SCREENING, DIAGNOSIS AND THERAPY OF TESTICULAR INTRAEPITHELIAL NEOPLASIA (TIN)

Testicular intraepithelial neoplasia (TIN) of the testis formerly defined as carcinoma in situ) has been described as the presursor of all types of testicular germ cell cancer except for spermatocytic seminoma. At present the diagnosis of TIN is based on light microscopic examination of a testis biopsy specimen. In a prospective study, 90 consecutive patients with unilateral testicular cancer underwent contralateral testis biopsy at the time of orchiectomy. Five cases (5.5%) were found to harbor TIN in the contralateral testis, one patient (1.2%) had a synchronous bilateral seminoma. All patients with TIN were treated by testicular radiation with 20 Gy; the patient with bilateral seminoma was treated by unilateral orchiectomy, contralateral tumor enucleation and testicular radiation. Six months after radiation a testicular biopsy was performed in order determine the efficacy of radiation: in all cases a germinal aplasia was found. After a median follow-up of 32 months no local recurrence occurred. Non of the 84 patients without TIN developed a second testis tumor after a median follow-up of 42 months. Diagnosis and therapy of TIN facilitates a testis-sparing approach in young male patients and avoids exogen androgen substitution. Testicular biopsy should be performed routinely in patients with unilateral testicular cancer at the time or orchiectomy.