title: Serous ovarian and primary peritoneal cancers: A comparative analysis of clinico-pathological features, molecular subtypes and treatment outcome.
abstract: OBJECTIVE
  Primary peritoneal cancer is rare and considered equivalent to stage III/IV ovarian cancer, but questions remain concerning its underlying biology, prognosis and optimal management.
  
  
  METHODS
  Clinico-pathological and treatment details of primary peritoneal (n=120) and ovarian cancer (n=635) were obtained on women recruited to the Australian Ovarian Cancer Study. Log-rank test was used to compare survival and cox proportional hazards models were fitted to obtain hazard ratios and 95% confidence intervals, both unadjusted and adjusted for age, grade, FIGO stage, residual disease and treatment with neoadjuvant chemotherapy. Molecular subtype was determined by gene expression profiling using published data.
  
  
  RESULTS
  Compared with advanced serous ovarian cancer, primary peritoneal cancer patients were older (mean age 65.5 vs. 60.2years, p<0.001), more often treated with neoadjuvant chemotherapy (38.4% vs. 11.4%, p<0.001). Gene expression profiling classified a substantially higher proportion of primary peritoneal carcinomas as C1 (mesenchymal, reactive stromal infiltration) subtype (70.6% vs. 32.1%, p=0.029), which was associated with lower complete surgical resection rate. Women with primary peritoneal cancer had significantly shorter progression-free (11.6 vs. 13.6months, p=0.007) and overall survival (31.7 vs. 39.8months, p=0.012). In multivariate analysis, residual disease and neoadjuvant chemotherapy were both independently associated with increased risk of progression and death.
  
  
  CONCLUSIONS
  Primary peritoneal cancer patients were more frequently treated with neoadjuvant chemotherapy and had inferior survival. Different tumor biology characterized by activated stromal fibrosis in primary peritoneal cancer may underlie the differences in treatment and clinical outcome.
authors.affiliation: Crown Princess Mary Cancer Care Centre, Westmead Hospital, Sydney, NSW, Australia; The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Bo
authors.initials: B
authors.lastname: Gao
authors.affiliation: Crown Princess Mary Cancer Care Centre, Westmead Hospital, Sydney, NSW, Australia; NHMRC Clinical Trials Centre, Sydney, NSW, Australia; Department of Gynecological Cancer, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lindemann
authors.affiliation: Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: Lyndal
authors.initials: L
authors.lastname: Anderson
authors.affiliation: Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Sian
authors.initials: S
authors.lastname: Fereday
authors.affiliation: The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia; Department of Gynecological Oncology, Westmead Hospital, Sydney, NSW, Australia.
authors.forename: Jillian
authors.initials: J
authors.lastname: Hung
authors.affiliation: Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Alsop
authors.affiliation: Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Tothill
authors.affiliation: NHMRC Clinical Trials Centre, Sydney, NSW, Australia.
authors.forename: Val
authors.initials: V
authors.lastname: Gebski
authors.affiliation: The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia; Department of Gynecological Oncology, Westmead Hospital, Sydney, NSW, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: Kennedy
authors.affiliation: The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia; Pathology West ICPMR, Westmead, NSW, Australia.
authors.forename: Rosemary L
authors.initials: RL
authors.lastname: Balleine
authors.affiliation: Crown Princess Mary Cancer Care Centre, Westmead Hospital, Sydney, NSW, Australia; The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Harnett
authors.affiliation: Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Department of Pathology, University of Melbourne, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; Ovarian Cancer Action Research Centre, Department of Surgery and Cancer, Imperial College London, UK; The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, NSW, Australia.
authors.forename: David D L
authors.initials: DD
authors.lastname: Bowtell
authors.affiliation: The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia; Department of Gynecological Oncology, Westmead Hospital, Sydney, NSW, Australia. Electronic address: anna.defazio@sydney.edu.au.
authors.forename: Anna
authors.initials: A
authors.lastname: DeFazio
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D017024:Chemotherapy, Adjuvant; D018284:Cystadenocarcinoma, Serous / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D010534:Peritoneal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D016896:Treatment Outcome
keywords: Interval debulking; Molecular subtypes; Neoadjuvant chemotherapy; Ovarian cancer; Primary peritoneal cancer; Survival