Patterns of care and outcomes of patients with METAstatic soft tissue SARComa in a real-life setting: the METASARC observational study

BACKGROUND: Well-designed observational studies of individuals with rare tumors are needed to improve patient care, clinical investigations, and the education of healthcare professionals. METHODS: The patterns of care, outcomes, and prognostic factors of a cohort of 2225 patients with metastatic soft tissue sarcomas who were diagnosed between 1990 and 2013 and documented in the prospectively maintained database of the French Sarcoma Group were analyzed. RESULTS: The median number of systemic treatments was 3 (range, 1–6); 27% of the patients did not receive any systemic treatment and 1054 (49%) patients underwent locoregional treatment of the metastasis. Half of the patients who underwent chemotherapy (n = 810) received an off-label drug. Leiomyosarcoma was associated with a significantly better outcome than the other histological subtypes. With the exception of leiomyosarcomas, the benefit of a greater than third-line regimen was very limited, with a median time to next treatment (TNT) and overall survival (OS) ranging between 2.3 and 3.7 months and 5.4 and 8.5 months, respectively. The TNT was highly correlated with OS. Female sex, leiomyosarcoma histology, locoregional treatment of metastases, inclusion in a clinical trial, and treatment with first-line polychemotherapy were significantly associated with improved OS in the multivariate analysis. CONCLUSIONS: The combination of doxorubicin with a second drug, such as ifosfamide, represents a valid option, particularly when tumor shrinkage is expected to provide clinical benefits. After failure of the second-line therapy, best supportive care should be considered, particularly in patients with non-leiomyosarcoma histology who are not eligible to participate in a clinical trial. Locoregional treatment of metastasis should always be included in the therapeutic strategy when feasible. TNT may represent a useful surrogate endpoint for OS in clinical studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-017-0831-7) contains supplementary material, which is available to authorized users.