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

Adjuvant and Neoadjuvant Treatment of Skin Cancer

Skin cancer represents a broad classification of malignancies, which can be further refined by histology, including basal cell carcinoma, squamous cell carcinoma and melanoma. As these three cancers are distinct entities, we review each one separately, with a focus on their epidemiology, etiology including relevant genomic data, and the current evidence-based recommendations for adjuvant and neoadjuvant therapy. We also discuss future directions and opportunities for continued therapeutic advances.

Modeling PpIX effective light fluence at depths into the skin for PDT dose comparison

BACKGROUND

Daylight-activated PDT has seen increased support in recent years as a treatment method for actinic keratosis and other non-melanoma skin cancers. The inherent variability observed in broad-spectrum light used in this methodology makes it difficult to plan and monitor light dose, or compare to lamp light doses.

METHODS

The present study expands on the commonly used PpIX-weighted effective surface irradiance metric by introducing a Monte Carlo method for estimating effective fluence rates into depths of the skin. The fluence rates are compared between multiple broadband and narrowband sources that have been reported in previous studies, and an effective total fluence for various treatment times is reported. A dynamic estimate of PpIX concentration produced during pro-drug incubation and treatment is used with the fluence estimates to calculate a photodynamic dose.

RESULTS

Even when there is up to a 5x reduction between the effective surface irradiance of the broadband light sources, the effective fluence below 250 μm depth is predicted to be relatively equivalent. An effective threshold fluence value (0. 70Jeff/cm2) is introduced based on a meta-analysis of previously published ALA-PpIX induced cell death. This was combined with a threshold PpIX concentration (50 nM) to define a threshold photodynamic dose of 0.035 u M Jeff/cm2.

CONCLUSIONS

The threshold was used to generate lookup tables to prescribe minimal treatment times to achieve depth-dependent cytotoxic effect based on incubation times and irradiance values for each light source.

A non-toxic approach for treatment of breast cancer and its metastases: capecitabine enhanced photodynamic therapy in a murine breast tumor model

AIM

Breast cancer (BCA) in women is a leading cause of mortality and morbidity; distant metastases occur in ~40% of cases. Here, as an alternative to ionizing radiation therapy and chemotherapy and their associated side effects, we explored a new combination approach using capecitabine (CPBN) and aminolevulinate-based photodynamic therapy (PDT). We had previously developed a combination PDT approach in which 5-fluorouracil (5FU), a differentiation-promoting agent, increases the levels of protoporphyrin IX (PpIX) in cancer cells when given as a neoadjuvant prior to aminolevulinic acid (ALA). However, 5FU can be toxic when administered systemically at high levels. We reasoned that CPBN, a known chemotherapeutic for BCA and less toxic than 5FU (because CPBN is metabolized to 5FU specifically within tumor tissues), might work equally well as a PDT neoadjuvant.

METHODS

Murine 4T1 BCA cells harboring a luciferase transgene were injected into breast fat pads of female nude mice. CPBN (600 mg/kg/day) was administered by oral gavage for 3 days followed by intraperitoneal ALA administration and PDT with red light (633 nm) on day 4. Tumor growth and regression were monitored in vivo using bioluminescence imaging. Histological changes in primary tumors and metastases were assessed by immunohistochemistry after necropsy.

RESULTS

CPBN pretreatment of 4T1 tumors increased cellular differentiation, reduced proliferation, raised PpIX levels, enhanced tumor cell death, and reduced metastatic spread of 4T1 cells post-PDT, relative to vehicle-only controls.

CONCLUSION

The use of CPBN as a non-toxic PDT neoadjuvant for treatment of BCA represents a novel approach with significant potential for translation into the clinic.

Fabrication of Red Blood Cell-Based Multimodal Theranostic Probes for Second Near-Infrared Window Fluorescence Imaging-Guided Tumor Surgery and Photodynamic Therapy

The therapeutic efficacy of fluorescence image-guided tumor surgery and photodynamic therapy (PDT) is impaired by the penetration depth limitation, low signal-to-noise ratio of traditional first near-infrared window (NIR I) fluorescence and the hypoxic tumor microenvironment. Here, a "red blood cell-based multimodal probe" was proposed to achieve enhanced tumor targeting and retention of fluorescent probes after an intravenous injection, so that second near-infrared window (NIR II) fluorescence bioimaging-guided complete tumor resection and high-efficiency photodynamic therapy could then be realized. Methods: The hexanoic acid ester-modified rose bengal (RB-HA), RGD (Arginine-Glycine-Aspartic) peptide and avidin were covalently coupled onto amine-modified upconversion nanoparticles (UCNPs) via EDC/NHS reaction (UCNPs@RB@RGD@avidin). Afterwards, the complex of ICG with bovine serum albumin (BSA) was loaded into RBCs through hypotonic dialysis (RBC@ICG). Then, the membrane proteins of RBC@ICG were biotinylated by biotin-modified phospholipids (RBC@ICG@biotin). Finally, the RBCp (Red Blood Cell based probe) was obtained by crosslinking UCNPs@RB@RGD@avidin to RBC@ICG@biotin through the interaction of avidin and biotin. The obtained multimodal RBCp was extensively characterized, both in vitro and in vivo, including analysis of chemical, physical and fluorescent features, O2 delivery ability, tumor accumulation, NIR II fluorescence bioimaging ability, photodynamic therapeutic efficiency, and biosafety. Results: The RBCp experienced efficient tumor targeting and long tumor retention for almost 4 h after intravenous injection, and the superior signal-to-noise ratio at the optimal time window can be used for guiding precise tumor resection under an 808-nm laser irradiation to facilitate lymph popliteal metastasis surgical delineation. Meanwhile, the RBCp can provide laser-responsive O2 release to enhance the PDT efficiency of popliteal lymph node metastasis under NIR II fluorescence bioimaging guidance. These excellent performances obviously lead to remarkably enhanced synergistic therapeutic effects of tumor surgery and metastatic inhibition. Conclusion: The proposed strategy will develop a new platform to increase surgical resection completeness and improve PDT efficiency, resulting in the successful and complete inhibition of tumor and metastasis, which could offer a promising approach for the clinical translation of malignant tumor treatment.

