Rhabdomyosarcoma of the parotid region occurring in childhood and adolescence: A report from the intergroup rhabdomyosarcoma study group

BACKGROUND. Rhabdomyosarcoma (RMS) of the parotid region is rare and to the authors' knowledge little information is available regarding the site of tumor origin, clinical presentation, and outcome in these patients. Therefore, the authors reviewed the files of all patients with RMS of the parotid region who were registered on the Intergroup Rhabdomyosarcoma Studies (IRS) I-IV. METHODS. Patient charts and the Intergroup Rhabdomyosarcoma Study Group (IRSG) database were reviewed. RESULTS. Sixty-two patients presenting with a mass in the parotid region were identified. None of the tumors was localized exclusively to the parotid gland, so the primary site was referred to as the "parotid region." The tumor invaded a parameningeal site in 30 patients. These cases have been designated as parameningeal-parotid tumors to distinguish them from 32 cases that did not invade a parameningeal site and were designated as nonparameningeal-parotid tumors. The majority of patients had Group III tumors in both the nonparameningeal-parotid and parameningeal-parotid subgroups. However, although there were 16 patients with Group I or II tumors in the nonparameningeal-parotid subgroup, no patients with Group I or II tumors were found in the parameningeal-parotid subgroup (P = 0.001). Fifty-six of 62 patients (90%) received radiotherapy. The parameningeal primary site designation resulted in intensification of both chemotherapy and radiotherapy for patients with parameningeal-parotid RMS. The 5-year failure-free survival rate was 81% and the 5-year survival rate was 84%. There were no deaths reported among patients with Group I or II tumors. The 5-year failure-free survival did not appear to differ when comparing patients with parameningeal-parotid tumors with patients with nonparameningeal-parotid tumors (P = 0.21). CONCLUSIONS. Treatment as defined by the IRS protocols has been reported to be highly effective for patients with RMS of the parotid region. Outcome for the more aggressively treated patients with parameningeal-parotid RMS appears similar to that for patients with nonparameningeal-parotid RMS.