Combined CO2 Laser With Photodynamic Therapy for the Treatment of Nodular Basal Cell Carcinomas

Lasers for the Treatment of Nonmelanoma Skin Cancer: A Systematic Review of the Literature

BACKGROUND

Lasers may present an alternative treatment modality for the management of nonmelanoma skin cancer (NMSC).

OBJECTIVE

To investigate lasers as a definitive treatment of NMSC.

METHODS

A comprehensive search was performed on MEDLINE, the Cochrane Library, and the National Institutes of Health ( www.clinicaltrials.gov ). The Preferred Reporting Items for Systematic Reviews and Meta-Analysis was used to finalize a list of relevant literature studies evaluating the role of laser therapy for NMSC. Articles published through May 1, 2023, were included.

RESULTS

The authors identified 37 studies investigating nonablative and ablative lasers alone and in combination with other lasers, noninvasive imaging, and additional modalities for the treatment of basal cell carcinomas, 10 focusing on squamous cell carcinoma in situ and 3 focusing on the treatment of both basal and squamous cell carcinomas.

CONCLUSION

Although surgical management continues to be superior to laser therapy for the management of high-risk and cosmetically sensitive tumors, laser therapy may be an acceptable alternative for low-risk lesions on the trunk and extremities. However, further studies are needed to optimize parameters, determine maximal efficacy, and provide long-term follow-up before the adoption of laser therapy for NMSC into daily clinical practice.

Combined Carbon Dioxide Laser with Photodynamic Therapy for Nodular Basal Cell Carcinoma Monitored by Reflectance Confocal Microscopy

Introduction: Basal cell carcinoma (BCC) represents around 80% of all malignant skin cancers worldwide, constituting a substantial burden on healthcare systems. Due to excellent clearance rates (around 95%), surgery is the current gold-standard treatment. However, surgery is not always possible or preferred by patients. Numerous non-surgical therapies, sometimes combined, have been associated with promising tumor free survival rates (80-90%) in non-melanoma skin cancers (NMSCs). Most research has enrolled superficial basal cell carcinomas (sBCCs), with limited recent studies also involving low-risk nodular BCCs (nBCCs). Given lower efficacy rates compared to surgery, close monitoring during the follow-up period is essential for patients treated with non-surgical therapies. Monitoring with dermoscopy is constrained by low sensitivity rates. Reflectance confocal microscopy (RCM) is more sensitive in monitoring non-surgically treated NMSCs. Case presentation: A 41-year-old woman with a single nBCC relapse following photodynamic therapy (PDT) located on the dorsum of the nose presented to our center. Given the aesthetically sensitive location of the lesion and the patient's preference for a non-surgical approach, a combined treatment of CO2 laser and PDT was prescribed. A superpulsed CO2 laser (power: 0.5-3 W, frequency: 10 Hz, spot size 2 mm) with two PDT sessions (2 weeks apart) were conducted. At 6 weeks follow-up, monitoring performed with RCM revealed a reduction but not eradication of basaloid tumor islands. Another 2 sessions of PDT were recommended. At 3, 12 and 30 months of follow-up, the nasal dorsum area of the previous nBBC lesion was noted to be slightly hypopigmented (observed clinically), with a mild erythematous background (observed by dermoscopy). RCM evaluation confirmed the absence of RCM BCC criteria. The cosmetic outcome was very much improved. Conclusions: Combined CO2 laser and PDT for the treatment of a localized nBCC on the dorsum of the nose of a 41-year-old proved to offer tumor free survival at 30-month follow-up, as monitored with RCM. RCM is useful for the evaluation of non-surgical therapies as it has comparably higher sensitivity than dermoscopy and is especially useful in cases of suspected late recurrence. Further studies are needed to validate ongoing tumor free survival following this combined nonsurgical approach in the treatment of nBCC.

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.

The combined effect of CO2 laser, topical diclofenac 3%, and imiquimod 5% in treating high-risk basal cell carcinoma

BACKGROUND

Some basal cell carcinoma (BCC) patients are considered as a high risk regarding the site, size, histopathological variant, or recurrence. High-risk BCC is a challenging therapeutic problem due to the trial to balance between complete surgical excision from one side and tissue preservation from the other side.

AIM

To evaluate the efficacy of combining ablative CO₂  laser, imiquimod 5%, and diclofenac 3% as a therapeutic regimen in high-risk and inoperable BCC.

PATIENTS/METHODS

The study was conducted on 14 patients that were assessed clinically and pathologically then categorized regarding the site, size, histopathology, and fitness for surgery as high-risk inoperable BCC. They received an ablative session of CO₂  laser, followed by application of diclofenac sodium 3% gel once daily for 5 days and imiquimod 5% cream for another 2 days.

