Photodynamic therapy (PDT), locally applied to solid C6 rat glioma tumors in the foot of CD1 nude mice, eradicated the primary tumor and also decreased the rate of groin and lung metastases. Pd-Bacteriopheophorbide (Pd-Bpheid), a novel photosensitizer synthesized in our laboratory, was used in our study. The primary lesion in the hind leg was treated by an i.v. injection of 5 mg/kg of Pd-Bpheid and immediate illumination (650 -800 nm, 360 J/cm 2 ). This protocol and the surgical amputation of the leg were compared for local and metastasis responses. Following PDT, hemorrhage, inflammation with tumor necrosis and flattening were observed and histologically verified in the photodynamically treated tumor. Whereas local tumor control rates were up to 64% following PDT, in surgically treated animals, local tumor control was absolute. The rates of metastases in the groin and the lungs were at least 12-fold lower in the photodynamically treated animals compared with untreated or surgerytreated groups. The overall cure rates after PDT or surgery were 36% and 6%, respectively, at 8 weeks. These findings suggest that local PDT with Pd-Bpheid, which acts primarily on the tumor vasculature, efficiently eradicates the solid C6 tumors. In addition, the local PDT of the primary lesion has beneficial therapeutic effects on remote C6 metastasis, which is not obtained with surgery. It is therefore suggested, that although surgery is highly efficient for the immediate removal of the primary tumor, it lacks such systemic, therapeutic effects on distant metastases. Pd-Bpheid-PDT may thus offer a potentially superior curative therapy for C6 glioma tumors in the limb by eradicating the target tumor and by reducing the rate of metastasis in the groin and lung, possibly due to innate immunity. © 2002 Wiley-Liss, Inc. Key words: photodynamic therapy; surgery; Pd-bacteriopheophorbide; C6 glioma tumor; metastasisPhotodynamic therapy (PDT) is based on the destruction of tumors by cytotoxic reactive oxygen species (ROS) produced upon local tumor illumination in patients administered with a photosensitizer. 1-3 Following health agency approval for photofrin-based PDT in many countries, this anti-cancer treatment modality entered clinical use for the local treatment of an increasing number of indications including skin, esophageal, lung, gastric, cervical and bladder cancers. 4 PDT is usually considered a local anti-tumor treatment modality. However, reports from several laboratories suggest that PDT also induces beneficial systemic effects. Following in vitro hematoporphyrin-based PDT, adhesiveness and metastatic potential decline in DHD-K12-cultured colon carcinoma cells. Moreover, intravenous or s.c. injection of these PDT-treated cells to rats resulted in a reduced number of lung metastases compared with untreated cell injection. 5,6 Although this observation may be due to local photodynamic damage, the potential beneficial effect may be viewed as systemic. Other in vivo studies showed that local PDT with various photosensitizers mediates ...

We describe here a strategy for photodynamic eradica-tion of solid melanoma tumors that is based on photo-induced vascular destruction. The suggested protocol relies on synchronizing illumination with maximal circulating drug concentration in the tumor vasculature attained within the first minute after administrating the sensitizer. This differs from conventional photodynamic therapy (PDT) of tumors where illumination coincides with a maximal concentration differential of sensitizer in favor of the tumor, relative to the normal surrounding tissue. This time window is often achieved after a delay (3-48 h) following sensitizer administration. We used a novel photosensitizer, bacteriochlorophyll-serine (Bchl-Ser), which is water soluble, highly toxic upon illumination in the near-infrared (max 765-780 nm) and clears from the circulation in less than 24 h. Nude CD1 mice bearing malignant M2R melanotic melanoma xenografts (76-212 mm 3) received a single complete treatment session. Massive vascular damage was already apparent 1 h after treatment. Changes in vascular permeability were observed in vivo using contrast-enhanced magnetic resonance imaging (MRI), with the contrast reagent Gd-DTPA, by shortening spin-spin relaxation time because of hemorrhage formation and by determination of vas-cular macromolecular leakage. Twenty-four hours after treatment a complete arrest of vascular perfusion was observed by Gd-DTPA-enhanced MRI. Histopathology performed at the same time confirmed primary vascular damage with occlusive thrombi, hemorrhage and tumor necrosis. The success rate of cure of over 80% with Bchl-Ser indicates the benefits of the short and effective treatment protocol. Combining the sensitizer administration and illumination steps into one treatment session (30 min) suggests a clear advantage for future PDT of solid tumors. ¶Posted on the website on 20 December 2000.

ABSTRACT

Some patients with perioral dermatitis are not relieved despite many medications. These patients confront pain, psychological bother and social/occupational limitations. Being efficient for a wide variety of diseases including infectious inflammative degenerative or tumoral, photodynamic therapy holds a good chance to cure diseases of unknown origin, such as perioral dermatitis. This study presents the results of three women with chronic perioral dermatitis that persisted for years with partial response to medical regimen. They asked for photodynamic treatment to ease off their suffering. The duration of follow-up was up to five years. Following PDT (photodynamic therapy), the patients discontinued medications, redness decreased and eruption disappeared. In these patients, a single PDT treatment provided prolonged relief of perioral dermatitis for up to three years. These data are encouraging but not sufficient. Further study is warranted.

No abstract