ABSTRACT
Early detection of cancer can enhance the probability of successful therapy. The recurrence of cancer after photodynamic therapy is shown for 57 early-stage carcinomas of the pharynx, esophagus, and tracheobronchial tree. Follow-up ranges from 6 months to 7 years. These results were obtained using either 3 mg/kg hematoporphyrin derivative or 2 mg/kg Photofrin II, with light exposure 72 hr after intravenous (i.v.) injection [60- to 150-J/cm2 continuous wave (CW) light at 630 nm]. The observed kinetics will be correlated in the future, among other parameters, with the staging of the early cancer, in particular, with its degree of vascularization. When autofluorescence measurements, as a function of excitation wavelength, are performed, a cube beam splitter replaces the dichroic mirror, and a rotating filter wheel with the selected barrier filters for the excitation light is used. This allows quick changes of the excitation wavelength.
