Very long-term survivors among patients with metastatic soft tissue sarcoma

Metastatic soft tissue sarcomas (STS) are a group of rare and heterogeneous mesenchymal tumors with a poor prognosis. The aim of this study was to evaluate the incidence of long-term survivors and describe their presentation and management in a large cohort of patients with metastatic STS.

We collected information of patients with metastatic STS managed in Centre Leon Berard between 1985 and 2015 aiming to compare the group of patients alive 5 years after the diagnosis of metastases vs the others. Prognostic factors of patients and tumors characteristics were investigated by logistic regression analysis. For "long-term survivors," we explored therapeutic strategies at metastatic stage.

Out of 436 patients enrolled, 39 (9%) were still alive 5 years after diagnostic of metastases with a median survival of 146 months (12 years). This "long-term survivors" group included more female and younger patients, with better performance status, more synovial sarcoma or endometrial stromal sarcoma, more patients with simple genomic sarcomas, lower tumor grade, smaller tumor, and longer disease-free interval. In multivariate analysis, age below 55 at metastatic stage (P = 0.0002) and grade 1 tumor (P < 0.0001) were significantly associated with the "long-term survivors." Their therapeutic management was usually aggressive (intensified or polychemotherapy, repeated local treatment of metastases), leading to 62% of complete response in first-line setting.

Very long-term survivors are observed in metastatic STS. Selection of patients in good condition with less aggressive tumor and administration of intensive treatment may lead to obtain these motivating results in a poor prognosis disease.