Analysis of prognostic factors in patients with nonmetastatic rhabdomyosarcoma treated on intergroup rhabdomyosarcoma studies III and IV: The Children's Oncology Group

Purpose The outcome for localized rhabdomyosarcoma (RMS) or undifferentiated sarcoma (UDS) is affected by age, histology, primary anatomic site, extent of disease, and therapy. Patients and Methods We evaluated patient and disease characteristics for their ability to predict outcome for patients with nonmetastatic RMS or UDS treated on Intergroup Rhabdomyosarcoma Study (IRS)-III (1984 to 1991) or IRS-IV (1991 to 1997). Results The estimated 5-year failure-free survival (FFS) rate was 90% for patients with embryonal RMS (ERMS) stage 1, group I or IIa; stage 2, group I; or group III orbit. The estimated 5-year FFS rate was 87% for patients with ERMS stage 1, group IIb or IIc; stage 1, group III nonorbit; stage 2, group II; and stage 3, group I or II; and 73% for patients with ERMS stage 2 or 3, group III. The estimated 5-year FFS rate was poor for patients with stage 2 or 3, group III ERMS with invasive (T2) tumors who were age younger than 1 year or 10 years or older (56%) and patients with stage 2 or 3, group III extremity primary tumors (43%). Overall, outcomes for patients with alveolar RMS (ARMS) or UDS were worse than for patients with ERMS. However, the 5-year FFS rate was good for patients with ARMS/UDS at favorable sites with group I or II (80%) or group III (76%) disease. The FFS rate was poorer for patients with ARMS/UDS at unfavorable sites with group I or II (66%) or group III (45%) disease. The estimated 5-year FFS rate was 31% for patients with group III ARMS/UDS at unfavorable sites with regional lymph node disease, which is similar to metastatic RMS. Conclusion Patient and disease characteristics identify distinct subsets with different outcomes, allowing the Soft Tissue Sarcoma Committee of the Children's Oncology Group to refine risk-adapted therapy assignment.