Outcomes of relapsed/refractory extracranial germ cell tumors treated on conventional salvage chemotherapy without stem cell rescue: Experience from a tertiary cancer center.

BACKGROUND AND AIMS: Data on the outcome and prognostic indicators in extracranial relapsed/refractory germ cell tumors (rel/ref-GCTs) in children are limited to a few studies. This study looks at remission rates and outcomes of rel/ref-GCTs treated with conventional salvage chemotherapy (SC) regimens without stem cell rescue at a single center in the developing world. METHODS: Patients treated at our center from January 2009 to December 2018 were included. Risk at primary presentation was stratified as all completely excised teratomas and stage I gonadal tumors being low risk (LR); stage IV ovarian, stage III-IV extragonadal GCTs as high risk (HR), and the remaining as intermediate risk (IR). SC regimens were: vinblastine-ifosfamide-cisplatin/carboplatin or paclitaxel-ifosfamide-cisplatin/carboplatin, or cisplatin/carboplatin-etoposide-bleomycin. Local therapy was either surgery and/or radiotherapy. RESULTS: The analyzable cohort comprised 50 patients (44 = rel-GCTs; 6 = ref-GCTs) with a median age of 3.8 years and male:female ratio of 1.27:1. Primary location was ovary in 16 (32%), testicular in 10 (20%), and extragonadal in the rest (48%). Local, metastatic, and combined progression was noted in 28 (56%), 14 (28%), and eight (16%) patients, respectively, at a median time of 8.5 months. At a median follow-up of 60 months, the 5-year event-free survival (EFS) and overall survival (OS) of the entire cohort (n = 50) were 42.4% and 50.0%, respectively. In patients previously exposed to platinum analogs (n = 38), 5-year-EFS and OS were 27.7% and 31.7%, respectively. Local relapses did better when compared to metastatic and combined relapses (5-year EFS: 64% vs. 23% vs. 0%; p = .009). LR and IR tumors did better compared to HR (5-year EFS: 81.5% vs. 49.3% vs. 6.5%; p = .002). Patients with normalization of tumor markers after two cycles had a superior EFS (57.6% vs. 0%; p < .001). Relapsed tumors fared better than primary refractory GCTs (5-year EFS: 48.6% vs. 0%; p < .001). CONCLUSIONS: Primary refractory GCTs, extragonadal rel-GCTs, and rel/ref-GCTs with a poor biochemical response did poorly with conventional SC and need alternative treatment strategies. The rel/ref-testicular GCTs had the best chance of salvage despite a second recurrence (5-year EFS and OS: 28.60% and 42.90%, respectively).