Cardiology Resident MedVet Medical and Cancer Center for Pets Worthington, Ohio
Pericardial effusion (PE) secondary to right atrial (RA) masses in dogs carries a poor long-term prognosis with limited treatment options. Our objective was to assess combination radiation and chemotherapy outcome in dogs with PE and RA masses.
Medical records between January 2010 and June 2019 were reviewed retrospectively to identify treatment group dogs diagnosed with PE and RA masses via echocardiography that received both radiation and chemotherapy. A retrospective disease matched control group without radiation and chemotherapy was also sought. Data collected included presenting temperature, heart rate, blood pressure, ascites, arrhythmias, need for pericardiocentesis, and metastasis along with time to initial radiation treatment, radiation protocol, chemotherapy protocol, survival time, and cause of death.
Eighteen treatment group and 22 control group dogs were identified. Treatment group median survival time was 124.5 days (range 4-358 days), and survival was unaffected by chemotherapy protocol or presenting heart rate, temperature, blood pressure, ascites, arrhythmias, pericardiocentesis, or metastasis. Control group median survival time following pericardiocentesis was 7.5 days (range 1-77 days). For survival comparison, dogs that received radiation after 6 days (mean time to initial radiation treatment) and control dogs that died before 6 days were excluded. Baseline characteristics were similar between groups. Treatment group survival was longer than the control group (p < 0.01). Radiation and chemotherapy were tolerated.
This study suggests combination radiation and chemotherapy is viable and extends survival time in dogs with PE secondary to RA masses, compared to control dogs. Further research is needed to determine independent effects of radiation therapy.