RESULTS

The study included 11 males and 3 females. Nine lesions were located on the scalp, 4 on the face, and one lesion on the trunk. All lesions were of large size >5 cm in diameter. Histopathology showed 4 patterns: nodular type in 8 patients, infiltrating type in 3 patients, metatypical type in 2 patients, and micronodular type in one patient. At the end of the treatment period, 9 patients showed significant (moderate to marked) improvement while 5 patients showed weak (poor to mild) response. Significant improvement was more observed in nodular type. Relapse was more observed during the 5^th to 6th months with 2 patients showed no relapse.

CONCLUSION

This combined regimen is a good alternative therapeutic modality in high-risk inoperable BCC especially the nodular pathologic pattern.

Treatment of cutaneous basal cell carcinoma with combined laser extirpation and methyl aminolevulinic acid: five-year success rates

INTRODUCTION

Basal cell carcinoma is the most common cancer. Excisional surgery is associated with a high clearance rate, at the expense of significant functional and aesthetic morbidity, especially within the T-zone or for extensive lesions. We report five-year follow-up outcomes for carbon dioxide laser extirpation of cutaneous basal cell carcinoma, assisted by immediate methyl aminolevulinate photodynamic therapy and cost-benefit considerations.

MATERIALS AND METHODS

Retrospective cohort database analysis of adult patients with biopsy-proven primary cutaneous basal cell carcinoma, completing five years of follow-up. Direct per-lesion cost was compared with conventional wide local excision. Patients with morphoeic basal cell carcinoma were excluded.

RESULTS

Treated lesions were up to 1% total body surface area and up to 3.8mm (1.38 ± 0.695cm, mean ± standard deviation) in biopsy-proven depth. At the five-year follow-up mark, 93.6% of treated areas remained free of recurrence. Nodular basal cell carcinoma was the most common subtype (41.5%). A mean tumour depth greater than 2 ± 0.872mm was significantly associated with recurrence (Mann-Whitney, p = 0.0487). For a service delivered through the NHS at 2015 prices, we report a 43% saving, equating to a saving of £235 per basal cell carcinoma or a national annualised saving of £70 million by 2025 for the NHS.

CONCLUSION

Our results suggest that CO2-assisted photodynamic therapy is non-inferior to excision but may offer better functional and cosmetic preservation at a fraction of the direct like for like cost of operative surgery. Investigation of this method by randomised controlled methodology is warranted.

Methyl aminolevulinate photodynamic therapy after partial debulking in the treatment of superficial and nodular basal cell carcinoma: 3-years follow-up

BACKGROUND

The increase in the number of basal cell carcinoma (BCC) lesions has prompted use of minimally invasive therapies, including Photodynamic therapy (PDT). . The objective of the present work was to analyze the efficacy of methyl aminolevulinate-mediated photodynamic therapy (MAL-PDT) in patients suffering from superficial or nodular BCCs.

METHODS

A total of 220 BCC lesions (76 superficial and 144 nodular), clinically diagnosed and confirmed by histopathology analysis, were treated in 174 patients (mean age 72.5). Debulking using curettage was performed before two or three MAL-PDT sessions (λ = 630 nm; 90 J/cm²; 23 min) at 4-week intervals. Analyses of clinical clearance and cosmetic outcome were carried out by direct examination, dermoscopy, photographs, as well as by fluorescence diagnosis using a Wood's lamp. Evaluations were carried out at the different PDT sessions and follow-ups over a 3-year period.

RESULTS

MAL-PDT was safe and highly tolerated. After an average of 2.6 MAL-PDT sessions, the overall clearance rate at 3-year follow-up was 96.1 % (95 % confidence interval [CI] 100 %-92 %) for superficial BCCs and 95.2 % (95 % [CI] 99 %-92 %) for nodular BCCs after an average of 2.7 sessions. Minimal side effects such as crushing, erythema and edema were reported. All BCC lesions showed excellent or good cosmetic results.

