Patterns of relapse and treatment outcome after active surveillance or adjuvant carboplatin for stage I seminoma: a retrospective study of the Spanish Germ Cell Cancer Group.

Purpose: Active surveillance (AS) and adjuvant chemotherapy (AC) with carboplatin are valid alternatives for managing stage I seminoma, and most relapses can be cured with cisplatin-based chemotherapy. However, some reports suggest that AC may modify the classical pattern of recurrences.
Methods: We analyzed all relapses observed in a series of 879 patients with stage I seminoma included in 4 consecutive studies of the Spanish Germ Cell Cancer Group. After a median follow-up of 67 months, recurrences were detected in 56/467 (12%) low-risk cases on AS and 13/412 (3%) high-risk cases after AC (p < 0.001). The objective was to describe clinical features, treatment and outcome. Univariate comparisons were performed between both groups.
Results: No significant differences were found between relapses on AS and those after AC in terms of time to relapse (13 vs 17 months), size (26 vs 27 mm), location (retroperitoneum in 88% vs 85%), and method of detection (computed tomography in 77% vs 69%). Treatment consisted of chemotherapy (etoposide + cisplatin ± bleomycin) in 89% and 92%, respectively. Late relapses (after > 3 years) were seen in 11% vs 7.7% (p = NS) and second or successive recurrences in 1.8 vs 23% (p < 0.05). With a median follow-up of 130 moths, two patients died of seminoma-unrelated causes (AS group) and the rest are alive and disease-free.
Conclusion: In the setting of a risk-adapted treatment of stage I seminoma, the administration of two courses of AC in patients with tumor size > 4 cm and/or rete testis invasion is associated with a higher incidence of second recurrences but does not significantly modify the pattern of relapses or their outcome.