Clinical outcomes of de novo versus relapsed early metastatic testicular seminoma treated with contemporary radiation therapy.

International journal of radiation oncology, biology, physics
Publication type
Journal Article

BACKGROUND: Chemotherapy (CHT) or radiation therapy (RT) are first line treatments for clinical stage II testicular seminoma (CS-II). Historically, clinical stage I (CS-I) seminoma was also treated with CHT or RT, but in the past two decades practice has shifted towards active surveillance for CS-Iwith RT or CHT reserved for patients with progression to CS-II. Limited data exist on contemporary RT techniques and patient stratification, i.e. 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 two institutions.METHODS: A retrospective review identified 73 patients treated with RT for CS-II A or B seminoma between 2001-2022. 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 while 35 (48%) patients had relapsed CS-II. Median follow-up 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 following RT compared to 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).CONCLUSION: 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 to 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 chemotherapy after radiation.

Year of Publication
International journal of radiation oncology, biology, physics
Date Published
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