title: Evaluation of a modified proportional margins approach for surgical resection of mast cell tumors in dogs: 40 cases (2008-2012).
abstract: OBJECTIVE
  To evaluate a modified proportional margins approach to resection of mast cell tumors (MCTs) in dogs.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  40 dogs with subcutaneous and cutaneous MCTs undergoing curative intent surgery.
  
  
  METHODS
  Medical records were searched to identify dogs with a cytologically or histologically confirmed diagnosis of MCT that had not previously been treated surgically and that had undergone full oncological staging. In those dogs, tumors were resected with lateral margins equivalent to the widest measured diameter of the tumor and a minimum depth of 1 well-defined fascial plane deep to the tumor. Surgical margins were evaluated histologically. Cutaneous tumors were graded by use of the Patnaik system and the 2-tier system described by Kiupel et al. The prognosis for subcutaneous tumors was assessed in accordance with published recommendations. Follow-up information on dog health status was obtained through clinical examination, the dog owners, and the referring veterinarians.
  
  
  RESULTS
  The 40 dogs had 47 tumors. Forty-one (87%) tumors were cutaneous, and 6 (13%) were subcutaneous. On the basis of the Patnaik system, 21 (51%) cutaneous tumors were considered grade I, 18 (44%) were considered grade II, and 2 (5%) were considered grade III. On the basis of the Kiupel system, 37 (90%) cutaneous tumors were considered low grade, and 4 (10%) were considered high grade. The prognosis for the 6 subcutaneous tumors was classified as likely resulting in a shorter (2) or longer (4) survival time. Forty tumors were deemed to have been excised with clear margins and 7 with incomplete margins. Local recurrence was not recorded for any dog but was suspected for 1 (2%) tumor, although not confirmed. Interval from tumor excision to follow-up ranged from 30 to 1,140 days (median, 420 days).
  
  
  CONCLUSIONS
  The modified proportional margins system resulted in satisfactory local disease control in dogs with MCTs.
authors.affiliation: School of Veterinary Medicine, College of Medical and Veterinary Life Sciences, University of Glasgow, Glasgow, G61 1QH, Scotland.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Pratschke
authors.forename: Matt J
authors.initials: MJ
authors.lastname: Atherton
authors.forename: Jack A
authors.initials: JA
authors.lastname: Sillito
authors.forename: Catherine G
authors.initials: CG
authors.lastname: Lamm
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D006801:Humans; D034701:Mastocytosis, Cutaneous / Q000601:surgery / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000662:veterinary; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000601:surgery / Q000662:veterinary*; D016896:Treatment Outcome