Low-level light-assisted photodynamic therapy using a wearable cap-like device for the treatment of actinic keratosis of the scalp

BACKGROUND

Daylight photodynamic therapy (dlPDT) is a painless and increasingly cost-effective treatment for actinic keratosis (AK). New protocols avoid incubation, minimizing pain and adverse events. However, it is time-consuming and dependent on specific weather conditions. In patients with AK of the scalp, we evaluated the efficacy of indoor photodynamic therapy (PDT) using a wearable low-level light therapy (LLLT) device, without pre-incubation with a photosensitizing agent.

METHODS

In this pilot study, 27 patients with thin and moderately thick AK (Olsen Grades I-II) underwent a single 15-minute session of LLLT using a wearable cap-like device immediately after application of methyl-aminolevulinate (MAL) cream, with no prior preparation of the affected area. Treatment efficacy was quantified by measuring the reduction in AK lesion number and the AK quality of life (AKQoL) score. All AK lesions were mapped at baseline for follow-up 2 months later. Paired pre/post scalp biopsies from 5 patients were analysed using histological and immunohistochemical techniques (p53, p27, cyclin D1, p63, and Ki67 expression). Data were analysed using the Wilcoxon signed-rank test.

RESULTS

In all patients we observed a global reduction in the number of AK lesions (71%; p < 0.0001) and AKQoL score (from 5.6 to 4.4; p = 0.034) 2 months after treatment. Histology and immunohistochemistry of skin biopsies from 5 patients also revealed marked improvements after LLLT. No patients reported any pain during treatment.

CONCLUSION

PDT using LLLT is a rapid, painless, and efficacious modality for the treatment of AK.

Comment on "Coadministration of iRGD with Multistage Responsive Nanoparticles Enhanced Tumor Targeting and Penetration Abilities for Breast Cancer Therapy"

Nanomedicine is at the forefront of targeted drug delivery for cancer therapy. An improved combinatorial approach is highlighted for breast cancer treatment by Hu et al. in this issue of ACS Applied Materials and Interfaces. The authors demonstrated that, by combining multistage-responsive nanoparticles carrying a therapeutic drug, doxorubicin, a photothermal agent, indocyanine green, and a nitric oxide donor with photothermal therapy and intravenous injection of a tumor-homing iRGD peptide, one could achieve efficient therapeutics distribution deep inside the tumor and nearly eradicate primary tumor growth. An in-depth understanding of this approach in combination with other strategies such as the use of immunomodulators would facilitate treating metastasis  in distant organs, and clinical translation of this platform, benefiting cancer patients by providing long-lasting efficacy.

Daylight Photodynamic Therapy for Actinic Keratoses

Topical photodynamic therapy (PDT) using daylight is effective in the treatment of actinic keratoses (AKs), offering the potential for treatment of large fields such as full face and balding scalp, but with minimal therapy-associated pain. Comparison with conventional PDT indicates similar efficacy for thin and moderate-thickness AKs, but with significantly less discomfort/pain, driving a patient preference for daylight-mediated PDT (DL-PDT) compared with conventional PDT using high-intensity office/hospital-based light sources. Treatment protocol involves the application of a photosensitizing agent without occlusion and subsequent exposure to ambient daylight within 30 min, with patients exposed to daylight for 1.5-2.0 h. Pivotal randomized controlled trials in Europe and Australia have confirmed the efficacy of methyl aminolevulinic acid (MAL) DL-PDT in comparison with conventional MAL-PDT for mild and moderate-thickness lesions on the face and scalp. Initial clearance rates of 70-89% are reported. DL-PDT using a nanoemulsion aminolevulinic acid (ALA) has recently been shown to be at least as effective as MAL DL-PDT in treating mild and moderate-thickness AKs. DL-PDT may offer a better-tolerated method for treating patients with extensive AK disease. There is emerging literature on the potential for field PDT to reduce the number of new AKs developing, potentially preventing/slowing skin cancer development. Conventional PDT remains established as a therapy for Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas (BCCs), and AKs. The evidence for the use of DL-PDT beyond AK is limited, although has been reported in actinic cheilitis, superficial BCC, and acne and cutaneous leishmaniasis. There is emerging interest in combination therapy for AK, using one or more field therapies such as DL-PDT as an option to complement with localized treatment for residual lesions. We review current recommendations and consider the appropriate place for DL-PDT in our treatment armamentarium.

ATR-IR study of skin components: Lipids, proteins and water. Part II: Near infrared radiation effect

Near infrared (NIR) radiation has been widely used in medicine and biomedical engineering. In spite of numerous studies the molecular mechanism of NIR radiation on biological systems has not been established as yet. The objective of this work was examination of the effect of NIR irradiation on the skin components. Modifications of lipid organization after NIR exposure vs. temperature (from 20 to 90 °C) have been investigated using Attenuated Total Reflectance Infrared (ATR-IR) spectroscopy. This work is a continuation of our previous studies on the temperature effect on skin components [1]. After NIR exposure a temperature shift of the phase transition from the orthorhombic to hexagonal packing (≈40 °C) has been observed. In contrast, the second phase transition temperature (≈70 °C) is almost invariable. The phase transitions in lipids were correlated with modifications of the structure of water and proteins. To our knowledge, for the first time the temperatures of the phase transitions after NIR exposure were investigated.

Topical application of Photofrin® for photodynamic diagnosis of malignant cutaneous neoplasms

OBJECTIVES

The prognosis of patients suffering from malignant cutaneous neoplasms can be improved by early diagnosis. Exact demarcation of tumor margins could contribute to optimum results in surgical excision and reconstruction. The purpose of our study is to evaluate Photofrin^® with a new diagnostic procedure, photodynamic diagnosis (PDD), for the detection of Bowen's disease (squamous cell carcinoma (SCC) in situ), SCC, and basal cell carcinoma (BCC).

