Randomized comparison of photodynamic therapy with topical 5-fluorouracil in Bowen's disease

5-Aminolevulinic acid-mediated photodynamic therapy to superficial malignant skin tumors using Super Lizer

Photodynamic therapy (PDT) using topically applied 5-aminolevulinic acid (ALA) has become a generally accepted treatment modality for superficial malignant skin tumors. However, the costly excimer-dye laser, diode laser and light-emitting diode (LED) frequently used to administrate PDT are impractical to use in most dermatology clinics. This study evaluated the effectiveness of ALA-mediated PDT using a Super Lizer (Tokyo Iken, Tokyo, Japan) equipped with band-pass filters in 38 patients with superficial malignant skin tumors (33 cases of actinic keratosis and five cases of Bowen's disease). Twenty-one cases (18 cases of actinic keratosis and three cases of Bowen's disease) were successfully treated, and the other 17 cases (15 cases of actinic keratosis and two cases of Bowen's disease) showed partial remission after single or repeated administration of PDT. PDT repeated three times at weekly intervals was more effective against actinic keratosis than randomly repeated procedures. The Super Lizer is easy to handle and move, and is less expensive than other known machinery and is useful for PDT in dermatology, especially under the protocol of three times at weekly intervals for the treatment of actinic keratosis.

Future of oncologic photodynamic therapy

Photodynamic therapy (PDT) is a tumor-ablative and function-sparing oncologic intervention. The relative simplicity of photosensitizer application followed by light activation resulting in the cytotoxic and vasculartoxic photodynamic reaction has allowed PDT to reach a worldwide audience. With several commercially available photosensitizing agents now on the market, numerous well designed clinical trials have demonstrated the efficacy of PDT on various cutaneous and deep tissue tumors. However, current photosensitizers and light sources still have a number of limitations. Future PDT will build on those findings to allow development and refinement of more optimal therapeutic agents and illumination devices. This article reviews the current state of the art and limitations of PDT, and highlight the progress being made towards the future of oncologic PDT.

Dermatologic management, sun avoidance and vitamin D status in organ transplant recipients (OTR)

It is well known that skin cancer, especially cutaneous squamous cell carcinoma (SCC), in organ transplant recipients (OTRs) has higher incidence rates, behaves more aggressively and has higher rates of metastasis. OTRs who have been treated for many years with immunosuppressive medication are at the highest risk for developing malignant skin tumors. Protection against solar and artificial UV-radiation is crucial to prevent skin cancer in OTRs. However, investigations have revealed that solar UV-B-exposure and serum 25(OH)D levels positively correlate with decreased risk for various internal malignancies (e.g. breast, colon, prostate, and ovarian cancer) and other severe diseases. Therefore, it is important to detect and treat vitamin D deficiency in OTRs. This review discusses guidelines for the optimal management of these patients, that require communication between the transplant teams, the treating dermatologist and other clinicians.

An overview of topical photodynamic therapy in dermatology

This article is a review of the use of topical photodynamic therapy in dermatology and its current role in 2009 and future developments. The content of this article was presented at the EPPM in Wroclaw, September 2009.

Pain associated with aminolevulinic acid-photodynamic therapy of skin disease

BACKGROUND

Pain during topical aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) limits the use of this treatment of skin diseases.

OBJECTIVE

We sought to summarize the effectiveness of interventions to reduce ALA-PDT-related pain, and to explore factors contributing to pain induction.

METHODS

A PubMed search was performed to identify all clinical PDT trials (2000-2008) that used ALA or methyl-ALA, enrolled at least 10 patients per trial, and used a semiquantitative pain scale.

RESULTS

In all, 43 articles were identified for review. Pain intensity is associated with lesion size and location and can be severe for certain diagnoses, such as plaque-type psoriasis. Results are inconsistent for the correlation of pain with light source, wavelength of light, fluence rate, and total light dose. Cooling represents the best topical intervention.

