Hyperpigmentation induced by topical 5-aminolaevulinic acid plus visible light

Jet-injection assisted photodynamic therapy for superficial and nodular basal cell carcinoma: A pilot study

BACKGROUND

Photodynamic therapy (PDT) with topical δ-Aminolevulinic acid (ALA) has efficacy in treating basal cell carcinoma (BCC) but is limited by incomplete penetration of ALA into the deeper dermis. This prospective open-label pilot trial investigated the safety and efficacy of photosensitizer jet injection for PDT (JI-PDT) for BCC treatment. It was performed with 15 patients (n = 15) with histologically confirmed, untreated, low-risk nodular BCCs at a single institution.

METHODS

For the intervention, JI-PDT patients (n = 11) received two sessions of jet-injected ALA with PDT separated by four to 6 weeks. To further understand treatment technique, another group of patients (n = 4) received jet-injected ALA followed by tumor excision and fluorescence microscopy (JI-E). Treatment tolerability was assessed by local skin responses (LSR) score at five distinct time intervals. Fluorescence microscopy assessed protoporphyrin IX penetration depth and biodistribution within the tumor. At the primary endpoint, tumor clearance was evaluated via visual inspection, dermoscopy and reflectance confocal microscopy. Postinjection and postillumination pain levels, and patient satisfaction, were scored on a 0-10 scale.

RESULTS

Fifteen participants with mean age of 58.3, who were 15/15 White, non-Hispanic enrolled. The median composite LSR score immediately after JI-PDT was 5 (interquartile range [IQR] = 3) which decreased to 0.5 (IQR = 1) at primary endpoint (p < 0.01). Immunofluorescence of excised BCC tumors with jet-injected ALA showed photosensitizer penetration into papillary and reticular dermis. Of the 13 JI-PDT tumors, 11 had tumor clearance confirmed, 1 recurred, and 1 was lost to follow-up. 1/11 patients experienced a serious adverse event of cellulitis. 70% of patients had local scarring at 3 months. Patients reported an average pain level of 5.6 (standard deviation [SD] = 2.3) during jet injection and 3.7 (SD = 1.8) during light illumination.

CONCLUSIONS

Jet injection of ALA for PDT treatment of nodular low-risk BCC is tolerable and feasible and may represent a novel modality to improve PDT.

Photodynamic Therapy in Pigmented Basal Cell Carcinoma-A Review

This review summarizes the effectiveness of photodynamic therapy (PDT) in the treatment of the pigmented subtype of basal cell carcinoma (BCC) based on the current literature. PDT is a light-activated treatment, non-invasive, that selectively destroys tumor cells and tissues via the interaction of a photosensitizer, light, and molecular oxygen. It can induce cancer cell death through direct tumor vascular damage or via the induction of immune response. However, human skin is also an absorption and scattering medium since it contains hemoglobin and melanin that act as chromophores. Eumelanin can be considered a light-absorber and an intracellular antioxidant that can neutralize PDT-induced ROS and, therefore, decrease PDT success. Various factors, including tumor depth, the degree of pigmentation in malignant cells, and the individual's skin phototype, can impact the outcome of this intricate biochemical process. It has been widely recognized that PDT exhibits limited efficacy in the treatment of pigmented lesions. However, new combination techniques such as curettage or debulking before PDT show promising results in the treatment of pigmented BCC.

Understanding the Photodynamic Therapy Induced Bystander and Abscopal Effects: A Review

Photodynamic therapy (PDT) is a clinically approved minimally/non-invasive treatment modality that has been used to treat various conditions, including cancer. The bystander and abscopal effects are two well-documented significant reactions involved in imparting long-term systemic effects in the field of radiobiology. The PDT-induced generation of reactive oxygen and nitrogen species and immune responses is majorly involved in eliciting the bystander and abscopal effects. However, the results in this regard are unsatisfactory and unpredictable due to several poorly elucidated underlying mechanisms and other factors such as the type of cancer being treated, the irradiation dose applied, the treatment regimen employed, and many others. Therefore, in this review, we attempted to summarize the current knowledge regarding the non-targeted effects of PDT. The review is based on research published in the Web of Science, PubMed, Wiley Online Library, and Google Scholar databases up to June 2023. We have highlighted the current challenges and prospects in relation to obtaining clinically relevant robust, reproducible, and long-lasting antitumor effects, which may offer a clinically viable treatment against tumor recurrence and metastasis. The effectiveness of both targeted and untargeted PDT responses and their outcomes in clinics could be improved with more research in this area.