MATERIALS AND METHODS

Sixty patients with cutaneous neoplasms received 2.5 mg/mL Photofrin^® solution topically. After a period of 3 hours, the patients underwent fluorescence illumination (λex = 370-450 nm). Guided by their visible fluorescence, lesions were biopsied at four suspicious sites in each patient. All specimens were analyzed and measured by a pathologist. A quantitative analysis of the fluorescence contrast between the neoplasms and healthy tissue was performed using the Red, Blue, and Green (RGB) Mode and Gray Scale (GS). Statistical analysis was performed by the analysis of variance (ANOVA) test for multiple comparisons.

RESULTS

Of the 60 patients (20 Bowen's disease, 20 SCC, and 20 BCC), malignant neoplasms could be clearly distinguished from adjacent healthy tissue under fluorescence illumination (P < 0.0001). The sensitivity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 92.74% in image results. The specificity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 95.77%.

CONCLUSION

Light-induced fluorescence detection using topical Photofrin^® provides a sensitive, noninvasive technique for the early identification of malignant cutaneous neoplasms.

Topically applied hypericin exhibits skin penetrability on nude mice

Hypericin, a powerful natural photosensitizer in photodynamic therapy (PDT), is suitable for treating skin diseases involving excess capillary proliferation. In the present study, we aimed to evaluate the skin penetrability of topically applied hypericin, expecting a reduced risk of prolonged skin photosensitivity, which often occurs after systemic administration. Firstly, the Franz diffusion cell assays were performed to evaluate the penetration effects of different enhancers, including menthol, propylene glycol, camphanone, azone, and carbamide. In view of above evaluation results, we selected menthol as the enhancer in the subsequent in vivo studies. The setting groups were as follows: the blank control group, the light-exposure control group, the gel-base control group, the hypericin gel group, and a hypericin gel-containing menthol group. Except for the blank control, all other animals were irradiated by a LED light. Then, fluorescence microscopy was performed to examine the distribution of hypericin in the skin of nude mouse. Macroscopic and microscopic analyses were also carried out to detect pathological changes in the skin after topical hypericin-PDT treatment. Immunohistochemistry was used to determine the expression change of PECAM-1. As shown in the results, menthol facilitated hypericin penetrate the skin of nude mice most. The results of in vivo assays revealed that hypericin penetrated nude mouse skin, spread to the dermis, and resulted in obvious photosensitivity reaction on the dermal capillaries. Moreover, skin injured by the photosensitive reaction induced by hypericin-PDT treatment was replaced by normal skin within 7 days. We concluded that topical applied hypericin could penetrate nude mouse skin well and has a great potential in PDT treatment of skin diseases.

Is a single day patient friendly methyl aminolevulinate photodynamic therapy illumination scheme for superficial basal cell carcinoma feasible? A randomized multicenter pilot trial

BACKGROUND

Topical methyl aminolevulinate photodynamic therapy (MAL-PDT) is highly effective for the treatment of superficial basal cell carcinoma (sBCC). Current European treatment protocol requires two hospital visits, which is costly and unpractical. The aim of this study was to evaluate the efficacy of fractionated MAL-PDT, using two light fractions at 3 and 4 h compared to illumination at 3 and 5 h after MAL-application.

METHODS

Thirty patients were randomized into two groups. The first group received illumination at 3 and 4 h (20 + 55 J/cm²) after MAL-application (3/4 group). In the other group, two light fractions were performed at 3 and 5 h (20 + 55 J/cm²) after MAL-application (3/5 group). The lesion response was evaluated at 3 and 12 months posttreatment.

RESULTS

In the 3/5 group, 70.0% showed a complete response (CR) at 3 months compared to 63.6% in the other group. At 12 months, 100% showed a CR in the 3/5 group compared to 80.0% in the other group. However, most failures/recurrences were eventually due to the presence of a more aggressive BCC subtype, mostly caused by sampling error of the primary punch biopsy.

CONCLUSION

Single day protocol for MAL-PDT for sBCC is feasible and this study shows promising results.

Photodynamic therapy corrects abnormal cancer-associated gene expression observed in actinic keratosis lesions and induces a remodeling effect in photodamaged skin

BACKGROUND

Actinic keratoses (AK) are proliferations of neoplastic keratinocytes in the epidermis resulting from cumulative exposure to ultraviolet radiation (UVR), which are liable to transform into squamous cell carcinoma (SCC). Organ Transplant Recipients (OTR) have an increased risk of developing SCC as a consequence of long-term immunosuppressive therapy. The aim of this study was to determine the molecular signature of AKs from OTR prior to treatment with methyl aminolevulinate-photodynamic therapy (MAL-PDT), and to assess what impact the treatment has on promoting remodeling of the photo-damaged skin.

METHODS

Seven patients were enrolled on a clinical trial to assess the effect of MAL-PDT with biopsies taken at screening prior to the first treatment session (week 1), and six weeks after completion of final treatment (week 18). Whole-genome gene expression analysis was carried out on skin biopsies isolated from an AK lesion, an area surrounding the lesion, and a non-sun exposed region of the body. Quantitative PCR was utilized to confirm the differential expression of key genes.

RESULTS

MAL-PDT treatment corrected abnormal proliferation-related gene profiles, corrected aberrantly expressed cancer-associated genes and induced expression of dermal extracellular matrix genes in photo-exposed skin.

CONCLUSION

The efficacy of the MAL-PDT on AK lesions was confirmed at whole-genome gene expression level. A transcriptional signature of remodeling, identified through assessing the effect of MAL-PDT on photodamaged skin, supports the use of MAL-PDT for treating photodamaged skin and field cancerized areas.