LIMITATIONS

Pain perception differs widely between patients and can contribute to variability in the reported results.

CONCLUSION

Gamma-aminobutyric acid receptors, cold/menthol receptors (transient receptor potential cation channel, subfamily M, member 8), and vanilloid/capsaicin receptors (transient receptor potential cation channel, subfamily V, member 1) may be involved in pain perception during ALA-PDT and are therefore worthy of further investigation.

Methyl aminolevulinate (Metvix®) photodynamic therapy - practical pearls

Topical photodynamic therapy (PDT) is an effective treatment for certain non-melanoma skin cancers (NMSCs), including superficial and nodular basal cell carcinomas (sBCC and nBCC), actinic keratosis (AK) and Bowen's disease. Methyl aminolevulinate (MAL, Metvix) is licensed in Europe for use in PDT for sBCC, nBCC and thin or non-hyperkeratotic and non-pigmented AK on the face and scalp, where other therapies are unsuitable. Optimal PDT response can be achieved through appropriate patient selection and lesion preparation. Evidence of efficacy is reviewed from guidelines and clinical experience. Red light from an LED source offers a relatively efficient method of activating the photodynamic reaction. The most common side effect of PDT is pain, burning or stinging discomfort at the site of treatment, although most patients do not request pain relief. The incidental observation of surface fluorescence three hours after photosensitizer application can be utilized for tumour detection as well as delineation. Topical PDT using Metvix MAL offers a practical non-invasive therapy option with the potential for high efficacy and good cosmesis.

Terapia fotodinâmica em dermatologia: princípios básicos e aplicações

A terapia fotodinâmica envolve a administração de uma droga fotossensibilizante e sua ativação subsequente pela luz de comprimento de onda correspondente ao espectro de absorção do fotossensibilizador. Atualmente, a terapia fotodinâmica tópica é aprovada para o tratamento de condições oncológicas cutâneas como queratoses actínicas, doença de Bowen e carcinoma basocelular superficial em diversos países do mundo. Estudos multicêntricos controlados e randomizados demonstram a alta eficácia e resultado cosmético final superior dessa modalidade terapêutica em relação aos tratamentos convencionais. Para condições cutâneas não oncológicas, como acne vulgar, verrugas virais e esclerodermia localizada, há também relatos e série de casos confirmando o potencial terapêutico da terapia fotodinâmica. O desenvolvimento de fotossensibilizantes tópicos, ácido 5-aminolevulínico (ALA) ou seu metiléster (MAL), frente aos derivados da hematoporfirina de aplicação sistêmica, permitiu um grande avanço na popularidade da TFD na dermatologia, uma vez que tanto ALA quanto MAL tópicos não induzem mais fotossensibilidade generalizada prolongada. A produção de intermediários reativos de oxigênio, como oxigênio singlet, depende da concentração, da localização do fotossensibilizante no tecido alvo, assim como da dose de luz utilizada. Tanto as lâmpadas de amplo espectro quanto os LEDs (do inglês light emitting diodes) constituem fontes de luz adequadas para que os efeitos citotóxicos da terapia fotodinâmica resultem na destruição do tumor ou seus efeitos imunomodulatórios atuem melhorando as condições inflamatórias cutâneas.

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.

Photodynamic therapy of superficial nasal planum squamous cell carcinomas in cats: 55 cases

BACKGROUND

Squamous cell carcinomas (SCCs) are common skin tumors in cats. We investigated photodynamic therapy (PDT) using the photosensitizing agent 5-aminolaevulinic acid (5-ALA) topically and a high-intensity red light source.

HYPOTHESIS

PDT is a safe and effective treatment for feline SCCs.

ANIMALS

Fifty-five client-owned cats with superficial nasal planum SCCs.

METHODS

Prospective, uncontrolled clinical trial. PDT was performed using topical 5-ALA and light of peak wavelength 635 nm. Adverse effects, response, and tumor control were evaluated.

