Outcome in 41 patients with late relapse germ cell tumors (GCT) treated with high-dose chemotherapy (HDCT)

Abstract

5086 Background: The management of patients (pts) with late-relapse GCT and unresectable tumors or very high tumor markers is controversial. Methods: A total of 41 late-relapse pts were identified among a group of 216 pts with refractory or relapsed GCT who were treated in an open, prospective, randomized, multicenter phase III trial. Late relapse was defined as any relapse occurring more than 2 years after completion of initial chemotherapy for GCT. Treatment consisted of either one cycle cisplatin 100 mg/m2, etoposide 375 mg/m2 and ifosfamide 6 g/m2 (VIP) plus three cycles of high-dose carboplatin 1,500 mg/m2 and etoposide 1,500 mg/m2 (CE, arm A) or of three cycles of VIP plus one cycle high-dose carboplatin 2,200 mg/m2, etoposide 1,800 mg/m2 and cyclophosphamide 6,400 mg/m2 (CEC, arm B). Each HDCT was followed by reinfusion of autologous peripheral blood progenitor cells. Results: Overall 20 pts with late-relapse GCT received sequential HDCT and 21 pts single HDCT when the study was stopped due to excess treatment-related mortality in arm B; median time to late relapse in 41 pts was 5.4 years (range 2–18 years); 8/41 (20%) pts had seminomatous GCT, 32/41 (78%) pts had nonseminomatous GCT with or without teratoma; one pt (2%) had unknown GCT histology. No non-GCT histologies were included. The retroperitonum was most commonly involved in 30/41 (73%) pts. 29 of 41 (71%) pts had unresectable, multifocal disease and 20/41 (49%) pts also had very high markers. A complete remission to chemotherapy alone was achieved in 4/41 (10%) pts, 16/41 (39%) pts achieved a partial remission with negative tumor markers. The remaining 21/41 (51%) either had a transient or no response despite HDCT. Residual tumor resections were performed in 17/41 (41%) pts. Residual tumor histology was viable cancer in 8/17 (47%) pts, teratoma in 4/17 (24%) pts and necrosis in 5/17 (25%) pts. With a minimum follow-up of 1 year and a median follow-up of 3 years the estimated Kaplan-Meier rates are 17%, 20% and 32% for event-free, progression-free and overall survival. Conclusion: Treatment outcome after HDCT was inferior in late-relapse pts compared to the group of pts who relapsed within less than 2 years. Despite an overall poor prognosis, HDCT can still result in long-term remissions in selected late-relapse GCT pts. No significant financial relationships to disclose.