Photodynamische Therapie mit Methylaminooxopentanoat (MetvixR) und einer Breitbandlichtquelle (PhotoDyn 501): Praktische Erfahrungen bei Problem-Patienten mit Aktinischen Keratosen und Basalzellkarzinomen. Photodynamic therapy with methylaminooxopentanoate (MetvixR) and a broad band light source (PhotoDyn 501): Experiences in complicated patients with actinic keratoses and basal cell carcinomas

Recent developments in photodynamic therapy and its application against multidrug resistant cancers

Recently, photodynamic therapy (PDT) has received a lot of attention for its potential use in cancer treatment. It enables the therapy of a multifocal disease with the least amount of tissue damage. The most widely used prodrug is 5-aminolevulinic acid, which undergoes heme pathway conversion to protoporphyrin IX, which acts as a photosensitizer (PS). Additionally, hematoporphyrin, bacteriochlorin, and phthalocyanine are also studied for their therapeutic potential in cancer. Unfortunately, not every patient who receives PDT experiences a full recovery. Resistance to different anticancer treatments is commonly observed. A few of the resistance mechanisms by which cancer cells escape therapeutics are genetic factors, drug-drug interactions, impaired DNA repair pathways, mutations related to inhibition of apoptosis, epigenetic pathways, etc. Recently, much research has been conducted to develop a new generation of PS based on nanomaterials that could be used to overcome cancer cells' multidrug resistance (MDR). Various metal-based, polymeric, lipidic nanoparticles (NPs), dendrimers, etc, have been utilized in the PDT application against cancer. This article discusses the detailed mechanism by which cancer cells evolve towards MDR as well as recent advances in PDT-based NPs for use against multidrug-resistant cancers.

Combined CO2 laser and photodynamic therapy enhances the efficacy of treatment of basal cell carcinomas

BACKGROUND AND OBJECTIVES

In selected cases, conventional photodynamic therapy (C-PDT) is a valid alternative to surgery for the treatment of basal cell carcinoma (BCC). However, it is limited to superficial BCCs. Pretreatment of BCCs with ablative lasers may enhance its efficacy. We evaluated the C-PDT and CO₂ laser combination therapy for the treatment of superficial and nodular BCCs.

PATIENTS AND METHODS

In this prospective, interventional, monocentric study, patients affected by BCC were treated with CO₂ laser therapy, using a continuous superpulsed CO₂ laser for nodular BCCs and a fractional CO₂ laser for superficial BCCs. All patients were subsequently treated with photodynamic therapy using methyl aminolevulinate cream and an Aktilite CL128® (Galderma) lamp.

RESULTS

32 patients (20 males, 12 females) aged from 45 to 96 years (with a total of 181 BCCs) were treated using a CO₂ laser combined with C-PDT. A 100 % cure rate was achieved at three months, with no signs of relapse in 97.2 % of the cases during the mean follow-up period (10.7 months, range 4 to 18 months). We observed mild adverse reactions and good aesthetic results.

CONCLUSIONS

We recommend this combination therapy in selected cases, based on its high efficacy, good aesthetic results and few side effects.

Type I interferons in anticancer immunity

Type I interferons (IFNs) are known for their key role in antiviral immune responses. In this Review, we discuss accumulating evidence indicating that type I IFNs produced by malignant cells or tumour-infiltrating dendritic cells also control the autocrine or paracrine circuits that underlie cancer immunosurveillance. Many conventional chemotherapeutics, targeted anticancer agents, immunological adjuvants and oncolytic viruses are only fully efficient in the presence of intact type I IFN signalling. Moreover, the intratumoural expression levels of type I IFNs or of IFN-stimulated genes correlate with favourable disease outcome in several cohorts of patients with cancer. Finally, new anticancer immunotherapies are being developed that are based on recombinant type I IFNs, type I IFN-encoding vectors and type I IFN-expressing cells.

5-ALA for photodynamic photorejuvenation—optimization of treatment regime based on normal-skin fluorescence measurements

BACKGROUND AND OBJECTIVES

Photodynamic therapy using 20% 5 aminolevulinic acid (5-ALA) has recently been introduced as a new tool in optical skin rejuvenation. The primary objective of this study was to optimize incubation time, the topical delivery mechanism (vehicle) and the concentration of 5-ALA by detecting the dynamic changes of normal skin after 5-ALA application. The secondary objective was to develop a treatment regime which minimizes post-treatment photosensitivity.

STUDY DESIGN/MATERIALS AND METHODS

Skin fluorescence distribution patterns after topical application of low concentrations of 5-ALA (0.5% and 1% preparations encapsulated in liposomes), were investigated. Twenty percent 5-ALA in moisturizing cream was used as a control. Ten healthy volunteers participated, and skin fluorescence was documented by fluorescent photography. The fluorescent intensity was measured in % of maximum obtained fluorescence after 3 hours 5-ALA application.

RESULTS

Skin fluorescence intensity after topical application of 0.5% and 1% non-occluded liposome-encapsulated 5-ALA application was heterogeneous distributed and reached saturation level after approximate 2 hours. The maximal fluorescence for 0.5% and 1% 5-ALA treated areas was 4.2% (SD: 3.5%) and 2.4% (SD: 2%), respectively, and this difference was statistically significant (P = 0.036). The fluorescence decayed linearly shortly (within 15 minutes) after end of application and was back to baseline within 8 hours. In contrast, the fluorescence of areas treated more than 1 hour with 20% 5-ALA was very uniform and a linear relationship (r2 = 0.998) to the incubation time (0-3 hours) was registered. Furthermore, fluorescence intensity (15.2-57.9%) continued to increase after the end of 5-ALA application. The maximum fluorescence reach a level of 1.6-9 times the fluorescence measured by end of the 5-ALA application and occurred 8:13 hours (SD: 0:49 hours) after the end of 20% 5-ALA application. The average skin surface fluorescence induced by the liposome-encapsulated 0.5% 5-ALA applied for longer than 2 hours, was found to be statistically equal (P = 0.47) to the average measured skin surface fluorescence (4.2%) obtained after 30 minutes exposure to 20% 5-ALA cream (4.3%).

CONCLUSION

Changing the 5-ALA vehicle from a moisturizing cream to liposome encapsulation, the 5-ALA concentration can be lowered by a factor of 40, and still induce the same skin fluorescence and at the same time eliminates the need for occlusion. The low post-treatment fluorescence also suggests a significantly reduced risk of post-treatment phototoxicity.