Maintenance treatment with trofosfamide in patients with advanced soft tissue sarcoma - a retrospective single-centre analysis

Background: The prognosis of patients with advanced soft tissue sarcoma (STS) remains dismal. Trofosfamide (TRO) has been proposed as a well-tolerated oral maintenance therapy. This retrospective analysis aims to determine the value of this therapy. Methods: Fifty-nine patients with advanced STS who received TRO maintenance therapy between 2016 and 2022 were reviewed and analysed regarding clinical parameters and outcomes. Results: The median age was 48 years; the most common histological subtype was synovial sarcoma (n = 22, 37%), and 71% of patients (n = 42) presented with metastatic disease. No radiological evidence of disease (NED) before the start of maintenance was reported in 36% of patients (n = 21). The median follow-up was 38.2 months with a median maintenance duration of 9.0 months. The median event-free survival (EFS) and overall survival (OS) were 9.5 and 33.2 months, respectively. In metastatic patients achieving NED before the initiation of TRO, the median EFS was 29.4 months, while the median OS was not reached. In metastatic patients with anthracycline + ifosfamide (AI) as first-line induction therapy without prior metastasis-directed local therapy, the median EFS and OS from the start of AI were 13.9 and 26.8 months, respectively. Multivariate analysis of the overall cohort demonstrated that NED before the start of maintenance was significantly associated with a prolonged EFS (p = 0.024, hazard ratio [HR] = 0.26), and G2 histology correlated with longer OS (p = 0.030, HR = 0.16, reference: G3). Interpretation: Oral maintenance therapy with TRO appears to improve outcomes in patients with advanced STS. Metastatic patients who achieve NED through prior metastasectomy may particularly benefit from TRO maintenance.