RESULTS

53/55 (96%) cats responded to therapy, and there was a complete response in 47/55 (85%). Six cats (11%) had a partial response. Of the 47 cats with complete response to a single treatment, 24 recurred (51%), with a median time to recurrence of 157 days (95% confidence interval, 109-205 days). Repeat PDT was performed in 22 cats, and at a median follow-up of 1,146 days, 23 (45%) cats were alive and disease free, 17 (33%) had to be euthanized due to tumor recurrence, and 11 (22%) were euthanized for other reasons. Only transient mild local adverse effects were observed after treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

PDT using 5-ALA and a red light source was safe, well tolerated, and effective in the treatment of superficial nasal planum SCCs of cats and offers an alternative to conventional therapy. Although initial response rates were high, this treatment did not lead to a durable remission or cure in all cases.

[Photodynamic therapy in dermatooncology]

Non-melanoma skin cancers are the most common skin tumors. Because of their frequent localization on the face and hand, aesthetic aspects of the therapeutic procedures should also be considered. Surgical excision still remains the first choice, but recently several new alternative therapies have emerged, especially for the treatment of superficial skin cancer. Photodynamic therapy has become a widely accepted therapeutic method for certain non-melanoma skin tumors. Photodynamic therapy involves the use of light to activate a photosensitizer, localized in diseased tissues. Photosensitizers are tumor-selective: their accumulation in rapidly proliferating cells and newly formed blood vessels is significantly higher than in the surrounding healthy tissues. During photodynamic therapy, cytotoxic reactive oxygen species are formed from the photosensitizer, leading to changes in subcellular pathways or apoptosis of the cells. Efficacy of the photodynamic therapy has been proven in solar keratosis, superficial basal cell carcinoma and morbus Bowen, with significantly better cosmetic outcome than that of the conventional therapeutic methods. Side effects, like erythema, crusting, serous discharge, or oedema, are usually moderate, and dissolve rapidly. The present article summarizes the authors' experiences with photodynamic treatment (212 non-melanoma skin cancer patients were treated with PDT between December 2003 and January 2006), at the Department of Dermatology and Allergology, University of Szeged, Hungary, and reviews the literature of photodynamic therapy in dermatooncology.

Management of nonmelanoma skin cancer in 2007

As the incidence of nonmelanoma skin cancer (NMSC) increases, so does the number of modalities used to treat this condition. Surgery is the most frequent approach used to treat NMSC, and clinicians usually perform Mohs micrographic surgery, conventional excision, electrodesiccation and curettage or cryosurgery. The 'gold standard' for treatment continues to be Mohs micrographic surgery, but owing to the time and expense involved with this procedure, it is indicated only in patients with aggressive tumors or those where disfigurement or functional impairment is a risk. Although radiation therapy is effective, its use is limited because of the side effects induced; radiation therapy can be used in certain patients who are not surgical candidates. Newer noninvasive options for NMSC include topical chemotherapeutics, biological-immune-response modifiers, retinoids, and photodynamic therapy, which can be used particularly in patients with superficial tumors. Treatments should be tailored to tumor type, location, size, and histological pattern, and although surgical methods remain the most frequently used, newer noninvasive treatments can be used in select tumors and may reduce morbidity.

