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.