Slow release cisplatin combined with radiation for the treatment of canine nasal tumors

Thirteen dogs with malignant tumors of the nasal cavity were treated with a combination of slow release cisplatin and megavoltage radiation, Radiation was delivered on a Monday through Friday schedule using a 6 MV linear accelerator, The median total dose was 49.5 Gy (range 49.5-56 Gy). Cisplatin was given using an open-cell polylactic acid polymer, impregnated with the drug and implanted intramuscularly at a distant site, as a slow release delivery system (OPLA(R)-Pt [THM Biomedical, Inc]). The median dose used was 60 mg/m(2) (range 60-100 mg/m(2)). When combined with radiation, this delivery system caused no systemic drug toxicity, and a local tissue reaction was seen in only two dogs. Acute side effects to normal tissue from radiation mere not enhanced, as measured by subjective assessment, When compared to a group of historical controls that received radiation without OPLA-Pt, the dogs that received combined radiation and cisplatin had longer overall survival times, with a median of 580 days, The control group had a median survival of 325 days. Previously reported median survival times for comparable megavoltage radiation treatment range from 6 to 13 months. Some dogs in both groups also received adjuvant chemotherapy but this did not influence survival time. By multivariate analysis, only the use of OPLA-Pt was found to significantly influence survival, with a p value of p = 0.023. Mega-voltage radiation and slow release cisplatin appears to be a well tolerated combination that may favorably affect survival of dogs with nasal tumors.