Of all patients with clinical stage I seminoma, approximately 20% experience relapse. While tumor size and rete testis invasion have been identified as relapse risk factors, there is little evidence to support the use of these risk factors in clinical decision-making.
Histologic slides from orchiectomy specimens were retrieved from patients who were diagnosed with clinical stage I seminoma between January 2013 and December 2018. The slides were blindly reviewed. Cox regression analysis was used to identify the association between prespecified potential clinical and histopathologic prognostic factors and relapse.
A total of 924 patients were included in the study. Of those patients, 148 (16%) relapsed during a median follow-up of 6.3 years. Invasion of the testicular hilum (rete testis and hilar soft tissue), lymphovascular invasion, and elevated levels of β-human chorionic gonadotropin and lactate dehydrogenase prior to orchiectomy were independent predictors of relapse.
The estimated 5-year risk of relapse was 6% in patients with no factors and 62% in patients with all 4 risk factors with tumor extension into the hilar soft tissue of the testicular hilum. The prognostic model was internally validated and had an overall concordance statistic of 0.70.
The risk factors identified in this study could be used to replace current risk factors. They could be utilized in future studies on risk-adapted follow-up and treatment strategies, according to the researchers.