Photodynamic therapy of superficial basal cell carcinoma with 5-aminolevulinic acid with dimethylsulfoxide and ethylendiaminetetraacetic acid: a comparison of two light sources

Photodynamic Therapy in Treating a Subset of Basal Cell Carcinoma: Strengths, Shortcomings, Comparisons with Surgical Modalities, and Potential Role as Adjunctive Therapy

Basal cell carcinoma (BCC) is the most common skin cancer, for which there are multiple treatment options, including the gold standard Mohs micrographic surgery (MMS), surgical excision, electrodesiccation and curettage, radiation therapy, cryosurgery, and photodynamic therapy (PDT). While PDT is currently approved for treating actinic keratosis, it has been used off-label to treat BCC patients who may not tolerate surgery or other treatment modalities. We present a review of the efficacy of these modalities and describe important considerations that affect the usage of PDT and MMS. ALA-PDT and MAL-PDT are both efficacious treatment options for lower-risk BCC that can serve as non-invasive alternatives to surgical excision with favorable cosmetic outcomes in patients unsuitable to undergo surgery. In particular, PDT may be considered an adjuvant for the prevention and treatment of BCC lesions in patients with some genetic syndromes such as Gorlin syndrome, and in combination with surgical excision in lesions presenting in certain locations. Limitations to PDT include lack of margin control to prevent recurrence, pain, and cost of certain photosensitizers. Future studies should investigate the role of PDT as adjunctive therapy, standardization of protocols, and causes and ways to address recurrence following PDT treatment.

Advances in chlorin-based photodynamic therapy with nanoparticle delivery system for cancer treatment

Introduction: The treatment of tumors is one of the most difficult problems in the medical field at present. Patients often use a comprehensive therapy that combines surgery, radiotherapy, and chemotherapy. Photodynamic therapy (PDT) has prominent potential for eradicating various cancers. Chlorin-based photosensitizers (PSs), as one of the most utilized photosensitizers, have many advantages over conventional photosensitizers; however, a successful chlorin-based PDT needs multi-functional nano-carriers for selective photosensitizer delivery. The number of researches about nanoparticles designed for improved chlorin-based PSs is increasing in the current era. In this article, we give a brief review focused on the recent research progress in design of chlorin-based nanoparticles for the treatment of malignant tumors with photodynamic therapy.Areas covered: This review focuses on the current nanoparticle platforms for PDT, and describes different strategies to achieve controllable PDT by chlorin-nano-delivery systems. The challenges and prospects of PDT in clinical applications are also discussed.Expert opinions: The requirement for PDT to eradicate cancers has increased exponentially in recent years. The major clinically used photosensitizers are hydrophobic. The main obstacles in effective delivery of PSs are associated with this intrinsic nature. The design of nano-delivery systems to load PSs is pivotal for PSs' widespread use.

Interventions for basal cell carcinoma of the skin

BACKGROUND

Basal cell carcinoma (BCC) is the commonest cancer affecting white-skinned individuals, and worldwide incidence is increasing. Although rarely fatal, BCC is associated with significant morbidity and costs. First-line treatment is usually surgical excision, but alternatives are available. New published studies and the development of non-surgical treatments meant an update of our Cochrane Review (first published in 2003, and previously updated in 2007) was timely.

OBJECTIVES

To assess the effects of interventions for BCC in immunocompetent adults.

SEARCH METHODS

We updated our searches of the following databases to November 2019: Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and LILACS.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of interventions for BCC in immunocompetent adults with histologically-proven, primary BCC. Eligible comparators were placebo, active treatment, other treatments, or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcome measures were recurrence at three years and five years (measured clinically) (we included recurrence data outside of these time points if there was no measurement at three or five years) and participant- and observer-rated good/excellent cosmetic outcome. Secondary outcomes included pain during and after treatment, early treatment failure within six months, and adverse effects (AEs). We used GRADE to assess evidence certainty for each outcome.

