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

Abstract

The present peer‐reviewed veterinary literature contains conflicting information regarding the impact of surgical margin completeness on risk of local tumour recurrence in canine soft tissue sarcoma (STS). This systematic review and meta‐analysis was designed to answer the clinical question: “Does obtaining microscopically tumour‐free surgical margins reduce risk for local tumour recurrence in canine cutaneous and subcutaneous STS?” A total of 486 citations were screened, 66 of which underwent full‐text evaluation, with 10 studies representing 278 STS excisions ultimately included. Cumulatively, 16/164 (9.8%) of completely excised and 38/114 (33.3%) of incompletely excised STS recurred. Overall relative risk of 0.396 (95% confidence interval = 0.248‐0.632) was calculated for local recurrence in STS excised with complete margins as compared to STS excised with incomplete margins. Risk of bias was judged to be low for all studies in terms of selection bias and detection bias but high for all studies in terms of performance bias and exclusion bias. The results of the present meta‐analysis, coupled with the results of individual previous studies, strongly suggest that microscopically complete surgical margins confer a significantly reduced risk for local tumour recurrence in canine STS. Future studies ideally should adhere to standardized conducting and reporting guidelines to reduce systematic bias.

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?

“…Local recurrence rates of 3% to 22% have been reported following complete histologic excision of cutaneous and subcutaneous STSs, 2% of dogs with subcutaneous MCTs, and 2% to 11% of dogs with low‐grade cutaneous MCTs, and 36% of high‐grade cutaneous MCTs . 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 …”

“…Logistically, local tumour recurrence may be missed because follow‐up times may be inadequate in some studies. This has been recognized as a design flaw with one recent meta‐analysis of margins and STSs in dogs only including studies with a minimum of 2 years follow‐up …”

“…For dogs with subcutaneous or cutaneous STSs, local recurrence rates of 17%, 19% and 28% have been reported following incomplete histologic excision. In a systematic review and meta‐analysis of the impact of the completeness of histologic excision on local tumour recurrence in dogs with subcutaneous or cutaneous STSs, complete histologic excision was defined as a HTFM >0 mm and studies which included close histologic margin terminology were considered completely excised. Ten studies were included in this meta‐analysis with a total of 278 STS surgical resections with a minimum follow‐up time of 2 years; the local recurrence rates for completely and incompletely excised STSs were 9.8% and 33.3%, respectively .…”

“…In a systematic review and meta‐analysis of the impact of the completeness of histologic excision on local tumour recurrence in dogs with subcutaneous or cutaneous STSs, complete histologic excision was defined as a HTFM >0 mm and studies which included close histologic margin terminology were considered completely excised. Ten studies were included in this meta‐analysis with a total of 278 STS surgical resections with a minimum follow‐up time of 2 years; the local recurrence rates for completely and incompletely excised STSs were 9.8% and 33.3%, respectively . In one study of 236 marginally excised subcutaneous STSs, the local recurrence rate was 0% following complete histologic excision and dependent on histologic grade if incompletely excised with local recurrence rates of 7%, 34% and 75% in dogs with incompletely excised grade I, II and III STSs, respectively; however, the minimum follow‐up time in this study was only 12 months.…”

Emerging therapeutic approaches for canine sarcomas: Pushing the boundaries beyond the conventional

“…Treatment of canine soft tissue sarcomas is largely similar to treatment in humans, with surgery, radiation therapy (RT) and chemotherapy providing the underlying platform for both species . Surgical resection with complete histologic margins is the treatment of choice for soft tissue tumours and yields long‐term control in many paediatric and canine patients; incomplete margin status is associated with a high likelihood of tumour recurrence . In dogs, wide excision is recommended and local tumour recurrence is more likely following conservative excision, with high‐grade or undifferentiated tumours more likely to recur .…”