Testicular germ cell cancer despite previous local radiotherapy to the testis.

ABSTRACT

BACKGROUND: Testicular intraepithelial neoplasia (TIN, also carcinoma in situ of the testis) is the uniform precursor of testicular germ cell cancer. Local radiotherapy to the testis with dosages of 18-20 Gy has been found to safely eradicate TIN and germ cells, too. Thus, the general assumption is that the development of invasive germ cell tumours can be prevented by this radiotherapy. PATIENTS AND METHODS: Herein, we report two patients with one-sided testicular tumour and biopsy-proven contralateral TIN. Both of them developed germ cell neoplasms in the remaining testis although local radiotherapy with 20 Gy had been applied to the testis. RESULTS: One patient developed pure seminoma 7 years after completion of radiotherapy, the other developed a combined tumour consisting of embryonal carcinoma and seminoma after 5 years. Treatment consisted of orchiectomy in each of the cases. Histologically, both had TIN in the testicular tissue surrounding the new growths. CONCLUSIONS: Pathogenetically, a small fraction of radioresistent TIN cells overcoming irradiation and progressing to full-blown germ cell cancer in the later course may be the histogenetic clue to explain these unexpected events. Other explanations, though less probable, could be technical radiotherapeutic failure due to targeting problems and a pre-existing radioresistent germ cell tumour in the irradiated testicle.