Prognosis of canine oral (gingival) squamous cell carcinoma after surgical therapy. A retrospective analysis in 40 patients

Abstract

Retrospective analysis of dogs with gingival squamous cell carcinoma (SCC) surgically treated using jaw resection. Material and me- thods: A total of 40 dogs were enrolled in the study. Dogs with incomplete tumour resection or metastases were subjected to adjuvant chemotherapy using carboplatin. Breed, age, tumour localisation, postsurgical complications, survival times and prognostic factors were evaluated. There were no breed predispositions. The median age was 9.5 years (mean 8.6 years; range 0.5-15.5 years). At the time of presentation, two dogs (5%) had lymph node metastases (N1). The median survival time (ST) of all the patients was 44.8 months. In 15 patients, the tumour was located in the maxilla, whereas 25 dogs had a mandibular tumour location. The median ST in dogs with maxillary tumours was 39 months (95% confidence interval [CI] 24 months), while patients with maxillary tumours survived a median of 43 months (95% CI 33-70 months). There was no significant difference in the ST in patients with maxillary versus man- dibular tumours (p = 0.985). On multivariate analysis, only the tumour stage was found to be significantly associated with survival (p = 0.0047). Patients with stage N0 survived a median of 44 months (95% CI 36-80 months). The two dogs with lymph node metastasis (N1) sur- vived 18 and 70 months following jaw resection and carboplatin chemotherapy, respectively. According to the histological findings, tumour resection was incomplete in five patients. These dogs received adjuvant carboplatin chemotherapy, resulting in an ST of between 6 and 146 months. Prognosis depends on the tumour stage, while for complete local excision of the affected jaw segment a good prognosis can be given and the majority of the patients can be cured. The supposedly more malignant behaviour of gingival SCCs located in the caudal aspects of the oral cavity could not be confirmed. Patients with metastasis of the local lymph nodes can achieve acceptable survival times. Jaw resections have low complication rates and a good functional outcome.