Purpose: To review the pathologic findings from children with gross residual rhabdomyosarcoma (RMS) of the bladder and compare the treatment outcome of those who underwent cystectomy with those who did not. Patients and Methods: Primary and follow-up records and pathology specimens for 28 patients with gross residual disease entered onto the Intergroup Rhabdomyosarcoma Study (IRS) III were reviewed. These patients were assigned to receive 20 weeks of multiagent induction chemotherapy and 4 weeks of radiotherapy. Future therapy decisions were based on clinical and histologic evaluation at 20 weeks. Results: All patients had a clinical and histologic response. Thirteen patients underwent cystectomy at intervals that ranged from 1.5 to 38 months after the start of therapy. All but one patient are alive and well without recurrence. Reasons for cystectomy included presumed evidence of tumor growth from imaging studies, findings at cystoscopy, or histologic interpretation of biopsies. In HE GOAL OF THE Intergroup Rhabdomyosarcoma Study (IRS) for patients with primary bladder or bladder/prostate rhabdomyosarcoma (RMS) is not only survival, but survival with an intact and functioning bladder.3 Retention of the bladder may also minimize some of the long-term problems of sexual dysfunction associated with cystectomy. The use of partial cystectomy has been fostered to attain this goal, but is applicable in a relatively limited number of cases. 4 5 Among patients in IRS III with gross residual disease after biopsy, subsequent cystectomies were performed most frequently in patients with intravesical primary tumors (43%), less often in those with prostatic primary tumors (36%), and least often in those with extravesical primary tumors that did not extend through the bladder wall (14%). Because more cystectomies were performed for intravesical primary tumors and subsequent biopsies more readily obtained at cystoscopy, this group was chosen for review. Pathologic review of primary and follow-up specimens was made, comparing findings between those patients who retained the bladder and those who underwent cystectomy. PATIENTS AND METHODS Patient Selection One hundred three patients were entered onto IRS III with primary tumors that involved the bladder between November 1984 and September 1988. There were 35 patients with positive biopsies from intravesical bladder sites, 24 with abdominal or pelvic masses with bladder attachment, and 44 with prostatic or bladder/prostate involvement. Among the 35 intravesical tumors, four were group I cases (no gross or microscopic residual disease after initial surgery) and all are living and well following partial cystectomy and chemotherapy. A single group II patient (microscopic residual disease) underwent cystectomy as primary therapy for an intravesical tumor that extended through the bladder wall to an abdominal mass. This patient died of pneumonia after 8 months of chemotherapy and radiotherapy. Two of 30 patients with group III disease died following 2 and 3 weeks of therapy from toxicity related to chemotherapy. The remaining 28 group III patients comprise the current study. Treatment After initial biopsy, patients with gross residual disease (group III) were scheduled to be treated with 20 weeks of induction chemo
