Diagnosis and Management of Intratubular Germ Cell Neoplasia In Situ: A Systematic Review

Purpose:We performed a systematic review of studies assessing the diagnosis and effectiveness of management strategies for germ cell neoplasia in situ.Materials and Methods:Paired investigators independently searched for studies on the diagnosis and management of testicular germ cell neoplasia in situ using PubMed®, Embase® and the Cochrane Central Register of Controlled Trials from January 1, 1980 through August 2018. The reviewers then extracted data and assessed quality.Results:Eighteen studies met inclusion criteria. Among patients with a testicular germ cell tumor the prevalence of contralateral germ cell neoplasia in situ was 4.0% to 8.1%. No significant difference in the risk of metachronous malignancy was identified between unscreened groups vs those with routine contralateral testicular screening (cumulative incidence 1.9% vs 3.1%, p=0.097, respectively). Patients who presented with a history of testicular atrophy, age less than 40 years or cryptorchidism had an elevated risk of germ cell neoplasia in situ. In patients with germ cell neoplasia in situ the use of 18 to 20 Gy radiation therapy demonstrated the lowest rate of disease on followup biopsies (0% to 2.5%), compared to a median of 30% on biopsies in patients treated with cisplatin based chemotherapy. Carboplatin based treatment regimens demonstrated positive disease in 66% to 75% on repeat biopsies. Rates of treatment related hypogonadism were 30.8% to 38.5% and 13% to 20% for patients treated with 18 to 20 Gy and cisplatin based chemotherapy, respectively.Conclusions:In patients with a testicular germ cell tumor the risk of having contralateral germ cell neoplasia in situ is 4% to 8%, with a greater risk in patients with testicular atrophy, cryptorchidism or age less than 40 years. The risk is high enough to support use of contralateral testicular biopsy in patients with these risk factors for germ cell neoplasia in situ. However, routine screening is not advised. Radiation therapy with 18 to 20 Gy was associated with much better eradication of germ cell neoplasia in situ than chemotherapy. Chemotherapy may eradicate germ cell neoplasia in situ in up to two-thirds of patients undergoing chemotherapy as adjuvant treatment for a primary germ cell tumor. Further research and data are needed to strengthen many aspects of the evidence base.