Local tumour response to neoadjuvant therapy with 2-aminoethyl dihydrogen phosphate in dogs with soft tissue sarcoma

Abstract

Background: In cases of soft tissue sarcoma (STS), neoadjuvant therapy is indicated to downstage the tumour prior to surgery to achieve enhanced local tumour control. The antineoplastic phospholipid compound 2-aminoethyl dihydrogen phosphate (2-AEH2F) is an alkyl phosphate ester capable of inhibiting cell proliferation and inducing cell death by modifying the asymmetry of phospholipids in the cytoplasmic membrane. Objectives: This clinical study was designed to investigate local antitumoural effects of neoadjuvant therapy with 2-AEH2F in dogs with naturally occurring STS. Material and methods: Dogs (n = 11) received four consecutive weekly intravenous injections of 2-AEH2F (70 mg/kg) prior to tumour resection. Tomographic (CT) and thermal (TE) images were used to investigate changes in tumour size and local temperature in response to treatment. Results: Comparative analysis of CT images (n = 9/11) failed to reveal complete or partial remission according to selected assessment criteria (RECIST, WHO and volumetric). Comparative analysis of TE images (n = 10/11) revealed significantly (p = 0.01416) lower temperatures in tumoural areas relative to surrounding tissues over the course of treatment. Conclusions: 2-AEH2F had no cytoreductive effects when used at doses and intervals described in this study. However, significant drop in skin temperatures recorded in tumoural areas suggest induction of physiological changes.