Australia and New Zealand (ANZ) outcomes of high-dose chemotherapy and stem cell transplantation for relapsed or refractory germ cell tumors (GCT) from 1999 to 2019: Multicenter registry-based study with ABMTRR.

Abstract

382 Background: High dose chemotherapy (HDCT) with autologous stem-cell transplant (ASCT) is effective in advanced germ cell tumours (GCT) that are refractory to, or progress after, first-line therapies. Five-year overall survival in North American and European series range from 48-60%1,2,3. This study aimed to assess ANZ outcomes for quality assurance. Methods: Retrospective multi-centre audit of all male patients with GCT who underwent HDCT and ASCT from 1999-2019. Patients were identified from the Australasian Bone Marrow Transplant Recipient Registry. Primary outcomes included overall and progression- free survival (OS, PFS). Results: 111 patients were identified at 13 centres, each treating a median (range) of 7 (1-27) patients. Median (range) age was 30 (14-68) years. 88 (79%) had testicular primary. 16% were pure seminoma. Median time from first diagnosis to first stem cell cycle was 11 months (range 3 months-38 years). Prior to ASCT, 35% had primary refractory disease and 65% had relapsed. IPFSG risk score was very low in 5%, low in 13%, intermediate in 36%, high in 25%, and very high in 21%. HDCT regimen was CE in 78% (as part of TI-CE regimen in 38%), Carbop-EC-T in 6%, ICE in 6%, CEC in 5% and other in 4%. 89% completed all planned HDCT and ASCT cycles. Five treatment related deaths occurred. Progressive disease on treatment occurred in 14%. At median follow-up time 4.4 years (95% CI: 2.9 to 6.0), 51% were disease-free, 13% alive with disease, 34% deceased. 3 patients displayed late progression over 2 years after ASCT. The estimated 1, 2 and 5-year PFS rates were 62%, 57% and 52% respectively and OS rates were 73%, 65% and 61%. Survival by IPFSG and IGCCG risk categories are displayed in the table below. Conclusions: This is the first registry-based audit of HDCT for metastatic GCT from ANZ, which has demonstrated our outcomes are comparable with best international practice.