Safety evaluation of repeated intravenous infusion of sinoporphyrin with and without PDT in rats

Photodynamic therapy (PDT) is a promising antineoplastic modality in the oncology field. We assessed the safety of repeated intravenous administrations of sinoporphyrin, a porphyrin derivative, with and without illumination in rats. Toxicokinetic studies of single and multiple administrations of sinoporphyrin were also carried out. Sprague-Dawley rats were randomly assigned to the dark-toxicity and PDT groups. Animals in the dark toxicity group received an i.v. infusion of sinoporphyrin at 3 doses: 2 mg kg^-1, 6 mg kg^-1, and 18 mg kg^-1. The PDT group included 2 doses of sinoporphyrin (2 mg kg^-1 and 18 mg kg^-1), and the rats received 60 J of 630 nm laser illumination 24 h after photosensitizer infusion. The treatments were repeated every 7 days for 5 cycles and were followed by a 14-day recovery period. Systematic analyses were conducted at the end of treatment and recovery periods. Blood samples were obtained 5 min, 30 min, 2 h, 8 h, 24 h, 48 h, 72 h, and 96 h after the first and fifth treatments for toxicokinetic studies. Sinoporphyrin-PDT led to the death of one out of 270 rats; the dead animal had been treated with 18 mg kg^-1 sinoporphyrin and died at the end of the fifth PDT treatment. Liver injury, the primary toxicity observed in the study, was identified using biochemical tests, necropsy, and histopathology. Elevated white blood cell and neutrophil counts were found in the rats in both the dark toxicity and PDT groups. Skin lesions at the illumination site were obvious in the PDT group. Pigment deposits were detected in multiple organs such as the liver, spleen, lymph nodes, and ovaries in the 6 mg kg^-1 and 18 mg kg^-1 groups. No other abnormalities were observed. The toxicokinetic parameters of single and multiple sinoporphyrin administrations were calculated and compared. Repeated sinoporphyrin administrations both alone and in combination with laser illumination were tolerable, and all toxicities were transient. The no observed adverse effect level (NOAEL) for repeated sinoporphyrin administration and sinoporphyrin-PDT was 6 mg kg^-1 and 2 mg kg^-1, respectively. Further studies are warranted.

Photodynamic diagnosis with methyl-5-aminolevulinate in squamous intraepithelial lesions of the vulva: Experimental research

The incidence of the High-grade Squamous Intraepithelial Lesion of the vulva, formerly vulvar intra-epithelial neoplasia is progressively increasing. Today, an early detection and a precise localization of vulvar lesions are still problematic issues, due to the lack of accuracy of the available diagnostic tool. A new approach is the photodynamic diagnosis based on the fluorescence detection of protoporphyrin IX (PpIX) in cancer cells after topical application of a cream of methyl amino-levulinic acid. This study aimed to evaluate the effectiveness of photodiagnosis in order to discriminate the intensity of PpIX fluorescence between vulvar tumor and healthy skin. After topical application of the cream, the fluorescence on xenografted A431 tumor and adjacent skin was non-invasively measured with optical fiber. The tumor to skin fluorescence ratios were 1.38 and 1.41 at respectively 3h and 6h after application, which were significantly higher compared to those observed before application. PpIX accumulation at different depths of the tumor was investigated by spectrofluorimetry after PpIX chemical extraction from tumor sections at 3h and 6h post-application. It was noticed at both application times that the concentration of PpIX within the tumor progressively decreased. However PpIX fluorescence was always detectable up to 2.5 mm, a depth equivalent to more than three quarters of the tumor. The tumor to exposed skin ratios of PpIX fluorescence showed a good selectivity up to1mm depth at 3h post-application and up to 1.5mm at 6h post-m-ALA. Thus, the photodynamic diagnosis using in vivo topical methyl amino-levulinic acid appears to be a promising way to detect the intraepithelial lesions of the vulva. Our results open the possibility for implementation of topical methyl amino-levulinic acid in clinical settings for recognition of vulvar high-grade squamous intraepithelial lesions.

5-Aminolevulinic-acid-mediated Photodynamic Diagnosis Enhances the Detection of Peritoneal Metastases in Biliary Tract Cancer in Mice

BACKGROUND/AIM

Previous studies on the accuracy of 5-aminolevulinic-acid-mediated photodynamic diagnosis (5-ALA PDD) have been reported for various cancers and brain surgery. However, biliary tract cancer is rare. Therefore, 5-ALA PDD has not been fully evaluated in biliary tract cancers. Small biliary tract cancer lesions such as peritoneal dissemination, liver metastases, and lymph node metastases are negative prognosticators in patients with biliary cancer. The purpose of this exploratory study was to determine if 5-ALA PDD could detect small biliary tract cancer lesions in murine models of biliary cancers.

MATERIALS AND METHODS

Biliary cancer cell lines (TFK-1, HuCCT-1, G415, HuH28, SSP25, RBE, KKU055 and KKU100) and Normal human dermal fibroblast cells were used to evaluate protoporphyrin IX (PpIX) accumulation in vitro. Subcutaneous tumor mice were established using two cell lines (TFK-1 and HuCCT-1). 5-ALA (250 mg/kg) was administered intraperitoneally, and fluorescent 5ALA-PDD was performed 3 h later to evaluate tumoral PpIX accumulation. A murine peritoneal disseminated nodule model was established by intraperitoneal injection of TFK-1 cells. Four weeks later, 5-ALA was administered intraperitoneally, and 5-ALA-PDD was performed 3 h post administration to evaluate PpIX accumulation in the disseminated nodules. The presence of tumor cells in tumors and nodules was confirmed by haematoxylin and eosin staining.

RESULTS

Compared TO non-cancerous cell lines, PpIX accumulation was increased in biliary tract cancer cell lines. PpIX accumulation led to a strong fluorescent signal in all subcutaneous tumors. In the murine model of peritoneal dissemination, microdisseminated nodules (<1 mm) that could not be detected under white light were clearly visible using 5-ALA-PDD.

