Clinical Outcomes of De Novo Versus Relapsed Early Metastatic Testicular Seminoma Treated With Contemporary Radiation Therapy

Purpose: Chemotherapy (CHT) or radiation therapy (RT) are first -line treatments for clinical stage II (CS -II) testicular seminoma. Historically, clinical stage I (CS -I) seminoma was also treated with CHT or RT, but in the past 2 decades practice has shifted toward active surveillance for CS -I with RT or CHT reserved for patients with progression to CS -II. Limited data exist on contemporary RT techniques and patient stratification (ie, de novo [CS -II at orchiectomy] vs relapsed [CS -II diagnosed during surveillance after orchiectomy for CS -I]). We investigated outcomes in CS -II patients treated with RT in the modern era across 2 institutions. Methods and Materials: A retrospective review identified 73 patients treated with RT for CS -II A or B seminoma between 2001 and 2022. Recurrence -free survival (RFS) was calculated by the Kaplan -Meier method and univariate analyses were performed with log -rank or Cox proportional hazard regression. Recurrence was defined as biopsy -proven metastatic seminoma after RT completion. Second malignancies were defined as a biopsy -proven malignancy originating in the prior RT field. Results: Thirty-eight (52%) patients presented with de novo CS -II and 35 (48%) patients had relapsed CS -II. Median followup was 4.8 years (IQR: 2.3-8.1). Five-year RFS was 82% overall (92% in relapsed patients and 73% in de novo patients). Relapsed CS -II disease had lower recurrence rates after RT compared with de novo CS -II disease. All recurrences occurred outside the prior RT field and were salvaged. Disease -specific survival was 100%. Two second malignancies occurred (prostate, colorectal cancer at 67 months and 119 months post-RT, respectively). Conclusions: In patients with CS-II seminoma treated with modern RT, there were no in -field recurrences. Presentation with de novo CS-II is associated with out -of -field recurrence. Subject to further larger-scale validation, our results suggest that compared with CS-II at time of relapse, de novo CS-II may portend more aggressive or micrometastatic disease beyond the retroperitoneum, raising the possibility of benefit from CHT after radiation. (c) 2023 Elsevier Inc. All rights reserved.