Comparison of photodynamic therapy with phthalocyanine and photofrin in human colorectal carcinoma.

Photodynamic therapy (PDT) has been developed in recent years as a new modality for the treatment of various neoplastic and non-neoplastic lesions. Although the method of combining light with photosensitizers for treatment has been around for a century, further understanding has been evolved over the past decades. The method is based on the phenomenon involving the combination of photosensitizer and light. Neither drug nor light alone are effective as therapeutic agents. The antitumour effects result from direct cell damage, destruction of tumor vasculature and activation of a nonspecific immune response. The more accepted use of PDT is still restricted for ophthalmology, dermatology and treatment of some stages of esophageal, lung and urinary bladder cancer. In our experiments, the effect of phototherapy with disulfonated hydroxyaluminium phthalocyanine (Al(OH)S2Pc) and photofrin (control group) on the growth of human colorectal carcinoma on nude mice was studied. We chose colorectal carcinoma, because the Czech population has the highest incidence and it is still increasing. We try to offer a new possibility of treatment for patients with this severe disease.