Basic and clinical research on photodynamic therapy at Tokyo Medical University Hospital.

BACKGROUND AND OBJECTIVES: We have been engaged in basic and clinical research on photodynamic therapy (PDT) and photodynamic diagnosis (PDD) for more than 25 years. STUDY DESIGN/MATERIALS AND METHODS: PDT for 264 centrally located early-stage lung cancer lesions yielded an initial complete response (CR) rate of 84.8%. PDT is now becoming a standard option for centrally located stage 0 (TisN0M0) and stage I (T1N0M0) lung cancer. It is an attractive option for elderly patients in poor physical condition. RESULTS: Recent results of interstitial PDT for peripheral-type lung cancers suggest that it may be a promising local curative treatment modality for lesions less than 1.0 cm in diameter. CONCLUSIONS: In this article, we introduce our recent clinical trials of PDT for lung cancers (both central and peripheral), and new techniques of PDD in sentinel node navigation biopsy for breast cancers. Moreover, we introduce basic research on cancers and infectious diseases in order to expand the clinical applications of PDT.

[A case of advanced gastric cancer treated with neoadjuvant chemotherapy of low-dose CPT-11 + CDDP].

Side effects due to administration of anti-cancer drugs often cause the treatment to be abandoned or a decrease in the amount of anti-cancer drugs. Recently, the anti-tumor effects of "low-dose CPT-11", which can be administered at the outpatient clinic, are reported. We performed "low-dose CPT-11 + CDDP" as a neoadjuvant chemotherapy to a patient with advanced gastric cancer. CPT-11 and CDDP combination chemotherapy caused very few side effects, so we could continue the treatment and achieve anti-tumor effects. Consequently, surgery could be performed, but disseminated metastasis was found so that the surgery ended as a non-curative operation. However, it was considered that this method of "low-dose CPT-11 + CDDP" was very effective as the neoadjuvant chemotherapy in a patient with advanced gastric cancer.

Localization of experimental submucosal esophageal tumor in rabbits by using mono-L-aspartyl chlorin e6 and long-wavelength photodynamic excitation.

BACKGROUND AND OBJECTIVE: To increase the applicability of photodynamic diagnosis with regard to deep-seated tumor, we illuminated tumors with a long-wavelength laser beam after photosensitization with mono-L-aspartyl chlorin e6 (NPe6). STUDY DESIGN/MATERIALS AND METHODS: Rabbits with VX2 esophageal tumors were divided into four groups. The control group was not treated, and the other three groups were injected with 1, 2.5, and 5 mg/kg mono-L-aspartyl chlorin e6 (NPe6), respectively. After excitation with a 664-nm laser beam (10 mW, 10 seconds), the fluorescence image and the relative fluorescence intensity (tumor/normal tissue) were recorded every 2 hours up to 8 hours by a newly developed diode laser endoscopic fluorescence imaging system. The tissue concentration of NPe6 was examined by high performance liquid chromatography at 2, 4, and 6 hours after injection with 1 and 5 mg/kg NPe6. RESULTS: The diode laser endoscopic fluorescence imaging system was able to selectively detect fluorescence from submucosal tumor by comparison with the surrounding normal mucosa after NPe6 injection. The fluorescence intensity correlated with NPe6 dose, selectively accumulated in the tumor tissue and relative intensity peaked at 6 hours after injection. No fluorescent images were detected in controls. CONCLUSION: Given intravenously, NPe6 at a dose of 5 mg/kg and excited with a 664-nm wavelength laser beam 6 hours later can define experimentally induced deep-seated esophageal carcinoma in rabbits, by using an endoscopic fluorescence imaging system.