Evaluation of the Tumor Bed Biopsy Technique in Canine and Feline Oncologic Surgery

Introduction
The objective of this preliminary retrospective study was to establish the feasibility, advantages and limitations of the tumour bed biopsy technique as an adjunct to the standard vertical sectioning technique for histopathologic margin assessment in small animal oncologic surgery.

Materials and Methods
The veterinary histopathology database of the University of Cambridge was searched for cases in which tumor bed biopsies had been submitted in addition to an excised neoplasm between 2002 and 2013. The surgical margins on the vertical sections cut from the main piece of tissue excised are termed ‘main margins’ for the purposes of this study. Data retrieved for each case included species, tumour diagnosis, whether or not neoplastic cells were evident in the main margins, whether or not neoplastic cells were evident in the tumor bed biopsy/biopsies, surgeon and pathologist.

Results
Sixty-one cases met the inclusion criteria including 12 cats and 49 dogs. Main margin assessment agreed with tumour bed biopsy assessment in 85.2% of cases (52/61), with both being free of neoplastic cells in 70.5% of cases (43/61), and both containing neoplastic cells in 14.8% of cases (9/61). Of the 14.8% of cases (9/61) in which the main margin assessment disagreed with the tumour bed biopsy assessment, neoplastic cells were identified in the main margins but not the tumour bed biopsies in 9.8% of cases (6/61). This left 4.9% of cases (3/61) in which neoplastic cells were identified in the tumour bed biopsies but not the main margins.  [...]