Systemic toxicity associated with doxorubicin administration in cats

Area of Science:

• Veterinary Medicine
• Cardiology
• Nephrology

Background:

• Doxorubicin is a widely used chemotherapeutic agent.
• Cardiotoxicity and nephrotoxicity are known dose-limiting toxicities of doxorubicin in various species.
• Limited data exists on the systemic toxicity of doxorubicin in feline models.

Purpose of the Study:

• To evaluate the systemic toxicity of doxorubicin in cats.
• To assess the cardiac and renal effects of doxorubicin chemotherapy in felines.
• To establish a feline model for studying doxorubicin-induced toxicities.

Main Methods:

• Six cats received doxorubicin (30 mg/m2 BSA every 21 days) to a cumulative dose of 300 mg/m2.
• Monitoring included appetite, body weight, gastrointestinal signs, renal function tests (BUN, creatinine, urine specific gravity, creatinine clearance), electrocardiograms, and echocardiograms.
• Complete necropsies and histological examinations were performed post-treatment.

Main Results:

• All cats experienced anorexia and significant weight loss after cumulative doses of 150 mg/m2 BSA.
• Echocardiographic evidence of doxorubicin-induced cardiomyopathy was observed in four cats (cumulative doses 170-240 mg/m2 BSA).
• Histological examination revealed myocyte vacuolization and myocytolysis in all hearts; renal dysfunction and histological renal disease were noted in two and all cats, respectively.

Conclusions:

• Doxorubicin administration in cats leads to significant systemic toxicity, including anorexia, weight loss, and cardiac and renal damage.
• The feline model demonstrated susceptibility to doxorubicin-induced cardiomyopathy and nephrotoxicity, consistent with findings in other species.
• These findings highlight the importance of monitoring cardiac and renal function during doxorubicin chemotherapy in cats.