CONCLUSION

5-ALA PDD was useful for diagnosis of biliary tract cancer and detection of small peritoneal metastatic lesions in murine models of biliary cancers. Clinical studies and applications of 5-ALA PDD for biliary tract cancer are expected in the future.

Long-term efficacy data for daylight-PDT

INTRODUCTION

Conventional photodynamic therapy (c-PDT) is an established successful treatment for non-melanoma skin cancers (NMSC). Daylight PDT (DL-PDT) was introduced to overcome the main inconveniencies associated with c-PDT such as pain during illumination and long clinic visits. DL-PDT was shown to have similar short-term efficacy to c-PDT for the treatment of mild/moderate actinic keratosis (AKs) but it is associated with better tolerability. Since AKs tend to regress and reoccur over time, data on long-term efficacy of DL-PDT become crucial.

EVIDENCE ACQUISITION

We performed a systematic review search up to February 2018 of available studies on DL-PDT long-term efficacy using the MEDLINE database and made a manual search of selected references.

EVIDENCE SYNTHESIS

Most current studies on DL-PDT have limited follow-up periods of 3 to 6 months. Only 2 randomized, intra-individual studies provided efficacy data on AK treatment at 12 month-follow-up and supported the long-term efficacy of this novel treatment modality showing a low recurrence rate, varying from 8.7% to 13%. Current evidences for other NMSCs are limited and efficacy seems to be not as good as for AK.

CONCLUSIONS

DL-PDT is a very promising treatment for mild to moderate AKs of the face and scalp. Efficacy outcomes of DL-PDT are similar to those of c-PDT in the short-term. Additional studies are required to increase our knowledge on DL-PDT long-term efficacy, as limited data are currently available.

Comparison of 10 efficient protocols for photodynamic therapy of actinic keratosis: How relevant are effective light dose and local damage in predicting the complete response rate at 3 months?

BACKGROUND

Topical photodynamic therapy is an established treatment modality for various dermatological conditions, including actinic keratosis. In Europe, the approved protocols for photodynamic therapy of actinic keratosis involve irradiation with either an Aktilite CL 128 lamp or daylight, whereas irradiation with the Blu-U illuminator is approved in the United States. Many other protocols using irradiation by a variety of light sources are also clinically efficient.

OBJECTIVES

This paper aims to compare 10 different protocols with clinically proven efficacy for photodynamic therapy of actinic keratosis and the available spectral irradiance of the light source. Effective irradiance, effective light dose, and local damage are compared. We also investigate whether there is an association between the complete response rate at 3 months and the effective light dose or local damage.

METHODS

The effective irradiance, also referred to as protoporphyrin IX-weighted irradiance, is obtained by integrating the spectral irradiance weighted by the normalized absorption spectrum of protoporphyrin IX over the wavelength. Integrating the effective irradiance over the irradiation time yields the effective light dose, which is also known as the protoporphyrin IX-weighted light dose. Local damage, defined as the total cumulative singlet oxygen molecules produced during treatment, is estimated using mathematical modeling of the photodynamic therapy process. This modeling is based on an iterative procedure taking into account the spatial and temporal variations in the protoporphyrin IX absorption spectrum during treatment.

RESULTS

The protocol for daylight photodynamic therapy on a clear sunny day, the protocol for daylight photodynamic therapy on an overcast day, the photodynamic therapy protocol for a white LED lamp for operating rooms and the photodynamic therapy protocol for the Blu-U illuminator perform better than the six other protocols-all involving red light illumination-in terms of both effective light dose and local damage. However, no association between the complete response rate at 3 months and the effective light dose or local damage was found.

CONCLUSIONS

Protocols that achieve high complete response rates at 3 months and low pain scores should be preferred regardless of the effective light dose and local damage. Lasers Surg. Med. 50:576-589, 2018. © 2018 Wiley Periodicals, Inc.

Photooxidatively crosslinked acellular tumor extracellular matrices as potential tumor engineering scaffolds

Acellular tumor extracellular matrices (ECMs) have limitations when employed as three-dimensional (3D) scaffolds for tumor engineering. In this work, methylene blue-mediated photooxidation was used to crosslink acellular tumor ECMs. Photooxidative crosslinking greatly increased the stiffness of acellular tumor ECM scaffolds but barely altered the Amide III band of the secondary structure of polypeptides and proteins. MCF-7, HepG2 and A549 cells cultured on photooxidatively crosslinked acellular tumor ECM scaffolds exhibited greater cell number per scaffold, more IL-8 and VEGF secretion, and increase migration and invasion abilities than cells cultured on uncrosslinked acellular tumor ECM scaffolds. The three tumor cell lines cultured on the stiffer photooxidatively crosslinked acellular matrices acquire mesenchymal properties (mesenchymal shift) and dedifferentiated phenotypes. Furthermore, the malignant phenotypes induced in vitro when cultured on the crosslinked scaffold promoted the in vivo tumor growth of BALB/c nude mice. Finally, the dedifferentiated cancer cells, including MCF-7, HepG2 and A549 cells, were less sensitive to chemotherapeutics. Thus, photooxidatively crosslinked acellular tumor ECMs have potentials as 3D tumor engineering scaffolds for cancer research.

STATEMENT OF SIGNIFICANCE

Natural material scaffolds have been successfully used as 3D matrices to study the in vitro tumor cell growth and mimic the in vivo tumor microenvironment. Acellular tumor ECMs are developed as 3D scaffolds for tumor engineering but have limitations in terms of elastic modulus and cell spheroid formation. Here we use methylene blue-mediated photooxidation to crosslink acellular tumor ECMs and investigate the influence of photooxidative crosslinking on structural, mechanical and biological characteristics of acellular tumor ECM scaffolds. It is the first study to evaluate the feasibility of photooxidatively crosslinked acellular tumor ECMs as 3D scaffolds for cancer research and the results are encouraging. Moreover, this study provides new research areas in regard to photodynamic therapy (PDT) for Cancer.

