Survival outcomes and toxicity in patients 40 years old or older with relapsed metastatic germ cell tumors treated with high-dose chemotherapy and peripheral blood stem cell transplantation

Background: High-dose chemotherapy (HDCT) plus peripheral blood stem cell transplantation (PBSCT) is effective salvage therapy for relapsed metastatic germ cell tumors (GCTs) but has potential toxicity. Historically, an age of ≥40 years has been associated with greater toxicity and worse outcomes.

Methods: This is a retrospective analysis of 445 consecutive patients with relapsed GCT treated with HDCT and PBSCT with tandem cycles at Indiana University from between 2004-2017 per our institutional regimen. Kaplan-Meier methods and log-rank tests were used for progression-free survival (PFS) and overall survival (OS) analysis.

Results: A total of 329 patients were <40 years of age, whereas 116 patients were ≥40 years of age; HDCT was used as second-line therapy in 85% and 79%, respectively. Median follow-up time was 42.5 months (range, 0.3-173.4 months). Grade ≥3 toxicities were similar between either group, except for greater pulmonary (P = .02) and renal toxicity (P = .01) in the ≥40-years-of-age group. Treatment-related mortality was similar between both age groups: 10 patients (3%) in the <40-years-of-age group and 4 patients (3.5%) in ≥40-years-of-age group died from complications of HDCT. Two-year PFS for <40 years of age versus ≥40 years of age was 58.7% versus 59.6% (P = .76) and 2-year OS was 63.9% versus 61.5% (P = .93). Factors predicting worse PFS included Eastern Cooperative Oncology Group performance status ≥1, platinum refractory disease, nonseminoma histology, and not completing 2 cycles of HDCT. Age was not an independent predictor of worse outcomes.

Conclusions: HDCT plus PBSCT is effective salvage therapy in patients ≥40 years of age with relapsed metastatic GCT. Patients ≥40 years of age experience similar rates of toxicity and treatment-related mortality as those <40 years of age.