Analysis of factors influencing wound heaking complications following wide excision of feline injection site sarcomas of the trunk

Wide surgery is the mainstay of the multimodal treatment for injection site sarcomas (ISS) in cats.1 The deep infiltration of ISS in the surrounding tissues often force the resection of a wide area of cutis, subcutis, muscles and amputation of the underlying bony structures,1 making the subsequent reconstruction challenging. Only little data is available on post‐surgical complications.2,3 The aim was to analyze the clinical, peri‐operative, and histopathological factors influencing the development and timing of wound healing complications (WHC) in a homogenous sample population of cats undergoing wide excision of ISS located on the trunk. Inclusion criteria were: newly‐detected histologically confirmed ISS, tumor location on the trunk, no distant metastasis, no neo‐adjuvant treatment, wide excision planned using contrast‐enhanced computed tomographic (CT) examination and performed by the same surgeon, skin reconstruction by direct apposition of the skin edges or by local advancement flaps. The prognostic effect of covariates (sex, age, weight, body condition score (BCS), site, clinical dimension (CD), computed tomographic dimension (CTD length and width), histotype, duration of surgery, excision pattern, reconstruction pattern, surgical margin status, local anesthesia) on total (Cox model), major (Fine and Gray model) and minor (Fine and Gray model) WHC was evaluated by univariate and bivariate analysis. The relationship between duration of surgery and clinical and imaging variables was evaluated. Forty‐nine cats were enrolled. No factors were associated to minor WHC onset. The main factor associated to the risk of total and major WHC was surgical time. Based on univariate analysis, pattern of reconstruction, CDT, CD, weight and BCS were significant prognostic factors for major WHC, but this was not confirmed in bivariate analysis. The duration of surgery was influenced by excision pattern and tumor CTD width. Wide excision of ISS is unequivocally advocated to achieve a successful oncologic outcome taking the priority over any concern about WHC.1,2 However, a risk factor analysis on WHC is warranted because the development of postoperative morbidity affects the patients’ outcome, implies a financial impact on the owner and may affect the timing of adjuvant oncologic therapy. An increased surgical time as the consequence of complex surgical procedures represented the best predictor for the development of WHC.