Localized thermo-cisplatin therapy: a pilot study in spontaneous canine and feline tumours.

Local hyperthermia combined with intralesional cisplatin chemotherapy is a logical and potentially effective therapeutic approach for localized cancers. A trial using outbred animals with spontaneously occurring tumours was initiated to evaluate the toxicity and efficacy of this approach. Treatment consisted of injection of a colloidal suspension of cisplatin into the tumour prior to hyperthermia once a week for 4 weeks. Immediately after intratumoral injection of a mixture of cisplatin and collagen, thermotherapy was given. The goal temperature was 42 +/- 1 degrees C for 30 min. Ten animals (nine dogs and one cat) with soft tissue neoplasms were treated with one to four hyperthermia and cisplatin sessions for a total of 30 treatment sessions. Complete responses occurred in 4/10 cases (one carcinoma, two sarcomas, one melanoma). One dog with haemangiopericytoma had partial response. The lack of systemic toxicity and the minimal local normal tissue reactions indicate that the treatments were well tolerated. These data provide preliminary evidence that a combination of local hyperthermia and intratumoral cisplatin chemotherapy is a safe and effective method for the treatment of selected localized neoplasms.