Surgical margins in the veterinary cancer patient

Abstract

In veterinary oncologic specimens, histopathology is the gold standard for determining adequacy of excision. Despite limitations of this technique, the pathologist's interpretation of margin status significantly impacts patient management, including indications for adjuvant therapy. This article aims to summarize peer-reviewed literature as it relates to histologic margin evaluation in veterinary cancer patients. The value of histologic tumour-free margins and technical factors influencing histopathologic margin outcomes are also discussed. We review alternative strategies for determining excisional status, and discuss how an evolving understanding of tumour biology might inform clinical and research perspectives on surgical margins. In doing so, we aim to provide context and a stimulus for future investigations into this important yet incompletely understood topic.

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

“…The observation that risk of local recurrence was reduced, but not eliminated, with complete excision reflects the imperfect accuracy of histopathology in predicting clinical outcomes for these patients. This finding can be at least partially understood by examination of technical limitations and biological factors, as previously summarized . When interpreting histopathology reports indicating microscopically incomplete excision of cutaneous and subcutaneous STS in dogs, it is important to balance the increased risk for local recurrence against the observation that two‐thirds of incompletely excised tumours did not recur.…”

“…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 . By including data from 10 different studies, the results of the present analysis should be representative across common histopathological methodologies.…”

“…Success of surgical resection in achieving complete removal of the tumour is evaluated through histopathology of the excised specimen using light microscopic examination of tissue sections trimmed from the surgical margins . Despite limitations of this methodology, completeness of excision has been suggested to be protective against local tumour recurrence and disease‐specific survival . However, lack of clinical recurrence despite presence of neoplastic cells at the surgical margin (ie, incomplete excision) has been documented in many of these same reports.…”

Fibrosarcoma oral de bajo grado histológico y elevada agresividad biológica: reporte de un caso

“…Há de se considerar, no entanto, que relatos de recorrência tumoral em tumores mesenquimais, apesar de uma ressecção histologicamente completa, bem como de tumores que não recidivaram mediante excisão incompleta, são encontrados na literatura e na prática clínica (Milovancev & Russel, 2017).…”

“…Ademais, Milovancev & Russel (2017), corroborando com a proposição, aduziram que a recorrência, pode estar intrinsecamente relacionada aos conceitos de campo de cancerização, heterogeneidade intratumoral e microambiente tumoral.…”