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Conventional chemotherapy involves the administration of a drug into a peripheral vein, which results in systemic dosing of the drug. When given intravenously, the drug also undergoes dilution prior to reaching the tumor (Vogl et al. 2008). The administration of intraarterial chemotherapy by interventional radiologists is common practice in human medicine. The major reason for administration of chemotherapy directly into a tumor’s arterial supply is that a higher concentration of drug can be accumulated locally (at the tumor site), with fewer systemic side effects (von Scheel and Golde 1984; Mortimer et al. 1988; Sileni et al. 1992; Kovács et al. 1999; Furutani et al. 2002). Intraarterial chemotherapy has not gained universal acceptance, likely due to variable success rates; however, head and neck malignancies have shown an overall response rate of 82–95% when treated with intraarterial chemotherapy (Mortimer et al. 1988; Sileni et al. 1992; Korogi et al. 1995).

Intraarterial chemotherapy administration has been evaluated in canine patients with lower urinary tract neoplasia (Culp et al. 2015b). In that study, a comparison between dogs receiving intraarterial chemotherapy and dogs receiving conventional intravenous chemotherapy was performed, and subsequent changes in tumor size were determined. Dogs undergoing intraarterial chemotherapy demonstrated a significantly greater decrease in several measurements including length, length percentage, width percentage, longest unidimensional measurement, and longest unidimensional measurement percentage. Additionally, adverse events such as anemia, lethargy, and anorexia were significantly less likely to occur in the intraarterial chemotherapy group vs. the intravenous chemotherapy group. Superselection of the arterial blood supply to the lower urinary tract was shown to be feasible, with minimal complications (Culp et al. 2015b).

In humans, intraarterial chemotherapy is often administered in conjunction with radiotherapy in an attempt to achieve better outcomes (Mokarim et al. 1997; Furutani et al. 2002). This concept has also been exploited in clinical veterinary cases of bladder carcinoma and osteosarcoma (McCaw and Lattimer 1988; Heidner et al. 1991; Powers et al. 1991; Withrow et al. 1993). In a study evaluating the combination of intraarterial chemotherapy (cisplatin) with radiation therapy for the treatment of bladder cancer, two dogs demonstrated an objective reduction in tumor size (McCaw and Lattimer 1988). Side effects and toxicity were minimal in these two dogs (McCaw and Lattimer 1988).

Three studies have combined intraarterial chemotherapy with radiation therapy in the treatment of canine osteosarcoma (Heidner et al. 1991; Powers et al. 1991; Withrow et al. 1993). In an appendicular osteosarcoma study, client‐owned dogs were treated with intraarterial cisplatin (2 doses, 21 days apart), and the majority also underwent radiation therapy (Withrow et al. 1993). This group of dogs experienced no significant renal or bone marrow toxicity that affected their long‐term outcome, and radiation side effects were rare. Median survival time in these dogs was 9.3 months. The authors noted that the survival time for these dogs was longer than would be expected for amputation alone, suggesting that there was a survival benefit to the intraarterial chemotherapy. Additionally, the metastasis‐free interval was better than what had been reported previously with radiation therapy alone. Dogs with > 75% tumor necrosis had significantly lower recurrence rates at one year (15%) vs. dogs with < 75% tumor necrosis (65%) (Withrow et al. 1993). In a separate study comparing different treatments for canine osteosarcoma, including intraarterial chemotherapy alone and intraarterial chemotherapy with radiation therapy, the percentage of tumor necrosis was 49.1 and 83.7%, respectively, for those treatment categories (Powers et al. 1991). That study demonstrated that a radiation dose of 28.1 Gy when combined with intraarterial chemotherapy resulted in 80% tumor necrosis (Powers et al. 1991). Another study documented a median survival time of 6.7 months in dogs receiving intraarterial cisplatin chemotherapy in conjunction with radiation therapy as an alternative to amputation or limb‐sparing surgery (Heidner et al. 1991).

There are a vast number of applications for intraarterial chemotherapy that should be investigated in veterinary patients. In humans, the combination of intraarterial chemotherapy and radiation therapy has been successful in treating head and neck malignancies (Wilson et al. 2001; Bertino et al. 2007). These experiences should be used as a scaffolding to develop new treatment strategies for our veterinary patients.