A clinical study comparing methyl aminolevulinate photodynamic therapy and surgery in small superficial basal cell carcinoma (8-20 mm), with a 12-month follow-up

OBJECTIVE

To compare the efficacy and cosmetic outcome (CO) of photodynamic therapy with topical methyl aminolevulinate (MAL-PDT) with simple excision surgery for superficial basal cell carcinoma (sBCC) over a 1-year period.

METHODS

In this multicentre, randomised, controlled, open study, patients were treated at baseline either with MAL-PDT (two sessions, 7 days apart, repeated 3 months later if incomplete clinical response) or surgery (at baseline). Primary endpoints were clinical lesion response (CR) 3 months after last treatment and CO assessed by the investigator 12 months after last treatment. Secondary endpoints were CR at 12 months (i.e. recurrence) and CO assessed by the investigator at 3 and 6 months and by the patient at 3, 6 and 12 months.

RESULTS

Overall, 196 patients were enrolled with 1.4 sBCC lesions on average per patient. Mean lesion count reduction at 3 months was 92.2% with MAL-PDT vs. 99.2% with surgery [per protocol (PP) population] confirming the non-inferiority hypothesis (95% confidence interval, -12.1, -1.9). A total of 92.2% lesions showed CR at 3 months with MAL-PDT vs. 99.2% with surgery (PP population). At 12 months, 9.3% lesions recurred with MAL-PDT and none with surgery. CO was statistically superior for MAL-PDT at all time points. At 12 months, 94.1% lesions treated with MAL-PDT had an excellent or good CO according to the investigator compared with 59.8% with surgery. This difference was confirmed with the patients' assessment. The proportion of excellent CO markedly improved with time with MAL-PDT unlike surgery.

CONCLUSIONS

MAL-PDT offers a similarly high efficacy and a much better CO than simple excision surgery in the treatment of sBCC.

Photodynamic therapy in dermatology--an update 2008

SUMMARY

Photodynamic therapy (PDT) is used for the prevention and treatment of non-melanoma skin cancer. Until recently, clinically approved indications have been restricted to actinic keratoses, nodular and superficial basal cell carcinoma, and--since 2006--Bowen disease. However, the range of indications has been expanding continuously. PDT is also used for the treatment of non-malignant conditions such as acne vulgaris and leishmaniasis, as well as for treating premature skin aging due to sun exposure. Here, PDT is used for the stimulation of immunomodulatory effects in contrast to the induction of necrosis and apoptosis as produced in the treatment of skin tumors. The porphyrin precursor 5-aminolevulinic acid (ALA) or its methyl ester (MAL, so far the only approved formulation in Europe) is applied topically as photosensitizer to exclude systemic reactions. Possible light sources include lasers as well as incoherent light sources; irradiation with incoherent light sources is cheaper and more appropriate for large treatment areas. The main advantages of PDT in comparison to other treatment modalities are its excellent cosmetic results and its high remission rates despite low invasiveness.This article provides up-to-date information about PDT with focus on recently published studies.

Outcome survey of insect venom allergic patients with venom immunotherapy in a rural population

BACKGROUND

Hymenoptera venom anaphylaxis is a frightening event that affects physical and psychical functioning.

PATIENTS AND METHODS

Retrospective survey of 182 Hymenoptera venom allergic patients living in a rural area using a questionnaire targeting on patients' satisfaction during therapy, fear of anaphylactic recurrences and changes in lifestyle before and after venom immunotherapy (VIT). Additionally, patients' self-assessment of quality of life, daily outdoor time and re-sting rate were recorded.

RESULTS

146 patients returned the questionnaire (58.9% male, 41.1% female, 25.3% honey bee allergic, 67.8% wasp allergic, 41.1% re-sting rate, mean follow-up time 6.5 years). Measurement of the parameters fear, satisfaction and changes in lifestyle revealed a significant improvement after VIT. This correlated with the patients'self-assessment of quality of life,when 89.7% declared an improvement after VIT. Although the improvement was higher in patients with re-stings, also patients without re-stings clearly benefited from VIT. Interestingly, females were significantly more affected by Hymenoptera venom allergy than males,whereas both genders showed a similar improvement after VIT.

