Childhood Rhabdomyosarcoma Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Previously Untreated Childhood Rhabdomyosarcoma
RT is an effective method for achieving local control of the tumor for patients with microscopic or gross residual disease following biopsy, initial surgical resection, or chemotherapy. Patients with completely resected embryonal rhabdomyosarcoma (Group I) do well without RT. An earlier study of Group I patients with alveolar rhabdomyosarcoma and undifferentiated soft tissue sarcoma found that omission of RT was followed by decreased local control. A subsequent review of patients with only alveolar rhabdomyosarcoma found that the improvement in outcome with RT did not reach statistical significance for patients with Stage 1 and 2 tumors. There were very few patients (n = 4) with large tumors (Stage 3, >5 cm) who did not receive RT, but their outcome was poor.[Level of evidence: 3iiiDii]
In more than 50% of Group II rhabdomyosarcoma patients, local recurrence was due to noncompliance with guidelines or omission of RT. A review of European trials conducted by the German Cooperative Weichteilsarkom Studien (CWS) Group between 1981 and 1998, in which RT was omitted for some Group II patients, demonstrated a benefit to using RT as a component of local tumor control for all Group II patient subsets, as defined by tumor histology, tumor size, and tumor site.
The predominant type of relapse for patients with Group III disease is local failure. Patients with tumor-involved regional lymph nodes at diagnosis also have a higher risk of local and distant failure compared with patients whose lymph nodes are uninvolved. As with the surgical management of patients with rhabdomyosarcoma, recommendations for RT depend on the site of primary tumor, the postsurgical (if performed) amount of residual disease (none vs. microscopic vs. macroscopic), and the presence of involved lymph nodes.
For optimal care of pediatric patients undergoing radiation treatments, it is imperative to have available a radiation oncologist, radiation technicians, and nurses who are experienced in treating children. An anesthesiologist may be necessary to sedate and immobilize young patients. Computerized treatment planning with a 3-dimensional planning system should be available. Techniques to deliver radiation specifically to the tumor while sparing normal tissue (e.g., conformal radiation therapy, intensity-modulated radiation therapy [IMRT], proton-beam therapy [charged-particle radiation therapy], or brachytherapy) are appropriate.[13,14,15,16]
- Comparison of proton-beam and IMRT treatment plans has shown that proton-beam radiation can spare more normal tissue adjacent to the targeted volume than IMRT.[17,18] Follow-up remains relatively short, and there are no data available to determine if the reduction in dose to adjacent tissue will result in improved functional outcome or reduce the risk of secondary malignancy. Because patient numbers are small, it is not possible to determine if the risk of local recurrence might be increased by reducing radiation dose in tissue adjacent to the primary tumor.
- A retrospective review of patients with intermediate-risk rhabdomyosarcoma compared conformal RT and IMRT.[Level of evidence: 2B] IMRT improved the target coverage but did not show a difference in local failure rate or EFS.
Standard RT of children with rhabdomyosarcoma includes the following: