title: Cancer risk in mothers of men operated for undescended testis.
abstract: BACKGROUND
  Undescended testis, or cryptorchidism, occurs in 2-5% of boys born at term, and by 12 months of age about 1% of all boys have manifest cryptorchidism. Several hormonal substances control this process and disruption of the foetal sex-hormones balance is a potential cause of undescended testis, however, to a great extent the aetiology of cryptorchidism is unclear.
  
  
  METHODS
  To study risk factors involved in the aetiology of undescended testis, we assessed cancer risk in 15,885 mothers of men operated for undescended testis in Sweden. Women were followed-up for a median period of 23 years during which 811 first primary malignancies occurred. Their cancer incidence was compared with that in the general population estimating standardized incidence ratio (SIR) and corresponding 95% confidence interval (CI).
  
  
  RESULTS
  The overall cancer risk experienced by the mothers of cryptorchid men did not differ significantly from that of the general population (SIR = 0.94; 95% C.I. = 0.88-1.01). Specifically, there was a reduction in ovarian cancer risk (SIR = 0.72; 95% C.I. = 0.51-0.99), while the risk of lung (SIR = 1.38 95% C.I. 1.03-1.81) and biliary tract/liver cancer (SIR: 1.76, 95% CI: 1.03-2.82) were increased.
  
  
  CONCLUSIONS
  Although we cannot rule out the role of chance, our data suggest a positive association between undescended testis and maternal lung cancer and a negative association with ovarian cancer, where the first may be partly attributable to smoking and the second to an altered hormonal milieu during pregnancy and thus both exposures may be risk factors for cryptorchidism.
authors.affiliation: Cancer Epidemiology Unit, CPO and CeRMS, University of Turin, Italy. hadrilac@gmail.com
authors.forename: Hadriano M
authors.initials: HM
authors.lastname: Lacerda
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Richiardi
authors.forename: Andreas
authors.initials: A
authors.lastname: Pettersson
authors.forename: Marine
authors.initials: M
authors.lastname: Corbin
authors.forename: Franco
authors.initials: F
authors.lastname: Merletti
authors.forename: Olof
authors.initials: O
authors.lastname: Akre
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003456:Cryptorchidism / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009035:Mothers; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000175:diagnosis; D012306:Risk; D012307:Risk Factors; D012907:Smoking; D013737:Testis / Q000473:pathology / Q000601:surgery