MAIN RESULTS

We included 52 RCTs (26 new) involving 6690 participants (median 89) in this update. All studies recruited from secondary care outpatient clinics. More males than females were included. Study duration ranged from six weeks to 10 years (average 13 months). Most studies (48/52) included only low-risk BCC (superficial (sBCC) and nodular (nBCC) histological subtypes). The majority of studies were at low or unclear risk of bias for most domains. Twenty-two studies were industry-funded: commercial sponsors conducted most of the studies assessing imiquimod, and just under half of the photodynamic therapy (PDT) studies. Overall, surgical interventions have the lowest recurrence rates. For high-risk facial BCC (high-risk histological subtype or located in the facial 'H-zone' or both), there may be slightly fewer recurrences with Mohs micrographic surgery (MMS) compared to surgical excision (SE) at three years (1.9% versus 2.9%, respectively) (risk ratio (RR) 0.64, 95% confidence interval (CI) 0.16 to 2.64; 1 study, 331 participants; low-certainty evidence) and at five years (3.2% versus 5.2%, respectively) (RR 0.61, 95% CI 0.18 to 2.04; 1 study, 259 participants; low-certainty evidence). However, the 95% CI also includes the possibility of increased risk of recurrence and no difference between treatments. There may be little to no difference regarding improvement of cosmetic outcomes between MMS and SE, judged by participants and observers 18 months post-operatively (one study; low-certainty evidence); however, no raw data were available for this outcome. When comparing imiquimod and SE for nBCC or sBCC at low-risk sites, imiquimod probably results in more recurrences than SE at three years (16.4% versus 1.6%, respectively) (RR 10.30, 95% CI 3.22 to 32.94; 1 study, 401 participants; moderate-certainty evidence) and five years (17.5% versus 2.3%, respectively) (RR 7.73, 95% CI 2.81 to 21.3; 1 study, 383 participants; moderate-certainty evidence). There may be little to no difference in the number of participant-rated good/excellent cosmetic outcomes (RR 1.00, 95% CI 0.94 to 1.06; 1 study, 326 participants; low-certainty evidence). However, imiquimod may result in greater numbers of good/excellent cosmetic outcomes compared to SE when observer-rated (60.6% versus 35.6%, respectively) (RR 1.70, 95% CI 1.35 to 2.15; 1 study, 344 participants; low-certainty evidence). Both cosmetic outcomes were measured at three years. Based on one study of 347 participants with high- and low-risk primary BCC of the face, radiotherapy may result in more recurrences compared to SE under frozen section margin control at three years (5.2% versus 0%, respectively) (RR 19.11, 95% CI 1.12 to 325.78; low-certainty evidence) and at four years (6.4% versus 0.6%, respectively) (RR 11.06, 95% CI 1.44 to 84.77; low-certainty evidence). Radiotherapy probably results in a smaller number of good participant- (RR 0.76, 95% CI 0.63 to 0.91; 50.3% versus 66.1%, respectively) or observer-rated (RR 0.48, 95% CI 0.37 to 0.62; 28.9% versus 60.3%, respectively) good/excellent cosmetic outcomes compared to SE, when measured at four years, where dyspigmentation and telangiectasia can occur (both moderate-certainty evidence). Methyl-aminolevulinate (MAL)-PDT may result in more recurrences compared to SE at three years (36.4% versus 0%, respectively) (RR 26.47, 95% CI 1.63 to 429.92; 1 study; 68 participants with low-risk nBCC in the head and neck area; low-certainty evidence). There were no useable data for measurement at five years. MAL-PDT probably results in greater numbers of participant- (RR 1.18, 95% CI 1.09 to 1.27; 97.3% versus 82.5%) or observer-rated (RR 1.87, 95% CI 1.54 to 2.26; 87.1% versus 46.6%) good/excellent cosmetic outcomes at one year compared to SE (2 studies, 309 participants with low-risk nBCC and sBCC; moderate-certainty evidence). Based on moderate-certainty evidence (single low-risk sBCC), imiquimod probably results in fewer recurrences at three years compared to MAL-PDT (22.8% versus 51.6%, respectively) (RR 0.44, 95% CI 0.32 to 0.62; 277 participants) and five years (28.6% versus 68.6%, respectively) (RR 0.42, 95% CI 0.31 to 0.57; 228 participants). There is probably little to no difference in numbers of observer-rated good/excellent cosmetic outcomes at one year (RR 0.98, 95% CI 0.84 to 1.16; 370 participants). Participant-rated cosmetic outcomes were not measured for this comparison. AEs with surgical interventions include wound infections, graft necrosis and post-operative bleeding. Local AEs such as itching, weeping, pain and redness occur frequently with non-surgical interventions. Treatment-related AEs resulting in study modification or withdrawal occurred with imiquimod and MAL-PDT.