CONCLUSIONS

Patients with Hymenoptera venom sting allergy significantly benefit from VIT in regard to both biological and psychological outcome. VIT should still be provided to all Hymenoptera venom allergic patients as standard of care.

Split-face-study using two different light sources for topical PDT of actinic keratoses:non-inferiority of the LED system

BACKGROUND

Photodynamic therapy (PDT) with 5-amino-4-oxo-pentanoate (methylaminolevulinate, MAL) is an effective and safe treatment option for actinic keratoses. Light-emitting diodes (LED) are suitable light sources for topical PDT. To evaluate the efficacy, painfulness, patient satisfaction and cosmesis of LED-based PDT a prospective, randomized and controlled split-face study was performed.

METHODS

Topical ALA-PDT was administered to 17 patients whose actinic ker-atoses (n = 131) were symmetrically distributed and suitable for a two-side comparison. After incubation with MAL (16%), irradiation was performed with the incoherent lamp (160 mW cm(-2); 100 J cm(-2), PDT 1200L, Waldmann Medizintechnik, Villingen-Schwenningen, Germany) on one side and the LED system (120 mW cm(-2); 40 J cm(-2), LEDA, WaveLight AG, Erlangen, Germany) on the other side. The patients were followed by re-evaluation up to 6 months.

RESULTS

Six months following treatment there was no significant difference between the infiltration and keratosis scores in both treatment regimes (p = 0.812). The remission rate was 78.5% (LED system) vs.80.3% (incoherent lamp). There was no significant difference between both light sources regarding the pain during therapy (p = 0.988). There was no significant difference between both treatment regimes regarding patient satisfaction (p = 1).

CONCLUSIONS

LEDA-based MAL-PDT is an effective alternative for the treatment of atinic keratoses. The remission rates and cosmetic results are not inferior to PDT using incoherent light systems. Both treatment regimes are similarly painful.

Photothermolysis of blood vessels using indocyanine green and pulsed diode laser irradiation in the dorsal skinfold chamber model

BACKGROUND AND OBJECTIVE

For the treatment of vascular lesions, the use of laser light absorbed by the endogenous chromophore hemoglobin may still be improved.

MATERIALS AND METHODS

Laser treatment (lambda(em) = 805 nm; fluence rate: 106 kW/cm2; fluence: 3.2 J/cm2 (3 milliseconds)), of blood vessels directly after i.v. application of indocyanine green (ICG) (ICG-concentration: 0, 2, or 4 mg/kg body weight (b.w.)) (n = 14,117) was investigated in the skinfold chamber model. Vessel diameters (1-351 microm) were measured using intravital fluorescence microscopy up to 24 hours following irradiation. Histology was taken 1 or 24 hours after irradiation. Results were compared to a mathematical model based on the finite element method.

RESULTS

The reduction of blood vessel perfusion was proportional to ICG-concentration and pulse duration; only a 30 milliseconds pulse duration (2 or 4 mg/kg b.w. ICG-concentration) induced a loss of perfusion even of blood vessels with a diameter <30 microm. Histology revealed photocoagulation of blood vessels up to 24 hours. Results were in agreement with mathematical calculations.

CONCLUSION

ICG-mediated laser irradiation induces irreversible photocoagulation of blood vessels of all diameters in this model.

