Previous studies have suggested that women with uterine rhabdomyosarcomas (RMS) represent a distinct group of patients who present at an older age, are less responsive to treatment, and have a poorer prognosis than patients with vaginal RMS. During the Intergroup Rhabdomyosarcoma Study (IRS) III and the IRS IV pilot study, 14 patients were registered with uterine primary RMS. Three patients presented with cervical tumors that were completely removed (group 1). Eight patients had initial biopsies with gross residual disease (group 3), and 3 had metastatic disease at presentation (group 4). Of the 5 patients treated with primary chemotherapy or chemotherapy and radiation, 2 had delayed hysterectomy and vaginectomy, 1 had no further surgery, and 2 had exploratory laparotomy with no evidence of disease. There were no relapses or deaths in this group. One patient underwent initial resection of a broad ligament mass, experienced an early (3-week) recurrence of the mass while on chemotherapy, and progressed to developing distant metastases and death. Four patients died of chemotherapy toxicity or sepsis, one after achieving a complete response from chemotherapy and hysterectomy. This primary chemotherapy or chemotherapy and radiotherapy regimen resulted in 8 of 9 (89%) patients (not including those who died of chemotoxicity) surviving between 1.5 and 6 years without evidence of disease. Of the surviving patients, 2 had hysterectomy and vaginectomy, but pathological specimens showed only localized microscopic residual tumor. This report suggests that less vigorous operative resection may be possible in combination with primary chemotherapy when treating uterine rhabdomyosarcomas.(ABSTRACT TRUNCATED AT 250 WORDS)