ObjectiveTo report demographic characteristics of a contemporary population of dogs with appendicular osteosarcoma and assess the relationship between demographic characteristics, site distribution, and phylogenetic breed clusters.DesignRetrospective case series.MethodsA search of the Veterinary Medical Database was performed for dogs with appendicular osteosarcoma as a new diagnosis. Entries were reviewed for the sex, neuter status, age at diagnosis, breed, affected limb, and tumor location. The reported breed for purebred dogs was used to categorize each dog into one of five phylogenetic groups based on microsatellite analysis.Results744 client-owned dogs were included in the study. Study dogs were represented by a male-to-female ratio of 0.95:1.0, the majority of which (80.9%) were neutered. Most dogs were diagnosed between 7–10 years of age. The majority (77.8%) of dogs were large or giant-breed dogs. Purebred dogs comprised 80.4% of the population. The most common purebred breed affected by OS was the Rottweiler (17.1%). The most common phylogenetic group represented was Mastiff-Terrier (M-T, 26.3%). OS was more commonly located in the forelimb (64.2%) versus the hindlimb (35.8%), and the humerus was the most common site (20.9%). The distribution of age groups and tumor locations were significantly different between phylogenetic clusters. The distribution of age groups and neuter status were significantly different between size groups.Conclusions and significanceThe demographic data of canine appendicular OS are similar to previous reports. The data on phylogenetic associations can guide future studies aimed at evaluating the genomic mutations that contribute to OS development and its biological behavior.

OBJECTIVE To assess the impact of prophylactic omeprazole and famotidine on the incidence and severity of gastrointestinal (GI) adverse events (AEs) in dogs with cancer treated with single agent piroxicam. ANIMALS 39 dogs with a cytologic or histologic diagnosis of cancer with no history of GI disease and received piroxicam. PROCEDURES A prospective, randomized, placebo-controlled, double-blinded clinical trial was performed. All dogs received piroxicam (0.3 mg/kg [0.14 mg/lb], PO, q 24 h) and either omeprazole (1 mg/kg [0.45 mg/lb], PO, q 12 h), famoti-dine (1 mg/kg, PO, q 12 h), or placebo (lactose; PO, q 12 h). Monthly assessments of GI AEs were performed and scored by using the Veterinary Comparative Oncology Group's Common Terminology Criteria for Adverse Events (version 1.1). RESULTS Compared with dogs in the placebo group, more dogs in the omeprazole group (84.6% vs 36.4%) and famotidine group (80.0% vs 36.4%) experienced GI AEs by day 56. The severity of GI AEs was higher in the omeprazole group, compared with the placebo group. CONCLUSIONS AND CLINICAL RELEVANCE Omeprazole was not helpful in reducing the frequency or severity of GI AEs and was associated with more frequent and severer GI AEs in dogs with cancer treated with single agent piroxicam. Proton-pump inhibitors and H2-receptor antagonists should not be prescribed as prophylaxis with NSAIDs for dogs with cancer. (J Am Vet Med Assoc 2021;259:385-391)

A 10-year-old male neutered Domestic Shorthair cat was referred for chronic inappetence, weight loss, and hematochezia and an abdominal mass. Abdominal ultrasonography revealed a heterogeneously hypoechoic transmural colonic mass, which extended beyond the serosa and into the adjacent mesentery. Cytology and clonality assays of fine needle aspirates of the mass and mesenteric nodules yielded a diagnosis of B-cell lymphoma. Colonic lymphoma with mesenteric involvement can have a similar appearance to carcinomatosis, therefore a definitive diagnosis requires sampling and further testing of the mesenteric lesions.

Background: Owners of companion animals with serious illnesses are likely to experience "caregiver burden." This topic has not been fully evaluated in veterinary oncology. Objectives: To examine owners of a dog or cat with suspected cancer for relationships between early caregiver burden and (a) psychosocial factors: depression, stress, and quality of life; (b) owner communication behavior; and (c) specific pet treatment plan factors. Animals: None. Methods: This cross-sectional, observational study recruited 164 owners of a cat or dog presenting for evaluation by a veterinary oncology service at a single referral institution. Measures of caregiver burden, psychosocial function, treatment plan elements, and demographics were collected online via owner self-report. Medical records were reviewed to identify factors including diagnosis, medications, treatment schedules, and owner communications. Results: Caregiver burden correlated with higher stress (r s = 0.40, P < .001), greater symptoms of depression (r s = 0.50, P < .001), and lower quality of life (r s = 0.39, P < .001). Pet treatment plan factors related to caregiver burden included changes in care routines, perception that compliance with new routines was challenging, and difficulty adhering to medication routines. There was low correlation between caregiver burden and owner-driven communications (r s = 0.15, P = .07).