Photodynamic therapy: update 2006. Part 2: Clinical results

In several randomized, controlled studies, the application of a standard preparation containing methyl-aminolevulinate (MAL; Metvix, Galderma, F), followed by red light irradiation proved effective and well tolerated in the treatment of actinic keratosis and basal cell carcinoma, and has now been approved for clinical use in European countries. A brand name aminolevulinic acid (ALA) solution (Levulan Kerastick, Dusa Pharmaceuticals Inc., Wilmington, MA) plus blue light exposure has been approved for the treatment of actinic keratosis in the USA. Randomized and controlled studies have shown that MAL as well as ALA are also effective in the treatment of Bowen's disease. In addition, a large and growing number of open studies or case reports have evaluated its use in the treatment of a broad range of other neoplastic, inflammatory and infectious skin diseases. However, efficacy and definite advantages over standard therapies remain to be clarified because the experimental design of these studies was often poor, the number of enrolled patients was generally low, and the follow-up was shorter than 12 months. However, these studies have suggested a few possible clinical applications worthy of further investigation. A growing number of laboratory and clinical findings suggest that several new synthetic sensitizers, besides ALA and MAL, may be helpful in the treatment of non-melanoma skin cancers, melanoma metastasis, and selected inflammatory and infective skin diseases. These compounds are deliverable intravenously, have short half-lives both in the blood and skin, and are highly efficient. However, they are as of yet not approved for clinical use.

Photodynamische Therapie bei epithelialen Hauttumoren

During the last years photodynamic therapy (PDT) has progressively established itself as a standard treatment for non-melanoma skin cancer. A number of clinical studies have demonstrated its efficacy--also compared to other treatment modalities--as well as good acceptance by patients and outstanding cosmetic results. For Bowen disease and superficial basal cell carcinoma, PDT can be regarded as the first-line non-invasive treatment. In the treatment of actinic keratoses PDT should be considered when cosmesis is crucial or in cases of field cancerization. In nodular basal cell carcinoma, effectiveness for lesions up to a thickness of 2 mm is well documented. In summary the evidence level seems sufficient to regard PDT as valuable treatment modality of which patients should not be deprived.

Treatment of post-transplant premalignant skin disease: a randomized intrapatient comparative study of 5-fluorouracil cream and topical photodynamic therapy

BACKGROUND

Organ transplant recipients (OTR) are at high risk of developing nonmelanoma skin cancer and premalignant epidermal dysplasia (carcinoma in situ/ Bowen's disease and actinic keratoses). Epidermal dysplasia is often widespread and there are few comparative studies of available treatments.

OBJECTIVES

To compare topical methylaminolaevulinate (MAL) photodynamic therapy (PDT) with topical 5% fluorouracil (5-FU) cream in the treatment of post-transplant epidermal dysplasia.

METHODS

Eight OTRs with epidermal dysplasia were recruited to an open-label, single-centre, randomized, intrapatient comparative study. Treatment with two cycles of topical MAL PDT 1 week apart was randomly assigned to one area of epidermal dysplasia, and 5-FU cream was applied twice daily for 3 weeks to a clinically and histologically comparable area. Patients were reviewed at 1, 3 and 6 months after treatment. The main outcome measures were complete resolution rate (CRR), overall reduction in lesional area, treatment-associated pain and erythema, cosmetic outcome and global patient preference.

RESULTS

At all time points evaluated after completion of treatment, PDT was more effective than 5-FU in achieving complete resolution: eight of nine lesional areas cleared with PDT (CRR 89%, 95% CI: 0.52-0.99), compared with one of nine lesional areas treated with 5-FU (CRR 11%, 95% CI: 0.003-0.48) (P = 0.02). The mean lesional area reduction was also proportionately greater with PDT than with 5-FU (100% vs. 79% respectively). Cosmetic outcome and patient preference were also superior in the PDT-treated group.

CONCLUSIONS

Compared with topical 5-FU, MAL PDT was a more effective and cosmetically acceptable treatment for epidermal dysplasia in OTRs and was preferred by patients. Further studies are now required to confirm these results and to examine the effect of treating epidermal dysplasia with PDT on subsequent development of squamous cell carcinoma in this high risk population.

[Topical therapy of squamous cell carcinoma]

Many forms of topical chemo- and immunotherapy are employed to treat skin cancers. Topical treatment is particularly attractive for field cancerization involving multiple non-melanoma skin cancers. The dermatologist must identify such patients and lesions and provide the most suited therapy.

