Maintenance oral etoposide (VP-16) after high-dose chemotherapy (HDCT) for patients with relapsed metastatic germ-cell tumors (mGCT).

Abstract

5051 Background: HDCT and peripheral-blood stem-cell transplant (PBSCT) can cure up to 60% of patients with relapsed mGCT. Maintenance daily oral VP-16 after salvage therapy has been shown effective in inducing remissions (J Clin Oncol 1995;13:1167-9). We evaluate the role of maintenance VP-16 post HDCT+PBSCT compared to observation. Methods: The prospectively maintained Indiana University testicular cancer database was interrogated. Patients with relapsed non-seminoma who completed HDCT+PBSCT and achieved serologic remission and hematologic recovery were evaluated. Outcomes of patients who received maintenance VP16 (N = 141) were compared to patients who were observed (N = 252). In this retrospective study, Kaplan-Meier method was used to analyze progression free survival (PFS) and overall survival (OS). Univariable and multivariable cox regression models were used to determine variables associated with PFS. Results: 2-year PFS in the maintenance VP-16 versus observation group was 55% vs. 44% (p = 0.008). 2-year OS was 61% vs. 52% (p = 0.01). A multivariable analysis was performed including the factors: primary tumor site (testis vs. mediastinum), IGCCCG risk, platinum refractory, HDCT line of therapy (2nd vs. ≥3rd), tumor marker amplitude at HDCT initiation, and receipt of maintenance VP-16 post HDCT vs. observation. Maintenance VP-16 was confirmed as an independent predictor of improved PFS with HR 0.48 [95% CI, 0.35-0.66] (p < 0.001). Conclusions: Maintenance oral VP-16 post HDCT+PBSCT improved PFS and OS. In a multivariable model including known adverse prognostic factors, maintenance VP-16 was an independent predictor of improved PFS. [Table: see text]