Evaluation of a Novel Cisplatin Poloxamer Gel Formulation in the Treatment of Incompletely Excised Soft-Tissue Sarcomas: 42 Dogs.

Soft-tissue sarcomas are a heterogenous group of mesenchymal tumours that occur in dogs. Complete surgical excision is the ideal treatment for this tumour, but often, the location of the tumour makes this challenging, and the morbidity and cost of such a procedure may be prohibitive. This study describes the use of intralesional cisplatin in a novel poloxamer gel formulation, injected into the tumour bed as an adjuvant treatment to try and lower rates of local recurrence following incomplete and marginal excision. This formulation of cisplatin transiently solidifies at body temperature and exposes the tumour bed to high concentrations of this cytotoxic drug. An overall recurrence rate of 36% (15/42) was recorded in this cohort, with recurrence more likely to occur in tumours that had previously recurred and in larger (≥50 mm) tumours. Whilst this drug formulation is easy to administer and is well tolerated, subsequent use should be weighed against other adjuvant options. Other clinical utilisations of poloxamers in veterinary oncology should be explored.