title: Which patients with microscopic disease and rhabdomyosarcoma experience relapse after therapy? A report from the soft tissue sarcoma committee of the children's oncology group.
abstract: OBJECTIVE
  To identify which patients with rhabdomyosarcoma and microscopic residual disease (group II) are likely to not respond to therapy.
  
  
  METHODS
  Six hundred ninety-five patients with group II tumors received chemotherapy and 90% received radiation therapy on Intergroup Rhabdomyosarcoma Study (IRS)-I to IRS-IV (1972 to 1997). Tumors were subgrouped depending on the presence of microscopic residual disease only (subgroup IIa), resected positive regional lymph nodes, (subgroup IIb), or microscopic residual disease and resected positive regional lymph nodes (subgroup IIc).
  
  
  RESULTS
  Overall, the 5-year failure-free survival rate (FFSR) was 73%, and patients with embryonal rhabdomyosarcoma treated on IRS-IV fared especially well (5-year FFSR, 93%; n = 90). Five-year FFSRs differed significantly by subgroup (IIa, 75% and n = 506; IIb, 74% and n = 101; IIc, 58% and n = 88; P = .0037) and treatment (IRS-I, 68%; IRS-II, 67%; IRS-III, 75%; IRS-IV, 87%; P < .001). Multivariate analysis revealed positive associations between primary site (favorable), histology (embryonal), subgroup IIa or IIb, treatment (IRS-III/IV), and better FFSRs. Patterns of treatment failure revealed local failure to be 8%, regional failure, 4%, and distant failure, 14%. The relapse pattern noted over the course of IRS-I to IRS-IV shows a decrease in the systemic relapse rates, particularly for patients with embryonal histology, suggesting that improvement in FFSRs is primarily a result of improved chemotherapy.
  
  
  CONCLUSIONS
  Group II rhabdomyosarcoma has an excellent prognosis with contemporary therapy as used in IRS-III/IV, and those less likely to respond can be identified using prognostic factors: histology, subgroup, and primary site. Patients with embryonal rhabdomyosarcoma are generally cured, although patients with alveolar rhabdomyosarcoma or undifferentiated sarcoma, particularly subgroup IIc at unfavorable sites, continue to need better therapy.
authors.affiliation: Primary Children's Medical Center, Salt Lake City, UT, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Smith
authors.forename: J R
authors.initials: JR
authors.lastname: Anderson
authors.forename: S J
authors.initials: SJ
authors.lastname: Qualman
authors.forename: W M
authors.initials: WM
authors.lastname: Crist
authors.forename: C N
authors.initials: CN
authors.lastname: Paidas
authors.forename: L A
authors.initials: LA
authors.lastname: Teot
authors.forename: A S
authors.initials: AS
authors.lastname: Pappo
authors.forename: M P
authors.initials: MP
authors.lastname: Link
authors.forename: H E
authors.initials: HE
authors.lastname: Grier
authors.forename: E S
authors.initials: ES
authors.lastname: Wiener
authors.forename: J C
authors.initials: JC
authors.lastname: Breneman
authors.forename: R B
authors.initials: RB
authors.lastname: Raney
authors.forename: H M
authors.initials: HM
authors.lastname: Maurer
authors.forename: S S
authors.initials: SS
authors.lastname: Donaldson
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003520:Cyclophosphamide / Q000008:administration & dosage; D003609:Dactinomycin / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011379:Prognosis; D012208:Rhabdomyosarcoma / Q000145:classification / Q000188:drug therapy / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000628:therapy; D015996:Survival Rate; D019772:Topotecan / Q000008:administration & dosage; D017211:Treatment Failure; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D003609:Dactinomycin; D014750:Vincristine; D019772:Topotecan; D003520:Cyclophosphamide