Carboplatin-induced myelosuppression as related to body weight in dogs.

Abstract

Smaller dogs are known to have an increased risk of chemotherapy-induced myelosuppression for doxorubicin, mitoxantrone and melphalan. This retrospective study aimed to determine if dogs <15&#x2009;kg and <10 kg experienced greater degrees of myelosuppression following treatment with carboplatin chemotherapy compared with dogs &#x2265;15&#x2009;kg. One hundred and one dogs treated with carboplatin for a variety of malignancies were retrospectively analysed. Eight dogs (61%) weighing <10 kg, three (38%) weighing 10 kg to <15&#x2009;kg and 14 (17%) weighing &#x2265;15&#x2009;kg experienced a grade 3 or 4 neutropenia. Five dogs (38%) weighing <10 kg, two (25%) weighing 10 kg to <15&#x2009;kg and 13 (16%) weighing &#x2265;15&#x2009;kg experienced a grade 3 or 4 thrombocytopenia. Dogs <10 kg were significantly more likely to develop a grade 3 or 4 neutropenia following carboplatin than dogs &#x2265;10 kg (3.5 RR; 95% CI, 1.9-6.3; P&#x2009;<&#x2009;.001). Dogs <15&#x2009;kg were also significantly more likely to develop a grade 3 or 4 neutropenia than dogs &#x2265;15&#x2009;kg (3 RR; 95% CI, 1.6-5.6; P = .004). Dogs <10 kg were significantly more likely to develop a grade 3 or 4 thrombocytopenia than those dogs &#x2265;10 kg (2.5 RR; 95% CI, 1.1-5.6; P = .006). Hospitalization was significantly more likely for dogs <10 kg vs &#x2265;10 kg (P = .014) as well as for dogs <15&#x2009;kg vs &#x2265;15&#x2009;kg (P = .039). This study demonstrates an increased risk of carboplatin-induced myelosuppression in dogs <15&#x2009;kg, and particularly those <10 kg. This information should be considered by clinicians when making decisions regarding the initial carboplatin dose for smaller canine patients, especially those <15&#x2009;kg.