The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

New antibacterial strategies are required in view of the increasing resistance of bacteria to antibiotics. One promising technique involves the photodynamic inactivation of bacteria. Upon exposure to light, a photosensitizer in bacteria can generate singlet oxygen, which oxidizes proteins or lipids, leading to bacteria death. To elucidate the oxidative processes that occur during killing of bacteria, Staphylococcus aureus was incubated with a standard photosensitizer, and the generation and decay of singlet oxygen was detected directly by its luminescence at 1,270 nm. At low bacterial concentrations, the time-resolved luminescence of singlet oxygen showed a decay time of 6 +/- 2 micros, which is an intermediate time for singlet oxygen decay in phospholipids of membranes (14 +/- 2 micros) and in the surrounding water (3.5 +/- 0.5 micros). Obviously, at low bacterial concentrations, singlet oxygen had sufficient access to water outside of S. aureus by diffusion. Thus, singlet oxygen seems to be generated in the outer cell wall areas or in adjacent cytoplasmic membranes of S. aureus. In addition, the detection of singlet oxygen luminescence can be used as a sensor of intracellular oxygen concentration. When singlet oxygen luminescence was measured at higher bacterial concentrations, the decay time increased significantly, up to approximately 40 micros, because of oxygen depletion at these concentrations. This observation is an important indicator that oxygen supply is a crucial factor in the efficacy of photodynamic inactivation of bacteria, and will be of particular significance should this approach be used against multiresistant bacteria.

Methyl aminolevulinate-photodynamic therapy for basal cell carcinoma

Basal cell carcinomas (BCCs) are the most common malignant tumors of the skin. Treatment of BCCs should be chosen according to clinical type, tumor size, and location. Methyl aminolevulinate (MAL) photodynamic therapy (PDT) has the potential to become a therapy with equal effectiveness to classical therapeutic modalities with an excellent cosmesis, but without complications like scar formation, requirement for grafts, need of repetitive treatments over longer time periods, or pigmentary changes. MAL is licensed in Europe, Australia, New Zealand, and Brazil for the treatment of actinic keratoses, Bowen's disease, and nodular and superficial BCC. Conclusions are drawn from extensive studies in past years using MAL-PDT for both nodular and superficial BCCs.

Disappointing results and low tolerability of photodynamic therapy with topical 5-aminolaevulinic acid in psoriasis. A randomized, double-blind phase I/II study

BACKGROUND

Based on good results in the treatment of superficial skin tumours, since the early 1990s topical photodynamic therapy with aminolaevulinic acid (ALA PDT) has been used for disseminated, inflammatory dermatoses including psoriasis. However, there is still a lack of well-documented trials.

OBJECTIVE

A prospective randomized, double-blind phase I/II intrapatient comparison study was conducted in 12 patients to investigate whether topical ALA PDT is an effective treatment for chronic plaque-type psoriasis.

METHODS

In each patient three psoriatic plaques were randomly treated with a light dose of 20 J/cm(2) and 0.1%, 1% and 5% ALA, respectively. Treatment was conducted twice a week until complete clearance or for a maximum of 12 irradiations. Therapeutic efficacy was assessed by weekly determination of the psoriasis severity index (PSI).

RESULTS

The mean percentage improvement was 37.5%, 45.6% and 51.2% in the 0.1%, 1% and 5% ALA-treated groups, respectively. Irradiation had to be interrupted several times because of severe burning and pain sensation.

CONCLUSION

Topical ALA PDT did not prove to be an appropriate treatment option for plaque-type psoriasis due to disappointing clinical efficacy, the time-consuming treatment procedure and its unfavourable adverse event profile.

Guidelines on the use of photodynamic therapy for nonmelanoma skin cancer: An international consensus

Topical photodynamic therapy (PDT) is used to treat nonmelanoma skin cancers, such as actinic keratoses, Bowen's disease, and basal cell carcinoma (superficial and nodular). This article presents up-to-date, practical, evidence-based recommendations on the use of topical PDT using 5-aminolevulinic acid or methyl aminolevulinate for the treatment (and prevention) of nonmelanoma skin cancers. A systematic literature review was conducted (using MEDLINE), and recommendations were made on the basis of the quality of evidence for efficacy, safety/tolerability, cosmetic outcome, and patient satisfaction/preference. Topical PDT is highly effective in the treatment of actinic keratoses, Bowen's disease, superficial and thin nodular basal cell carcinomas, with cosmesis typically superior to that achieved with existing standard therapies. PDT may also be a means of preventing certain nonmelanoma skin cancers in immunosuppressed patients.