AUTHORS' CONCLUSIONS

Surgical interventions have the lowest recurrence rates, and there may be slightly fewer recurrences with MMS over SE for high-risk facial primary BCC (low-certainty evidence). Non-surgical treatments, when used for low-risk BCC, are less effective than surgical treatments, but recurrence rates are acceptable and cosmetic outcomes are probably superior. Of the non-surgical treatments, imiquimod has the best evidence to support its efficacy. Overall, evidence certainty was low to moderate. Priorities for future research include core outcome measures and studies with longer-term follow-up.

Guidelines of care for the management of cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common form of human cancer and has an increasing annual incidence. Although most cSCC is cured with office-based therapy, advanced cSCC poses a significant risk for morbidity, impact on quality of life, and death. This document provides evidence-based recommendations for the management of patients with cSCC. Topics addressed include biopsy techniques and histopathologic assessment, tumor staging, surgical and nonsurgical management, follow-up and prevention of recurrence, and management of advanced disease. The primary focus of these recommendations is on evaluation and management of primary cSCC and localized disease, but where relevant, applicability to recurrent cSCC is noted, as is general information on the management of patients with metastatic disease.

The use of lasers in the treatment of skin cancer: A review

BACKGROUND

In considering skin cancer, a number of factors-including effectiveness, simplicity of treatment, cost, and esthetic outcomes-are important to ensure patient's satisfaction. There are several existing interventions, such as electrodessication and curettage, excision, Mohs surgery, radiation therapy, cryotherapy, and topical/oral treatments. Laser therapy has emerged as a new promising alternative that should be explored.

OBJECTIVE

To review the literature on the dermatological use of laser therapy in the treatment of skin cancer.

RESULTS

A review of articles available on the MEDLINE and Web of Science databases until May 2017 yielded 24 and 6 studies, respectively, on laser therapy in the treatment of skin cancers, particularly melanoma, basal cell carcinoma, and squamous cell carcinoma. The four laser subtypes included solid-state, diode, dye, and gas lasers.

CONCLUSION

Review of the literature demonstrates the progress of dermatological understanding of the clinical implications of laser therapy in the treatment of premalignant and malignant neoplasms of the skin, and suggests that this treatment modality might be a viable option for some patients.

The Antinociceptive Effect of Light-Emitting Diode Irradiation on Incised Wounds Is Correlated with Changes in Cyclooxygenase 2 Activity, Prostaglandin E2, and Proinflammatory Cytokines

Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined. Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α). Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy. Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1β and TNF-α were significantly decreased only in the L-I group compared with their levels in the I groups (p < 0.05). Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.

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.

Photodynamic therapy: a review and its prospective role in the management of oral potentially malignant disorders

With the unreliability of epithelial dysplasia as a predictor to determine the risk of future malignant development, subjectivity associated in evaluating dysplasia by pathologists and paucity of biomarkers that could accurately predict the progression risks in oral potentially malignant disorders (PMDs), eradication of the lesions appears to be the most desirable approach to minimize the risk of invasive cancer formation. Interventions, such as surgery and chemoprevention, have not shown promising long-term results in the treatment of these lesions, and lack of guidelines and general consensus on their management has incited much anxiety and doubts in both patients and community clinicians. Topical photodynamic therapy (PDT) is a minimally invasive and minimally toxic technique that in recent years has shown great promise in the management of PMDs. In this review, we describe the historical developments in the field of PDT, its basic mechanisms, as well as related clinical studies, and its challenges in the management of oral PMDs. Based on its high efficacy and low side effects, its high patient acceptance/compliance, the simplicity of the procedure and its minimal pretreatment preparation, topical PDT is believed to have potential to play an important role in the management of PMDs, especially of the low-grade dysplasia.