CONCLUSION

The protocol followed in the present study has shown that MAL-PDT is a safe and effective treatment for superficial and nodular types of BCC.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 1: treatment delivery and established indications - actinic keratoses, Bowen's disease and basal cell carcinomas

Topical photodynamic therapy (PDT) is a widely approved therapy for actinic keratoses, Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas. Recurrence rates when standard treatment protocols are used are typically equivalent to existing therapies, although inferior to surgery for nodular basal cell carcinoma. PDT can be used both as lesional and field therapies and has the potential to delay/reduce the development of new lesions. A protocol using daylight to treat actinic keratoses is widely practised, with conventional PDT using a red light after typically a 3-h period of occlusion employed for other superficial skin cancer indications as well as for actinic keratoses when daylight therapy is not feasible. PDT is a well-tolerated therapy although discomfort associated with conventional protocol may require pain-reduction measures. PDT using daylight is associated with no or minimal pain and preferred by patient. There is an emerging literature on enhancing conventional PDT protocols or combined PDT with another treatment to increase response rates. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical PDT in dermatology, prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

CO2 laser and photodynamic therapy: Study of efficacy in periocular BCC

Basal cell carcinoma (BCC), the most common type of skin cancer in the world, usually arises in sun-exposed areas of the skin. The therapeutic approach to periocular BCC has changed in the last few years. Currently the treatment, considering the delicate localization of the disease, must not only ensure complete recovery from the neoplastic disease, but must also satisfy functional and aesthetic criteria. In this study we tried to evaluate the efficacy of CO₂ laser and photodynamic therapy in periocular BCC.

Light-emitting diodes in photodynamic therapy in non-melanoma skin cancers--own observations and literature review

Photodynamic therapy (PDT) employs light activation of tissue-localized photosensitizer in an oxygen-dependent process which initiates oxidative stress, inflammation, and cell death. There are many indications for PDT, although the main ones are still non-melanoma skin cancers. The light sources used include coherent and non-coherent ones, but we would like to focus on the use of light-emitting diodes (LED) in PDT. We present four patients with skin lesions successfully treated with LED-based photodynamic therapy. The main advantage of that source is narrow emission spectrum that can correspond well with maximum absorption photosensitizers. Also, using LED source seems to be cheaper and simpler, and the field of irradiation is larger. The data showed good clinical and cosmetic outcome of LED-based PDT in actinic keratosis, basal cell carcinoma, and Bowen's disease. Since these diseases often appear on sun-exposed skin, aesthetic results are very important. The effect of LED treatment is as good or in some data even better than those in older types of PDT.

Combined Treatments with Photodynamic Therapy for Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common form of cancer in the Caucasian population. Among NMSC types, basal cell carcinoma (BCC) has the highest incidence and squamous cell carcinoma (SCC) is less common although it can metastasize, accounting for the majority of NMSC-related deaths. Treatment options for NMSC include both surgical and non-surgical modalities. Even though surgical approaches are most commonly used to treat these lesions, Photodynamic Therapy (PDT) has the advantage of being a non-invasive option, and capable of field treatment, providing optimum cosmetic outcomes. Numerous clinical research studies have shown the efficacy of PDT for treating pre-malignant and malignant NMSC. However, resistant or recurrent tumors appear and sometimes become more aggressive. In this sense, the enhancement of PDT effectiveness by combining it with other therapeutic modalities has become an interesting field in NMSC research. Depending on the characteristics and the type of tumor, PDT can be applied in combination with immunomodulatory (Imiquimod) and chemotherapeutic (5-fluorouracil, methotrexate, diclofenac, or ingenol mebutate) agents, inhibitors of some molecules implicated in the carcinogenic process (COX2 or MAPK), surgical techniques, or even radiotherapy. These new strategies open the way to a wider improvement of the prevention and eradication of skin cancer.

Usefulness of Photodynamic Therapy as a Possible Therapeutic Alternative in the Treatment of Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common cancer in individuals with fair skin type (I–II) and steadily increasing in incidence (70% of skin malignancy). It is locally invasive but metastasis is usually very rare, with an estimated incidence of 0.0028%–0.55%. Conventional therapy is surgery, especially for the H region of the face and infiltrative lesions; in case of inoperable tumors, radiotherapy is a valid option. Recently, topical photodynamic therapy (PDT) has become an effective treatment in the management of superficial and small nodular BCC. PDT is a minimally invasive procedure that involves the administration of a photo-sensibilizing agent followed by irradiation at a pre-defined wavelength; this determines the creation of reactive oxygen species that specifically destroy target cells. The only major side effect is pain, reported by some patients during the irradiation. The high cure rate and excellent cosmetic outcome requires considering this possibility for the management of patients with both sporadic and hereditary BCC. In this article, an extensive review of the recent literature was made, in order to clarify the role of PDT as a possible alternative therapeutic option in the treatment of BCC.

