High-dose chemotherapy and peripheral blood stem cell transplantation as salvage therapy in primary mediastinal nonseminomatous germ cell tumors: The Indiana University experience.

BACKGROUND

Patients with relapsed primary mediastinal nonseminomatous germ cell tumor have low cure rates with salvage chemotherapy or surgery. The authors report survival outcomes of patients who received high-dose chemotherapy (HDCT) and peripheral blood stem cell transplantation (PBSCT) at Indiana University.

METHODS

The prospectively maintained Indiana University germ cell tumor database identified 32 patients with primary mediastinal nonseminomatous germ cell tumor who progressed after first-line cisplatin-based combination chemotherapy and received HDCT and PBSCT between 2006 and 2021. Therapy included two consecutive courses of HDCT consisting of 700 mg/m carboplatin and 750 mg/m etoposide, each for 3 consecutive days, and each followed by PBSCT. A second course was not given if the patient experienced progressive disease or prohibitive toxicity. Progression-free survival and overall survival were analyzed using the Kaplan-Meier method. Medians with 95% confidence intervals were also calculated along with 2-year probabilities.

RESULTS

The median age at HDCT was 30 years (range, 18-61 years). With a median follow-up of 4.7 years (range, 1-14 years), the 2-year progression-free survival rate was 31% (95% confidence interval, 16%-47%), and the 2-year overall survival rate was 35% (95% confidence interval, 19%-52%). At last follow-up, nine patients (28%) remained without evidence of disease, including two platinum-refractory patients and two patients who were receiving HDCT as third-line therapy. There were three treatment-related deaths.

CONCLUSIONS

Salvage HDCT and PBSCT is an active combination in patients who have relapsed primary mediastinal nonseminomatous germ cell tumor with curative potential and prolonged survival, including in platinum-refractory and third-line settings. The authors recommend this approach for initial salvage chemotherapy in this patient population.