The diagnostic yield of preoperative screening for oral cancer in dogs over 15 years, part 1: locoregional screening.

OBJECTIVE: Determinelocoregionaldiagnosticyield of 4-site screening (head, neck, chest, and abdomen)todiagnosemetastatic disease or clinically significant comorbid diseases in dogs with oral cancer. ANIMALS: 381 dogs with histologically confirmed oral tumors. METHODS: Medical records from 381 dogs with histologically confirmed oral tumors that underwent preoperative screening were retrospectively reviewed. RESULTS: Skull and neck CT scan was performed on 348 patients. Bone lysis was present in 74.4% of tumors. Oral squamous cell carcinoma, sarcomas, and TZ-T3 (> 2 cm) tumors had a significantly (P < .05) increased incidence of lysis compared to odontogenic and Tl (< 2 cm) tumors, respectively. Minor incidental findings were present in 60.6% of CT scans. Major incidental findings were found in 4.6% of scans. The risk of diagnosing an incidental finding increased by 10% and 20% per year of age for minor and major findings, respectively. Lymph node metastasis was diagnosed with CT or cytology in 7.5% of cases (10.7% of nonodontogenic tumors, 0% of odontogenic tumors). Oral malignant melanoma, oral squamous cell carcinoma, and T3 tumors had the highest prevalence of metastatic disease at the time of staging. The presence of bone lysis was not associated with cervical metastasis. CLINICAL RELEVANCE: Major incidental findings were rare (< 5%) but primarily included secondary extraoral tumors. Lymphatic metastasis was diagnosed in 10.7% of nonodontogenic tumors, but cytology was not performed in the majority of cases and often included only a single mandibular node. Therefore, these results likely underestimate the incidence of Iymphatic metastasis. Guided Iymph node sampling is highly recommended, especially fororal malignant melanoma, squamous cell carcinoma, and T2-T3 tumors. [ABSTRACT FROM AUTHOR]