[Management of testicular intraepithelial neoplasia (TIN)--a review based on the principles of evidence-based medicine].

Testicular intraepithelial neoplasia (TIN; also called carcinoma in situ of the testis) is the uniform precursor of testicular germ cell tumors. There is general agreement on the biological significance of TIN, however, the treatment is still a matter of dispute. The present review summarizes the treatment options currently available. In general, the management of TIN has to be adapted to the particular clinical situation of the patient. Eradication of TIN usually implies the loss of fertility. Therefore, fertility aspects should be considered before any kind of treatment is employed. Usually, patients with TIN have only small residual potential of fertility. Nonetheless, individual patients may qualify for sperm banking or cryopreservation of testicular tissue for future sperm extraction (TESE) and assisted fertilization. The most common clinical situation is the case of contralateral TIN in the presence of unilateral testicular cancer. Low dose radiotherapy to the testis with 18 Gy is the standard management option in these patients. The same procedure may be applied to solitary testicles after partial orchiectomy for germ cell tumors. During follow-up, testosterone levels should be evaluated every six months. If chemotherapy is required due to metastatic disease of the primary tumor management of TIN should be deferred. After chemotherapy 30% of TIN cases will persist and approximately 42% will recur in the later course. Repeat biopsy should be done six months after completion of chemotherapy or later. Only in cases with persistent TIN additional radiotherapy should be administered. If one testicle is afflicted with TIN while the other testis is in healthy condition (conceivable in infertility cases or patients with primary extragonadal germ cell tumors), then the TIN-bearing testis should be excised. Radiotherapy is not feasible in these cases because of shielding problems with the healthy testis.