First Indicator of Relapse in Testicular Cancer and Implications for Follow-up: Analysis of the Swiss Austrian German Testicular Cancer Cohort Study (SAG TCCS)

Background and objective: Follow-up for patients with testicular cancer should ensure early detection of relapses. Optimal schedules and minimum requirements for cross-sectional imaging are not clearly defined, and guideline recommendations differ. Our aim was to analyse the clinical impact of different imaging modalities for detection of relapse in a large prospective cohort (Swiss Austrian German Testicular Cancer Cohort Study, SAG TCCS). Methods: Patients with seminoma or nonseminoma were prospectively enrolled between January 2014 and February 2023 after initial treatment (n = 1175). Follow-up according to the study schedule was individualised for histology and disease stage. Only patients who had received primary treatment were considered. We analysed the total number of imaging modalities and scans identifying relapse and the timing of relapse. Key findings and limitations: We analysed data for 1006 patients (64% seminoma, 36% nonseminoma); 76% had stage I disease. Active surveillance was the most frequent management strategy (65%). Recurrence occurred in 82 patients, corresponding to a 5-yr relapse-free survival rate of 90.1% (95% confidence interval 87.7–92.1%). Median follow-up for patients without relapse was 38.4 mo (interquartile range 21.6–61.0). Cross-sectional imaging of the abdomen was the most important indicator of relapse 57%, abdominal CT accounting for 46% and MRI for 11%. Marker elevation indicated relapse in 24% of cases. Chest X-ray was the least useful modality, indicating relapse in just 2% of cases. Conclusions and clinical implications: On the basis of findings from our prospective register, we have adapted follow-up schedules with an emphasis on abdominal imaging and a reduction in chest X-rays. These schedules might provide additional guidance for clinicians and will be prospectively evaluated as SAG TCCS continues to enrol patients. Patient summary: We analysed the value of different types of imaging scans for detection of relapse of testicular cancer. We used our findings to propose an optimum follow-up schedule for patients with testicular cancer.