Testicular germ cell tumour arising 15 years after radiotherapy with 18 Gy for germ cell neoplasia in situ

Purpose Germ cell neoplasia in situ (GCNis), the precursor of adult testicular germ cell tumours (GCTs), is found in 5–6% of contralateral testicles in patients with testicular GCT and in the tumour-surrounding tissue of > 90% of testes undergoing testis-sparing surgery (TSS) for GCT. Local radiotherapy to the testis with 18–20 Gy eradicates GCNis while preserving Leydig cells. The frequency of treatment failures is so far unknown. Methods A 22-year-old patient with right-sided seminoma clinical stage I and contralateral GCNis received radiotherapy with 18 Gy to his left testicle. Fifteen years later he underwent orchiectomy of the irradiated testis for seminoma with adjacent GCNis. The patient is well 1 year postoperatively while on testosterone-replacement therapy. The literature was searched for further cases with GCTs arising despite local radiotherapy. Results Six failures of radiotherapy have been reported previously. An estimated total number of 200 and 100 radiotherapeutic regimens with 18–20 Gy applied to cases with contralateral GCNis and with TSS, respectively, are documented in the literature. Conclusion Cumulative experience suggests that radiotherapy with 18–20 Gy to the testis may fail with an estimated frequency of around 1%. Reasons for failure are elusive. A primary radioresistant subfraction of GCNis is hypothesized as well as technical failures regarding application of the radiotherapeutic dose volume in small and mobile testes. Caregivers of patients with TSS and contralateral GCNis should be aware of local relapses occurring after intervals of > 10 years.