PP-050 Adjuvant treatment with intralesional phenol to prevent the recurrence of chondrosarcoma after surgery

Background The term chondrosarcoma is used to describe a heterogeneous group of tumours which have in common the production of a cartilaginous matrix, which represent 20% of malignant primary bone tumours. The most common, grade 1 chondrosarcoma (CS1), is a slow growing tumour considered refractory to radiotherapy and chemotherapy for which treatment is based on surgery. Adjuvant treatment with phenol after curettage may be effective in preventing local tumour recurrence. Purpose The objective was to develop an adequate phenol formulation to be used in the operating room after curettage and evaluate its safety and effectiveness in a report of one case. Material and methods Surgeons asked our pharmacy department to prepare an 85% phenol formulation. We made a bibliographic research on excipients potentially suitable on Martindale, Micromedex and Pubmed and finally ethanol was chosen because phenol solubility in ethanol is very high and it would not crystalise. Traumatology surgeons used the phenol formulation after curettage in 3 patients. Its effectiveness was assessed measuring the time until tumour recurrence based on imaging and analytical parameters. Results All of the process was developed in a horizontal laminar flow cabinet and we started heating crystalised pure phenol (ACOFARMA) in a circulator at 60°C until it melted, which took about 1 hour. Next, using a 20 mL Luer-Lock syringe, we took 17 mL of liquefied phenol and added it to 3 mL of absolute ethanol (Farmacia Carreras) at 60°C, and invert the syringe several times until they mixed. Then, we filtered the solution using a 0.22 µm sterilising filter to a new syringe, fitted a plug and packed it into a photoresist bag, with 7 days of stability at 25°C. Phenolisation after curettage was practiced in 1 patient, a 34-year-old man with a free survival until image progression of 20 months. Conclusion This formulation of phenol 85% in ethanol appears to be a well tolerated adjuvant treatment after curettage in chondrosarcoma surgery. Further studies are needed to discern where to use it, and to assess its efficacy. References and/or acknowledgements Quint U, Vanhofer U, Harstrick A, Muller RT. Cytotoxicity of phenol to musculoskeletal tumours. J Bone Joint Surg [Br]1996; 78-B :984–5. No conflict of interest