Dogs receiving any type of treatment for central nervous system lymphoma lived longer than cases described in previous historical reports. Further studies are needed to elucidate the importance of specific treatment modalities.

Vincristine is included in vincristine, cyclophosphamide, doxorubicin and prednisone (CHOP) chemotherapy protocols, which are the gold-standard treatment for high-grade canine lymphoma. Vincristine can result in relatively high rates of gastrointestinal toxicity, whereas vinblastine is generally well tolerated and thus may represent an under-utilized and minimally toxic alternative to vincristine. Our objective was to determine the response rate and toxicity associated with a single dose of vinblastine administered to dogs with treatment-naïve, intermediate to large-cell, multicentric lymphoma. Twenty client-owned dogs were enrolled with signed owner consent. A Simon's minimax, phase II, two-stage trial was performed to test the efficacy of vinblastine administered at 2 mg/m IV followed by a pilot trial of vinblastine at 2.5 mg/m . No dogs were administered concurrent steroids or other chemotherapy. One out of 14 dogs receiving vinblastine at 2 mg/m demonstrated a partial response. Three out of five dogs demonstrated a partial response to vinblastine at 2.5 mg/m . Gastrointestinal toxicity was infrequent and low grade for both groups. The majority of dogs (80%) in the 2.5 mg/m dosing group developed neutropenia 1-week post administration. Vinblastine was well tolerated but minimally efficacious at a dose of 2 mg/m IV in dogs with treatment-naive, multicentric lymphoma. Because of poor response rates, treatment at this dose is not recommended. A small subset of dogs administered 2.5 mg/m had significantly improved response rates (P = 0.04), suggesting that higher doses may have improved efficacy, although further research is indicated to confirm these preliminary findings.

OBJECTIVE To evaluate effects of substituting mitoxantrone for doxorubicin in a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapeutic protocol for first-line treatment of dogs with multicentric intermediate- to large-cell lymphoma. DESIGN Retrospective cohort study. ANIMALS 44 dogs treated with cyclophosphamide, mitoxantrone, vincristine, and prednisone (CMOP) and 51 dogs treated with CHOP at 12 referral institutions. PROCEDURES Medical records were reviewed to determine response to treatment, progression-free survival time, and overall survival time. For dogs treated with CMOP, adverse events were also recorded. RESULTS All 44 (100%) dogs treated with CMOP and 37 of 38 (97.4%) dogs treated with CHOP had a complete or partial response. Median progression-free survival time for dogs treated with CMOP was 165 days (95% confidence interval [CI], 143 to 187 days), and median overall survival time was 234 days (95% CI, 165 to 303 days). For dogs treated with CHOP, median progression-free survival time was 208 days (95% CI, 122 to 294 days), and median overall survival time was 348 days (95% CI, 287 to 409 days). Progression-free and overall survival times were not significantly different between groups. Overall, 9 of the 44 (20%) dogs treated with CMOP had adverse events likely or probably related to mitoxantrone, but all of these adverse events were mild. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that mitoxantrone may be a reasonable substitution in a CHOP protocol for treatment of dogs with multicentric intermediate- to large-cell lymphoma when doxorubicin is contraindicated.

Background Greater than 90% of dogs with appendicular osteosarcoma will develop pulmonary metastasis despite the standard of care. Available treatments have limited efficacy for stage III disease. Zoledronate, a bisphosphonate, induces apoptosis of canine osteosarcoma cells and appears to modulate the tumour microenvironment. Objectives This prospective, single institutional phase IIa trial investigated the use of single agent zoledronate in dogs with pulmonary metastases from osteosarcoma. Methods Zoledronate was administered once monthly, and thoracic radiographs were used to assess response. Results Eleven dogs were enrolled. Stable disease was achieved in two of eight dogs available for response assessment. The median progression‐free survival was 28 days (range: 4–93 days). The median stage III‐specific survival time was 92 days. Adverse events were reported in four dogs; two dogs developed grade III or higher toxicities. Notable adverse events included conjunctivitis, fever, hypocalcaemia, and hypophosphatemia. Conclusions Zoledronate appears to have limited efficacy as a single agent for stage III osteosarcoma and may be associated with unexpected toxicity in this population. This clinical trial was registered on the AVMA Animal Health Studies Database (AAHSD004396).

A 4‐year‐old American Yorkshire barrow (Sus scrofa domesticus) presented for masses on the left ventral palpebra and convex pinnae bilaterally. Multiple incisional biopsies were consistent with cutaneous squamous cell carcinoma. The pig was hospitalised for three sessions of electrochemotherapy, with intralesional bleomycin chemotherapy conducted over 1 month. No significant complications from the chemotherapy occurred. Long‐term follow‐up for newly developing lesions on the pinnae and periocular skin included treatment with CO2 laser and cryosurgery with success. Although squamous cell carcinoma is a common finding in food animals, methods other than humane euthanasia for long‐term management of this disease in pigs is poorly documented. Pigs are increasingly becoming popular pet animals, and veterinarians need to consider new modalities and treatment approaches for management of cutaneous neoplasms. This case report describes a comprehensive clinical workup, treatment and long‐term management of squamous cell carcinoma in a domesticated, pet American Yorkshire barrow not intended for food consumption.