Possibility for the Conjugated Use of Photodynamic Therapy and Electrosurgical Devices

Because tissue optics limits the treated volume during anti-tumor Photodynamic Therapy (PDT), its conjugation with prior tissue debulking has been suggested clinically. In this context, the conjugation of radiofrequency ablation and PDT has already been demonstrated. However, the basic principles that enable the success of these protocols have not been discussed. This proof-of-principle study analyzes the possibility of conjugating electrosurgery (ES) and PDT, analyzing different sequences of photosensitizer (PS) administration in an animal model. The animals were distributed over five groups: ES, PS+Light, PS+ES, ES+PS+Light and PS+ES+Light. The PS Photogem was administered systemically. An electrosurgical unit (480 kHz) was used to remove a portion of the liver, leaving a plane surface for PDT illumination (630 nm, 150 J/cm²). Fluorescence was collected during the stages of the experiment to monitor the PS accumulation. After 30 hours, histological processing was performed. The fluorescence spectra revealed strong Photogem emission in both administration sequences (ES+PS; PS+ES), and little PS bleach after ES was observed. The maximum necrosis depth was observed for the PS+ES+Light group-(716 ± 75) μm-higher than its respective control group (160 ± 28) μm, proving successful conjugation. Histological features from ES and PDT on both conjugation sequences were observed. Pre-photosensitized tissue presented decreased ES-related thermal damage. A simple physical hypothesis, based on the Joule effect and the tissue electrical conductivity, was proposed to support these findings. In conclusion, the results successfully demonstrated the possibility of conjugating ES and PDT in a single protocol.

Photodynamic therapy combined with cryotherapy for the treatment of nodular basal cell carcinoma

Carbon dioxide (CO₂) laser ablation in combination with photodynamic therapy (PDT) has previously been successfully used to treat superficial basal cell carcinoma (BCC). However, the efficacy of this treatment modality is limited in the treatment of deeper lesions and the more aggressive subtypes of BCC. In order to improve the outcome of PDT, 8 BCC lesions of variable depths (4 lesions ≤2 mm and 4 lesions >2 mm) and subtypes (1 superficial, 6 nodular and 1 infiltrative) were treated with CO₂ laser ablation in combination with PDT, followed by modified cryotherapy. The mean number of treatment sessions was 1.5 and the follow-up period was 22 months. All of the patients demonstrated a complete response and no recurrence of disease, while the majority of patients were satisfied with the cosmetic results upon follow-up examination. The combination therapy of CO₂ laser ablation with PDT followed by modified cryotherapy demonstrated a good efficacy and satisfactory cosmetic outcomes in the treatment of nodular BCC.

European guidelines for topical photodynamic therapy part 1: treatment delivery and current indications - actinic keratoses, Bowen's disease, basal cell carcinoma

Topical photodynamic therapy (PDT) is a widely used non-invasive treatment for certain non-melanoma skin cancers, permitting treatment of large and multiple lesions with excellent cosmesis. High efficacy is demonstrated for PDT using standardized protocols in non-hyperkeratotic actinic keratoses, Bowen's disease, superficial basal cell carcinomas (BCC) and in certain thin nodular BCC, with superiority of cosmetic outcome over conventional therapies. Recurrence rates following PDT are typically equivalent to existing therapies, although higher than surgery for nodular BCC. PDT is not recommended for invasive squamous cell carcinoma. Treatment is generally well tolerated, but tingling discomfort or pain is common during PDT. New studies identify patients most likely to experience discomfort and permit earlier adoption of pain-minimization strategies. Reduced discomfort has been observed with novel protocols including shorter photosensitizer application times and in daylight PDT for actinic keratoses.

The application of Levulan-based photodynamic therapy with imiquimod in the treatment of recurrent basal cell carcinoma

BACKGROUND

Common skin tumors like basal- and squamous-cell carcinoma present a serious problem in modern medicine. Exposure to ultraviolet solar radiation is the main cause of these lesions. Since application of Aldara and PDT separately is well documented, we decided to use both methods together. The aim of our study was to evaluate the effectiveness of local photodynamic therapy supplemented with topical application of Aldara in basal-cell carcinoma.

MATERIAL/METHODS

Thirty-four patients ages 50 to 68 years were enrolled to the trial and underwent PDT treatment. Each case of BCC was histopathologically confirmed. Ten patients were subjected to local Levulan-PDT and placebo (Eucerin as vehicle cream), and 24 patients were subjected to Levulan-PDT and imiquimod. Photodynamic diagnosis (PDD) was used to detect and visualize suspicious foci (including cancer lesions).

RESULTS

In the group of patients who were treated using Levulan-PDT and placebo, 6 patients (60%) were totally cured and 4 lesions (40%) significantly decreased in size. In the group of patients treated with Levulan-PDT and imiquimod, 18 lesions totally disappeared (75%), 6 lesions significantly diminished, and in 1 patient small foci of previously excised BCC developed again in scar tissue 10 month after the first control examination.