Photodynamic therapy in dermatology: Dundee clinical and research experience

Topical photodynamic therapy (PDT) is increasingly accepted and used as a highly effective treatment for superficial non-melanoma skin cancer and dysplasia. We describe the developments in topical PDT for the treatment of skin diseases in our own PDT Centre in Dundee, both clinically and from a research base. Improvements in PDT could be achieved by optimisation of photosensitiser and light delivery, and these goals underpin the aims of our centre. We hope to facilitate the dissemination of use of PDT in dermatology throughout Scotland and outline some of the progress in these areas.

Non-melanoma skin cancers: photodynamic therapy, cryotherapy, 5-fluorouracil, imiquimod, diclofenac, or what? Facts and controversies

Surgical modalities-excision, Mohs micrographic surgery, and electrodesiccation with curettage-are the preferred treatments for nonmelanoma skin cancer (NMSC). When used within guidelines, they have cure rates greater than 90%. Despite this, many other treatments have been studied and utilized for NMSC. We present a comprehensive review of the literature on these topical treatments. Photodynamic therapy (PDT) is administered under numerous and significantly varied regimens, and there are a wide range of cure rates reported. Even with aggressive regimens, PDT is not as effective as surgery is, and it is not a first-line therapy for NMSC. The cryotherapy regimen aggressive enough to adequately treat NMSC carries adverse effects and cosmetic outcomes poor enough to negate its usefulness. Topical 5-fluorouracil and imiquimod are efficacious and safe for the treatment of superficial basal cell carcinoma (BCC) but not other BCC subtypes or squamous cell carcinoma. They are self-administered twice daily for several weeks; therefore, patient and tumor selection are vital to ensuring adherence. There are currently insufficient data to support the use of topical diclofenac and ingenol mebutate for NMSC.

Network geometry shows evidence sequestration for medical vs. surgical practices: treatments for basal cell carcinoma

OBJECTIVES

Basal cell carcinoma (BCC) is the most common cancer with 2 million treatments per year with little evidence-based guidelines for treatment. There are three classes of interventions (surgical, destructive, and topical) for BCC, and this study aimed to determine whether there are preferences or avoidances in comparisons of different types of treatments for BCC in randomized controlled trials (RCTs).

STUDY DESIGN AND SETTING

PubMed, Cochrane Central Registry of Clinical Trials, and ClinicalTrials.Gov were used to identify eligible published and registered ongoing RCTs.

RESULTS

Fifty-five trials (42 published and 13 registered trials) were identified. Only one unpublished registered trial compared a topical vs. a surgical intervention, and only one trial compared a topical vs. a destructive intervention. Conversely, 44 of the 55 trials compared interventions within the same treatment class and 9 of 55 trials compared surgical vs. destructive interventions. In most trials, selection of same-class comparators was not necessitated by the type of BCC lesions (nonaggressive superficial or nodular vs. aggressive, infiltrative, morpheic BCCs, P = 0.155) or their location (face vs. nonfacial, P = 0.137).

CONCLUSION

This is the first time that an evaluation of network geometry is applied to address issues of comparisons between different families of interventions that belong to different specialties and practices (medical vs. surgical). Previous evaluations of homophily have addressed different families of interventions, in which all interventions are medical (drugs) and performed in the same health-care settings. The noncommunicating bodies of evidence between medical and surgical interventions that we document highlight a problem of unnecessary sequestration of the evidence and the corresponding health-care practices.