Guidelines for practical use of MAL-PDT in non-melanoma skin cancer

Methyl aminolaevulinate photodynamic therapy is increasingly practiced in the treatment of actinic keratoses, Bowen's disease and basal cell carcinomas. This method is particularly suitable for treating multiple lesions, field cancerization and lesions in areas where a good cosmetic outcome is of importance. Good treatment routines will contribute to a favourable result. The Norwegian photodynamic therapy (PDT) group consists of medical specialists with long and extensive PDT experience. With support in the literature, this group presents guidelines for the practical use of topical PDT in non-melanoma skin cancer.

Photodynamic therapy in dermatology: a review

Photodynamic therapy (PDT) is used for the prevention and treatment of non-melanoma skin cancer. Until recently, clinically approved indications have been restricted to actinic keratoses, nodular and superficial basal cell carcinoma, and, since 2006, Bowen disease. However, the range of indications has been expanding continuously. PDT is also used for the treatment of non-malignant conditions such as acne vulgaris and leishmaniasis, as well as for treating premature skin aging due to sun exposure. The production of reactive oxygen intermediates like singlet oxygen depends on the light dose applied as well as the concentration and localization of the photosensitizer in the diseased tissue. Either cytotoxic effects resulting in tumor destruction or immunomodulatory effects improving inflammatory skin conditions are induced. Treating superficial non-melanoma skin cancer, PDT has been shown to be highly efficient, despite the low level of invasiveness. The excellent cosmetic results after treatment are beneficial, too.

Long-term follow-up of photodynamic therapy with a self-adhesive 5-aminolaevulinic acid patch: 12 months data

BACKGROUND

Photodynamic therapy with a self-adhesive 5-aminolaevulinic acid (5-ALA) patch shows high efficacy rates in the treatment of mild to moderate actinic keratosis (AK) in short term trials.

OBJECTIVES

The purpose of the trial was to follow up patients after successful 5-ALA patch-PDT at 3 month intervals over a total period of 12 months. Patients who had received placebo-PDT or cryosurgery served for comparison.

PATIENTS/METHODS

Three months after therapy, 360 patients from two separate randomized parallel group phase III studies (one superiority trial vs. placebo-PDT, one noninferiority trial vs. cryosurgery) were suitable for the follow-up study. Patients had to show at least one successfully treated AK lesion after initial therapy. A total of 316 patients completed the follow-up.

RESULTS

Twelve months after a single treatment, 5-ALA patch-PDT still proved superior to placebo-PDT and cryosurgery (P < 0.001 for all tests). On a lesion basis, efficacy rates were 63% and 79% for PDT, 63% for cryosurgery and 9% and 25% for placebo-PDT. Recurrence rates of patch-PDT proved superior to those of cryosurgery (per protocol set: P = 0.011, full analysis set: P = 0.049). While 31% of cryosurgery lesions were still hypopigmented after 1 year, the 5-ALA patch-PDT groups showed hypopigmentation in 0% (superiority trial) and 3% (noninferiority trial) of the treated lesions.

CONCLUSION

Twelve months after a single 5-ALA patch-PDT the majority of lesions were still cleared with an excellent cosmetic outcome. 5-ALA patch-PDT proved to be superior to cryosurgery in the noninferiority study setting.

