title: Intratubular germ cell neoplasia of the contralateral testis in testicular cancer: defining a high risk group.
abstract: OBJECTIVE
  We define a group of testis cancer patients who are at high risk for carcinoma in situ of the contralateral testis and, therefore, a second germ cell tumor.
  
  
  METHODS
  The histology was reviewed in 186 testis cancer patients who underwent contralateral testicular biopsy either because of a history of testicular maldescent or an atrophic contralateral testis (defined as a volume of 12 ml. or less). Testicular volume, semen analysis, serum gonadotropin levels, serum testosterone and estradiol levels were assessed in the majority of patients.
  
  
  RESULTS
  Univariate analyses identified contralateral testicular atrophy, low sperm density, young age at presentation and low Johnsen score as factors associated with increased risk of a positive biopsy. A history of maldescent in the absence of atrophy was associated with carcinoma in situ prevalence of only 4%. Multivariate analysis identified only testicular atrophy and age at presentation as independent determinants of a positive biopsy. Testis cancer patients with a small contralateral testis had a 20% and those presenting at age 30 years or younger had a 34% prevalence, respectively, of carcinoma in situ on contralateral testis biopsy (95% confidence interval 20 and 46%, respectively).
  
  
  CONCLUSIONS
  Testis cancer patients with an atrophic contralateral testis who present before the age of 31 years are at high risk for carcinoma in situ of the contralateral testis and, therefore, a second germ cell tumor. It is estimated that this group comprises 6% of all testis cancer patients. We predict that a policy of performing contralateral testicular biopsy will produce positive results for carcinoma in situ in a third of these patients and will detect contralateral carcinoma in situ in approximately 40% of all testis cancer patients.
authors.affiliation: Medical Research Council Testicular Tumour Working Party, London, United Kingdom.
authors.forename: S J
authors.initials: SJ
authors.lastname: Harland
authors.forename: P A
authors.initials: PA
authors.lastname: Cook
authors.forename: S D
authors.initials: SD
authors.lastname: Fossa
authors.forename: A
authors.initials: A
authors.lastname: Horwich
authors.forename: G M
authors.initials: GM
authors.lastname: Mead
authors.forename: M C
authors.initials: MC
authors.lastname: Parkinson
authors.forename: J T
authors.initials: JT
authors.lastname: Roberts
authors.forename: S P
authors.initials: SP
authors.lastname: Stenning
mesh_terms: D000328:Adult; D001284:Atrophy; D002278:Carcinoma in Situ / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D003456:Cryptorchidism / Q000150:complications / Q000473:pathology; D018237:Germinoma / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009378:Neoplasms, Multiple Primary / Q000150:complications / Q000453:epidemiology*; D012307:Risk Factors; D013736:Testicular Neoplasms / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D013737:Testis / Q000473:pathology