Page 443 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 22 Soft Tissue Sarcomas 421

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A B

C D

E
• Fig. 22.16 Aggressive resection of injection-site sarcomas, with 5-cm lateral margins and one to two
uninvolved fascial layers for deeps margins, is required for the best opportunity for complete histologic
excision and local tumor control. (A) Planned lateral surgical margins are indicated with a sterile marker
pen 5 cm in all directions around an interscapular injection-site sarcoma. (B) An incision is then performed
along the marked margins, and continued deeply to include two uninvolved fascial layers. (C) In this cat,
ostectomy of the dorsal spinous processes was performed with bone cutters to achieve deep surgical
margins and compartmental resection of the injection-site sarcoma. (D) The wound defect after these
aggressive wide resections can be large, but primary closure is almost always achievable (E).

neoadjuvant chemotherapy with three doses of epirubicin fol- postoperative RT results in better rates of local tumor control than
lowed by compartmental resection of interscapular ISSs resulted more conservative surgical approaches alone. 213,232–236
in an overall local recurrence rate of 14% in 21 cats after a median In two studies investigating preoperative RT, local tumor recur-
follow-up time of 1072 days. 229 rence was reported in 40% to 45% of cats at a median of 398 to
584 days postoperatively. 232,234 In both studies, complete resection
Surgery and Radiation Therapy significantly improved the time to local recurrence, with a 700- to
Although aggressive surgical resection is recommended for the 986-day median DFI for completely excised tumors and 112- to
management of cats with ISSs, this may not always be feasible. 292-day median DFI for tumors resected with incomplete mar-
In these cases, multimodality therapy with either preoperative or gins. 232,234 However, complete resection after preoperative RT does