Guidelines for topical photodynamic therapy: update

Multicentre randomized controlled studies now demonstrate high efficacy of topical photodynamic therapy (PDT) for actinic keratoses, Bowen's disease (BD) and superficial basal cell carcinoma (BCC), and efficacy in thin nodular BCC, while confirming the superiority of cosmetic outcome over standard therapies. Long-term follow-up studies are also now available, indicating that PDT has recurrence rates equivalent to other standard therapies in BD and superficial BCC, but with lower sustained efficacy than surgery in nodular BCC. In contrast, current evidence does not support the use of topical PDT for squamous cell carcinoma. PDT can reduce the number of new lesions developing in patients at high risk of skin cancer and may have a role as a preventive therapy. Case reports and small series attest to the potential of PDT in a wide range of inflammatory/infective dermatoses, although recent studies indicate insufficient evidence to support its use in psoriasis. There is an accumulating evidence base for the use of PDT in acne, while detailed study of an optimized protocol is still required. In addition to high-quality treatment site cosmesis, several studies observe improvements in aspects of photoageing. Management of treatment-related pain/discomfort is a challenge in a minority of patients, and the modality is otherwise well tolerated. Long-term studies provide reassurance over the safety of repeated use of PDT.

Different pain sensations in photodynamic therapy of nodular basal cell carcinoma Results from a prospective trial and a review of the literature

BACKGROUND

Pain is a major side effect of topical photodynamic therapy (PDT), a relatively new and non-invasive treatment for particular types of basal cell carcinoma (BCC). In this study, we sought to characterise in more detail the quality and intensity of pain associated with PDT. Furthermore, we studied if gender, tumour size and localization as well as different light sources with comparable wavelengths had an influence on the pain.

METHODS

A total of 64 nodular BCCs in 55 patients, of which 48 BCCs underwent preceding debulking, were treated with 5-aminolevulinic acid (ALA-PDT). Two metal halogen light sources were randomly used. Pain assessment was performed using a visual analogue scale (VAS).

RESULTS

All patients experienced pain during illumination and 41.8% after illumination. The mean pain intensity was 3.88 with most patients experiencing burning (82.5%) or stinging (36.8%) sensations. Illumination with the Medeikonos(®) light source was experienced less painful than the Waldmann(®) lamp (4.64 versus 3.40; p=0.027). Gender as well as tumour localization and size did not alter the pain scores. Likewise, no differences were observed between patients who underwent debulking and those who did not.

CONCLUSIONS

Treatment of single BCCs with ALA-PDT rarely results in unbearable pain. However, the degree of pain can vary depending on the light source used. Further studies are needed to unravel the pathomechanisms underlying the development of pain in PDT in order to develop adequate solutions for this undesirable side effect.

Blue light inhibits melanin synthesis in B16 melanoma 4A5 cells and skin pigmentation induced by ultraviolet B in guinea-pigs

BACKGROUND

Little has been known about the effects of visible light in mammalian cells. We recently found that blue light not only suppressed the growth of B16 melanoma cells in a time-dependent manner but also inhibited metastasis of the B16 melanoma cells to the lung. These findings suggest that exposure to blue light modifies the functions of B16 melanoma cells. The present study investigated the effects of blue light on B16 melanoma 4A5 cells and Weiser-Maple guinea-pigs to confirm the biological effect of blue light on melanin formation.

METHODS

The effect of red, green, and blue light on melanin synthesis in B16 melanoma 4A5 cells was measured. The back skin of brown Weiser-Maple guinea-pigs was exposed to ultraviolet B (UVB; 588 mJ/cm(2) (0.7 mW/cm(2)x 14 min) three times a week for 2 weeks to induce melanin deposition. Thirty minutes after each UVB exposure, blue light was applied for 30 min. Pigmentation of the exposed areas of skin was checked once a week, and photographs of the skin were taken by digital camera. Observation was continued for 18 days after the final UVB exposure.

RESULTS

Melanin synthesis in B16 melanoma 4A5 cells was selectively suppressed by blue light, but blue light did not induce decolorization of previously produced melanin. In the back skin of brown guinea-pigs, the brightness of the sites exposed to UVB began to decrease on the fifth day of the experiment, decreasing further from the 12th day to the 18th day after UVB exposure. The brightness of the sites exposed to UVB and blue light decreased in a manner similar during the UVB exposure, but remained relatively unchanged from the 12th day to the 30th day.

CONCLUSIONS

These results suggest that blue light suppresses melanin formation following repeated UVB exposure. Further investigation with various light such as blue light may lead to a new approach to the care of ultraviolet-affected skin such as hyperpigmentation.