In vivo confocal scanning laser microscopy in dermatology

The need to improve the diagnostic accuracy and sensitivity for skin tumours has led to the development of new non-invasive, in vivo techniques including ultrasound, dermoscopy, digital photography, confocal scanning laser microscopy, magnetic resonance imaging and optical coherence tomography. Of all these in vivo techniques, only confocal scanning laser microscopy allows for the examination of the epidermis and papillary dermis at a resolution approaching histological detail. This review article looks at some of the most important applications of this new technology, highlighting its qualities and limitations.

Safety Testing of Indocyanine Green in an Ex Vivo Porcine Retina Model

PURPOSE

To assess retinal toxicity of indocyanine green (ICG) in a porcine ex vivo perfusion organ culture model, and to measure intraretinal penetration of ICG applied to the retinal surface.

METHODS

The retinal surface of fresh porcine retinal tissue was exposed to ICG 0.1% and 1% dissolved in glucose 5% for 1 and 30 minutes with and without concomitant illumination. Specimens were then kept in perfusion organ culture for 24 hours before examination by light microscopy and the TUNEL technique. Tissue samples treated with DNAse served as positive controls, and samples exposed to saline served as negative controls. Fluorescence microscopy was used to localize ICG at 1 minute, 60 minutes, 2 hours, and 3 hours after a 1-minute exposure of the retinal surface to ICG 1%.

RESULTS

No increase in TUNEL-positive cells was observed after exposure to ICG 0.1% for 1 minute. Moderate apoptosis was found after 1-minute exposure to ICG 1% and 30-minute exposure to ICG 0.1%, and severe apoptosis was found after 30-minute exposure to ICG 1%. Concomitant application of light did not influence the degree of apoptosis. No signs of cell necrosis were found. After 1-minute exposure of the retinal surface, ICG 1% gradually penetrated the entire retina.

CONCLUSIONS

ICG induced apoptosis but not necrosis in all nuclear retinal layers in a dose-dependent manner. Brief exposure to ICG 0.1% for 1 minute and illumination for 3 minutes simulated the intraoperative use of ICG. No retinal apoptosis or necrosis was observed. ICG briefly applied to the retinal surface gradually penetrated the entire retina.

Photodynamic therapy in dermatology

Currently, topical photodynamic therapy (PDT) has received approval for the treatment of dermato-oncologic conditions like actinic keratoses, Bowen's disease, in-situ squamous cell carcinoma and basal cell carcinoma in many countries all over the world. For many non-neoplastic dermatological diseases like localized scleroderma, acne vulgaris and viral warts a therapeutical benefit of PDT is evident, too. Unlike the formerly used, only systemically-applicable haematoporphyrin derivates, the recently developed topical photosensitizers 5-aminolevulinic acid (ALA) or its methyl ester (MAL) induce photosensitizing porphyrins. Moreover, the latter do not induce strong generalized cutaneous photosensitization. Due to the easy accessibility of skin to light activation, incoherent lamps or LED arrays are suitable for PDT. The production of reactive oxygen intermediates like singlet oxygen depends on the applied light dose as well as the concentration and localization of the photosensitizer in the diseased tissue. Either cytotoxic effects resulting in tumor destruction or immunomodulatory effects improving inflammatory skin conditions are induced. Treating superficial non-melanoma skin cancer, PDT has been shown to be highly efficient despite the low level of invasiveness. The excellent cosmetic results after treatment are beneficial, too.

Towards a more specific therapy: targeting nonmelanoma skin cancer cells

Epithelial cancers of the skin, e.g. basal cell carcinoma and squamous cell carcinoma, are the most common tumours in humans with increasing incidence. Hence the development of new therapeutic strategies is of utmost interest. For many years the most often used conventional therapies for these diseases were surgical procedures such as curettage and electrodesiccation, excision or, with so far the best outcome in terms of remission rates, micrographic surgery. Other ablative treatment modalities are cryotherapy, radiation therapy or the use of lasers (Er:YAG, CO(2)). All those above-mentioned treatments have in common that they are quite unspecific and do not target the tumour itself or its environment, thus leading to unwanted effects in the surrounding tissue such as scar formation or other cosmetically disfiguring events. Therefore, the development of novel, more pathogenesis-based therapies such as the use of retinoids, cyclooxygenase inhibitors, topical immunomodulators, inhibitors of the sonic-hedgehog signalling pathway or photodynamic therapy are challenging new approaches.