Methyl aminolevulinate: actinic keratoses and Bowen's disease

Topical photodynamic therapy (PDT) using the methyl ester of 5-aminolaevulinic acid (MAL) is an effective therapy for actinic keratoses and Bowen's disease. Thin and moderate thickness facial actinic keratoses respond best, with clearance rates equivalent or superior (depending on protocol) to current therapy, and with notably superior cosmetic outcome. Patients with areas of field cancerization and organ transplant recipients may particularly benefit from topical MA-PDT. The response rate of Bowen's disease to MAL-PDT is also at least equivalent to cryotherapy and 5-fluorouracil, again with superior cosmesis. Patients with large or multiple lesions of Bowen's disease or those in whom standard therapy, including surgery, is relatively contraindicated may particularly benefit from PDT.

Therapeutic options for Bowen's disease

Multiple therapeutic options are available for treatment of Bowen's disease. The choice of therapy depends on clinical circumstance and medical practitioner experience. Newer therapies have more extensive support from the literature, but more established therapies may be preferred because of accessibility, cost and efficacy. An overview of the current therapeutic options for Bowen's disease is presented.

Aminolevulinic Acid Photodynamic Therapy for Skin Cancers

Aminolevulinic acid photodynamic therapy (ALA-PDT) is an effective and noninvasive therapy for superficial basal cell carcinoma (BCC) and Bowen's disease. It also may have a role in the treatment of nodular BCC and other cutaneous malignancies, including localized cutaneous lymphomas. ALA-PDT offers multiple advantages over traditional treatments, including little to no scarring, excellent cosmetic results, and the ability to treat multiple lesions simultaneously. It is not an effective therapy for aggressive subtypes of BCC or for invasive squamous cell carcinoma. Finally, ALA-PDT may be a useful way to prevent new skin cancers in certain high-risk patients.

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

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

Guidelines for management of Bowen's disease: 2006 update

This article represents a planned regular updating of the previous British Association of Dermatologists (BAD) guidelines for management of Bowen's disease. They have been prepared for dermatologists on behalf of the BAD. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines.

Photodynamic Therapy in Oncology

Photodynamic therapy (PDT) is increasingly being recognized as an attractive, alternative treatment modality for superficial cancer. Treatment consists of two relatively simple procedures: the administration of a photosensitive drug and illumination of the tumor to activate the drug. Efficacy is high for small superficial tumors and, except for temporary skin photosensitization, there are no long-term side effects if appropriate protocols are followed. Healing occurs with little or no scarring and the procedure can be repeated without cumulative toxicity. Considering the efficacy and lack of long-term toxicity of PDT, and the fact that the first treatment of cancer with PDT was done more than 100 years ago, one might expect that this treatment had already become an established therapy. However, PDT is currently offered in only a few selected centers, although it is slowly gaining acceptance as an alternative to conventional cancer therapies. Here, we show the developmental steps PDT underwent and summarize the current clinical applications. The data show that, when properly used, PDT is an effective alternative treatment option in oncology.

Our PDT experience in the treatment of non-melanoma skin cancer over the last 7 years

BACKGROUND

Topical photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) was first described by Kennedy et al. in 1990; currently, accumulated evidence shows that topical PDT is effective in the treatment of actinic keratoses, Bowen's disease and superficial basal cell carcinoma, being potentially advantageous where size, anatomical location or number of lesions limit the efficacy and/or the acceptability of conventional therapies. It involves the use of photosensitizing drugs and the administration of an appropriate light source to activate the sensitizing agent, which leads to the production of activated oxygen species for tissue destruction. The topically administered prodrug 5-ALA is converted within cells into the active photosensitizer protoporphyrin IX, via haem cycle, with preferential accumulation in tumour cells.

METHODS

The authors describe their experience with topical PDT, using 20% 5-ALA and two different incoherent light sources, 'Waldman 1200 L' and 'VersaLight', in the treatment of non-melanoma skin cancer and precursor lesions. More than 100 patients were treated since 1997, with up to a 7-year follow-up period.

