Laparoscopically implanted tissue expander radiotherapy in canine transitional cell carcinoma.

Area of Science:

• Veterinary Oncology
• Radiation Oncology
• Surgical Innovation

Background:

• External beam radiotherapy for intraabdominal tumors is limited by organ motion and adjacent structure injury.
• Minimizing radiation dose to critical organs like the colon is crucial for effective treatment of bladder tumors.

Purpose of the Study:

• To evaluate the efficacy and safety of Laparoscopically Implanted Tissue Expander Radiotherapy (LITE-RT) for treating canine urinary bladder transitional cell carcinoma (TCC).
• To assess the ability of LITE-RT to exclude the colon from the radiation field during helical tomotherapy for bladder TCC.

Main Methods:

• Two dogs with histologically confirmed bladder TCC underwent LITE-RT using a custom-shaped tissue expander placed between the colon and bladder.
• Helical tomotherapy delivered 45 Gy in 18 fractions, with volumetric megavoltage computed tomography used for interfractional repositioning.
• Tumor response and normal tissue effects were monitored via cystoscopy and colonic biopsies post-treatment.

Main Results:

• LITE-RT resulted in a mean dose reduction to the colon of 53% and 31% in the two dogs.
• No clinical signs of chronic colitis or enteritis were observed; however, mild cystitis occurred during treatment.
• Complications included tissue expander detachment requiring reoperation in both dogs and bladder rupture in one dog.

Conclusions:

• LITE-RT demonstrates potential for treating canine bladder TCC by significantly reducing radiation dose to the colon.
• The technique showed a lack of acute colitis and enteritis, suggesting a favorable safety profile for adjacent organs.
• Despite some complications, LITE-RT offers a promising approach for improving radiotherapy outcomes in canine bladder cancer.