A threshold dose distribution approach for the study of PDT resistance development: A threshold distribution approach for the study of PDT resistance

Photodynamic therapy (PDT) is a technique with well-established principles that often demands repeated applications for sequential elimination of tumor cells. An important question concerns the way surviving cells from a treatment behave in the subsequent one. Threshold dose is a core concept in PDT dosimetry, as the minimum amount of energy to be delivered for cell destruction via PDT. Concepts of threshold distribution have shown to be an important tool for PDT results analysis in vitro. In this study, we used some of these concepts for demonstrating subsequent treatments with partial elimination of cells modify the distribution, which represents an increased resistance of the cells to the photodynamic action. HepG2 and HepaRG were used as models of tumor and normal liver cells and a protocol to induce resistance, consisted of repeated PDT sessions using Photogem® as a photosensitizer, was applied to the tumor ones. The response of these cells to PDT was assessed using a standard viability assay and the dose response curves were used for deriving the threshold distributions. The changes in the distribution revealed that the resistance protocol effectively eliminated the most sensitive cells. Nevertheless, HepaRG cell line was the most resistant one among the cells analyzed, which indicates a specificity in clinical applications that enables the use of high doses and drug concentrations with minimal damage to the surrounding normal tissue.

Photosensitizers in prostate cancer therapy

The search for new therapeutics for the treatment of prostate cancer is ongoing with a focus on the balance between the harms and benefits of treatment. New therapies are being constantly developed to offer treatments similar to radical therapies, with limited side effects. Photodynamic therapy (PDT) is a promising strategy in delivering focal treatment in primary as well as post radiotherapy prostate cancer. PDT involves activation of a photosensitizer (PS) by appropriate wavelength of light, generating transient levels of reactive oxygen species (ROS). Several photosensitizers have been developed with a focus on treating prostate cancer like mTHPC, motexafin lutetium, padoporfin and so on. This article will review newly developed photosensitizers under clinical trials for the treatment of prostate cancer, along with the potential advantages and disadvantages in delivering focal therapy.

Coralyne, a protoberberine alkaloid, causes robust photosenstization of cancer cells through ATR-p38 MAPK-BAX and JAK2-STAT1-BAX pathways

Photodynamic therapy (PDT) provides an effective cancer treatment option but it requires sufficient cellular oxygen concentration to exert its photosensitizing effects. Due to hypoxic nature of most tumors, widespread clinical application of PDT is restricted and warrants development of photosensitizers which can kill cancer cells in ROS independent manner. Previously, we reported significant enhancement of the anti-cancer property of coralyne in presence of ultraviolet-A (UVA) light exposure against several human carcinoma cell lines. This study aimed at unravelling molecular cascades of events in CUVA treatment (coralyne and UVA light)-mediated photosensitization of human skin cancer. The CUVA-treatment caused robust apoptosis of A431 cancer cells, primarily through mitochondrial and lysosomal dysfunctions. Silencing of BAX conferred a significant protection against CUVA-induced apoptosis. Both lysosomal proteases and caspase-8 activation contributed to BID cleavage. Further, our results revealed that a dual signaling axis e.g., ATR-p38 MAPK and JAK2-STAT1 pathways functioned upstream of BAX activation in apoptosis response. Moreover, transient silencing of ATR and pharmacological inhibition of p38-MAPK or JAK2 significantly abolished the effect of CUVA treatment induced BAX expression and cell death, linking the extrinsic and intrinsic pathways with the observed cell death. Our data suggest that coralyne, which is known topoisomerase-I inhibitor, may be an attractive agent for photo-chemotherapeutic treatment of human skin cancers.

Activating TiO2 Nanoparticles: Gallium-68 Serves as a High-Yield Photon Emitter for Cerenkov-Induced Photodynamic Therapy

The classical photodynamic therapy (PDT) requires external light to activate photosensitizers for cancer treatment. However, limited tissue penetration of light has been a long-standing challenge for PDT to cure malignant tumors in deep tissues. Recently, Cerenkov radiation (CR) emitted by radiotracers such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) has become an alternative and promising internal light source. Nevertheless, fluorine-18 (F-18) only releases 1.3 photons per decay in average; consequently, injection dose of F-18 goes beyond 10-30 times more than usual to acquire therapeutic efficacy because of its low Cerenkov productivity. Gallium-68 (Ga-68) is a favorable CR source owing to its ready availability from generator and 30-time higher Cerenkov productivity. Herein, we report, for the first time, the use of Ga-68 as a CR source to activate dextran-modified TiO₂ nanoparticles (D-TiO₂ NPs) for CR-induced PDT. Compared with ¹⁸F-FDG, ⁶⁸Ga-labeled bovine serum albumin (⁶⁸Ga-BSA) inhibited the growth of 4T1 cells and exhibited significantly stronger DNA damage to tumor cells. In vivo studies showed that the tumor growth was almost completely inhibited when tumor-bearing mice were treated with a combination of D-TiO₂ NPs and ⁶⁸Ga-BSA. This study proved that Ga-68 is a more potent radionuclide for PDT than F-18 both in vitro and in vivo offered a promising strategy of using a diagnostic dose of radioactivity to achieve depth-independent cancer therapy without using any external light source.

Treatment of Multiple Relapsing Non-Melanoma Skin Cancers in a Patient with Severe Hemophilia A

Although non-melanoma skin cancers are the most predominant malignancies in the Caucasian population and hemophilia A is one of the most frequent hereditary bleeding disorders, medical literature data about the management of non-melanoma skin cancers in patients with hemophilia are surprisingly scarce. In this case report we describe the treatment of a patient with multiple recurrent non-melanoma skin cancers and severe hemophilia A. The management of such patients could be very challenging, with possible significant bleeding complications, and requires a multidisciplinary approach.

