title: Local failure in parameningeal rhabdomyosarcoma correlates with poor response to induction chemotherapy.
abstract: BACKGROUND
  Local control remains a challenge in pediatric parameningeal rhabdomyosarcoma (PM-RMS), and survival after local failure (LF) is poor. Identifying patients with a high risk of LF is of great interest to clinicians. In this study, we examined whether tumor response to induction chemotherapy (CT) could predict LF in embryonal PM-RMS.
  
  
  METHODS
  We identified 24 patients with embryonal PM-RMS, age 2 to 18 years, with complete magnetic resonance imaging and gross residual disease after surgical resection. All patients received proton radiation therapy (RT), median dose 50.4 GyRBE (50.4-55.8 GyRBE). Tumor size was measured before initial CT and before RT.
  
  
  RESULTS
  With a median follow-up time of 4.1 years for survivors, LF was seen in 9 patients (37.5%). The median time from the initiation of CT to the start of RT was 4.8 weeks. Patients with LF had a similar initial (pre-CT) tumor volume compared with patients with local controlled (LC) (54 cm(3) vs 43 cm(3), P=.9) but a greater median volume before RT (pre-RT) (40 cm(3) vs 7 cm(3), P=.009) and a smaller median relative percent volume reduction (RPVR) in tumor size (0.4% vs 78%, P<.001). Older age (P=.05), larger pre-RT tumor volume (P=.03), and smaller RPVR (P=.003) were significantly associated with actuarial LF on univariate Cox analysis.
  
  
  CONCLUSIONS
  Poor response to induction CT appears to be associated with an increased risk of LF in pediatric embryonal PM-RMS.
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Matthew M
authors: MM
authors: Ladra
authors: The Royal Marsden Hospital, London, United Kingdom.
authors: Henry C
authors: HC
authors: Mandeville
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Andrzej
authors: A
authors: Niemierko
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Timothy P
authors: TP
authors: Padera
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Alison M
authors: AM
authors: Friedmann
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Shannon M
authors: SM
authors: MacDonald
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: David
authors: D
authors: Ebb
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Yen-Lin
authors: YL
authors: Chen
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors: Nancy J
authors: NJ
authors: Tarbell
authors: Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: tyock@partners.org.
authors: Torunn I
authors: TI
authors: Yock
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D060828:Induction Chemotherapy; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018233:Rhabdomyosarcoma, Embryonal / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D017211:Treatment Failure; D016896:Treatment Outcome; D047368:Tumor Burden