Preclinical evaluation of 5‐aminolevulinic acid‐based photodynamic therapy for canine transitional cell carcinoma

Abstract

As a prelude to photodynamic therapy, 5-aminolevulinic acid (ALA) was given orally to healthy dogs. ALA-induced protoporphyrin IX (PpIX) fluorescence significantly increased in the mucosa of the urinary bladder in an ALA dose-dependent fashion. Vomiting occurred after ALA administration in 70% of the dogs but did not affect PpIX fluorescence. ALA-based photodynamic therapy (PDT) of the urinary bladder in healthy dogs caused only submucosal oedema within the bladder wall. No haematologic or serum biochemistry abnormalities were observed after ALA administration. Microscopic haematuria was observed in all the dogs after PDT but was mild and self limiting. ALA-based PDT was administered to six dogs with transitional cell carcinoma (TCC) of the lower urinary tract. ALA-based PDT resulted in tumour progression-free intervals from 4 to 34 weeks in five dogs; one dog with pre-existing hydronephrosis died shortly after PDT. Dogs with TCC represent an outbred, spontaneous, tumour model for developing PDT protocols for humans with bladder cancer.

Vinorelbine rescue therapy for dogs with primary urinary bladder carcinoma

“…Three‐dimensional ultrasonography may provide more accurate measurements of bladder tumours than 2D ultrasonography, however, the availability of this modality is currently very limited . Therefore the use of 2D AUS as the primary method of monitoring bladder tumour response to various treatments is common both in clinical practice and in the recent veterinary literature . Improvements in tumour burden and clinical status based on AUS and client recall were encouraging in this study; however, standardized objective tumour measurements would be ideal, despite increased effort and cost.…”

Tumors of the Urinary System

“…If other drugs have failed and a given patient does not have other options, then the clinician and pet owner would need to carefully consider the risk versus potential benefit before deciding to use intravesical therapy. 66 In five dogs with TCC treated with ALA-based PDT, the progression-free interval ranged from 4 to 34 weeks (median was 6 weeks). Experimentally, paclitaxel gelatin nanoparticles have been delivered intravesically to dogs with TCC, but this approach is not in routine use.…”

Evaluation of cisplatin administered with piroxicam in dogs with transitional cell carcinoma of the urinary bladder

“…1,2 Numerous treatments for urinary bladder TCC in dogs have been evaluated including surgery, radiation therapy, photodynamic therapy, and chemotherapy. [3][4][5] Surgical intervention has been largely unrewarding because of the typical trigonal tumor location (where complete resection is not possible) and the potential for metastatic and recurrent disease. 2,4 Full-course and intraoperative radiation therapy can be effective against TCC, but urinary bladder fibrosis, urinary incontinence, cystitis, and toxic effects in surrounding organs have been common posttreatment complications.…”