title: Evaluation of the effect of photodynamic therapy with hematoporphyrin monomethyl ether on VX2 tumors implanted in the rectal submucosa of rabbits.
abstract: We evaluated the influence of the photodynamic therapy (PDT) dosage with hematoporphyrin monomethyl ether (HMME) on its therapeutic efficacy in a rabbit model of in situ rectal cancer. VX2 cells were injected into the rectal submucosa of a rabbit to establish a carcinoma model in situ. After 10-14days, the tumors were treated with PDT at three dosages: a low dose (5mg/kg HMME; 60J/cm(2) laser power), intermediate dose (5mg/kg; 240J/cm(2)), and high dose (10mg/kg; 360J/cm(2)). Tumor growth, animal survival, histopathological changes, general conditions, and adverse reactions were analyzed. PDT showed inhibitive effects on rectal cancer in all PDT groups, and the efficacy was correlated with the PDT dosage. The high dose PDT group had the best efficacy with a remarkable response rate of 20% and slight response rate of 80%, but it also had the highest death rate of 80% at day 7. The intermediate dose PDT group had a total response rate of 80% (60% remarkable plus 20% slight) and a 40% death rate. Comparably, the low dose PDT group had a 40% slight response rate and 60% death rate. Therefore, the intermediate dose of PDT was considered to be optimal among the three groups. Based on endoscopy findings, we also found that high dose PDT presented more side effects including inflammation, intestinal obstruction, rectal dysfunction, and death when PDT was performed on tumors inside the rectal tract. Our results indicate that a moderate PDT dose is more appropriate to treat tumors located in tract or cavity tissues.
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Hao
authors: H
authors: Gao
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Lei
authors: L
authors: Shi
authors: Laboratory of Laser Medicine, Institute of Medical Engineering, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300192, China. Electronic address: yinzi490@163.com.
authors: Huijuan
authors: H
authors: Yin
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Honglei
authors: H
authors: Wang
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Jian
authors: J
authors: Shen
authors: Laboratory of Laser Medicine, Institute of Medical Engineering, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300192, China.
authors: Chao
authors: C
authors: Wang
authors: Laboratory of Laser Medicine, Institute of Medical Engineering, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300192, China.
authors: Qing
authors: Q
authors: Niu
authors: Laboratory of Laser Medicine, Institute of Medical Engineering, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300192, China.
authors: Yingxin
authors: Y
authors: Li
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Wen
authors: W
authors: Li
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Mo
authors: M
authors: Dong
authors: Tianjin People's Hospital, Tianjin 300191, China.
authors: Ying
authors: Y
authors: Lu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D006415:Hematoporphyrins / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D009092:Mucous Membrane / Q000473:pathology*; D010778:Photochemotherapy / Q000009:adverse effects / Q000379:methods*; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D019736:Prostheses and Implants; D011817:Rabbits; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology*; D016019:Survival Analysis; D047368:Tumor Burden / Q000187:drug effects / Q000528:radiation effects
chemical_list: D006415:Hematoporphyrins; D017319:Photosensitizing Agents; C494379:hematoporphyrin monomethyl ether
keywords: Effect evaluation; HMME; Photodynamic therapy; Rectal cancer; VX2 cell