Surveillance versus adjuvant radiotherapy for patients with high-risk stage I seminoma.

Background: The optimal treatment strategy for patients with clinical stage I (CS-1) seminoma is controversial. The objective of the current study was to evaluate the outcomes for patients considered to be at high risk of disease recurrence with a tumor size ≥6 cm. Patients were treated with either adjuvant radiotherapy (RT) or followed with surveillance.

Methods: From the Danish Testicular Cancer database, the authors identified 473 patients with CS-1 seminoma with a tumor size ≥6 cm. Of these, 254 patients underwent adjuvant RT and 219 were followed with surveillance. Cumulative incidence function was applied to estimate the risk of disease recurrence, risk of second malignant neoplasm, and risk of receiving >1 line of treatment. Survival of the 2 groups was compared with the log-rank test and Cox model including age at diagnosis.

Results: No significant differences were found with regard to overall survival or risk of a second malignant neoplasm. Patients undergoing adjuvant RT received more treatments per patient than patients followed with surveillance, but there was no significant difference noted with regard to the risk of receiving >1 line of treatment. The 10-year cumulative incidence of disease recurrence was 32% versus 2.8%, respectively, for patients followed with surveillance and adjuvant RT. In patients followed with surveillance who developed disease recurrence, there was a high incidence of second recurrences after RT.

Conclusions: The 10-year overall survival was found to be similar irrespective of primary treatment. Adjuvant RT was found to effectively reduce the rate of disease recurrence but resulted in the overtreatment of approximately two-thirds of the patients. The high incidence of second disease recurrences after RT in the patients followed with surveillance needs be addressed in future studies. Cancer 2017;123:1212-1218. © 2016 American Cancer Society.