Pain associated with aminolevulinic acid-photodynamic therapy of skin disease

Photodynamic therapy light': An enhanced treatment protocol for actinic keratoses with minimal pain and optimal clinical outcome by combining laser-assisted low irradiance PDT with shortened daylight PDT

BACKGROUND

Between 2003 and 2016, 546 patients in our clinic discontinued outpatient treatment for actinic keratoses (AKs) using conventional photodynamic therapy (PDT) because of intolerable pain, thereby necessitating the use of a less painful procedure. Therefore, we developed a novel off-label PDT protocol: 'PDT light'.

METHODS

Laser-assisted low irradiance PDT (li-PDT) was performed beginning in 2014. The dosage was gradually lowered to 8-12 J/cm² in 2018, so that we achieved considerable pain reduction while maintaining comparable therapeutic efficacy. A further considerable reduction in pain was achieved from 2018 onwards by combining the advantages of li-PDT with daylight PDT (DLPDT), thereby resulting in 2018 in the new technique 'PDT light'. Patients with AK Olsen grades 1 or 2 and field cancerization initially received a mild-fractionated CO2 laser pretreatment prior to MAL-incubation (methyl aminolaevulinate, Metvix ®) under occlusion for 1.5-3 h. Then, patients were illuminated on average for 1.02 min with the Aktilite-LED and, after application of an UV-screen on the illuminated area, sent out into daylight for 1 h.

RESULTS

Between March and November 2019, we successfully treated 152 cases using the enhanced 'PDT light' procedure, with 137 cases achieving at follow-up 1 (on average after 8.14 months) good-to-excellent clearance rates (CLA and CLB together 90%) and minimal adverse effects.

CONCLUSIONS

The novel 'PDT light' protocol proved to be an excellent and nearly painless method with an average visual-analogue scale (VAS) score of 1.19. Additional advantages included reduced illumination time, shorter outpatient stays in the clinic, fewer adverse effects, and better patient compliance than with DLPDT alone.

Clinical trial of two-step photodynamic therapy for reduced pain in the treatment of precancerous squamous lesions (Actinic keratoses)

BACKGROUND

Pain associated with aminolevulinic acid photodynamic therapy (ALA-PDT) for the treatment of facial dermatoses results in low patient compliance. Two-step photodynamic therapy (two-step PDT) may improve comfort by optimizing light amplitude and exposure time.

OBJECTIVE

To investigate the efficacy of two-step PDT in reducing the pain generated during the treatment of facial skin disorders.

METHODS

Twenty-six patients with AK were randomly divided into two groups; the experimental group was treated with two-step photodynamic therapy and the control group was treated with conventional photodynamic therapy. The pain intensity of the patients at different times was assessed using the pain numerical rating scale (NRS).

RESULTS

A total of 26 patients completed three ALA-PDT treatments, 13 and 13 patients in each group, respectively. The mean NRS scores of patients in the experimental group (3.28±1.41, 3.33±1.43, 3.42±1.78) were lower than those of the control group (5.00±1.94, 5.09±1.86, 4.86±1.64) on each occasion. The incidence of certain adverse reactions was lower in the experimental group than in the control group. There was no difference between the two groups in terms of clinical outcome, recurrence rate and patient satisfaction.

CONCLUSION

Two-step photodynamic therapy can reduce pain and the incidence of some adverse reactions, but does not affect clinical efficacy, recurrence rate and patient satisfaction.

Pilot Study on High-Intensity Focused Ultrasound (HIFU) for Basal Cell Carcinoma: Effectiveness and Safety

Background: The rising incidence of Basal Cell Carcinoma (BCC), especially among individuals with significant sun exposure, underscores the need for effective and minimally invasive treatment alternatives. Traditional surgical approaches, while effective, often result in notable cosmetic and functional limitations, particularly for lesions located on the face. This study explores High-Intensity Focused Ultrasound (HIFU) as a promising, non-invasive treatment option that aims to overcome these challenges, potentially revolutionizing BCC treatment by offering a balance between efficacy and cosmetic outcomes. Methods: Our investigation enrolled 8 patients, presenting a total of 15 BCC lesions, treated with a 20 MHz HIFU device. The selection of treatment parameters was precise, utilizing probe depths from 0.8 mm to 2.3 mm and energy settings ranging from 0.7 to 1.3 Joules (J) per pulse, determined by the lesion's infiltration depth as assessed via pre-procedure ultrasonography. A key component of our methodology included dermatoscopic monitoring, which allowed for detailed observation of the lesions' response to treatment over time. Patient-reported outcomes and satisfaction levels were systematically recorded, providing insights into the comparative advantages of HIFU. Results: Initial responses after HIFU treatment included whitening and edema, indicative of successful lesion ablation. Early post-treatment observations revealed minimal discomfort and quick recovery, with crust formation resolving within two weeks for most lesions. Over a period of three to six months, patients reported significant improvement, with lesions becoming lighter and blending into the surrounding skin, demonstrating effective and aesthetically pleasing outcomes. Patient satisfaction surveys conducted six months post-treatment revealed high levels of satisfaction, with 75% of participants reporting very high satisfaction due to minimal scarring and the non-invasive nature of the procedure. No recurrences of BCC were noted, attesting to the efficacy of HIFU as a treatment option. Conclusions: The findings from this study confirm that based on dermoscopy analysis, HIFU is a highly effective and patient-preferred non-invasive treatment modality for Basal Cell Carcinoma. HIFU offers a promising alternative to traditional surgical and non-surgical treatments, reducing the cosmetic and functional repercussions associated with BCC management. Given its efficacy, safety, and favorable patient satisfaction scores, HIFU warrants further investigation and consideration for broader clinical application in the treatment of BCC, potentially setting a new standard in dermatologic oncology care. This work represents a pilot study that is the first to describe the use of HIFU in the treatment of BCC.

Painless photodynamic therapy for facial actinic keratoses: A retrospective cohort study of the post-treatment inflammatory response

INTRODUCTION

Photodynamic therapy (PDT) is a safe, non-mutagenic, and non-scarring treatment for actinic keratoses (AK).

BACKGROUND

'Painless' photodynamic therapy (p-PDT) is a regimen for AK that employs simultaneous aminolevulinate incubation and blue light illumination. The efficacy of p-PDT resembles that of traditional PDT, but detailed mechanisms of action for p-PDT are not well understood.

METHODS

To characterize the inflammatory effects of the p-PDT procedure 48 h following treatment and determine the association of inflammation with precancer burden, we performed a retrospective cohort study of 104 patients with AK of face or scalp treated with p-PDT between 2017 and 2019. Patients self-reported their side effects 48 h following p-PDT and took photographs of their face and scalp. Photographs were edited to define seven anatomic regions, and erythema was scored by four investigators.

RESULTS

Ninety-eight patients provided photographs suitable for erythema evaluation. Most patients experienced 2 or more side effects and some pain 48 h post-procedure. Females experienced more pain (p = 0.01) and side effects (p = 0.002) compared to males. AK burden was positively associated with post p-PDT erythema response (p < 0.0001) at all sites, but particularly in the temples (p = 0.002) and supralabial area (p = 0.009).

DISCUSSION

This study confirms a strong clinical inflammatory response after p-PDT. Severity of inflammation is positively associated with AK tumor burden, suggesting that post-treatment inflammation may be a pre-requisite for p-PDT efficacy. Interestingly, the results also identify certain gender-related differences in the severity of side effects experienced by patients post-PDT.

