Treatment of localized nonorbital, nonparameningeal head and neck rhabdomyosarcoma: Lessons learned from Intergroup Rhabdomyosarcoma Studies III and IV

Purpose: The characteristics and clinical outcomes of children and adolescents with localized nonorbital, nonparameningeal head and neck rhabdomyosarcoma (RMS) treated on national protocols from the Intergroup Rhabdomyosarcoma Group are reported. Patients and Methods: We conducted a retrospective review of 164 children and adolescents enrolled in the third and fourth Intergroup Rhabdomyosarcoma Studies. Variables analyzed included age, sex, primary tumor site, histologic subtype, clinical group, therapy, site and rate of treatment failure, and time to initial recurrence. Results: Localized nonorbital, nonparameningeal RMS accounted for 9% of all cases of RMS. The median age at diagnosis was 5 years; the median follow-up was 6.6 years. Estimated 5-year failure-free survival (FFS) and survival (S) rates were 76% (95% CI, 69% to 83%) and 83% (95% CI, 77% to 89%), respectively. In multivariate analysis, patients with clinically involved regional nodes (N1) had worse FFS (P = .02). For patients with embryonal tumors, FFS was significantly improved, especially among patients with Group I/II without nodal disease clinical Group I, II NO. For patients with alveolar/undifferentiated histology, FFS was significantly worse in children under the age of 1 year. Actuarial estimates of recurrences at 15 years were local (19%), regional (5%), and distant (9%). Conclusion: More than 80% of patients with RMS of the head and neck are cured of their disease using surgery and vincristine, dactinomycin ± cyclophosphamide with or without radiotherapy. Our results indicate that early, limited exposure to cyclophosphamide might reduce recurrence in low-risk embryonal patients and that reduced dosages might achieve comparable results with improved toxicity profiles. These hypotheses will be tested in the next generation of trials from the Soft Tissue Committee of the Children's Oncology Group.