Variability in tumor margin reporting for soft tissue sarcoma and cutaneous mast cell tumors in dogs: A systematic review

Abstract

To identify which classification systems have been used for tumor margin reporting and to determine whether factors (publication year, tumor type, and specialty of the contributing authors) influenced trends in margin reporting within literature describing canine soft tissue sarcoma (STS) and cutaneous mast cell tumors (MCT). Study design: Systematic literature review. Methods: Eligible articles were identified through electronic database searches performed for STS and MCT. Data abstracted from relevant studies included publication year, author list, specialty of contributing authors, criteria used to report the planned surgical margins, and the status of histologic margins. Categorization of papers was based on the classification systems used to report surgical and histologic tumor margins. Results: Fifty-three articles were included, 11 on STS, 37 on MCT, and five that included both tumor types. Criteria for classifying the planned surgical margins were described in only 50.9% of studies. Articles that listed a veterinary surgeon as a contributing author (P = .01) and STS articles compared to MCT papers (P = .01) were more likely to report surgical margins. Most (56.6%) studies reported the status of histologic margins dichotomously as "complete" or "incomplete." Although a previously published consensus statement recommended that quantitative criteria be used to report histologic margins, only 7.5% of articles used quantitative methods.

Outcome with surgical treatment of canine soft tissue sarcoma in the region of the ischiatic tuberosity: A veterinary society of surgical oncology retrospective study

“…Another large limitation of this study is the lack of standardized assessment and reporting of tumour margins. This is a well‐known controversy throughout the veterinary community with margin categorization and reporting being a topic of wide debate 50,51 with many different interpretations of how pathologists, surgeons and clinicians approach margin evaluation and use that information to guide therapy recommendations 52 . It is difficult to speak accurately about how therapeutic intervention affects long‐term prognosis and overall survival, let alone make treatment recommendations, when there is little agreement amongst the most influential players about what the final goal should be.…”

Surgical Margins in Canine Cutaneous Soft-Tissue Sarcomas: A Dichotomous Classification System Does Not Accurately Predict the Risk of Local Recurrence

“…Given the lack of standardization of histological margin assessment, it is difficult to compare the impact of histological margin width on LR after surgical excision observed in this caseload with previous studies on canine STS. A recent systematic literature review highlighted the variability of margin classification among studies [16], pointing out the application of different classification systems and arbitrary cut-offs for each category; of 11 papers dealing with STS, five applied a dichotomous and six a trichotomous classification system, with cut-offs varying between 0 to 10 mm to indicate complete margins and/or 1 to 3 mm for CbCM [16]. The assessment of the actual risk of LR based on the existing literature may be particularly challenging for STS excised with CbCM, considering that even in studies that apply a trichotomous system for histological margin classification, CbCM are arbitrarily included either in the tumor-free or infiltrated margin category for LR risk analysis [7,10,11,31].…”

“…A recent metanalysis on canine STS confirmed the impact of surgical margins on LR, with LR rates of 9.8% for STS with tumor-free margins and 33.3% with infiltrated margins, with a significantly lower risk of LR for STS excised with tumor-free margins (overall relative risk of 0.4) [7]. Consensus on margin assessment and reporting are still lacking for canine STS, with different studies considering different and arbitrary cut-offs for histologic safe margins and mostly without validated correlation with prognosis [5,7,[9][10][11][12][13][14][15][16].…”

“…The consensus statement of veterinary surgical pathologists by Kamstock and colleagues (2010) suggests the application of objective measurements of the distance between the tumor limits and the surgical tissue edges to objectively assess histological margins [17]. However, clinical studies on canine STS report the use of qualitative criteria for margin categorization, with dichotomous and trichotomous classifications being the most commonly used [13,16,17]. In the dichotomous system, histological margins are classified as tumor-free or infiltrated, while the trichotomous system embodies an additional intermediate category defined as "narrow" or "clean but close" margins (CbCM) [1,4,5,10,11,[18][19][20].…”

“…Additionally, cases included in the CbCM category are reported as being inconsistently at risk or not for LR [7,10,11]. Hence, identification of those dogs that may benefit from local adjuvant treatments to prevent LR following STS surgical excision is not straightforward in the instance of CbCM, with a high risk of under-or overtreatment [15,16].…”