The use of nanomaterials in advancing photodynamic therapy (PDT) for deep-seated tumors and synergy with radiotherapy

Photodynamic therapy (PDT) has been under development for at least 40 years. Multiple studies have demonstrated significant anti-tumor efficacy with limited toxicity concerns. PDT was expected to become a major new therapeutic option in treating localized cancer. However, despite a shifting focus in oncology to aggressive local therapies, PDT has not to date gained widespread acceptance as a standard-of-care option. A major factor is the technical challenge of treating deep-seated and large tumors, due to the limited penetration and variability of the activating light in tissue. Poor tumor selectivity of PDT sensitizers has been problematic for many applications. Attempts to mitigate these limitations with the use of multiple interstitial fiberoptic catheters to deliver the light, new generations of photosensitizer with longer-wavelength activation, oxygen independence and better tumor specificity, as well as improved dosimetry and treatment planning are starting to show encouraging results. Nanomaterials used either as photosensitizers per se or to improve delivery of molecular photosensitizers is an emerging area of research. PDT can also benefit radiotherapy patients due to its complementary and potentially synergistic mechanisms-of-action, ability to treat radioresistant tumors and upregulation of anti-tumoral immune effects. Furthermore, recent advances may allow ionizing radiation energy, including high-energy X-rays, to replace external light sources, opening a novel therapeutic strategy (radioPDT), which is facilitated by novel nanomaterials. This may provide the best of both worlds by combining the precise targeting and treatment depth/volume capabilities of radiation therapy with the high therapeutic index and biological advantages of PDT, without increasing toxicities. Achieving this, however, will require novel agents, primarily developed with nanomaterials. This is under active investigation by many research groups using different approaches.

Treatment of antibiotic-resistant bacteria colonizing diabetic foot ulcers by OLED induced antimicrobial photodynamic therapy

We evaluate the efficacy of antimicrobial Photodynamic Therapy (APDT) for inactivating a variety of antibiotic-resistant clinical strains from diabetic foot ulcers. Here we are focused on APDT based on organic light-emitting diodes (OLED). The wound swabs from ten patients diagnosed with diabetic foot ulcers were collected and 32 clinical strains comprising 22 bacterial species were obtained. The isolated strains were identified with the use of mass spectrometry coupled with a protein profile database and tested for antibiotic susceptibility. 74% of isolated bacterial strains exhibited adaptive antibiotic resistance to at least one antibiotic. All strains were subjected to the APDT procedure using an OLED as a light source and 16 µM methylene blue as a photosensitizer. APDT using the OLED led to a large reduction in all cases. For pathogenic bacteria, the reduction ranged from 1.1-log to > 8 log (Klebsiella aerogenes, Enterobacter cloaca, Staphylococcus hominis) even for high antibiotic resistance (MRSA 5-log reduction). Opportunistic bacteria showed a range from 0.4-log reduction for Citrobacter koseri to > 8 log reduction for Kocuria rhizophila. These results show that OLED-driven APDT is effective against pathogens and opportunistic bacteria regardless of drug resistance.

Acne Vulgaris-Novel Treatment Options and Factors Affecting Therapy Adherence: A Narrative Review

Acne vulgaris is an extremely common skin condition, affecting a large population of adolescents, but at the same time, remaining a quite common issue in the group of adult patients. Its complex pathogenesis includes increased sebum secretion, impaired follicular keratinization, colonization of sebaceous glands with Cutibacterium acne bacteria, and the development of inflammation in pilosebaceous units. Although there are many methods of treatment available targeting the mechanisms mentioned above, a large percentage of patients remain undertreated or non-compliant with treatment. Ineffective treatment results in the formation of acne scars, which has a major impact on the well-being and quality of life of the patients. The aim of this publication was a review of available evidence on widely used and novel methods of topical and systemic treatment of acne, additionally including current literature-based analysis of factors affecting patients' compliance. The strengths and limitations of novel substances for treating acne were discussed. We conclude that an effective acne treatment remains a challenge. A better understanding of current treatment options and factors affecting patients' compliance could be a helpful tool in choosing a proper treatment option.

Sandpaper curettage: A simple method to improve PDT outcomes for actinic keratosis

INTRODUCTION

Photodynamic therapy (PDT) is a non-scarring, repeatable, and safe treatment for actinic keratosis (AK), but improvements in efficacy are still needed.

BACKGROUND

Devices such as steel blades, needle rollers, and lasers are currently used to remove hypertrophic stratum corneum on AKs to improve PDT outcomes. However, curettage with fine sandpaper could be a gentler, effective alternative.

METHODS

A retrospective study was designed to compare PDT with or without sandpaper curettage. Patients were selected from a database registry of patients with face and scalp AKs (ClinicalTrials.gov NCT03319251). Patients in Group 1 underwent PDT alone (20% ALA, 15 min; blue light 417 nm, 30 min). Patients in Group 2 were pretreated with gentle sandpaper curettage prior to ALA and illumination. The two groups were compared using multivariate matching, normalizing for age, sex, initial AK counts, and time to follow-up.

RESULTS

Sixty-six patients were selected for matching analysis (n=38, PDT only; n=28, PDT+curettage). Demographics between the groups were similar (mean ± SD), including age (71.0 ± 8.3 vs. 71.0 ± 8.0 years), baseline AK count (53 ± 39 vs. 44± 32), and time to post-PDT follow-up (111 ± 28 vs. 113 ± 32 days). At follow-up, patients who received curettage showed an overall 55% improvement in scalp AK clearance compared to patients who did not receive curettage, adjusting for sex, age, time to follow-up, and baseline AK count (p = 0.0322, multivariable linear regression).

DISCUSSION

Sandpaper curettage before PDT treatment is an easy and inexpensive method to significantly improve AK clearance rates.

Effect of 5-Aminolevulinic Acid Photodynamic Therapy with Transfer Factor Capsules in the Treatment of Multiple Plantar Warts

BACKGROUND

Plantar warts are a common cutaneous disease of the sole of the foot caused by human papillomavirus. Photodynamic therapy has gained increasing attention in the treatment of plantar warts.

OBJECTIVE

To investigate the effect of photodynamic therapy combined with transfer factor capsules in the treatment of multiple plantar warts.

METHODS

Sixty-one patients with multiple plantar warts who visited our outpatient department from September 2017 to August 2019 were randomly divided into two groups. Twenty-three patients received photodynamic therapy (treatment group) and thirty-eight received cryotherapy (control group). Both groups also received immune modulator transfer factor capsules. Skin lesion score, numeric rating scale- (NRS-) 10 score, recurrence rate, adverse reactions, and Dermatology Life Quality Index (DLQI) were analyzed in both groups.

RESULTS

The mean skin lesion score improved from 13.39 ± 3.88 before treatment to 1.48 ± 2.50 after the last treatment in the treatment group and from 12.47 ± 2.99 before treatment to 4.47 ± 3.67 after the last treatment in the control group. The success rate after 3 months of treatment was 86.96% in the treatment group and 39.47% in the control group. After 3 months of follow-up, the recurrence rate was significantly lower in the treatment group (20%) than in the control group (53.33%). The mean DLQI score at three months after treatment was significantly lower in the treatment group (3.61 ± 1.16) than in the control group (6.31 ± 2.59).

CONCLUSION

Photodynamic therapy combined with immunomodulators significantly increased the cure rate and reduced the recurrence rate of multiple plantar warts compared with traditional cryotherapy combined with immunomodulators.

