2024 article
Use of Cystourethroscopy to Define the Gross Tumour Volume in Radiation Treatment Planning for Canine Genitourinary Carcinomas
Freemyer, C. C., Gieger, T. L., Vaden, S. L., & Nolan, M. W. (2024, September 23). VETERINARY AND COMPARATIVE ONCOLOGY.
author keywords: canine genitourinary carcinoma; cystourethroscopy; gross tumour volume (GTV); radiotherapy (RT)
UN Sustainable Development Goal Categories
3. Good Health and Well-being
(OpenAlex)
Source: Web Of Science
Added: September 30, 2024
ABSTRACT Radiotherapy (RT) is increasingly utilised for definitive‐intent treatment of canine genitourinary carcinomas (CGUC). At our institution, the standard approach is to irradiate tomographically abnormal tissues gross tumour volume (GTV) plus a clinical target volume (CTV) expansion of 2 cm. Cystourethroscopy is often incorporated into the treatment planning workflow, though an optimal approach has yet to be defined. This observational study evaluated cystourethroscopy as a tool for identifying gross lesions that can be targeted with RT. We hypothesised that in most cases, addition of cystourethroscopy would result in a larger GTV than would be drawn with computed tomography (CT) alone. Medical records from 54 dogs diagnosed with CGUC between 2013 and 2023 were reviewed; each had been evaluated before RT using CT and cystourethroscopy. The GTV was initially defined as the tomographically evident disease on a post‐contrast sagittal plane CT scan, and then lesions visualised with cystourethroscopy (suspected or confirmed to be tumour) were added. Beyond what was visible on CT, cystourethroscopy extended the GTV by a median of 6.5 cm distally into the urethra (range: 1.5–31.8 cm) and therefore resulted in GTV enlargement in 26 of 54 (48%) cases. Addition of our standard 2 cm CTV expansion to a CT‐defined GTV (without use of data from cystourethroscopy) would have underestimated the extent of grossly abnormal tissue in 35% (19/54) of cases. These results suggest that incorporating cystourethroscopy into treatment planning workflows may improve local tumour control by reducing the risk of a geographic miss.