Response to first-line treatment and histology are associated with achieving complete remission after the first salvage high-dose chemotherapy in relapsing germ cell tumor patients

Sequential high-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) is a curative option in relapsing germ cell tumor (GCT) patients, and complete remission (CR) after the first ASCT (early CR2) is associated with favorable outcome. Prognostic factors predicting early CR2 have not been investigated so far. We analyzed consecutive patients with a first relapse of GCT treated with three sequential cycles of carboplatin/etoposide-based HDCT with ASCT in the two largest academic centers in Switzerland. The cohort comprised 96 relapsing GCT patients, with 19 (19.8%) patients achieving early CR2 after the first HDCT cycle. The median progression-free survival and overall survival were not reached in patients achieving early CR2, whereas they were 9.6 months (P = 0.0301) and 34.8 months (P = 0.0684) for patients missing early CR2. Patients with early CR2 more often had CR1 after first-line bleomycin, etoposide, and cisplatin chemotherapy (68.4 vs. 31.6%; P = 0.0037) and an interval longer than 2 years between initial diagnosis and first HDCT (36.8 vs. 15.6%; P = 0.0373), but less often a histology of mixed nonseminomatous tumor (46.8 vs. 21.1%; P = 0.0418). These data suggest that response to first-line chemotherapy, late relapse, and histology are associated with achieving early CR2 after a first HDCT with ASCT in relapsing GCT patients.