From Humans to Dogs and Back: The Translational Lesson of Metronomic Chemotherapy

The main priority in veterinary oncology is to maintain patient quality of life. It is important that new chemotherapy strategies aim to minimize side effects, thus making the treatment attractive for owners as well as their pets. Metronomic chemotherapy has been shown to have an important stabilizing effect on human cancer (including chemotherapy-resistant disease) resulting in prolonged clinical benefit. In addition, this form of treatment has been shown to have positive effects on the quality of life of patients with various types of cancer. These positive effects are obtained without any indication of high grade toxicity. Moreover, low cost and oral administration (which reduces the need for hospitalization and enables patients to stay at home longer) are key characteristics of this schedule, offering important advantages in frail subgroups of patients (e.g., old patients) for whom new therapeutic options are greatly needed. From another perspective, use of metronomic chemotherapy in dogs could reveal new and innovative schedules that could be applied to humans. Veterinary oncology cases treated with metronomic schedules represent the unique opportunity to ethically investigate novel drugs or combination treatments that may be highly translatable to the human community. The aim of the present review was to describe how this new form of treatment has evolved in canine patients thus far.