The treatment effect and adverse reactions of PDT on rabbits with rectal cancer in-situ / 国际生物医学工程杂志

ABSTRACT

Objective To evaluate the influence of dosage,operation method,adverse reaction of endoscopic photodynamic therapy (EPDT) on its therapeutic efficacy in rabbit models of in-situ rectal cancer,so as to provide preclinical basis of photodynamic therapy for rectal cancer.Methods 20 rabbits with in-situ VX2 rectal cancer were randomly divided into control group,PDT low dose group,intermediate dose group,and high dose group.At 24 h before PDT,photosensitizer (hermimether) was intravenously injected into rabbits.630 nm semiconductor laser was used as light source.The growth of the tumor was observed by conventional endoscopy and endoscopic ultrasonography,and the survival time,general conditions and adverse reactions were recorded.The histopathological changes were observed by hematoxylin-eosin staining.Results At 7 d after PDT,the total response rates of low dose,intermediate dose and high dose group respectively were 40％ (slight),80％ (60％ remarkable and 20％ slight),100％ (20％ remarkable and 80％ slight).The average survival times of the three groups were 14 d,10 d and 5 d,respectively.The main adverse reactions were inflammation,intestinal obstruction,intestinal peristalsis loss and death.Conclusions The dosage of PDT is an important factor to influence the curative effect.The appropriate dose of PDT will have a better effect on the treatment of rectal cancer.A thorough study of these problems is helpful to the clinical application of PDT in the treatment of rectal cancer.