Photodynamic therapy with 5-aminolevulinic acid induces distinct microcirculatory effects following systemic or topical application

In photodynamic therapy (PDT) the photosensitiser 5-aminolaevulinic acid (ALA) can be used by systemic or topical application. Previous experiments showed that the photodynamic effects might not be mediated solely by porphyrins localized in the parenchyma, but also by porphyrins in the microvasculature. Therefore, the microcirculatory effects of PDT following systemic versus topical application of ALA have been investigated. Amelanotic melanomas were implanted in the dorsal skin fold chamber of Syrian Golden hamsters. ALA was injected i.v. for systemic PDT before irradiation, whereas ALA was applied to the chambers for topical PDT before irradiation with an incoherent lamp. FITC-labelled erythrocytes were injected to determine red blood cell velocity (RBCV) and functional vessel density (FVD). Twenty-four hours after PDT tissue was taken for histology and immunohistochemistry to reveal the degree of apoptosis and to show the accumulation of leukocytes. FVD or RBCV was not altered significantly by systemic or topical low-dose PDT (10 J cm(-2)), whereas a significant reduction of RBCV and FVD was detected after high-dose PDT (100 J cm(-2)) following systemic or topical application of ALA. Systemic PDT with 100 J cm(-2) stopped the flow only in the tumor center, whereas topical PDT with 100 J cm(-2) lead to a breakdown of RBCV in all chamber areas. Two hours and 24 h after systemic high-dose PDT, perfused microvessels and capillaries could be detected in normal tissue and tumor periphery, in contrast to topical high-dose PDT leading to a shut down of FVD 24 h after irradiation in all areas of the chamber tissue. Histological staining revealed a more pronounced intracellular oedema and swelling of cells after topical high-dose PDT than systemic high-dose PDT. These results indicate that topical high-dose PDT with ALA has a more pronounced effect on microcirculation as compared to systemic high-dose PDT in this model.

Photodynamic therapy for non-melanoma skin cancer

Photodynamic therapy is a treatment modality that has been shown to be effective mainly for the dermato-oncologic conditions: actinic keratosis, Bowen's disease, in situ squamous cell carcinoma and basal cell carcinoma. Recent work has focused on the development and evaluation of topical photosensitizers like the haem precursor 5-aminolevulinic acid or its methyl ester, both inducing photosensitizing porphyrins. These drugs do not induce strong generalized cutaneous photosensitization, unlike the systemically applied porphyrins or their derivatives. For dermatological purposes incoherent lamps or light-emitting diode arrays can be used for light activation. Cure rates reported for very superficial lesions (tumour thickness <2-3 mm) are comparable to those achieved by other therapeutic modalities. Photodynamic therapy is a minimally invasive therapy associated with excellent cosmetic results. For actinic keratosis and basal cell carcinoma, methyl aminolevulinate-photodynamic therapy is already approved in Europe, Australia and New Zealand, and is now also approved for actinic keratosis in the US.

