Objective—To assess the usefulness of histologic evaluation of surgical margins to predict local recurrence of cutaneous malignant tumors in dogs and cats treated by means of surgical excision.
Design—Prospective case series.
Animals—40 dogs and 20 cats.
Procedures—60 surgically excised tumors (20 soft tissue sarcomas [STSs], 20 mast cell tumors [MCTs], and 20 carcinomas) were examined histologically. Margins were classified as clean, close, or infiltrated; histologic grade was assessed in STSs and MCTs. Recurrence rates and recurrence-free intervals (RFIs) during a 24-month follow-up period were recorded, and method accuracy was calculated.
Results—Surgical margins were clean in 29 of 60 (48%) tumors, close in 11 (18%), and infiltrated in 20 (33%). Tumors recurred in 27 of 60 (45%) animals, with a mean ± SD RFI of 229 ± 173 days. Recurrence rates for animals that had tumors with infiltrated (16/20) or close (8/11) margins were significantly higher than recurrence rate for animals that had tumors with clean margins (3/29). Margin classification was a significant predictor of RFI. Accuracy of the method to predict recurrence was 94% for carcinomas, 87% for STSs, and 76% for MCTs.
Conclusions and Clinical Relevance—Histologic assessment of margin status was useful for predicting local recurrence of cutaneous malignant tumors in dogs and cats treated by means of excision alone. Method accuracy varied among tumor types and grades. Recurrence times suggested postsurgical follow-up should continue for ≥ 2 years. Results were similar for animals with infiltrated and close tumor margins, and careful postsurgical management is recommended for both.
To determine an optimal time interval between amputation and initiation of adjuvant chemotherapy (TIamp-chemo) in dogs with appendicular osteosarcoma without distant metastases and whether TIamp-chemo was associated with outcome.
168 client-owned dogs treated at 9 veterinary oncology centers.
Data were collected from the dogs’ medical records concerning potential prognostic variables and outcomes. Dogs were grouped as to whether they received chemotherapy within 3, 5, 7, 10, 15, 20, 30, or > 30 days after amputation of the affected limb. Analyses were performed to identify variables associated with time to tumor progression and survival time after limb amputation and to determine an optimal TIamp-chemo.
Median TIamp-chemo was 14 days (range, 1 to 210 days). Median time to tumor progression for dogs with a TIamp-chemo≤ 5 days (375 days; 95% CI, 162 to 588 days) was significantly longer than that for dogs with a TIamp-chemo > 5 days (202 days; 95% CI, 146 to 257 days). Median overall survival time for dogs with a TIamp-chemo≤ 5 days (445 days; 95% CI, 345 to 545 days) was significantly longer than that for dogs with a TIamp-chemo > 5 days (239 days; 95% CI, 186 to 291 days).
CONCLUSIONS AND CLINICAL RELEVANCE
Findings indicated that early (within 5 days) initiation of adjuvant chemotherapy after limb amputation was associated with a significant and clinically relevant survival benefit for dogs with appendicular osteosarcoma without distant metastases. These results suggested that the timing of chemotherapy may be an important prognostic variable.