An Update on Photodynamic Therapy of Psoriasis—Current Strategies and Nanotechnology as a Future Perspective

Psoriasis (PS) is an immune-mediated skin disease with substantial negative effects on patient quality of life. Despite significant progress in the development of novel treatment options over the past few decades, a high percentage of patients with psoriasis remain undertreated and require new medications with superior long-term efficacy and safety. One of the most promising treatment options against psoriatic lesions is a form of phototherapy known as photodynamic therapy (PDT), which involves either the systemic or local application of a cell-targeting photosensitizing compound, followed by selective illumination of the lesion with visible light. However, the effectiveness of clinically incorporated photosensitizers in psoriasis treatment is limited, and adverse effects such as pain or burning sensations are frequently reported. In this study, we performed a literature review and attempted to provide a pooled estimate of the efficacy and short-term safety of targeted PDT in the treatment of psoriasis. Despite some encouraging results, PDT remains clinically underutilized. This highlights the need for further studies that will aim to evaluate the efficacy of a wider spectrum of photosensitizers and the potential of nanotechnology in psoriasis treatment.

Two-step irradiance schedule for condyloma acuminatum and the influencing factors of analgesic effect: A prospective randomized study

BACKGROUND

The two-step irradiance schedule in photodynamic therapy (PDT) is an emerging treatment method with a remarkable analgesic effect. We evaluated the influencing factors of pain in condyloma acuminate (CA) treatment with a two-step irradiance schedule.

METHODS

All patients were randomly divided into a two-step irradiance group and control group. The two-step irradiance group used 40 mW/cm² for the first 8min, followed by 80 mW/cm² for 16 min, while the control group used 80 mW/cm² for 20 min. The Numerical Rating Scale (NRS) scores and pain-influencing factors were recorded accordingly.

RESULTS

In the two-step irradiance and control groups, 64 and 63 patients completed the treatment, respectively. The NRS scores of the two-step irradiance group were significantly lower than that of the control group (p < .001), with a low fluence rate inducing less pain compared with a high fluence rate (p < .001). Moreover, when the total fluence accumulated to 57.6 J/cm² , the pain experienced by patients reached its peak. The NRS score of the urethral orifice group was the highest, and the male external genitalia group was the lowest. The NRS score was at its lowest in the first session and highest in the second session. There was a linear relationship between pain and wart size. Among these influencing factors, the fluence rate had the greatest impact on pain.

CONCLUSION

The two-step irradiance schedule provides better analgesic effects than standard treatment irradiation while showing similar treatment efficacy. Factors that influence pain include high fluence rate, CA at the urethral orifice, second therapy session, wart size, and the interval between CO₂  laser and ALA-PDT.

Significant improvement of facial actinic keratoses after blue light photodynamic therapy with oral vitamin D pretreatment: An interventional cohort-controlled trial

BACKGROUND

In mouse models of skin cancer, high-dose oral vitamin D3 (VD3; cholecalciferol) combined with photodynamic therapy (PDT) can improve the clearance of squamous precancers (actinic keratoses [AKs]).

OBJECTIVE

To determine whether oral VD3 can improve the clinical efficacy of a painless PDT regimen in humans with AK.

METHODS

The baseline lesion counts and serum 25-hydroxyvitamin D₃ levels were determined. In group 1, 29 patients underwent gentle debridement and 15-minute aminolevulinic acid preincubation with blue light (30 minutes; 20 J/cm²). In group 2, 29 patients took oral VD3 (10,000 IU daily for 5 or 14 days) prior to debridement and PDT. Lesion clearance was assessed at 3 to 6 months.

RESULTS

In group 1, the mean clearance rates of facial AK were lower in patients with VD3 deficiency (25-hydroxyvitamin D₃ level < 31 ng/dL; clearance rate, 40.9% ± 42%) than in patients with normal 25-hydroxyvitamin D₃ levels (62.6% ± 14.2%). High-dose VD3 supplementation (group 2) significantly improved the overall AK lesion response (72.5% ± 13.6%) compared with that in group 1 (54.4% ± 22.8%). No differences in side effects were noted.

LIMITATIONS

Nonrandomized trial design (interventional cohort matched to registry-based controls).

CONCLUSIONS

Oral VD3 pretreatment significantly improves AK clinical responses to PDT. The regimen appears promising and well tolerated.

Topical Photodynamic Therapy with Different Forms of 5-Aminolevulinic Acid in the Treatment of Actinic Keratosis

Photodynamic therapy (PDT) is safe and effective in the treatment of patients with actinic keratosis (AK). The aim of the study was to assess the efficacy, tolerability and cosmetic outcome of topical PDT in the treatment of AKs with three forms of photosensitizers: 5-Aminolevulinic acid hydrochloride (ALA-HCl), 5-Aminolevulinate methyl ester hydrochloride (MAL-HCl) and 5-Aminolevulinate phosphate (ALA-P). The formulations were applied onto selected scalp/face areas. Fluorescence was assessed with a FotoFinder Dermoscope 800 attachment. Skin areas were irradiated with Red Beam Pro+, Model APRO (MedLight GmbH, Herford, Germany). Applied treatments were assessed during the PDT as well as 7 days and 12 weeks after its completion. Ninety-four percent of patients rated obtained cosmetic effect excellent. The efficacy of applied PSs did not differ significantly. However, pain intensity during the PDT procedure was significantly lower in the area treated with ALA-P (5.8 on average) in comparison to the areas treated with ALA-HCl or MAL-HCl (7.0 on average on 0-10 scale). Obtained results show that ALA-P may undergo more selective accumulation than ALA-HCl and MAL-HCl. Our promising results suggest that PDT with the use of ALA-P in AK treatment may be an advantageous alternative to the already used ALA-HCl and MAL-HCl.

Modified 5-aminolevulinic acid photodynamic therapy reduces pain and improves therapeutic effects in cutaneous squamous cell carcinoma mouse model

BACKGROUND AND OBJECTIVES

Conventional ALA-PDT (C-PDT) has limited efficacy in cutaneous squamous cell carcinoma (cSCC), and there is obvious pain during treatment, which limits its clinical application. We sought to modify photodynamic therapy into a more painless and effective treatment.

METHODS

We modified C-PDT by reducing the incubation time of the pro-sensitizer and increasing the light dose; we named this method modified ALA-PDT (M-PDT). We compared the pain response and curative effect between C-PDT and M-PDT in cSCC mouse models. Pain-related proteins were examined by western blot analysis and immunohistochemistry. Tumor progression-associated signaling pathways were analyzed by RNA-seq and western blot analysis. Reactive oxygen species (ROS) generation was measured with a ROS test kit and Microplate reader.

RESULTS

M-PDT greatly reduced pain during treatment. Interestingly, when the cSCC tumor volume increased to 150-200 mm³ , M-PDT almost completely eliminated the tumors, while C-PDT did not. The better curative effect of M-PDT might be due to the stronger suppression of the Stat3, Erk1/2, and mTOR signaling pathways. Moreover, flow cytometry demonstrated that M-PDT could recruit CD8⁺ T cells to inhibit cSCC progression. Further investigation determined that the different mechanisms of C-PDT and M-PDT were related to more ROS generation induced by M-PDT.

CONCLUSIONS

Our results suggest that M-PDT, which is more painless and effective than C-PDT, is expected to provide a solution for the treatment of cSCC.

A new photodynamic therapy protocol for nodular basal cell carcinoma treatment: Effectiveness and long-term follow-up

BACKGROUND

Photodynamic therapy (PDT) has been reported as an excellent option for the treatment of small nodular basal cell carcinomas (nBCC). The standard protocol consists of two sessions, one week apart. Sometimes, returning to the hospital after one week can be impractical for elderly patients, due to comorbidities and mobility issues. Therefore, a new technique performed in one day could be superior for those patients.

