Clinical outcomes of stage IIA/IIB seminoma treated with radiotherapy and chemotherapy: Should regional therapy be considered the preferred treatment approach?

629 Background: With the publication of the Surgery in Early Metastatic Seminoma Trial there has been increasing interest in the use of regional therapy as first line treatment (reserving systemic therapy for relapse) in patients with testicular seminoma with low volume with retroperitoneal lymphadenopathy. Herein, we sought to evaluate outcomes with both management approaches. Methods: A prospectively maintained single-institutional database was retrospectively queried for patients diagnosed between 1995-2016 with de novo clinical stage IIA/B (CSIIA/B) or who relapsed on surveillance (Rel-CSIIA/B) treated with radiotherapy or chemotherapy. All patients were reviewed by the multidisciplinary team; while the preferred management policy during this period was radiotherapy, all treatment decisions were individualized at the physician/patient level. Results: The median follow-up was 7.1 years (IQR 4.3-9.9). There were 153 patients: 67 had de novo CSIIA/B (IIA-32, IIB-35) and 86 patients had Rel-CSIIA/B seminoma (IIA-51, IIB-35). One hundred and twenty patients (78%) received radiotherapy (IIA-78, IIB-42) and 33 (22%) received platinum-based chemotherapy (IIA-5, IIB-28). Eleven patients (IIA- 9/78, IIB- 2/42) relapsed following radiotherapy and 1 patient (IIB) relapsed following chemotherapy, corresponding to 5-year relapse rates of 10% for radiotherapy and 3% for chemotherapy. All 12 patients who relapsed were treated successfully with salvage chemotherapy. Conclusions: Regional therapy in patients with testicular seminoma with low volume with retroperitoneal lymphadenopathy gives excellent treatment results – recognising that a small proportion of patients will need salvage chemotherapy for cure, thereby exposing these patients to the morbidity of two treatment strategies. Our results support the view that regional therapy is a reasonable treatment option in this setting and should be discussed with all patients.