Patient and physician satisfaction in an observational study with methyl aminolevulinate daylight photodynamic therapy in the treatment of multiple actinic keratoses of the face and scalp in six European countries

BACKGROUND

Guidelines recommend treating actinic keratoses (AKs) as they are recognized as precursors of invasive squamous cell carcinoma.

OBJECTIVE

The objective of this study was to collect real-world clinical data on the use of methyl aminolevulinate daylight photodynamic therapy (MAL DL-PDT) for the treatment of face and scalp AK in Europe.

METHODS

A prospective, multicenter, non-interventional study was conducted in six European countries in patients receiving a single treatment of MAL DL-PDT for face and/or scalp AK. Patient-reported outcomes were assessed by patient questionnaires at baseline and at 3 months after treatment, efficacy was assessed at 3 months using a 6-point global improvement scale, and adverse events (AE) were recorded at each visit.

RESULTS

Overall, 325 patients were enrolled from 52 investigational centres, 314 of whom attended the 3-month visit. Most patients had multiple lesions (58.4% had >10 lesions) with lesions mainly located on the scalp (60.0%) and/or forehead (54.2%). AKs were predominantly grade I (39.4%) or grade II (33.2%), and 10.5% of patients had grade III lesions. The proportions of patients and physicians that were overall satisfied to very satisfied with the MAL DL-PDT treatment were 80.4% and 90.3%, respectively. The vast majority of patients (90.0%) would consider using MAL DL-PDT again if needed. Physician-assessed efficacy at 3 months was at least much improved in 83.5% of patients, with 45.9% of patients requiring no retreatment. Related AEs were reported in 15% of patients.

CONCLUSION

Use of MAL DL-PDT for multiple face and/or scalp AKs resulted in high levels of patient and physician satisfaction in clinical practice in Europe, reflecting the good efficacy and high tolerability of this convenient procedure.

Daylight photodynamic therapy - Experience and safety in treatment of actinic keratoses of the face and scalp in low latitude and high brightness region

Daylight photodynamic therapy has been used in countries with high latitudes during the summer for actinic keratoses treatment with reports of similar efficacy to conventional photodynamic therapy. We evaluate its safety in 20 patients in the city of Fortaleza, a local with low latitude and high brightness. Sixteen patients did not report any discomfort due to the procedure. Daylight photodynamic therapy is an easy application method with great tolerability by the patient and has the possibility of being performed throughout the year in these regions. It can mean a promising tool in the control of skin cancer.

Photodynamic therapy in the treatment of vulvar lichen sclerosus

BACKGROUND

Vulvar lichen sclerosus is a chronic and incurable disease that causes various unpleasant symptoms and serious consequences.

OBJECTIVE

The purpose of the study was to assess the effectiveness of photodynamic therapy in the treatment of vulvar lichen sclerosus.

METHODS

Participants in the study included 102 female patients aged 19-85 suffer from vulvar lichen sclerosus. The patients underwent photodynamic therapy (PDT). In the course of PDT the 5% 5- aminolevulinic acid was used in gel form. The affected areas were irradiated with a halogenic lamp PhotoDyn 501 (590-760nm) during a 10-min radiation treatment. The treatment was repeated weekly for 10 weeks.

RESULT

PDT has brought about a good therapeutic effect (complete or partial clinical remission), with 87.25% improvement rate in patients suffering from lichen sclerosus. The greatest vulvoscopic response was observed in the reduction of subepithelial ecchymoses and teleangiectasia (78.95%), and the reduction of erosions and fissures (70.97%). A partial remission of lichenification with hyperkeratosis was observed in 51.61% of cases. The least response was observed in the atrophic lesions reduction (improvement in 37.36% of cases).

CONCLUSION

Our patients suffering from vulvar lichen sclerosus demonstrated positive responses to photodynamic therapy and the treatment was well tolerated. Photodynamic therapy used to treat lichen sclerosus yields excellent cosmetic results.

Forearm skin aging: characterization by instrumental measurements

BACKGROUND

The intrinsic ageing and photoaged skin present biomechanical and morphological differences, which are reflected in the appearance of roughness, superficial and deep wrinkles, atrophy, reduced elasticity, hypo- and hyperpigmentation and actinic keratosis.

OBJECTIVE

To evaluate and compare the characteristics of the flexor (with a predominance of intrinsic ageing) and extensor (chronically exposed to sunlight and other environmental factors, with a predominance of photoageing) skin surfaces of the forearms.

METHODS

Interventional, prospective, diagnostic study, including 23 females, aged over 60 years. The extensor and flexor faces of forearms were compared in relation to clinical parameters and non-invasive instrumental measurements, such as skin surface, elasticity, hydration as well as dermal thickness and echogenicity.

RESULTS

Regarding the water content of the stratum corneum, the flexor face presented an average value higher than the extensor face. The average of measures obtained through images of high-frequency ultrasound demonstrated greater echogenicity of flexor face compared to the extensor face. The measurements of the skin surface showed significant differences between the faces. The roughness and scaliness were lower in the flexor face. Regarding the depth of wrinkles, there was no significant difference between the faces. The average of the measurements was slightly higher in the flexor face, which demonstrated that wrinkles are present in the intrinsic ageing and photoageing. The presence of elastosis and the reduction in elasticity in the clinical aspect of the photoaged face of forearms were according to the results of the non-invasive measurements.

CONCLUSION

Meaningful differences in the biophysical characteristics of the extensor and flexor faces of the forearms were detected. Because the non-invasive instrumental measurements correlated with clinical findings, they may represent useful tools to assess efficacy and safety of skin ageing treatments in clinical research.

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.

Photodynamic therapy for actinic keratosis: Is the European consensus protocol for daylight PDT superior to conventional protocol for Aktilite CL 128 PDT?

BACKGROUND

Topical photodynamic therapy (PDT) is an established treatment modality for various dermato-oncologic conditions. In Europe, initially requiring irradiation with red light, PDT of actinic keratosis (AK) can now also be carried out with exposure to daylight that has been clinically proven to be as effective as and less painful than red light.

