title: Preventing bladder tumor implantation with photodynamic therapy in a rat model mimicking post-fluorescence guided transurethral resection.
abstract: OBJECTIVE
  Fluorescence guided transurethral resection has gained acknowledgment from the urological community and it is progressively becoming more applied. It has been shown to decrease the recurrence rate of nonmuscle invasive bladder cancer due to incomplete resection due to lack of visualization. The implantation of viable tumor cells seeded during transurethral resection is another reason for recurrence. We investigated whether applying photodynamic therapy on sensitized tumor cells would decrease the amount of viable intraluminal cells and tumor cell implantation.
  
  
  METHODS
  Two models were designed to mimic the situation after fluorescence guided transurethral resection, including partly or fully de-epithelialized bladders and circulating tumor cells loaded with protoporphyrin IX. Photodynamic therapy was performed. Controls consisted of no drug with no light, light only and drug only. Immediately after photodynamic therapy the intravesical contents were retrieved and clonogenic assays were performed on cells. Bladders were harvested 10 days after cell administration and subjected to pathological analysis.
  
  
  RESULTS
  In the photodynamic therapy and control groups tumor volume was proportional to the instilled cell load. Clonogenic assays showed that viable cells were decreased a tenth of the initial administered amount. Tumor implantation decreased to less than a fifth of control values.
  
  
  CONCLUSIONS
  Photodynamic therapy can effectively decrease the amount of viable tumor cells in the bladder lumen. This results in a significant decrease in tumor implantation. This technique could possibly be used to further decrease the recurrence rate of nonmuscle invasive bladder cancer.
authors.affiliation: Centre de Recherche en Automatique de Nancy, Nancy University, CNRS and Centre Alexis Vautrin, Vandoeuvre lès Nancy, France.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Berrahmoune
authors.forename: Lina
authors.initials: L
authors.lastname: Bezdetnaya
authors.forename: Agnès
authors.initials: A
authors.lastname: Leroux
authors.forename: François
authors.initials: F
authors.lastname: Guillemin
authors.forename: Marie Ange
authors.initials: MA
authors.lastname: D'Hallewin
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005453:Fluorescence; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D009366:Neoplasm Seeding; D010778:Photochemotherapy; D051381:Rats; D011916:Rats, Inbred F344; D001743:Urinary Bladder / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000601:surgery; D013520:Urologic Surgical Procedures / Q000379:methods