CASE DESCRIPTION 4 dogs were examined because of pleural effusion and ventricular tachycardia, coughing and supraventricular tachycardia, appendicular osteosarcoma, and syncopal episodes.
CLINICAL FINDINGS In all 4 dogs, a heart base tumor was identified by means of thoracic CT.
TREATMENT AND OUTCOME In all 4 dogs, the heart base tumors were treated by means of stereotactic body radiation therapy. Dogs were anesthetized, and neuromuscular blockade was achieved with atracurium or vecuronium. A circle rebreathing system with 15 m (50 feet) of anesthetic tubing coursing through the vault wall was used to connect the patient to the anesthesia machine, which was located in the control room. After a brief period of hyperventilation, an inspiratory breath was held at 20 cm H2O for the duration of beam delivery. Each beam delivery lasted between 30 and 100 seconds. Immediately following the breath hold, assisted ventilation was resumed. Mean treatment delivery time for each patient was 26 minutes; mean total anesthesia time was 89 minutes. All patients recovered without complications. There was no evidence of hemoglobin desaturation or hypercapnia during the anesthetic procedure.
CLINICAL RELEVANCE The technique allowed for control of the respiration cycle from outside the radiation vault and a short overall treatment time. No adverse effects were encountered. This procedure should be considered when delivering radiation to structures within the thoracic cavity.
OBJECTIVE To evaluate potential associations between surgical approach and complication rate, progression-free survival time, and disease-specific survival time in cats with mammary adenocarcinoma.
DESIGN Retrospective case series.
ANIMALS 107 client-owned cats.
PROCEDURES Medical records of cats that underwent surgical excision of mammary adenocarcinoma by means of a unilateral or bilateral (staged or single-session) mastectomy at 9 hospitals between 1991 and 2014 were reviewed. Relevant clinicopathologic data and details of surgical and adjuvant treatments were recorded. Outcome data were obtained, including postoperative complications, progression-free survival time, and disease-specific survival time.
RESULTS Complications occurred in 12 of 61 (19.7%) cats treated with unilateral mastectomy, 5 of 14 (35.7%) cats treated with staged bilateral mastectomy, and 13 of 32 (40.6%) cats treated with single-session bilateral mastectomy. Complications were significantly more likely to occur in cats undergoing bilateral versus unilateral mastectomy. Median progression-free survival time was longer for cats treated with bilateral mastectomy (542 days) than for cats treated with unilateral mastectomy (289 days). Significant risk factors for disease progression included unilateral mastectomy, tumor ulceration, lymph node metastasis, and tumors arising in the fourth mammary gland. Significant risk factors for disease-specific death included lymph node metastasis and development of regional or distant metastasis. Among cats that did not develop metastasis, unilateral mastectomy was a significant risk factor for disease-specific death. Treatment with chemotherapy was associated with a significantly decreased risk of disease-specific death.
CONCLUSIONS AND CLINICAL RELEVANCE Results supported bilateral mastectomy for the treatment of mammary adenocarcinoma in cats to improve progression-free and disease-specific survival time. Performing bilateral mastectomy in a staged fashion may help to decrease the complication rate.