CONCLUSIONS

Cure was achieved without any scarring and with very good cosmetic effects. Although this is the preliminary report, the presented modification of PDT seems to be reasonable and promising in treating basal-cell carcinoma.

Do lasers or topicals really work for nonmelanoma skin cancers?

Novel strategies are urgently needed to address the millions of nonmelanoma skin cancers treated in the United States annually. The need is greatest for those patients who are poor surgical candidates or those prone to numerous nonmelanoma skin cancers and therefore at risk for marked disfigurement. Traditional treatment strategies include electrosurgery with curettage, radiation therapy, cryotherapy, excision, and Mohs micrographic surgery. Alternatives to traditional treatment, including topical medications and light or laser therapies, are becoming popular; however, there are various degrees of efficacy among these alternative tactics. These alternatives include topical retinoids, peels, 5-fluorouracil, imiquimod, photodynamic therapy, and lasers. The purpose of this paper is to review the available data regarding these alternative strategies and permit the reader to have a sense of which therapies are reasonable options for care.

Methylaminolevulinic acid-based photodynamic therapy: the patient's view

Topical photodynamic therapy (PDT) with methylaminolevulinate (MAL) for nonmelanomatous skin cancers (NMSC) has proven efficient and safe. Because pain and a phototoxic reaction (PTR) are frequent side effects, the ability to predict discomfort may improve the management of patient care. During a 3-month period, we enrolled 46 patients with a total of 120 precancerous actinic skin lesions or NMSCs. Patients were treated with MAL-PDT, and follow-up continued for 8 wk. PDT had no lasting side effects in 65% of the lesions, and nearly 90% healed. The most frequent adverse cosmetic effect was skin discoloration (26.7%). Scarring was observed more often on the nose (21%, 3 of 14 lesions). Women experienced erythema more often than men (24% vs. 6%). With approximately 80% of the lesions, the patient reported light or no PTR. The average patient-reported pain during irradiation was moderate (4.92 on a scale of 0 to 10). Pain was persistent in 45% of the cases, but it decreased rapidly thereafter (on average 1 d). Risk factors for a greater severity of pain were lesions on the scalp (average pain score: 6.62) and on the forehead (average: 7.00) and treatment over an extended area (average: 7.32). Treatment on the nose (average: 3.29) or on the thorax (average: 3.00) was less painful. The final level of satisfaction reported was good or very good by 90% of the patients. Based on our results, eligible patients can be individually identified and informed in advance about the likelihood of side effects, thereby improving their satisfaction.

Photodynamic therapy in the management of acne: an update

Acne, one of the most common dermatological diseases, is characterized by inflammatory and noninflammatory lesions that may progress to scars. Starting from pubertal age groups, it can affect adults in the age group 35-40 or more. The conventional therapies for treatment of acne are facing roadblocks because of the antibiotic resistance developing against Propionibacterium acnes. This has led to trying new therapies, of which photodynamic therapy (PDT) seems to be the one under intensive study. Promising results have been observed with PDT use in acne treatment, but it still has some more way to go to acquire the FDA approval for use in acne treatment. This is a review of the literature of use of PDT in treatment of acne, providing a starting point for dermatologists seeking to treat their patients with acne safely and effectively with this new method.

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.

Basal cell carcinoma treated successfully with combined CO2 laser and photodynamic therapy in a renal transplant patient: a case report

Renal transplant recipients are at significantly greater risk of developing skin malignancies due to combination immunosuppressive therapy. A significant number of patients present with lesions needing excision at multiple outpatient follow-up visits. For basal cell carcinoma, we have recently described how combining CO₂ laser with Photodynamic therapy greatly increases the efficacy of long-term tumour clearance compared with each modality alone. We present a case of a 66-year-old renal transplant therapy patient who repeatedly presents with new skin malignancies, in whom we treated successfully with Laser-Photodynamic therapy in a see-and-treat setting. This therapy offers patients the possibility of better cosmetic and functional results whilst obviating the need for repeated surgery. Other pre-cancerous lesions such as solar keratoses are prevalent in this patient group and respond extremely well to Photodynamic therapy monotherapy. We propose a regular clinic for renal transplant patients in a laser facility equipped with CO₂ laser and Photodynamic therapy, histopathology and punch-biopsy materials. This strategy allows simple and effective treatment of multiple lesions simultaneously, avoidance of numerous operations, avoidance of non-essential outpatient appointments that result in booking furthers visits for treatment, whilst facilitating diagnostic biopsies of potentially malignant lesions. We outline a care pathway for a see-and-treat clinic that implements this novel treatment modality improving the care of this unique patient population.

Photodynamic therapy in dermatology--an update 2008

SUMMARY

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