34th Annual Scientific Meeting proceedings

Surgery after radiation therapy presents both opportunities and challenges for the oncologic surgeon. In many clinical scenarios, it allows for optimal tumour control by treating residual disease, surgery can manage and resolve radiation-induced complications, or enabling functional reconstruction for example oro-nasal fistulae. Irradiated tissues behave differently however, with altered healing potential, increased fibrosis, and vascular compromise. Timing and planning of surgical intervention are important to mitigate these effects.

Post-radiation surgery is most frequently indicated for residual or recurrent disease and wound healing complications. In feline injection-site sarcomas (FISS), radiation therapy plays a pivotal but controversial role. Pre-operative radiation can reduce tumour size and sterilize the reactive zone, improving resectability. However, it also increases surgical morbidity, including poor wound healing and fibrosis. Post-operative radiation avoids immediate healing issues but may be associated with a broader treatment field. There is inherent difficulty in defining microscopic disease, making precise CT-guided planning essential.

In nasal tumours, radiotherapy is often the primary treatment of choice due to complex anatomy and frequent bilateral involvement. Stereotactic radiation therapy or conventional fractionated radiation can offer disease control with minimal disruption to function. In patients with partial response or ongoing clinical signs, surgery—via dorsal or ventral rhinotomy—may follow radiation to debulk residual disease or alleviate obstruction. Ventral approaches offer better cosmetic outcomes but have the risk of a non-healing oral wound, while dorsal rhinotomy provides improved access to the frontal sinuses, and arguably less critical side-effects.

This hybrid approach is not limited to the nasal cavity. In skull-based and axial bone tumours, stereotactic radiation can precede surgical resection. In some cases, surgeons can dissect directly through previously irradiated tumour to gain local control. While en bloc margins may not be achievable, the combination of cutting through sterilised cancer in the most anatomically critical areas improves outcomes over either modality alone. These cases highlight the need for careful preoperative imaging, collaboration between surgical and radiation oncologists, and long-term treatment planning.

In human oncology, the rationale for integrating surgery with radiation is well described. Pre-operative radiation in soft tissue sarcomas has been shown to reduce tumour burden and improve resectability while minimising late toxicity. Similar principles apply in veterinary settings, though logistical and financial constraints often dictate treatment order.

Surgeons should be prepared for the management of radiation-related complications. When operating in previously irradiated fields, careful flap planning, robust soft tissue coverage, and strict aseptic technique are essential.

Overall, the integration of surgery and radiation therapy, before, after, or in tandem, offers flexibility and potentially superior oncologic outcomes. Case selection, surgical precision, and interdisciplinary collaboration with radiation oncologists are vital to ensure success.