorbital head and neck tumors, wide excision of the primary tumor (when feasible) and ipsilateral neck lymph node sampling of clinically involved nodes are appropriate. Narrow resection margins (<1 mm) are acceptable because of anatomic restrictions. Cosmetic and functional factors should always be considered, but with modern techniques, complete resection in patients with superficial tumors need not be inconsistent with good cosmetic and functional results. Specialized, multidisciplinary surgical teams also have performed resections of anterior skull-based tumors in areas previously considered inaccessible to definitive surgical management, including the nasal areas, paranasal sinuses, and temporal fossa. These procedures should only be considered, however, in children with recurrent locoregional disease or residual disease following chemotherapy and RT.
For patients with head and neck primary tumors that are considered unresectable, chemotherapy and RT with organ preservation are the mainstay of primary management.[40,44,49,50,51,52] Several studies have reported excellent local control in patients with rhabdomyosarcoma of the head and neck treated with IMRT, fractionated stereotactic radiation therapy, or protons and chemotherapy. Further study is needed, but the use of IMRT and chemotherapy in patients with head and neck rhabdomyosarcoma may result in less severe late effects.[53,54,55]; [Level of evidence: 3iiiA]
Intensity-modulated radiation therapy (IMRT) can be used to spare the bone, yet provide optimal soft tissue coverage, and is used for the management of extremity rhabdomyosarcoma. Complete primary tumor removal from the hand or foot is not feasible in most cases because of functional impairment.[Level of evidence: 3iiA] For children presenting with a primary tumor of the hands or feet, COG studies have shown 100% 10-year local control using RT along with chemotherapy, avoiding amputation in these children.[Level of evidence: 3iiiA]
Primary re-excision prior to beginning chemotherapy (i.e., not delayed) may be appropriate in patients whose initial surgical procedure leaves microscopic residual disease that is deemed resectable by a second procedure.
Regional and in-transit lymph nodes
The Soft Tissue Sarcoma Committee of the COG (COG-STS) recommends systematic aggressive axillary node sampling for patients with upper-extremity primary tumors, even with clinically and radiographically negative nodes. The COG-STS also recommends inguinal and femoral triangle node sampling for patients with lower-extremity primary tumors, even with clinically and radiographically negative nodes. If clinically positive nodes are present, biopsy of more proximal nodes is recommended prior to sampling of the involved nodal region. Sentinel lymph node mapping is employed at some centers to identify the regional nodes that are the most likely to be involved.[59,60,61,62] However, the contribution of sentinel lymph node mapping is not yet clearly defined in pediatric patients.