Post‐operative complications following apocrine gland anal sac adenocarcinoma resection in dogs

Abstract

Describe the complications associated with surgical resection of primary apocrine gland anal sac adenocarcinoma (AGASACA) tumours study design multi-institutional retrospective cross-sectional cohort study Animals Client owned dogs with spontaneous disease using the Clavien-Dindo classification system, post-operative events were assigned and described. Logistic regression analysis was used to analyse for risk factors for a significant association with complications. One hundred sixty-one dogs were included in the analysis. The post-operative sequelae, complication, and failure to cure rates specific to the anal sac site was 14%, 17% and 1%, respectively. The majority (68%) of complications were grade II or higher, therefore requiring some form of intervention. Intra-operative complications were identified in 11 cases (7%) with anorectal wall perforation being most common. An intra-operative complication was significantly associated with post-operative complications (p < 0.001; OR 7.4) while anorectal wall perforation was the only significant risk factor on regression analysis (p < 0.001; OR 19). Surgical site infection was identified in 20 of 161 (12%) of cases. Local recurrence (LR) occurred in 18% of cases at a median of 374 days (95% CI: 318-430). The only risk factor significantly associated with LR was the presence of vascular or lymphatic invasion (p = 0.008; OR 3). Post-operative complications were relatively infrequent but the risk was significantly increased when there was an intraoperative complication during resection of a primary AGASACA tumour.This study provides information for the clinician regarding risk factors for postoperative complications.

Canine anal sac gland carcinoma with regional lymph node metastases treated with sacculectomy and lymphadenectomy: Outcome and possible prognostic factors

“…This improvement provided by radiation therapy could stem from the treatment of microscopic disease on the primary tumour site. Indeed, in our study, 66% of dogs had incomplete excision of the primary tumour and the risk of local recurrence has recently been associated with incomplete margins in ASGC 56 . As suggested in many humans carcinomas with positive histological margins, 57,58,59 post‐operative radiation therapy can be beneficial to decrease the risk of local recurrence and this is likely to be true in ASGC.…”

“…Indeed, in our study, 66% of dogs had incomplete excision of the primary tumour and the risk of local recurrence has recently been associated with incomplete margins in ASGC. 56 As suggested in many humans carcinomas with positive histological margins, 57,58,59 postoperative radiation therapy can be beneficial to decrease the risk of local recurrence and this is likely to be true in ASGC. This is suggested in the study by 63,64 Alternatively, the high rate of locoregional failure documented in our study could also suggest that the surgical technique could be improved, including a more aggressive excision of the primary tumour and a more thorough dissection of the sublumbar and pelvic LNs as is commonly performed in humans with urologic, 65 gynaecologic 66 and, to a lesser degree, rectal cancers.…”

Near‐infrared fluorescent image‐guided lymph node dissection compared with locoregional lymphadenectomies in dogs with mast cell tumours

“…Complications were classified as intra-or postoperative. Postoperative complications were further divided by a scheme proposed by Dindo et al (2004) (Follette et al 2020, Sterman et al 2021. A complication was defined as "any deviation from the standard postoperative course".…”

“…A complication was defined as "any deviation from the standard postoperative course". Complications were graded as follows: Grade I, no need of therapeutic intervention, excluding pharmacologic treatment with antiemetics, antipyretics, analgesics, diuretics, electrolytes; Grade II, pharmacologic treatment, blood transfusion, parenteral nutrition; Grade III, surgical, radiologic or endoscopic treatment without (a) or with general anaesthesia (b); Grade IV, live threatening complications or intensive care with single (a) or multi-organ dysfunction; grade V, death of the patient (Dindo et al 2004, Follette et al 2020, Sterman et al 2021.…”

Quantification of Canine Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) Tumor Specimen Shrinkage after Formalin Fixation

“…In this case, accounting for the amount of connective tissue shrinkage around a tumor can then be utilized to calculate the optimal amount of unfixed tissue required to ensure a safety zone of resection and in theory would have more bearing on the overall local control rate [ 15 ]. This is not so in AGASACA tumors where the extent of resection is always limited by anatomy and no study to date has proven that histologic margin is predictive of outcome [ 27 ]. Nevertheless, as a surrogate indicator, we analyzed if there was a difference between those tumors that were resected with a complete margin (R0) versus those that were resected incompletely (R1).…”