Selective photothermolysis of blood vessels following flashlamp-pumped pulsed dye laser irradiation: in vivo results and mathematical modelling are in agreement

Laser therapy using the pulsed dye laser is the standard treatment for port-wine stains (PWS). But the mechanism of action has not been elucidated completely, yet. The dorsal skin-fold chamber model in hamsters was used to investigate the effects of laser treatment (lambda(em)=585 nm; pulse duration: 0.45 ms; fluence: 6 J per cm2) on blood vessels. Vessels (n=3394) were marked with FITC dextran (MW 150 kDa) and diameters (2-186 microm) were measured using intravital fluorescence microscopy up to 24 h following irradiation. Histology (H&E, TUNEL, CD31) was taken 1 or 24 h after irradiation. The experimental results were compared with the predictions of a mathematical model based on the finite-element method. Following irradiation treatment the number of unperfused vessels decreases with decreasing vessel diameter in vivo. Histology indicated a restriction of tissue injury to the irradiated area after 1 h. Blood vessels contained aggregated red blood cells. After 24 h tissue damage occurred also outside the irradiated area and thrombus formation was visible. These results were in agreement with the mathematical calculations. In addition to initial physical effects after pulsed dye laser treatment delayed biological processes contribute significantly to the reduction of perfused blood vessels. Because of incomplete photocoagulation of smaller blood vessels (diameter 2-16 microm) a complete bleaching of PWS seems to be unlikely.

Topical aminolaevulinic acid-based photodynamic therapy as a treatment option for psoriasis? Results of a randomized, observer-blinded study

BACKGROUND

Topical aminolaevulinic acid-based photodynamic therapy (ALA-PDT) has recently been tried in small open studies for several inflammatory dermatoses including psoriasis.

OBJECTIVES

The purpose of this randomized, within patient comparison study was to investigate whether topical ALA-based PDT using a range of light doses can induce a satisfactory response in localized psoriasis.

PATIENTS AND METHODS

Twenty-nine patients with chronic plaque type psoriasis were enrolled in the study. After keratolytic pretreatment three psoriatic plaques in each patient were randomly allocated to PDT with 1% ALA and a light dose of 5 J cm(-2), 10 J cm(-2) or 20 J cm(-2), respectively. Treatment was performed twice weekly until complete clearance or for a maximum of 12 irradiations. As a measure of clinical response the psoriasis severity index (PSI) of the three target plaques was assessed separately by an observer blinded to the treatment at baseline, before each PDT treatment and 3-4 days after the last irradiation.

RESULTS

Eight patients withdrew prematurely from the study. Keratolytic pretreatment alone reduced the baseline PSI in all three dose groups by about 25%. Subsequent PDT with 20 J cm(-2) resulted in a final reduction of PSI by 59%, PDT with the lower doses of 10 J cm(-2) and 5 J cm(-2) decreased the baseline PSI by 46% and 49%, respectively. The difference in clinical efficacy between 20 J cm(-2) and 10 J cm(-2) or 5 J cm(-2) was statistically significant (P = 0.003; P = 0.02), whereas no difference was found between 10 J cm(-2) and 5 J cm(-2) (P = 0.4). All patients reported some degree of PDT-induced stinging or burning during irradiation.

CONCLUSIONS

The unsatisfactory clinical response and frequent occurrence of pain during and after irradiation renders topical ALA-based PDT an inadequate treatment option for psoriasis.

Severe contact urticaria to guar gum included as gelling agent in a local anaesthetic

We report the first case of a life-threatening immediate-type hypersensitivity caused by Dynexan, a local anaesthetic gel. After mucosal application by his dentist, a 63-year-old man rapidly developed urticaria, dyspnea and, at last, he collapsed and remained unconscious for 2 hr despite emergency care. While the standard prick tests were negative to all local anaesthetics tested including lidocaine, a 1-fold positive reaction was detected to Meyprogat 60, an ingredient of Dynexan. As the gelling agent Meyprogat represents a derivative of guar (synonymous guar gum, guaran, E-412), we subsequently tested different guar products derived from Cyamopsis tetragonoloba beans and, as control, the closely related locust bean gum E-410. In the prick-to-prick tests, the guar-derived food additive Provigel NAG 905 provoked a 1-fold positive reaction. Native guar beans pounded and resuspended in water showed a 2-fold positive reaction, whereas no reaction was found to derivatives of locust bean gum. Specific immunoglobulin E were negative in all cases. Despite the common use of guar as versatile food additive or gelling agent, this is the first case of a severe immediate-type hypersensitivity after mucosal contact.