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

Abstract

The aim of this study was to determine the outcome of dogs with soft tissue sarcoma (STS) within the region of the ischiatic tuberosity (ITSTS) treated surgically. This was a multi‐institutional retrospective study. Fifty‐two dogs met the inclusion criteria, which were: histologically confirmed STS in the region of the IT treated with surgical resection between March 1st, 2009 and March 1st, 2021 with a minimum follow‐up time of 6 months. Data collected included patient signalment, preoperative diagnostics, surgical intent/method, surgical complications, histopathology, margins, outcome and cause of death. Statistical analyses were performed to determine significant factors in the treatment and prognosis of ITSTS. Overall survival time (OST) and disease progression were negatively associated with tumour grade, while recurrence was positively associated with grade and incomplete margins. Of the 52 included dogs, there were 24 grade I, 20 grade II and 7 grade III tumours. Forty dogs had reported histopathologic margins of which 26 were reported to be complete and 14 were incomplete. OST and progression‐free survival was not reached for tumours graded as I or II and was 255 and 268 days respectively, for grade III. Median time to recurrence was not reached for tumours excised with complete margins and was 398 days for those with incomplete margins. The surgical complication rate was 25%. ITSTS was not found to be a unique clinical entity in dogs as tumour behavior, treatment recommendations, and prognosis were similar to STS in other locations, with overall outcome and prognosis influenced by histologic grade and margins. While surgical complications were common, none resulted in significant morbidity or mortality.

Integrated analysis of canine soft tissue sarcomas identifies recurrent mutations in TP53, KMT genes and PDGFB fusions

“…MAP kinase pathway activation was only observed in clusters H2-H4 with 90% of the grade III tumors. Although prognosis for this cancer is improved by surgical intervention, overall survival of dogs with grade III tumors is poor compared to dogs with grade I tumors 46 . Thus, the molecular and genetic driver characterization of canine STS subtypes may aid in diagnosis and the identification of novel therapies that improve the outcomes for canine and human patients with recurrent or metastatic disease.…”

Integrated analysis of canine soft tissue sarcomas identifies recurrent mutations inTP53, KMTgenes andPDGFBfusions

“…MAP kinase pathway activation was only observed in clusters H2-H4 with 90% of the grade III tumors. Although prognosis for this cancer is improved by surgical intervention, overall survival of dogs with grade III tumors is poor compared to dogs with grade I tumors (58). Thus, the molecular and genetic driver characterization of canine STS subtypes may aid in diagnosis and the identification of novel therapies that improve the outcomes for canine and human patients with recurrent or metastatic disease.…”

Fascial plane mapping for superficial tumor resection in dogs. Part III: Hindlimb and pelvis

“…This concern is supported by a recent study documenting that over a third of attempted wide excisions of ischial tuberosity soft tissue sarcoma failed to achieve histologically complete margins. 10 Given the paucity of previous work describing options for excision in the region, it is possible that some surgeons may not have been aware of the qualities of tissues deep to their target lesion, resulting in a failure to achieve an anticipated effective fascial plane, with subsequent compromise of resection margins. As such, some patients may benefit from a planned limited resection to minimise morbidity, with adjuvant therapy if indicated.…”

“…While the exposed ischium at the caudal pelvis could be managed with partial ischiectomy for maintenance of a fascial plane, the thin fascia at the ischiorectal fossa and challenging intersections involved with genitalia may still result in a complex and morbid resection with a higher risk of incomplete excision. This concern is supported by a recent study documenting that over a third of attempted wide excisions of ischial tuberosity soft tissue sarcoma failed to achieve histologically complete margins 10 . Given the paucity of previous work describing options for excision in the region, it is possible that some surgeons may not have been aware of the qualities of tissues deep to their target lesion, resulting in a failure to achieve an anticipated effective fascial plane, with subsequent compromise of resection margins.…”