Single-agent Carboplatin AUC10 in Metastatic Seminoma: A Multi-centre UK Study of 216 Patients

Background: Radiotherapy and cisplatin-based combination chemotherapy are accepted standard-of-care treatments for metastatic seminoma with excellent survival outcomes but with established short- and long-term morbidity. Carboplatin monotherapy may be a less toxic alternative; however early historic studies at AUC7 showed inferior outcomes.

Objectives: To evaluate multi-institutional data on and toxicity and longer-term survival for metastatic seminoma patients treated with the single-agent carboplatin AUC10.

Methods: We undertook a multi-institutional analysis incorporating all men with the International Germ Cell Cancer Collaborative Group good-prognosis metastatic seminoma treated until 2018. Carboplatin AUC10 was given every 21 days. Toxicity, progression-free survival (PFS), disease-specific survival (DSS) and overall survival were noted. Variables predictive of progression were identified.

Results And Limitations: 216 patients were treated. The three-year PFS rate was 96.5%, and five-year DSS was 98.3%. There were seven relapses, of which 5 were successfully salvaged with further chemotherapy ± surgery, and three non-seminoma-related deaths. There were no treatment-related deaths. Of 148/216 evaluable patients for toxicity, 37% and 27% suffered >/ = grade III neutropenia and thrombocytopenia, respectively. Twelve percent of patients needed a platelet or blood transfusion (or both). The incidence of febrile neutropenia was 5%.

Conclusion: For metastatic seminoma, carboplatin AUC10 harbours a similar oncological efficacy to established therapies, with a low failure risk. The major acute toxicity was myelosuppression. Our study establishes carboplatin AUC10 as another standard-of-care treatment option for good-prognosis metastatic seminoma, with a potentially lower toxicity profile than other therapies.