OBJECTIVE

Evaluate the effectiveness of a PDT Single-visit protocol comparing to the standard protocol, as well as pain and long-term recurrence-free follow-up for nBCC.

METHODS

A total of 120 nBCC were treated through a Standard PDT protocol(two sessions, one week apart), and 120 nBCC were treated through a Single-visit PDT(two sessions in one day). A 30-day-after biopsy was performed in order to evaluate the results after the treatment. The lesions that had successful treatment were clinically and dermoscopically evaluated every 6 months up to 60 months. The pain score was compared between the groups(assessed every 3 min during PDT).

RESULTS

A complete response at 30-days-after PDT biopsy was observed in 85% of Standard PDT and in 93.3% of Single-visit PDT. Regarding the pain during the illumination, less pain was observed during the second session of the Single-visit PDT. The recurrence-free follow up showed, after 60 months, an 69.0% cumulative probability of recurrence-free for Standard PDT and 80.6% for Single-visit PDT.

CONCLUSIONS

The suggested Single-visit PDT protocol resulted in better outcomes at 30-day-after PDT biopsy and in lower recurrence rates than the Standard PDT protocol. A more comfortable and more efficient treatment was offered for the patients, with lower pain.

Non-Surgical Treatments for Keratinocyte Carcinomas

Skin cancer is the most common malignancy worldwide, comprising approximately 30% of all human tumors. In recent decades, the incidence of keratinocyte carcinomas, which include basal cell carcinoma and cutaneous squamous cell carcinoma, has been steadily increasing globally (Rogers et al. in JAMA Dermatol 151(10):1081-1086. https://doi.org/10.1001/jamadermatol.2015.1187 , 2015; Nehal and Bichakjian in N Engl J Med 379(4):363-374. https://doi.org/10.1056/nejmra1708701 , 2018). Most tumors are cured with surgical excision; however, some tumors are best treated with non-surgical approaches. Superficial tumors can often be cured with non-surgical methods whereas more advanced stage tumors may not be amenable to surgery. Additionally, surgical treatment may not be available for all populations depending on geographic location and accessibility to care. This article reviews commonly utilized nonsurgical options such as cryotherapy, photodynamic therapy, topical treatments, and radiation as well as systemic treatments including immunotherapies and chemotherapies.

RANDOMIZED CONTROLLED TRIAL FOR EVALUATION OF EFFICACY AND PAIN DURING PHOTODYNAMIC THERAPY FOR ACTINIC KERATOSIS OF FACE AND SCALP COMPARING TWO IRRADIATION PROTOCOLS

BACKGROUND

Pain is a frequent adverse event during photodynamic therapy, which can limit treatment acceptance. This study aimed to evaluate the efficacy and pain during photodynamic therapy with two irradiation protocols in patients with actinic keratosis on the face and scalp.

METHODS

In this intra-patient randomized controlled trial, participants were randomly allocated to receive photodynamic therapy with methyl aminolevulinate and red light on the right or left side with protocol 1 (irradiation device in contact with the skin) and protocol 2 (device 3 cm away from the skin). There was a 15-day interval between the protocols. The primary outcome was the frequency of mean intensity of moderate or severe pain during photodynamic therapy. Secondary outcomes were actinic keratosis clearance rate, protoporphyrin IX consumption, participant preference, skin appearance, and adverse events.

RESULTS

Forty-one participants were included, yielding 47 and 50 randomized sites for protocols 1 and 2. There was no difference in the frequency of moderate and severe pain, with a relative risk of 1.09 (95% CI 0.70-1.70), p>0.05. An actinic keratosis count reduction >60% was observed in both protocols (p<0.01), with no difference between them. There was no difference in protoporphyrin IX consumption. Most treated sites were of good to excellent quality. There was a greater patient preference for protocol 2 (p<0.01).

CONCLUSIONS

The pain intensity was similar between the protocols, and the protocols were equally effective for actinic keratosis clearance, protoporphyrin IX consumption, and improvement in the quality of the treated areas. Both protocols can be considered safe.

Photodynamic therapy for leishmaniasis: Recent advances and future trends

Leishmaniasis has infected more than 12 million people worldwide. This neglected tropical disease, causing 20,000-30,000 deaths per year, is a global health problem. The emergence of resistant parasites and serious side effects of conventional therapies has led to the search for less toxic and non-invasive alternative treatments. Photodynamic therapy is a promising therapeutic strategy to produce reactive oxygen species for the treatment of leishmaniasis. In this regard, natural and synthetic photosensitizers such as curcumin, hypericin, 5-aminolevulinic acid, phthalocyanines, phenothiazines, porphyrins, chlorins and nanoparticles have been applied. In this review, the recent advances on using photodynamic therapy for treating Leishmania species have been reviewed.

Clinical Pharmacokinetics and Safety of a 10% Aminolevulinic Acid Hydrochloride Nanoemulsion Gel (BF-200 ALA) in Photodynamic Therapy of Patients Extensively Affected With Actinic Keratosis: Results of 2 Maximal Usage Pharmacokinetic Trials

The nanoemulsion‐based 10% aminolevulinic acid (ALA) hydrochloride gel BF‐200 ALA optimizes epidermal penetration of its active ingredient and is approved for topical photodynamic therapy (PDT) for the treatment of actinic keratosis in the United States and Europe. To characterize systemic absorption from dermal application during PDT, ALA and its key active metabolite protoporphyrin IX (PpIX) were analyzed in 2 maximal usage pharmacokinetic trials (MUsT) in patients severely affected with actinic keratosis. The primary objective of both MUsTs was to assess baseline‐adjusted plasma concentration–time curves for ALA and PpIX after a single PDT treatment applying either 2 g (1 tube) of BF‐200 ALA on the face (MUsT‐1) or applying 6 g (3 tubes) of BF‐200 ALA on the face/scalp or body periphery (MUsT‐2), to 20 or 60 cm², respectively. All PDTs were performed using red light at around 635 nm wavelength. Safety and tolerability were documented along with pharmacokinetics. In both MUsTs, ALA plasma concentrations were transiently increased to a maximum concentration at about 2.5 to 3.3 times above endogenous baseline with time to maximum concentration at ≈3 hours after dosing. Plasma levels subsequently returned to baseline within 10 hours after dosing. Overall baseline‐adjusted mean area under the baseline‐adjusted plasma concentration‐time curve from time zero to the last sampling time point at which the concentration was at or above the lower limit of quantification ranged from 142.8 to 146.2, indicating that a similar, minor fraction of topical ALA is systemically absorbed under both dosing regimens. Systemic PpIX exposure after administration of either dose of BF‐200 ALA was equally minimal. Application site skin reactions were treatment area size‐related, albeit transient and consistent with the known safety profile of BF‐200 ALA.

Current Advances in Photoactive Agents for Cancer Imaging and Therapy

Photoactive agents are promising complements for both early diagnosis and targeted treatment of cancer. The dual combination of diagnostics and therapeutics is known as theranostics. Photoactive theranostic agents are activated by a specific wavelength of light and emit another wavelength, which can be detected for imaging tumors, used to generate reactive oxygen species for ablating tumors, or both. Photodynamic therapy (PDT) combines photosensitizer (PS) accumulation and site-directed light irradiation for simultaneous imaging diagnostics and spatially targeted therapy. Although utilized since the early 1900s, advances in the fields of cancer biology, materials science, and nanomedicine have expanded photoactive agents to modern medical treatments. In this review we summarize the origins of PDT and the subsequent generations of PSs and analyze seminal research contributions that have provided insight into rational PS design, such as photophysics, modes of cell death, tumor-targeting mechanisms, and light dosing regimens. We highlight optimizable parameters that, with further exploration, can expand clinical applications of photoactive agents to revolutionize cancer diagnostics and treatment.

