All children with rhabdomyosarcoma require multimodality therapy with systemic chemotherapy, in conjunction with either surgery, radiation therapy, or both modalities for local tumor control.[1-3] This entails surgical resection, if feasible without major functional/cosmetic impairment, followed by chemotherapy. Some patients with initially unresected tumors may undergo second-look surgery to remove residual tumor. Since rhabdomyosarcoma is sensitive to chemotherapy and radiation therapy, surgery is delayed if it will result in disfigurement or will interfere with organ function. Chemotherapy and possibly radiation therapy are administered in advance with the hope that subsequent surgical resection will be successful without undesirable side effects. Radiation therapy is indicated for patients with microscopic residual (group II) disease and gross residual (group III) disease. It is also recommended for group I patients with alveolar histology. The discussion of treatment options for children with rhabdomyosarcoma is therefore divided into separate sections describing surgery, chemotherapy, and radiation therapy.

Before biopsy of a suspected tumor mass, imaging studies of the mass and baseline laboratory studies should be obtained. After the diagnosis of rhabdomyosarcoma has been made, an extensive evaluation to determine the extent of the disease should be done prior to instituting therapy. This evaluation should include a chest x-ray, computed tomography (CT) scan of the chest, bilateral bone marrow aspirates and biopsies, bone scan, magnetic resonance imaging of the base of the skull and brain (for parameningeal primary tumors only), and CT scan of the abdomen and pelvis (for lower extremity or genitourinary primary tumors).

The treatment of rhabdomyosarcoma by the Children's Oncology Group and in Europe, as exemplified by the Intergroup Rhabdomyosarcoma Study Group (IRSG) trials and the International Society of Pediatric Oncology Malignant Mesenchymal Tumor (MMT) studies, respectively, differ in their management and overall treatment philosophies.[2] In the MMT trials, a primary objective is to reduce the use of local therapy, relying on initial frontline chemotherapy followed by alternate chemotherapy in the event of a poor response to initial therapy. Local therapy focused on surgical resection is then administered, reserving radiation therapy for use only after incomplete resection, documented regional lymph node involvement, or a poor clinical response to combination chemotherapy. This approach is designed to avoid major surgery and especially radiation therapy, and their attendant morbidities. Overall survival (OS) is the primary end point, accepting the possibility of an inferior event-free survival (EFS) that might accompany nonaggressive local therapy when compared with more routine and earlier use of surgery and radiation therapy. The necessity of salvage therapy for those who relapse is accepted in these trials. Conversely, the primary IRSG objective has been to employ local therapy soon after induction chemotherapy, using radiation therapy for patients with residual disease after initial surgery or biopsy only, and for all patients with alveolar histology. EFS is the target end point, attempting to avoid relapse and salvage therapy. Results of these two approaches confirm that the IRSG trials result in superior EFS and better OS than the most recently published MMT (MMT 89) therapy. In some subsets of patients defined by primary site, the survival differences are greater (extremities, nonparameningeal head and neck); in others, the results are largely similar (genitourinary). Nevertheless, the overall impression is that survival for most patient subsets is superior with the use of early local therapy, including irradiation. However, in the MMT trials, some patients are spared aggressive local therapy, which may reduce the potential for morbidities associated with such therapy.[1-3]

References

1. Donaldson SS, Meza J, Breneman JC, et al.: Results from the IRS-IV randomized trial of hyperfractionated radiotherapy in children with rhabdomyosarcoma--a report from the IRSG. Int J Radiat Oncol Biol Phys 51 (3): 718-28, 2001.  [PUBMED Abstract]
   
   
2. Stevens MC, Rey A, Bouvet N, et al.: Treatment of nonmetastatic rhabdomyosarcoma in childhood and adolescence: third study of the International Society of Paediatric Oncology--SIOP Malignant Mesenchymal Tumor 89. J Clin Oncol 23 (12): 2618-28, 2005.  [PUBMED Abstract]
   
   
3. Donaldson SS, Anderson JR: Rhabdomyosarcoma: many similarities, a few philosophical differences. J Clin Oncol 23 (12): 2586-7, 2005.  [PUBMED Abstract]
   
   

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