Background: Chemotherapy extravasation is a potentially serious complication. There is a paucity of information in the veterinary literature investigating extravasation events, treatments, and outcomes.

Objective: Evaluate chemotherapy extravasation events and treatments in dogs and cats, adverse events (AEs), and overall outcomes.

Animals: Twenty dogs and three cats were included.

Methods: Retrospective, multicenter, descriptive study including dogs or cats with suspected extravasation from chemotherapy. Information obtained included: signalment, extravasation details and treatment provided, AEs graded according to VCOG-CTCAE v2 criteria, and outcome.

Results: The most common drug extravasated was doxorubicin, followed by carboplatin. Carboplatin extravasation (n = 5) resulted in Grades III-IV AEs, all of which required surgical debridement. Doxorubicin extravasation (n = 9) resulted in Grades 0-V AEs, two of which amputation was ultimately recommended, and one of those two was euthanized instead. Extravasation of vinca alkaloids (n = 5) and rabacfosadine (n = 1) resulted in Grades II-III AEs, all managed in the outpatient setting. Mitoxantrone (n = 2) and dacarbazine (n = 1) extravasation resulted in no clinical signs associated with extravasation injury. Seventy-eight percent (18/23) cases had extravasation occur during one of the first four treatments of chemotherapy, with 30% (7/23) occurring during the first chemotherapy treatment.

Conclusions and clinical importance: Most cases (20/23) had mild to moderate or no AEs. Findings support that carboplatin should be considered a vesicant.

Martens E, Hritz R, Clifford C, Mullin C, Camero C, Shiu KB, Chan C, Del Alcazar C, DeRegis C, Donnelly L, Marker B, Purzycka K, Vickery K. A Retrospective Study of Chemotherapy-Related Extravasation Events in Dogs and Cats. J Vet Intern Med. 2025 May-Jun;39(3):e70042. doi: 10.1111/jvim.70042. PMID: 40135393; PMCID: PMC11937848.