RESULTS

Cases are illustrated and results are presented and discussed in the light of the relevant Literature.

CONCLUSION

The study suggests that 5-ALA PDT is effective in the treatment of superficial skin cancer and premalignant lesions.

A clinical review of PDT for cutaneous malignancies

More critical than for most other anatomy, intervention to cutaneous malignancy must not only be therapeutically successful but also achieve excellent cosmetic and functional outcome. As it can achieve those ends, PDT has moved to the forefront in the management of skin cancer. A number of well designed clinical trials and large patient series have reported outstanding outcomes for many histologies. This paper will review the rationale and outcomes of cutaneous PDT to malignancy using both topical and systemic photosensitizers. The benefits and drawbacks of cutaneous PDT are also examined.

Terapia fotodinámica en dermatología

Photodynamic therapy (PDT) is a therapeutic modality based on the photooxidation of biological materials induced by a photosensitizer, which selectively locates itself in certain tumorous cells or tissues, so that when illuminated by a light of the right length and at a sufficient dose, these cells are destroyed. In dermatology, PDT with topical 5-aminolevulinic acid or 5-methyl aminolevulinate is very effective in the treatment of actinic keratoses, basal cell carcinomas and Bowen's disease. In addition, very promising results have been obtained in inflammatory pathologies like morphea or sarcoidosis, infections like warts, and cosmetic processes such as photoaging, among others. This article reviews the most significant aspects of PDT in dermatology. First of all, we will review the basic fundamentals of photodynamic treatment. Next, we will outline its clinical applications in dermatology, both in oncological applications and all those dermatological processes in which PDT may play a role in their management. We will also discuss its promising cosmetic application in the treatment of photoaging. We will complete the review with photodiagnosis and the different non-invasive ways to monitor the effectiveness of PDT.

Photodynamic Therapy

ALA-PDT is a safe, well-tolerated, and effective treatment for many dermatologic conditions. Current data most strongly support its use in the treatment of actinic damage, but further investigation into alternative uses continues. Current efficacy is limited primarily by the depth of penetration of the photosensitizing agent and the activating light source. Even with this limitation, the potential applications of PDT are numerous. As new technology is developed to overcome current restraints, the future of PDT is wide open.

Photodynamic therapy in dermatology - an update

Topical photodynamic therapy (PDT) is a well-established treatment modality which has mainly shown to be effective for dermatooncologic conditions like actinic keratoses (AK), Bowen's disease, in situ squamous cell carcinoma and superficial basal cell carcinoma (BCC). However, a therapeutical benefit of PDT is also evident for inflammatory dermatoses like localized scleroderma, acne vulgaris and granuloma annulare. Recent work has been focused on the development and evaluation of topical photosensitizers like the heme precursor 5-aminolevulinic acid (5-ALA) or its methyl ester (methyl aminolevulinate) inducing photosensitizing porphyrins. These drugs do not induce strong generalized cutaneous photosensitization like the systemically applied porphyrins or their derivatives. For dermatological purposes, incoherent lamps or light-emitting diode arrays can be used for light activation. Depending on the applied light dose and the concentration of the photosensitizer either cytotoxic effects resulting in tumor destruction or immunomodulatory effects improving the inflammatory conditions occur. Treating superficial oncologic lesions (tumor thickness <2-3 mm) cure rates achieved by PDT are equal to the cure rates of the respective standard therapeutic procedure. The benefits of PDT are the low level of invasiveness and the excellent cosmetic results after treatment.

Therapieoptionen bei epithelialen Hauttumoren

There has been worldwide a significant rise in the incidence of epithelial skin tumors and their precursors in the past years with an increased number of younger patients affected. The risk factors are identified. The choice of the appropriate treatment for each individual is crucial. Major consideration include high cure rate, low long-term recurrence rate and few side effects. In the following article different therapeutic approaches for actinic keratoses, Bowen's disease, basal cell carcinoma and squamous cell carcinoma are presented and analysed.