Outcomes associated with local treatment of nasal planum squamous cell carcinoma in dogs: 89 cases (2003–2020)

Objective To describe the clinical characteristics, treatments, complications, and outcomes in dogs with nasal planum squamous cell carcinoma (SCC) undergoing local treatment. Methods A retrospective, multi-institutional study was performed. Medical records were searched to identify dogs diagnosed with nasal planum SCC. Variables were recorded from medical records and statistically analyzed. Results 89 dogs were included. The most common presenting complaint was a visible mass on the nasal planum (89%). Metastasis was detected in 12% of dogs at the time of local therapy. Local therapy consisted of surgical excision alone in 63 of 89 dogs (71%) and radiation therapy alone in 20 of 89 dogs (22%); 6 dogs had multiple local therapies. Tumor size decreased in 12 dogs (60%) undergoing radiation therapy alone. Local recurrence was reported in 19 of 89 dogs (21%), including 16 of 63 dogs (25%) treated with surgery alone. Median survival time of all dogs was 452 days (95% CI, 285 to 576). Median survival time among 33 dogs with documented disease progression was 336 days (95% CI, 189 to 458), versus 685 days (95% CI, 334 to 1,042) in 56 dogs that did not have documented disease progression, which was significantly different (P = .038). Documented disease progression was significantly associated with hazard of death (hazard ratio, 1.93; 95% CI, 1.03 to 3.63; P = .041). Conclusions Dogs undergoing local treatment of nasal planum SCC had a favorable prognosis. Metastasis at the time of treatment was uncommon. Long-term survival was possible, particularly in cases without disease progression. Clinical Relevance Aggressive local therapy, particularly surgical resection, should be considered in dogs with nasal planum SCC.