title: Characteristics of synchronous- and metachronous-type multiple primary neoplasms: a study of hospital-based cancer registry in Turkey.
abstract: OBJECTIVE
  The aim of this study was to evaluate the demographic, histologic, and topographic characteristics, and the association of synchronous and metachronous multiple primary neoplasms.
  
  
  METHODS
  Five hundred seventy-two multiple primary tumors (n = 286) of 20,895 tumors recorded from 1993 to 2005 by the office of Izmir Cancer Registry at the Izmir Ataturk Training and Research Hospital were analyzed. chi(2) and Student t test were performed.
  
  
  RESULTS
  One hundred fifty-eight patients had synchronous tumors whereas 128 had metachronous tumors. Both groups were more frequent among men and among patients aged > 50 years. The distribution of synchronous and metachronous tumors between sex and age groups was similar (P = .462 and P = .479, respectively). Carcinomas were more frequent and histologic compositions of both of the groups were significantly different (P = .009). Pairs of the same topographic origin were significantly more frequent in synchronous tumors (P = .019). The urogenital system was the most frequent location in all groups. The leading tumoral association was between urogenital-urogenital tumors, also. Detailed evaluation of the metachronous group revealed that the most frequent organ associations were of breast-ovary (n = 7) and bladder-larynx (n = 5).
  
  
  CONCLUSIONS
  Field cancerization in the epithelium, theory of a common clonal origin, or the screening effect might account for the relatively frequent association of urogenital tumors. The association of the tumors of breast-ovary might be related to the endocrine effect. Further studies complying with international rules and using data from different population-based tumor registries are necessary to elucidate site correlation.
authors.affiliation: Department of Radiation Oncology, Gaziantep University, Medical School, Gaziantep, Turkey. sevilkilciksiz@gmail.com
authors.forename: Sevil
authors.initials: S
authors.lastname: Kilciksiz
authors.forename: Tumay
authors.initials: T
authors.lastname: Gokce
authors.forename: Ali
authors.initials: A
authors.lastname: Baloglu
authors.forename: Aylin
authors.initials: A
authors.lastname: Calli
authors.forename: Canan
authors.initials: C
authors.lastname: Kaynak
authors.forename: Bülent
authors.initials: B
authors.lastname: Kilic
authors.forename: Erkan
authors.initials: E
authors.lastname: Eski
authors.forename: Gülten
authors.initials: G
authors.lastname: Nalbantoglu
authors.forename: Hacer Ari
authors.initials: HA
authors.lastname: Yigitbas
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology*; D012042:Registries; D014421:Turkey / Q000453:epidemiology; D014565:Urogenital Neoplasms / Q000453:epidemiology