Intratubular germ cell neoplasia of the contralateral testis in testicular cancer: Defining a high risk group

Purpose: 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. Materials and 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 mi. 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.