Radiologic Signs Of Adipocytic Maturation (Am) In Dedifferentiated Liposarcoma (Ddlps) Patients (Pts) Treated With Trabectedin (T): Correlation With Disease Control.

10561 Background: T has been shown to induce histological AM in myxoid liposarcoma (mLPS), but this has not previously been described in ddLPS. In this retrospective analysis, we analyzed the imaging studies in pts with various LPS subtypes (ddLPS, mLPS, pleomorphic LPS (pLPS), unclassified LPS (uLPS)) treated with T to see whether radiologic AM is detectable in clinical assessments. Methods: This single institution study, which enrolled 55 pts with LPS, was conducted as part of an expanded access trial of T (NCT00210665). Assessable pre- and post-T imaging studies were available for 48 pts (33M, 15F), including 24 ddLPS, 16 mLPS, 4 pLPS, and 4 uLPS. Mean age at diagnosis was 50 yr (range 24 – 74 yr). T was administered until disease progression, and restaging scans were performed approximately every 6 weeks. Radiologic evidence of AM (change of tumor to fat density), changes in lesion density and size, and best response per RECIST 1.1 were assessed at final T cycle. Clinical benefit and rate (CBR) was ba...