High-dose chemotherapy (HDC) and stem-cell rescue as salvage treatment for germ cell testicular tumors in second- and third-line, and outside clinical trials.

Abstract

557 Background: Germ-cells testicular tumors are the most common cancer in young males, usually curable in early stages. Therefore, only 25% of relapsed patients are long-term survivors. Previous non-randomized studies showed promising results with HDC, however, the only randomized trial did not support this approach. Here we report our experience in a Brazilian academic center Methods: We conducted a retrospective review of all consecutive patients treated with salvage HDC followed by Stem-Cell transplantation at our service (1996 – 2016). Survival curves were estimated by Kaplan-Maier method. Prognostic factors were determined by Cox regression model. Results: We found 36 eligible patients. The cohort median follow-up was 56 months (m). At 2 years 50.4% of the patients were alive, and 46.7% were disease-free. The median overall survival (OS) was not-reached and the median progression-free survival (PFS) was 21.8 m. The overall response-rate was 61.2% (22% had complete response and 39% had partial response). All patients who achieved complete response were alive at the last follow-up, and only one had progressive disease. Out of the patients who achieved partial response, one third were rescued with surgery (46% teratoma, 23% fibrosis, and 31% residual disease). Approximately 80% were alive in 2 years vs 20% not operated. Complete response (vs. others) and HDC as second line treatment (vs. 3rd and 4th) were good prognostic factors, (HR N/A; p 0,03, HR 0.19; CI: 0.04-0.88, p = 0.01 respectively). In 2 years, the OS in patients treated in 2nd line was approximately 80%, 50% for 3rd line, and 0% of those treated in 4th line. 89% of the patients experienced grade 3 toxicity, and 25% grade 4. The most common were neutropenic fever (69%), mucositis (36%) and diarrhea (25%). There were 3 deaths related to the treatment. Conclusions: Patients with complete response have sustained long-term survival, and represent the subgroup with evident benefit of the treatment. Surgery, when feasible, can rescue 80% of the patients with partial response. According to our data, we do not recommend this modality of treatment in 4th line.