Metastatic Potential of Small Testicular Germ Cell Tumors: Implications for Surveillance of Small Testicular Masses

Incidental detection of urogenital tumors has increased in recent decades owing to the greater use of ultrasonography and cross-sectional imaging. For patients with low-risk prostate cancer or small renal masses, active surveillance represents a valid treatment option. Similarly, for men with small testicular masses <10 mm, active surveillance has been discussed as an alternative to surgery, although little is known regarding the behavior of small testicular germ cell tumors (GCTs). In the Swiss Austrian German Testicular Cancer Cohort Study we identified 849 patients (546 seminoma, 303 nonseminoma) treated with radical inguinal orchiectomy for GCT with a median tumor diameter of 35 mm. A tumor diameter <10 mm was observed in 25 patients (13 seminoma, 12 nonseminoma). Of these, five patients (20%) presented with primary metastatic disease, all of whom had elevated tumor markers and nonseminomatous GCTs. Two patients (8%) with initially localized disease (1 seminoma, 1 nonseminoma) and without elevated tumor markers experienced relapse at 4 mo (nonseminoma) and 14 mo (seminoma) after orchiectomy, despite the fact that the latter had received adjuvant chemotherapy. These findings highlight the metastatic potential of small testicular GCTs and raise the question of whether active surveillance for small testicular masses is safe. Patient summary: This study on testicular cancer assesses the metastatic potential of small testicular germ cell tumors. Men with small testicular masses should be counseled about the malignant potential of small testicular germ cell tumors.