Clinical photodynamic diagnosis and therapy efficiency in oropharyngeal cancer

Abstract

Objectives; We studied photodynamic diagnosis (PDD) and therapy (PDT) applicability using NPe6 in with oropharyngeal cancer patients. Methods; Of 11 subjects diagnosed with oropharyngeal cancer undergoing PDT and PDD using NPe6, 6 were stage T1 and 5 stage T2. None had nodal or distant metastases. Four hours before PDD, NPe6 (40 mg/m2) was injected intravenously. Under general anesthesia, tumor fluorescence observed by laser irradiation, and marked was followed by PDT and pho-tobleaching was confirmed. Tissue collected from tumor centers confirming NPe6 was then compared to normal tissue specimens and the relationship between NPe6 concentration and treatment effectiveness studied. Results; Tumor marking enabled us ensure a safety margin because the fluorescence scope exceeded tumor scope to the naked eye. Photobleaching was confirmed in all subjects. NPe6 tumor tissue concentration was 1.57-6.84 μg/g, with a ratio of 2.32-5.69 compared to normal tissue. Treatment achieved complete recovery (CR) in all subjects and shortened hospitalization over other treatment such as radiation. Conclusion; PDD using NPe6 clearly benefited oropharyngeal cancer patients, and made PDT more accurate. NPe6 accumulated more than twice the level in tumor tissue than in normal tissue.