title: Peritoneal carcinomatosis from small intestinal neuroendocrine tumors: Clinical course and genetic profiling.
abstract: BACKGROUND
  One-fifth of all patients with small-intestinal neuroendocrine tumors (SI-NETs) present with or develop peritoneal carcinomatosis (PC). Our aim was to determine the prognosis and genetic profiles of tumors in patients with PC compared with tumors in patients without PC.
  
  
  METHODS
  We included SI-NET patients (cases with PC, n = 73, and controls without PC, n = 468) who underwent operation between 1985 and 2012. The Lyon prognostic index was used to correlate the amount of PC to survival. DNA samples from patients with (n = 8) and without (n = 7) PC were analyzed with a single-nucleotide polymorphism array (HumanOmni2.5 BeadChip, Illumina) to investigate genetic disparities between groups.
  
  
  RESULTS
  Patients with PC had poorer survival (median 5.1 years) than controls (11.1 years). An advanced postoperative Lyon prognostic index was a negative prognostic marker for survival by multivariable analysis (P = .042). Patients with and without PC clustered differently based on loss of heterozygosity and copy number variation data from single-nucleotide polymorphism array of the primary tumors (P = .042).
  
  
  CONCLUSIONS
  SI-NET patients with PC have poor survival, which diminishes with increasing PC load after surgery. Clustering based on copy number variation and loss of heterozygosity data suggests different genotypes in primary tumors comparing patients with and without PC.
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden. Electronic address: olov.norlen@me.com.
authors.forename: Olov
authors.initials: O
authors.lastname: Norlén
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Edfeldt
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Goran
authors.initials: G
authors.lastname: Akerstrom
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Westin
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hellman
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Peyman
authors.initials: P
authors.lastname: Bjorklund
authors.affiliation: Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Stalberg
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000235:genetics / Q000401:mortality / Q000556:secondary*; D015331:Cohort Studies; D056915:DNA Copy Number Variations; D018572:Disease-Free Survival; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007414:Intestinal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D007421:Intestine, Small / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018358:Neuroendocrine Tumors / Q000235:genetics* / Q000401:mortality / Q000556:secondary; D010534:Peritoneal Neoplasms / Q000235:genetics / Q000401:mortality / Q000556:secondary*; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis