Table 5. Radiation Therapy (RT) Dose According to Rhabdomyosarcoma Group, Histology, and Site of Disease (Children's Oncology Group [COG]) continued...
Girls with genitourinary primary tumors should have their ovaries shielded or possibly moved, in an effort to preserve fertility when they are receiving RT to the lower abdomen and pelvis.
Unusual primary sites
Rhabdomyosarcoma occasionally arises in sites other than those discussed above. Patients with localized primary rhabdomyosarcoma of the brain can occasionally be cured using a combination of tumor excision, RT, and chemotherapy.[Level of evidence: 3iiiDiii]
Patients with laryngeal rhabdomyosarcoma will usually be treated with chemotherapy and RT after biopsy in an attempt to preserve the larynx.
Patients with diaphragm tumors often have locally advanced disease that is not grossly resectable initially because of fixation to adjacent vital structures such as the lung, great vessels, pericardium, and/or liver. In such circumstances, chemotherapy and RT should be initiated after diagnostic biopsy, with the intent to consider removal of residual tumor at a later date if feasible.
Two well-documented cases of primary ovarian rhabdomyosarcoma (one Stage III and one Stage IV) have been reported to supplement the eight previously reported patients. These two patients were alive at 20 and 8 months after diagnosis. Six of the previously reported eight patients had died of their disease.[Level of evidence: 3iiiDiii] Treatment with combination chemotherapy followed by removal of the residual mass or masses can sometimes be successful.
Primary resection of metastatic disease at diagnosis (Stage 4, M1, Group IV) is rarely indicated.
The CWS Group reviewed four consecutive trials and identified 29 patients with M1 embryonal rhabdomyosarcoma and metastasis limited to the lung at diagnosis. They reported approximately 38% 5-year EFS for the cohort and did not identify any benefit for local control of pulmonary metastasis, whether by lung irradiation (n = 9), pulmonary metastasectomy (n = 3), or no targeted pulmonary therapy (n = 19).[Level of evidence: 3iiiA]
The IRSG reviewed 46 IRS-IV (1991–1997) patients with metastatic disease at diagnosis confined to the lungs. Only 11 (24%) had a biopsy of the lung, including six at the time of primary diagnosis. They were compared with 234 patients with single non-lung metastatic sites or multiple other sites of metastases. The lung-only patients were more likely to have embryonal rhabdomyosarcoma and parameningeal primary tumors than the larger group of 234 patients, and were less likely to have regional lymph node disease at diagnosis. Failure-free survival (FFS) and OS rates at 4 years were 35% and 42%, respectively, better than for those with two or more sites of metastases (P = .005 and .002, respectively). Being younger than 10 years at diagnosis was also a favorable prognostic factor. Lung irradiation was recommended by the protocols for the lung-only group, but many did not receive it. Those who did receive lung irradiation had better FFS and OS at 4 years than those who did not (P = .01 and P = .039, respectively).[Level of evidence: 3iiiB]