Reducing non-melanoma skin cancer risk in renal transplant recipients

With an increasing number of renal transplant recipients (RTRs) and improving patient survival, a higher incidence of non-melanoma skin cancer (NMSC) has been observed. NMSC in RTRs are often more numerous and biologically more aggressive than the general population, thus contributing towards an increase in morbidity and to a lesser degree, mortality. The resultant cumulative health and financial burden is a recognized concern. Proposed strategies in mitigating risks of developing NMSC and early therapeutic options thereof include tailored modification of immunosuppressants in conjunction with sun protection in all transplant patients. This review highlights the clinical and financial burden of transplant-associated skin cancers, carcinogenic mechanisms in association with immunosuppression, importance of skin cancer awareness campaign and integrated transplant skin clinic, and the potential role of chemoprotective agents. A scheme is proposed for primary and secondary prevention of NMSC based on the available evidence.

Painless Photodynamic Therapy Triggers Innate and Adaptive Immune Responses in a Murine Model of UV-induced Squamous Skin Pre-cancer

Painless photodynamic therapy (p-PDT), which involves application of photosensitizer and immediate exposure to light to treat actinic keratosis (AK) in patients, causes negligible pain on the day of treatment but leads to delayed inflammation and effective lesion clearance (Kaw et al., J Am Acad Dermatol 2020). To better understand how p-PDT works, hairless mice with UV-induced AK were treated with p-PDT and monitored for 2 weeks. Lesion clearance after p-PDT was similar to clearance after conventional PDT (c-PDT). However, lesion biopsies showed minimal cell death and less production of reactive oxygen species (ROS) in p-PDT treated than in c-PDT-treated lesions. Interestingly, p-PDT triggered vigorous recruitment of immune cells associated with innate immunity. Neutrophils (Ly6G+) and macrophages (F4/80+) appeared at 4 h and peaked at 24 h after p-PDT. Damage-associated molecular patterns (DAMPs), including calreticulin, HMGB1, and HSP70, were expressed at maximum levels around 24 h post-p-PDT. Total T cells (CD3+) were increased at 24 h, whereas large increases in cytotoxic (CD8+) and regulatory (Foxp3+) T cells were observed at 1 and 2 weeks post-p-PDT. In summary, the ability of p-PDT to eliminate AK lesions, despite very little overt cellular damage, appears to involve stimulation of a local immune response.

The place of 5-aminolaevulinic acid-photodynamic therapy in the treatment landscape of urethral warts: A systematic review

BACKGROUND

Human papilloma virus (HPV) infection is the most common sexually transmitted disease worldwide and the main cause of genital warts. Clear recommendations for the management of urethral warts, which are often hard to detect and difficult to treat, are still lacking.

OBJECTIVE

To summarize all available data describing treatment modalities of urethral warts, compare their efficacy and side effects, and provide physicians a treatment strategy outline.

MATERIAL AND METHODS

Till June 2020, we conducted a systematic review of articles studying the different treatment modalities of urethral condylomas. A chi-square test was used to compare the recurrence rates between treatment modalities, the complete clearance rates at first follow-up and the rates of adverse events.

RESULTS

A total of 26 articles with 1730 patients were included in our review. 61 % of patients were deemed completely cured on the first follow-up while 21 % recurred. 5-aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) was the most common treatment and yielded the lowest recurrence rate (7.5 %) followed by laser therapy (24 %) and topical therapy (31 %) (p < 0.01). ALA-PDT resulted in a higher rate of clearance on follow up (96 %) compared to laser therapy (69 %) and topical therapy (14 %) (p < 0.01). Adverse events were more frequent in the ALA-PDT group (69 %) compared to laser therapy (28 %) and topical treatment (30 %) (p < 0.01).

CONCLUSION

ALA-PDT appears to be the most effective treatment of urethral condylomas in term of clearance and recurrence rate, but with a higher risk of adverse events. Management should be tailored to the type of lesion found at presentation.

MAL-associated methyl nicotinate for topical PDT improvement

Photosensitization of all tissue in sufficient quantity to generate damage is one of the limiting factors for Photodynamic Therapy (PDT) efficiency. Methyl nicotinate (MN) is a thermogenic and vasodilating substance that facilitates the topical tissue penetration of some compounds. The topical MAL (methyl aminolevulinate) PDT is commonly used as a precursor of protoporphyrin IX (PpIX). This study investigates the safety of topical use in NM, as well as its ability to improve the efficiency of topical PDT. For this, we investigate the cytotoxicity of MN, as well as its actions in increasing cellular metabolism and vasodilation. Besides, its ability to optimize the formation of PpIX in the tissue when associated with MAL cream was investigated, besides assessing the severity of necrosis obtained by treatments. The cytotoxicity of MN was tested for concentrations of 0, 0.1, 0.25, 0.5, 0.75 and 1% in cell culture. For the concentration of 0.5%, the cellular metabolism was evaluated using confocal microscopy to calculate the redox rate. In the Chorioallantoic Membrane Model, vasodilation was evaluated for concentrations of 0.5 and 1% MN during 1 h of incubation. In the animal model, the healthy skin of Wistar rat was used to evaluate the production of PpIX in the tissue and the degree of necrosis obtained by Photodynamic therapy when using NM associated with methyl aminolevulinate. It was observed the non-cytotoxicity in vitro of MN in the concentration used (0.5%) and its ability to increase cellular metabolism. In a chorioallantoic model, the MN vasodilation power was demonstrated for different caliber of vessels. In vivo studies are showing that the incorporation of MN in the MAL cream increases the amount of PpIX produced in the tissue causing a higher effect on the epidermis after PDT. This improvement of the protocol may make the procedure more effective both in the destruction of tumor tissue and in the treatment of deeper cells decreasing possible recurrence, in addition to allowing improvements in the protocol, such as reducing the cream's incubation time.

Sulfonated hydroxyaluminum phthalocyanine-biogenic Au/Ag alloy nanoparticles mixtures for effective photo-eradication of Candida albicans

In response to the increasingly widespread resistance of fungi to traditional treatment, we have reported successful photodynamic inactivation of Candida albicans planktonic cells using di-(AlPcS₂) and trisulfonated (AlPcS₃) hydroxyaluminum phthalocyanines in combination with Au/Ag alloy nanoparticles synthesized by the cell-free filtrate of Trichoderma koningii. These nanostructures with Au:Ag molar ratios 2:1, 1:1 and 1:2 have individual plasmonic band at 513-515 nm, 505-509 nm and 486-489 nm, respectively. XPS analysis of the ratio of gold to silver on the surface of these alloys indicated that Au and Ag formed a bimetallic system, wherein Au was coated with Ag. The XRD pattern revealed the angles at 38.2, 44.5, 64.9 and 78.0°. TEM analysis indicated that the average diameter of the synthesized alloys was 9 ± 3 nm, 8 ± 3 nm and 16 ± 3 nm for structures with Au:Ag molar ratios 1:1, 1:2 and 2:1, respectively. The FTIR band absorption, SEM-EDS analysis and basic elemental composition obtained by XPS confirmed that these nanostructures are stabilized by protein(s). Diode laser with the peak-power wavelength ʎ = 650 nm (output power of 40 mW; power density of 105 mW cm^-2) was used as a light source. The mixture of AlPcS₂+Au/Ag-NPs (Au:Ag = 2:1) can be considered as an effective photosensitizer, because eradication of C. albicans, as required by the American Society of Microbiology (99.9 %), was achieved at a low dose of light of 31.5 J cm^-2. It was postulated that this low dose of light applied to the photo-induced fungicidal effect may be painless for potential patients.