OBJECTIVES

In this paper, we propose a comparison between the conventional protocol for Aktilite CL 128 (red light source) PDT and the European consensus protocol for daylight PDT - with the exposure is assumed to be performed during either a clear sunny day or an overcast day - in the treatment of AK with methyl aminolevulinate through a mathematical modeling.

METHOD

This already published modeling that is based on an iterative procedure alternating determination of the local fluence rate and updating of the local optical properties enables to estimate the local damage induced by the therapy.

RESULTS

The European consensus protocol for daylight PDT during a sunny day and an overcast day provides, on average, 6.50 and 1.79 times higher PDT local damages at the end of the treatment than those obtained using the conventional protocol for Aktilite CL 128 PDT, respectively.

CONCLUSIONS

Results analysis shows that, even performed during an overcast day, the European consensus protocol for daylight PDT leads to higher PDT local damages than the efficient conventional protocol for Aktilite CL 128.

Basal cell carcinoma: 10-year experience with electrochemotherapy

BACKGROUND

Electrochemotherapy (ECT), by combining manageable cytotoxic agents with short electric pulses, represents an effective palliative skin-directed therapy. The accumulated evidence indicates that ECT stands out as a safe and well-tolerated alternative treatment for patients with multiple or large basal cell carcinoma (BCC), who are not suitable for conventional treatments. However, long-term data and shared indications are lacking.

METHODS

In this observational study, we retrospectively analyzed 84 prospectively collected patients with multiple, recurrent or locally advanced BCC who were not candidate for standard therapies and received bleomycin-based ECT according to the European Standard Operative Procedures of ECT, from 2006 to 2016.

RESULTS

Disease extent was local, locally advanced and metastatic in 40 (48%), 41 (49%) and 3 (3%), respectively. Forty-four (52%) individuals had multiple BCCs. Grade 3 skin toxicity after ECT was observed in 6% of cases. Clearance rate was 50% (95% CI 39-61%). Primary presentation (p = 0.004), tumor size <3 cm (p < 0.001), well-defined borders (p = 0.021), absence of tumor ulceration (p = 0.001), non-aggressive BCC histology (p = 0.046) and age ≤69 years were associated with higher complete response rate. In patients with local BCC, the clearance rate was 72.5 and 85% after one or two ECT cycles, respectively. In the laBCC group, 32 patients (78%) achieved an objective response. Five-year recurrence rate for local and laBCC was 20 and 38%, respectively (p ≤ 0.001).

CONCLUSIONS

One or two ECT cycles with bleomycin may be a valuable palliative treatment in well-selected patients with multiple BCCs and favorable tumor features. Validation of predictive factors will be imperative to match patients with optimal ECT treatment modalities. Management of laBCC with ECT warrants further investigation. Trial registration ISRCTN14633165 Registered 24 March 2017 (retrospectively registered).

Comparison of the Treatment Guidelines for Actinic Keratosis: A Critical Appraisal and Review

There are currently several reputable guidelines on the treatment of actinic keratosis (AK) from groups in Canada, the United Kingdom, and Europe. These recommendations, based on evidence or expert consensus, offer clinicians a variety of treatment options for the different clinical presentations of AKs. Although the guidelines are similar in some regards, variations exist in treatment options, duration, and strength of recommendation. Some guidelines also lack input on specific therapies and certain types of AK, such as hypertrophic or thin presentations. The purpose of this article is to review and compare guidelines published by Canadian, UK, and European groups for the management of AKs in patients.

Cyclodextrin-gated mesoporous silica nanoparticles as drug carriers for red light-induced drug release

Long wavelength light-responsive drug delivery systems based on mesoporous silica nanoparticles (MSNs) have attracted much attention in the last few years. In this paper, a red light (660 nm)-responsive drug delivery system based on low-cost cyclodextrin (CD)-gated MSNs containing a photodynamic therapy (PDT) photosensitizer (Chlorin e6, Ce6) was developed for the first time. The drug release experiment in water demonstrated that with the irradiation of red light, Ce6 can be excited to generate singlet oxygen, which can further cleave the singlet oxygen sensitive linker to trigger the departure of CD and the release of cargo. Further in vitro release experiments confirmed that cargo can be released from MSNs with the irradiation of red light and spread into the entire cell. The relative low power density (0.5 W cm^-2) of excitation light together with the short irradiation time (one-three min) result in a low light dose (30-90 J cm^-2) for the drug delivery, contributing to their potential clinical applications.

Cationic Phosphorus Dendrimer Enhances Photodynamic Activity of Rose Bengal against Basal Cell Carcinoma Cell Lines

In the last couple of decades, photodynamic therapy emerged as a useful tool in the treatment of basal cell carcinoma. However, it still meets limitations due to unfavorable properties of photosensitizers such as poor solubility or lack of selectivity. Dendrimers, polymers widely studied in biomedical field, may play a role as photosensitizer carriers and improve the efficacy of photodynamic treatment. Here, we describe the evaluation of an electrostatic complex of cationic phosphorus dendrimer and rose bengal in such aspects as singlet oxygen production, cellular uptake, and phototoxicity against three basal cell carcinoma cell lines. Rose bengal-cationic dendrimer complex in molar ratio 5:1 was compared to free rose bengal. Obtained results showed that the singlet oxygen production in aqueous medium was significantly higher for the complex than for free rose bengal. The cellular uptake of the complex was 2-7-fold higher compared to a free photosensitizer. Importantly, rose bengal, rose bengal-dendrimer complex, and dendrimer itself showed no dark toxicity against all three cell lines. Moreover, we observed that phototoxicity of the complex was remarkably enhanced presumably due to high cellular uptake. On the basis of the obtained results, we conclude that rose bengal-cationic dendrimer complex has a potential in photodynamic treatment of basal cell carcinoma.