Dog genital tumor treated with vincristine and natural acetogenins

Abstract

Vincristine, an antimicrotubular alkaloid, is the standard treatment for transmissible venereal tumor in dogs due to its high rate of clinical remission. However, recent studies have explored its combination with natural bioactive compounds as a strategy to enhance therapeutic efficacy and reduce adverse effects. This study evaluated the clinical effectiveness of vincristine in combination with acetogenins phytochemicals derived from the leaves of Annona muricata in two female dogs with cytologically confirmed genital transmissible venereal tumor. Both patients received vincristine at a dose of 0.5 mg·m-² intravenously, once weekly for six weeks. In one of the dogs, a daily dose of 7.5 to 10 mg of acetogenins was administered from the first chemotherapy session for the initial 15 days. From the third vincristine application onward, the dose was increased to 14.5 to 20 mg·day-1 of acetogenins, divided into two oral administrations (one capsule in the morning and one in the evening) with food, and maintained for a total of four months. The dog treated with the combined protocol exhibited early tumor regression, with a significant reduction from the second week and a clinical remission of 99.85% by the end of treatment. No adverse effects associated with acetogenin administration were observed. In contrast, the dog treated with vincristine alone showed a partial response, with persistent tumor tissue at the end of the protocol. The combination of vincristine and acetogenins appears to be a promising therapeutic strategy that may enhance the efficacy of conventional transmissible venereal tumor treatment in dogs. However, these preliminary findings require validation through controlled clinical trials with a higher number of experimental units, as well as histopathological and molecular markers assessments to elucidate the underlying mechanisms of action and support the development of standardized therapeutic protocols.