Actinic keratosis area and severity index is not correlated with photodynamic therapy procedural pain

BACKGROUND

The Actinic Keratosis Area and Severity Index (AKASI) is a validated quantitative tool used to measure the severity of actinic keratoses. Given the success of AKASI in measuring outcomes and therapies related to actinic damage, we hypothesized that AKASI would be correlated to photodynamic therapy (PDT)-related pain. The aim of this study was to evaluate AKASI's correlation with PDT-associated pain for patients with AKs being treated with 5-Aminolevulinic acid (ALA) PDT.

METHODS

Thirty consecutive patients being treated for AKs with ALA PDT on the face and/or scalp were recruited from a single center. The AKASI of the treated areas were collected. The patient underwent a standard treatment with ALA-PDT for a total of 10 J/cm2 to treated area. Immediate post-procedural pain scores were measured using a visual-analog pain scale. Pain and AKASI scores were analyzed using Pearson's correlation coefficient.

RESULTS

AKASI was not correlated to pain score (Pearson correlation coefficient was 0.027, p = 0.87). In sub-group analyses, there was no strong correlation between the scalp AKASI or face AKASI and respective pain scores (p = 0.59 and p = 0.38, respectively). Furthermore, there was no strong correlation between the individual components of AKASI and pain score: distribution (p = 0.26), erythema (p = 0.66) and thickness (p = 0.43).

CONCLUSION

There is no correlation between the AKASI score and perceived pain from PDT. Therefore, the need for pain relief using a fan and evaporative cooling should be anticipated for all patients. We feel that this negative result is noteworthy as it supports mechanisms outside of AK destruction as the cause of immediate PDT-related pain.

Physical triggering strategies for drug delivery

Physically triggered systems hold promise for improving drug delivery by enhancing the controllability of drug accumulation and release, lowering non-specific toxicity, and facilitating clinical translation. Several external physical stimuli including ultrasound, light, electric fields and magnetic fields have been used to control drug delivery and they share some common features such as spatial targeting, spatiotemporal control, and minimal invasiveness. At the same time, they possess several distinctive features in terms of interactions with biological entities and/or the extent of stimulus response. Here, we review the key advances of such systems with a focus on discussing their physical mechanisms, the design rationales, and translational challenges.

Proposition of standardized protocol for photodynamic therapy for vulvar lichen sclerosus

Background: Photodynamic therapy (PDT) is an alternative treatment modality for vulvar lichen sclerosus (VLS) which is a chronic inflammatory mucosal condition. In literature, no consensus of optimal parameters of PDT for VLS is reached so far.Objectives: The aim of this narrative review is to develop a standardized treatment protocol for PDT in VLS.Methods: A systematic literature search was conducted to identify studies reporting on PDT in VLS and used treatment parameters, side-effects, and clinical outcomes were summarized.Results: Thirteen studies used 5-aminolevulinic acid (5-ALA) with concentrations of 20%, 10%, 5% and three studies used methyl aminolevulinate (MAL). Generally, the light source was red light (median 630 nm). Light dose varied between 9 and 180 J/cm² and light intensity between 40 and 700 mW/cm². Incubation period with the photosensitizer ranged from 2 to 6 h. All studies showed a substantial improvement in VLS-related pruritus, burning and pain.Conclusions: Based on a literature review, we suggest the following protocol for PDT in VLS: 5% 5-ALA as a photosensitizer applied for 3 h under occlusion before irradiation at the dose of 120 J/cm² with red light (590-760 nm) and intensity of 204 mW/cm².

Vitamin D and Other Differentiation-promoting Agents as Neoadjuvants for Photodynamic Therapy of Cancer

The efficacy of photodynamic therapy (PDT) using aminolevulinic acid (ALA), which is preferentially taken up by cancerous cells and converted to protoporphyrin IX (PpIX), can be substantially improved by pretreating the tumor cells with vitamin D (Vit D). Vit D is one of several "differentiation-promoting agents" that can promote the preferential accumulation of PpIX within the mitochondria of neoplastic cells, making them better targets for PDT. This article provides a historical overview of how the concept of using combination agents ("neoadjuvants") for PDT evolved, from initial discoveries about neoadjuvant effects of methotrexate and fluorouracil to later studies to determine how vitamin D and other agents actually work to augment PDT efficacy. While this review focuses mainly on skin cancer, it includes a discussion about how these concepts may be applied more broadly toward improving PDT outcomes in other types of cancer.

Photodynamic therapy for severe facial acne vulgaris with 5% 5-aminolevulinic acid vs 10% 5-aminolevulinic acid: A split-face randomized controlled study

BACKGROUND

Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) has been described as an effective treatment for severe acne. However, very little evidence exists on the optimal concentration of ALA used in PDT for severe acne.

OBJECTIVES

To compare the efficacy and safety of PDT with 5% ALA vs 10% ALA in severe acne.

METHODS

Twenty-three patients with severe facial acne were randomly assigned to receive PDT with 5% ALA or 10% ALA on the left or right side of the face. Four PDT sessions were conducted with a light dose of 96 J/cm2 . The reduction rates of lesion counts between the two groups were compared at the week-4 and week-12 follow-up visits. Effective rate at the week-12 visit was the primary clinical outcome. Pain and other side effects were evaluated at each visit.

RESULTS

The decrease in inflammatory lesions in the 10% ALA group was greater than that in the 5% ALA group at both week-4 (79.2% vs 62.5%, P = 0.009) and week-12 follow-up visits (88.5% vs 78.3%, P = 0.018), while the decrease in noninflammatory lesion counts between the two groups was not statistically significant at each follow-up visit. The effective rate in the 10% ALA group was significantly higher than that in the 5% ALA group (95.7% vs 69.6%, P = 0.02). No significant difference was observed in pain scores between the two groups except in the first treatment session.

CONCLUSIONS

Photodynamic therapy using 10% ALA was more effective for severe acne than PDT using 5% ALA.

Metalloporphyrin Pd(T4) Exhibits Oncolytic Activity and Cumulative Effects with 5-ALA Photodynamic Treatment against C918 Cells

Photodynamic therapy is a non-invasive method where light activates a photosensitizer bound to cancer cells, generating reactive oxygen species and resulting in cell death. This study assessed the oncolytic potential of photodynamic therapy, comparing European Medicines Agency and United States Food and Drug Administration-approved 5-aminolevulinic acid (5-ALA) to a metalloporphyrin, Pd(T4), against a highly invasive uveal melanoma cell line (C918) in two- and three-dimensional models in vitro. Epithelial monolayer studies displayed strong oncolytic effects (>70%) when utilizing Pd(T4) at a fraction of the concentration, and reduced pre-illumination time compared to 5-ALA post-405 nm irradiance. When analyzed at sub-optimal concentrations, application of Pd(T4) and 5-ALA with 405 nm displayed cumulative effects. Lethality from Pd(T4)-photodynamic therapy was maintained within a three-dimensional model, including the more resilient vasculogenic mimicry-forming cells, though at lower rates. At high concentrations, modality of cell death exhibited necrosis partially dependent on reactive oxygen species. However, sub-optimal concentrations of photosensitizer exhibited an apoptotic protein expression profile characterized by increased Bax/Bcl-2 ratio and endoplasmic stress-related proteins, along with downregulation of apoptotic inhibitors CIAP-1 and -2. Together, our results indicate Pd(T4) as a strong photosensitizer alone and in combination with 5-ALA against C918 cells.

MOP-dependent enhancement of methadone on the effectiveness of ALA-PDT for A172 cells by upregulating phosphorylated JNK and BCL2

BACKGROUND

Methadone, as a long-acting opioid analgesic, shows an ability to sensitize the treatment of ALA-PDT for glioblastoma cells (A172) in vitro by promoting apoptosis. However, the mechanisms how methadone enhances the effectiveness of ALA-PDT for tumor cells remains to be clarified.

METHODS

The expression of mu opioid receptor (MOP), apoptosis, phosphorylated c-Jun N-terminal kinase (JNK) and phosphorylated apoptosis regulator B cell lymphoma 2 (BCL2) were measured by flow cytometry. Cytotoxicity was determined using Cell Counting Kit-8 (CCK-8). A MOP antagonist, naloxone, was used to evaluate the role of MOP in the above process.

RESULTS

It was found that A172 cells show the expression of MOP and that naloxone inhibits the enhancement of the methadone effect on apoptosis following ALA-PDT (p < 0.05). Phosphorylated JNK and BCL2 induced by ALA-PDT were promoted in the presence of methadone (p < 0.05). These methadone effects were also inhibited by naloxone (p < 0.05).

CONCLUSIONS

The results suggest that apoptosis induced by ALA-PDT is enhanced by methadone, mostly MOP-mediated, through the upregulation of accumulation of phosphorylated JNK and BCL2, leading to a promotion of cytotoxicity of ALA-PDT for A172 cells.

A regimen to minimize pain during blue light photodynamic therapy of actinic keratoses: Bilaterally controlled, randomized trial of simultaneous versus conventional illumination

BACKGROUND

Blue light photodynamic therapy (PDT) is effective for actinic keratosis, but many patients experience stinging pain during illumination.

OBJECTIVE

To compare a conventional regimen (1 hour of 5-aminolevulinic acid [ALA] preincubation, followed by blue light) versus a new modified regimen in which blue light is started immediately after ALA application.

METHODS

A clinical trial with a bilaterally controlled, intrapatient study design was conducted with 23 patients. Topical 20% ALA was applied to the entire face and/or scalp. On 1 side of the body, blue light was started immediately and continued for either 30, 45, or 60 minutes (simultaneous PDT). On the contralateral side, the blue light began 1 hour after ALA application and lasted 1000 seconds (conventional PDT). Pain was evaluated on a scale from 0 to 10. Actinic keratosis lesion counts were determined by clinical examination and photography.

RESULTS

All patients experienced significantly less pain during simultaneous illumination than during the conventional regimen. At 3 months after treatment, lesion clearance was nearly identical on the 2 sides, as determined by statistical testing of noninferiority ± 15% margin.

LIMITATIONS

Although bilaterally controlled, the study was relatively small. Additional studies are recommended.

CONCLUSION

The modified PDT regimen is essentially painless, yet it provides treatment efficacy similar to a conventional regimen.

Efficacy and safety of photodynamic therapy with amino-5-laevulinate nanoemulsion versus methyl-5-aminolaevulinate for actinic keratosis: A meta-analysis

BACKGROUND

Photodynamic therapy is an effective treatment for actinic keratosis. 5-aminolevulinic acid nanoemulsion (BF-200 ALA) and methyl-5-aminolevulinate (MAL) are both prodrugs for the treatment of actinic keratosis with photodynamic therapy. A comparison of the efficacy and safety between the drugs is critical for clinical practice.

OBJECTIVES

To investigate if photodynamic therapy in combination with BF-200 ALA is superior to photodynamic therapy with MAL for actinic keratosis.

METHODS

We performed a meta-analysis to investigate the combination of photodynamic therapy with BF-200 ALA and with MAL. The PubMed, Cochrane Library, Web of Science and EMBASE databases were searched to select eligible randomized controlled trials. Our search was conducted on April 1, 2019, and included the search terms "5-aminolevulinic acid nanoemulsion or BF-200 ALA", "methyl-5-aminolevulinate or methyl aminolaevulinate" and "actnic keratosis". Cochrane Risk of Bias Tool was used to estimate the risk of bias.

RESULTS

The meta-analysis consisted of 5988 actinic keratosis lesions in five eligible randomized controlled trials, with a total of 2953 actinic keratosis lesions treated with BF-200 ALA and 3035 actinic keratosis lesions treated with MAL. BF-200 ALA in combination with photodynamic therapy showed significantly higher overall complete clearance rates (RR: 1.07, 95% CI 1.02-1.12, p = 0.01) and 3 month complete clearance rates (RR: 1.09, 95% CI 1.06-1.12, p < 0.00001) compared to MAL. A subgroup analysis was performed for photodynamic therapy combined with BF-200 ALA, revealing increased complete clearance rates of grade II-III lesions in comparison with MAL (RR: 1.24, 95% CI 1.05-1.46, p = 0.01). Compared with MAL, the pooled relative risk for the meta-analysis for recurrence was 0.67 (95% CI 0.48-0.92, p = 0.01) at 12 month after BF-200 ALA treatment.

CONCLUSION

Photodynamic therapy with BF-200 ALA has a 9% better chance of complete clearance at 3 months and a 24% better chance of grade II-III lesions after treatment than with MAL for patients with actinic keratosis.

Painless versus conventional photodynamic therapy for treatment of actinic keratosis: Comparison of cell death and immune response in a murine model

Aminolevulinic acid based photodynamic therapy (ALA-PDT) is a popular and efficacious treatment for actinic keratosis (AK). However, standard PDT can elicit stinging pain during illumination, and hence is not always favored by patients. In a new regimen called metronomic PDT (mPDT), similar to daylight PDT but using blue light, the illumination is delivered concurrently with ALA application rather than after a 1-hour pre-incubation (conventional regimen, cPDT). In the clinic, mPDT is not only painless but also nearly as effective as cPDT for AK lesion clearance. In this investigation, a murine AK model (generated by repeated UVB exposure) was treated with either mPDT or cPDT. Lesion clearance was followed by area measurement, and samples were harvested for mechanistic analyses. Compared to pretreatment (100%), the average lesion area was reduced to 47% and 32% in cPDT, and to 57% and 40% in mPDT at 1- and 2-weeks post PDT, respectively. Relative to untreated controls, enhanced cell death (histomorphology by H&E staining and apoptosis by TUNEL assay), and generation of Reactive Oxygen Species (ROS; CM-H2DCFDA staining) were observed in both cPDT and mPDT samples. Activation of cleaved Caspase-3 was specifically observed only in cPDT samples. Immunomodulation by inflammatory cells was observed by enhanced infiltration/retention of neutrophils and macrophages in metronomic PDT samples. Our results suggest that metronomic PDT can be just as effective as conventional PDT for treatment of AK, but the mechanisms may be quite different.

Dual wavelength 5-aminolevulinic acid photodynamic therapy using a novel flexible light-emitting diode unit

BACKGROUND

Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410 nm, 510 nm, 545 nm, 580 nm, and 630 nm. Although only red light around 635 nm and blue light around 400 nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.

OBJECTIVE

We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.

METHODS

HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50 J/cm² (day 0) and assessed daily until day 21.

RESULTS

The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.

CONCLUSION

We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas.

Optical techniques for the diagnosis and treatment of lesions induced by the human papillomavirus - A resource letter

Human papillomaviruses (HPV) are the most common sexually-transmitted virus, and carcinogenic HPV strains are reported to be responsible for virtually all cases of cervical cancer and its precursor, the cervical intraepithelial neoplasia (CIN). About 30% of the sexually active population are considered to be affected by HPV. Around 600 million people are estimated to be infected worldwide. Diseases related to HPV cause significant impact from both the personal welfare point of view and public healthcare perspective. This resource letter collects relevant information regarding HPV-induced lesions and discusses both diagnosis and treatment, with particular attention to optical techniques and the challenges involved to the implementation of those approaches.

