title: Effective treatment of 7,12-dimethylbenz(a)anthracene-induced hamster buccal pouch precancerous lesions by topical photosan-mediated photodynamic therapy.
abstract: BACKGROUND
  Previous studies found that topical photodynamic therapy (PDT) is very effective for human oral precancerous lesions.
  
  
  METHODS
  This study evaluated whether topical photosan-mediated PDT (topical photosan-PDT), using a 640-nm light-emitting diode (LED) light, is an effective treatment modality for hamster buccal pouch precancerous lesions. Fourteen 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch precancerous lesions were treated with topical photosan-PDT using the 640-nm LED light twice a week.
  
  
  RESULTS
  All 14 of the precancerous lesions showed a complete histologically confirmed response to the lesions after an average of 3.79 (range, 3-5) PDT treatments. Normal and precancerous pouch mucosae in the other 4 hamsters received 17 or 19 treatments of topical photosan-PDT showed no cumulative side effects. No recurrence of the lesions was found in these 18 PDT-treated hamsters after a follow-up period of 50 weeks.
  
  
  CONCLUSIONS
  Our findings indicate that topical photosan-PDT is a very effective treatment modality for DMBA-induced hamster buccal pouch precancerous lesions.
authors.affiliation: Graduate Institute of Oral Biology and Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Chun-Pin
authors.initials: CP
authors.lastname: Chiang
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: Huang
authors.forename: Jeng-Woei
authors.initials: JW
authors.lastname: Lee
authors.forename: Yih-Chih
authors.initials: YC
authors.lastname: Hsu
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology*; D000287:Administration, Topical; D000818:Animals; D001707:Biopsy, Needle; D002610:Cheek / Q000473:pathology; D006224:Cricetinae; D004195:Disease Models, Animal; D006415:Hematoporphyrins / Q000008:administration & dosage*; D007150:Immunohistochemistry; D008297:Male; D009062:Mouth Neoplasms / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011230:Precancerous Conditions / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology*; D011897:Random Allocation; D012016:Reference Values; D013050:Spectrometry, Fluorescence; D016896:Treatment Outcome
chemical_list: D006415:Hematoporphyrins; D017319:Photosensitizing Agents; C071875:photosan III; D015127:9,10-Dimethyl-1,2-benzanthracene