Clinical outcome of dogs with grade-II mast cell tumors treated with surgery alone: 55 cases (1996–1999)

Bernard Séguin DVM, MS, DACVS1,2, Nicole F. Leibman DVM, MS, DACVIM3,4, Victoria S. Bregazzi DVM, MS, DACVIM5,6, Gregory K. Ogilvie DVM, DACVIM7, Barbara E. Powers DVM, PhD, DACVP8, William S. Dernell DVM, MS, DACVS9, Martin J. Fettman DVM, PhD, DACVP10, and Stephen J. Withrow DVM, DACVS, DACVIM11
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  • 1 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 2 Present address is the Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 3 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 4 Present address is Ultravet Diagnostics, 220 E Jericho Turnpike, Mineola, NY 11501.
  • | 5 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 6 Present address is the Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, 1352 Boyd Ave, St. Paul, MN 55108.
  • | 7 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 8 Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 9 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 10 Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
  • | 11 Comparative Oncology Unit, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.

Abstract

Objective—To determine outcome for dogs with grade-II mast cell tumors treated with surgery alone.

Design—Retrospective study.

Animals—55 dogs.

Procedures—Medical records were examined, and signalment; location and size of tumor; staging status; dates of local recurrence, metastasis, death, or last follow-up examination; status of surgical margins; previous surgery; postoperative complications; and cause of death were recorded. Follow-up information was obtained via reexamination or telephone conversations with owners or referring veterinarians. Univariate analysis was performed to identify prognostic factors.

Results—60 tumors in 55 dogs were included. Median follow-up time was 540 days. Three (5%) mast cell tumors recurred locally; median time to local recurrence was 62 days. Six (11%) dogs developed another mast cell tumor at a different cutaneous location; median time to a different location was 240 days. Three (5%) dogs developed metastases; median time to metastasis was 158 days. Fourteen dogs died; 3 deaths were related to mast cell tumor, and 7 were unrelated. The relationship with mast cell tumor was not known for 4. Median survival times were 151, 841, and 827 days, respectively, for these 3 groups. Forty-six (84%) dogs were free of mast cell tumors during the study period. A reliable prognostic factor could not be identified.

Conclusions and Clinical Relevance—Results suggest that additional local treatment may not be required after complete excision of grade-II mast cell tumors and that most dogs do not require systemic treatment. (J Am Vet Med Assoc 2001;218:1120–1123)

Abstract

Objective—To determine outcome for dogs with grade-II mast cell tumors treated with surgery alone.

Design—Retrospective study.

Animals—55 dogs.

Procedures—Medical records were examined, and signalment; location and size of tumor; staging status; dates of local recurrence, metastasis, death, or last follow-up examination; status of surgical margins; previous surgery; postoperative complications; and cause of death were recorded. Follow-up information was obtained via reexamination or telephone conversations with owners or referring veterinarians. Univariate analysis was performed to identify prognostic factors.

Results—60 tumors in 55 dogs were included. Median follow-up time was 540 days. Three (5%) mast cell tumors recurred locally; median time to local recurrence was 62 days. Six (11%) dogs developed another mast cell tumor at a different cutaneous location; median time to a different location was 240 days. Three (5%) dogs developed metastases; median time to metastasis was 158 days. Fourteen dogs died; 3 deaths were related to mast cell tumor, and 7 were unrelated. The relationship with mast cell tumor was not known for 4. Median survival times were 151, 841, and 827 days, respectively, for these 3 groups. Forty-six (84%) dogs were free of mast cell tumors during the study period. A reliable prognostic factor could not be identified.

Conclusions and Clinical Relevance—Results suggest that additional local treatment may not be required after complete excision of grade-II mast cell tumors and that most dogs do not require systemic treatment. (J Am Vet Med Assoc 2001;218:1120–1123)