5-Fluorouracil Enhances Protoporphyrin IX Accumulation and Lesion Clearance during Photodynamic Therapy of Actinic Keratoses: A Mechanism-Based Clinical Trial

Purpose: Actinic keratoses (AK) are precancerous lesions that can progress to squamous cell carcinoma. Photodynamic therapy (PDT) and topical 5-fluorouracil (5FU) are commonly used agents for AK. Empirical reports suggest that combining them can improve the therapeutic response. However, the optimal combined regimen was not clear in terms of proper sequence, timing, and mechanism. This clinical study explored mechanisms of action for neoadjuvantal 5FU and PDT for treatment of AK.Patients and Methods: A bilaterally controlled trial (17 patients) was performed. One side of the body (face, scalp, forearms) received 5FU pretreatment for 6 days, whereas the other side served as no-pretreatment control. Methylaminolevulinate cream was applied to both sides for 3 hours, and protoporphyrin IX (PpIX) levels were measured by noninvasive fluorimetry and skin biopsy. After red light illumination, lesion clearance was assessed at 3, 6, 9, and 12 months after PDT.Results: PpIX levels were increased 2- to 3-fold in 5FU-pretreated lesions versus controls. Altered expression of heme-synthetic enzymes (coproporphyrinogen oxidase and ferrochelatase) and induction of p53 were observed, probably accounting for increased PpIX and subsequent cancer cell death. Relative clearance rates after PDT with or without 5FU pretreatment were 75% versus 45% at 3 months, and 67% versus 39% at 6 months, respectively; these differences were statistically significant.Conclusions: Serial 5FU and PDT improve AK clearance by at least two mechanisms, enhanced photosensitizer accumulation and p53 induction. Because 5FU and PDT are FDA-approved modalities, the combined regimen can be readily employed in clinical practice to reduce AK burden and reduce SCC risk. Clin Cancer Res; 24(13); 3026-35. ©2018 AACR.

Blue light versus red light for photodynamic therapy of basal cell carcinoma in patients with Gorlin syndrome: A bilaterally controlled comparison study

BACKGROUND

Photodynamic therapy (PDT) is a non-scarring alternative for treating basal cell carcinoma (BCC) in patients with Basal Cell Nevus Syndrome (BCNS), also known as Gorlin syndrome. In Europe, red light (635 nm) is the predominant source for PDT, whereas in the United States blue light (400 nm) is more widely available. The objective of this study was to conduct a head-to-head comparison of blue light and red light PDT in the same BCNS patients.

METHODS

In a pilot study of three patients with 141 BCC lesions, 5-aminolevulinate (20% solution) was applied to all tumors. After 4 h, half of the tumors were illuminated with blue light and the remainder with red light. To ensure safety while treating this many tumors simultaneously, light doses were escalated gradually. Six treatments were administered in three biweekly sessions over 4 months, with a final evaluation at 6 months. Tumor status was documented with high-resolution photographs. Persistent lesions were biopsied at 6 months.

RESULTS

Clearance rates after blue light (98%) were slightly better than after red light (93%), with blue light shown to be statistically non-inferior to red light. Eight suspicious lesions were biopsied, 5 after red light (5/5 were BCC) and 3 after blue light (1 was BCC). Blue light PDT was reportedly less painful.

CONCLUSION

Blue light and red light PDT appear to be equally safe and perhaps equally effective for treating BCC tumors in BCNS patients. Further studies to evaluate long-term clearance after blue light PDT are needed.

Assessing daylight & low-dose rate photodynamic therapy efficacy, using biomarkers of photophysical, biochemical and biological damage metrics in situ

BACKGROUND

Sunlight can activate photodynamic therapy (PDT), and this is a proven strategy to reduce pain caused byconventional PDT treatment, but assessment of this and other alternative low dose rate light sources, and their efficacy, has not been studied in an objective, controlled pre-clinical setting. This study used three objective assays to assess the efficacy of different PDT treatment regimens, using PpIX fluorescence as a photophysical measure, STAT3 cross-linking as a photochemical measure, and keratinocyte damage as a photobiological measure.

METHODS

Nude mouse skin was used along with in vivo measures of photosensitizer fluorescence, keratinocyte nucleus damage from pathology, and STAT3 cross-linking from Western blot analysis. Light sources compared included a low fluence rate red LED panel, compact fluorescent bulbs, halogen bulbs and direct sunlight, as compared to traditional PDT delivery with conventional and fractionated high fluence rate red LED light delivery.

RESULTS

Of the three biomarkers, two had strong correlation to the PpIX-weighted light dose, which is calculated as the product of the treatment light dose (J/cm²) and the normalized PpIX absorption spectra. Comparison of STAT3 cross-linking to PpIX-weighted light dose had an R=0.74, and comparison of keratinocyte nuclear damage R=0.70. There was little correlation to PpIX fluorescence. These assays indicate most of the low fluence rate treatment modalities were as effective as conventional PDT, while fractionated PDT showed the most damage.

CONCLUSIONS

Daylight or artificial light PDT provides an alternative schedule for delivery of drug-light treatment, and this pre-clinical assay demonstrated that in vivo assays of damage could be used to objectively predict a clinical outcome in this altered delivery process.

A review of BF-200 ALA for the photodynamic treatment of mild-to-moderate actinic keratosis

BF-200 ALA is a combination of a nanoscale-lipid vesicle formulation and the prodrug 5-aminolevulinic acid (5-ALA). The nanoemulsion stabilizes the prodrug and enhances its penetration through the stratum corneum. It has shown excellent therapeutic results in both lesion and field-directed photodynamic therapy of actinic keratosis (AK). AK is an early form of epidermal neoplasia and a precursor of invasive cutaneous squamous cell carcinoma. It is characterized by the combination of visible neoplastic lesions and surrounding tissue also harboring tumorigenic UV-induced mutations: a concept called field cancerization. A selective, field-directed treatment is ideal to meet the requirements of field change. Here, we review the clinical data on BF-200 ALA for AK along with a summary of molecular mechanisms and future perspectives.

Pain during topical photodynamic therapy - comparing methyl aminolevulinate (Metvix®) to aminolaevulinic acid (Ameluz®); an intra-individual clinical study

BACKGROUND

Actinic keratoses are often treated by photodynamic therapy. However, the main side effect of this treatment is pain during and shortly after illumination.

OBJECTIVES

To evaluate, in an intra-individual study, whether the pain response differ in treatment of actinic keratoses in scalp and forhead, using branded methyl aminolevulinate (MAL) and aminolaevulinic acid (ALA).

MATERIALS AND METHODS

Patients with mild to moderate actinic keratoses on forehead and scalp were treated with methyl aminolaevulinate (MAL)-PDT and aminolaevulinic acid (ALA)-PDT on two similar areas of forehead and scalp. The pain response were measured using visual analogue scale ranging from 0 to 10 during the illumination and 30min after the treatment.

RESULTS

Fourteen patients completed treatment to MAL and ALA-PDT. We found no significant difference in pain intensity between MAL and ALA-PDT, neither during the treatment (p-value=1) nor 30min after the treatment (p-value of 0.19).

CONCLUSIONS

This intra-individual study demonstrate no significant difference between the pain response during PDT using methyl aminolevulinate and aminolaevulinic acid.