title: Role of Adjuvant Radiation Therapy After Surgery for Abdominal Desmoplastic Small Round Cell Tumors.
abstract: To identify the prognostic role of adjuvant abdominal radiation therapy (RT) on oncologic outcomes as a part of multimodal treatment in the management of desmoplastic small round cell tumor (DSRCT) and to determine its impact according to the quality of surgical resection.
  
  
  
  All patients treated for primary abdominal DSRCT in 8 French centers from 1991 to 2014 were included. Patients were retrospectively staged into 3 groups: group A treated with adjuvant RT after cytoreductive surgery, group B without RT after cytoreductive surgery, and group C by exclusive chemotherapy. Peritoneal progression-free survival (PPFS), progression-free survival (PFS), and overall survival (OS) were evaluated. We also performed a direct comparison between groups A and B to evaluate RT after cytoreductive surgery. Radiation therapy was also evaluated according to completeness of surgery: complete cytoreductive surgery (CCS) or incomplete cytoreductive surgery (ICS).
  
  
  
  Thirty-seven (35.9%), thirty-six (34.9%), and thirty (28.0%) patients were included in groups A, B, and C, respectively. Three-year OS was 61.2% (range, 41.0%-76.0%), 37.6% (22.0%-53.1%), and 17.3% (6.3%-32.8%) for groups A, B, and C, respectively. Overall survival, PPFS, and PFS differed significantly among the 3 groups (P<.001, P<.001, and P<.001, respectively). Overall survival and PPFS were higher in group A (RT group) compared with group B (no RT group) (P=.045 and P=.006, respectively). Three-year PPFS was 23.8% (10.3%-40.4%) for group A and 12.51% (4.0%-26.2%) for group B. After CCS, RT improved PPFS (P=.024), but differences in OS and PFS were not significant (P=.40 and P=.30, respectively). After ICS, RT improved OS (P=.044). A trend of PPFS and PFS increase was observed, but the difference was not statistically significant (P=.073 and P=.076).
  
  
  
  Adjuvant RT as part of multimodal treatment seems to confer oncologic benefits for patients treated for abdominal DSRCT after cytoreductive surgery and perioperative chemotherapy.
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Atallah
authors.affiliation: Department of Digestive Surgery, Gustave-Roussy Institute, Paris, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Honore
authors.affiliation: Department of Pediatric Oncology, Curie Institute, Paris, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Orbach
authors.affiliation: Department of Pediatric Oncology, Curie Institute, Paris, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Helfre
authors.affiliation: Department of Radiation Oncology, Universitary Cancer Institute, Toulouse, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Ducassou
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Department of Radiation Oncology, Alexis-Vautrin Center, Nancy, France.
authors.forename: Mihai-Barbu
authors.initials: MB
authors.lastname: Levitchi
authors.affiliation: Department of Radiation Oncology, Cancerologie de l'ouest Institute, Nantes, France.
authors.forename: Augustin
authors.initials: A
authors.lastname: Mervoyer
authors.affiliation: Department of Radiation Oncology, Paoli-Calmette Institute, Marseille, France.
authors.forename: Salem
authors.initials: S
authors.lastname: Naji
authors.affiliation: Department of Radiation Oncology, Universitary Hospital, Bordeaux, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Dupin
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France.
authors.forename: Pauline J
authors.initials: PJ
authors.lastname: Bosco-Levy
authors.affiliation: Department of Pediatric Surgery, University Paris 7 Denis Diderot, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Philippe-Chomette
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Kantor
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France.
authors.forename: Benedicte
authors.initials: B
authors.lastname: Henriques de Figueiredo
authors.affiliation: Department of Radiation Oncology, Leon-Berard Center, Lyon, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Sunyach
authors.affiliation: Department of Radiation Oncology, Bergonie Institute, Bordeaux, France. Electronic address: p.sargos@bordeaux.unicancer.fr.
authors.forename: Paul
authors.initials: P
authors.lastname: Sargos
mesh_terms: D000008:Abdominal Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D058405:Desmoplastic Small Round Cell Tumor / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies