Comparison of histologic margin status in low‐grade cutaneous and subcutaneous canine mast cell tumours examined by radial and tangential sections

Abstract

These data indicate that for low grade MCTs, HTFMs >0 mm should not be considered completely excised, particularly when HTFM is <10.9 mm. This will inform future studies that use HTFM and overall excisional status as dependent variables in multivariable prognostic models.

Influence of surgical margin completeness on risk of local tumour recurrence in canine cutaneous and subcutaneous soft tissue sarcoma: A systematic review and meta‐analysis

“…Finally, variation among pathologists in how surgical margins were microscopically assessed for completeness of excision almost certainly represents an uncontrolled variable in the analysis. For example, commonly used trimming methods, such as radial sectioning, evaluate minimal margin tissue and alternatives such as tangential section are more likely to detect incomplete tumour resection . Additional details regarding the potential influence of tissue specimen trimming and sectioning methods on the interpretation and results of surgical margins in veterinary cancer patients are available .…”

“…The subgroup analysis focusing on excision of primary tumours (ie, excluding re-excisions) was planned a priori to evaluate for the poten- For example, commonly used trimming methods, such as radial sectioning, evaluate minimal margin tissue and alternatives such as tangential section are more likely to detect incomplete tumour resection. 27,28 Additional details regarding the potential influence of tissue specimen trimming and sectioning methods on the interpretation and results of surgical margins in veterinary cancer patients are available. 5 By including data from 10 different studies, the results of the present analysis should be representative across common histopathological methodologies.…”

Histologic margins and the residual tumour classification scheme: Is it time to use a validated scheme in human oncology to standardise margin assessment in veterinary oncology?

“…In one meta‐analysis of cutaneous and subcutaneous STSs in dogs, the overall local recurrence rate was 9.8% following complete histologic excision, defined as a HTFM >0 mm, in the 10 included studies . However, as discussed previously, the histologic assessment of the completeness of excision in all planes can be highly flawed …”

“…In one study, incomplete histologic excision was diagnosed in 49% of samples sectioned using a tangential technique, but only 15% of samples sectioned using a radial technique following breast conserving surgery for breast cancer . In a study of low grade and subcutaneous canine MCTs, incomplete histologic margins were detected in a significantly higher proportion of samples sectioned using a tangential technique compared with a radial technique; 23.1% of margins classified as complete (HTFM >0 mm) on radial sections were reclassified as incomplete on tangential sections. While tangential sectioning provides superior assessment of the completeness of histologic excision to other sectioning techniques, which are described in detail elsewhere, the entire surface area of the tumour is not examined (32.6% in one study following breast conserving surgery for breast cancer) and the width of the HTFMs cannot be assessed .…”

“…80 However, as discussed previously, the histologic assessment of the completeness of excision in all planes can be highly flawed. 26,39,84 The majority of commercial veterinary laboratories use a radial sectioning technique to evaluate surgical margins. This involves bisecting the tumour through its shortest axis and then each half is bisected along its longest axis, resulting in four quarters.…”