Topical combination of diclofenac, calcipotriol, and difluoromethylornithine has beneficial effects comparable to 5-fluorouracil for the treatment of non-melanoma skin cancer in mice

Non-melanoma skin cancer (NMSC) is the most common form of skin cancer. Owing to the significant adverse effects of existing treatments, alternatives are needed. The aim of this study was to evaluate the use of topically administered combination therapy and 5-flurouracil (5-FU) for the treatment of UVB induced NMSC in a mouse model. Ninety-six SKH-1 mice were randomized to one placebo group and two treatment groups (diclofenac+calcitriol+difluoromethylornithine (DFMO) and 5-FU). After UVB radiation for 20 weeks, the mice with tumours were treated topically for the following 17 weeks. Both treatments significantly reduced the number of tumours, number of mice with tumours as well as tumour area size compared with placebo. As the clinical use of 5-FU may induce more adverse effects, a combination of diclofenac+calcitriol+DFMO could be a promising alternative. Human studies are warranted to determine the beneficial effects and possible adverse effects of this new treatment.

Photodynamic therapy versus topical imiquimod versus topical fluorouracil for treatment of superficial basal-cell carcinoma: a single blind, non-inferiority, randomised controlled trial

BACKGROUND

Superficial basal-cell carcinoma is most commonly treated with topical non-surgical treatments, such as photodynamic therapy or topical creams. Photodynamic therapy is considered the preferable treatment, although this has not been previously tested in a randomised control trial. We assessed the effectiveness of photodynamic therapy compared with imiquimod or fluorouracil in patients with superficial basal-cell carcinoma.

METHODS

In this single blind, non-inferiority, randomised controlled multicentre trial, we enrolled patients with a histologically proven superficial basal-cell carcinoma at seven hospitals in the Netherlands. Patients were randomly assigned to receive treatment with methylaminolevulinate photodynamic therapy (MAL-PDT; two sessions with an interval of 1 week), imiquimod cream (once daily, five times a week for 6 weeks), or fluorouracil cream (twice daily for 4 weeks). Follow-up was at 3 and 12 months post-treatment. Data were collected by one observer who was blinded to the assigned treatment. The primary outcome was the proportion of patients free of tumour at both 3 and 12 month follow up. A pre-specified non-inferiority margin of 10% was used and modified intention-to-treat analyses were done. This trial is registered as an International Standard Randomised controlled trial (ISRCTN 79701845).

FINDINGS

601 patients were randomised: 202 to receive MAL-PDT, 198 to receive imiquimod, and 201 to receive fluorouracil. A year after treatment, 52 of 196 patients treated with MAL-PDT, 31 of 189 treated with imiquimod, and 39 of 198 treated with fluorouracil had tumour residue or recurrence. The proportion of patients tumour-free at both 3 and 12 month follow-up was 72.8% (95% CI 66.8-79.4) for MAL-PDT, 83.4% (78.2-88.9) for imiquimod cream, and 80.1% (74.7-85.9) for fluorouracil cream. The difference between imiquimod and MAL-PDT was 10.6% (95% CI 1.5-19.5; p=0.021) and 7.3% (-1.9 to 16.5; p=0.120) between fluorouracil and MAL-PDT, and between fluorouracil and imiquimod was -3.3% (-11.6 to 5.0; p=0.435. For patients treated with MAL-PDT, moderate to severe pain and burning sensation were reported most often during the actual MAL-PDT session. For other local adverse reactions, local skin redness was most often reported as moderate or severe in all treatment groups. Patients treated with creams more often reported moderate to severe local swelling, erosion, crust formation, and itching of the skin than patients treated with MAL-PDT. In the MAL-PDT group no serious adverse events were reported. One patient treated with imiquimod and two patients treated with fluorouracil developed a local wound infection and needed additional treatment in the outpatient setting.

INTERPRETATION

Topical fluorouracil was non-inferior and imiquimod was superior to MAL-PDT for treatment of superficial basal-cell carcinoma. On the basis of these findings, imiquimod can be considered the preferred treatment, but all aspects affecting treatment choice should be weighted to select the best treatment for patients.

FUNDING

Grant of the Netherlands Organization for Scientific Research ZONMW (08-82310-98-08626).

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.

Anti-inflammatory effects of low-level light emitting diode therapy on Achilles tendinitis in rats

BACKGROUND AND OBJECTIVES

The present study investigated the effects of low-level light emitting diode (LED) therapy (880 +/- 10 nm) on inflammatory process in a experimental model of Achilles tendinitis induced by collagenase.

STUDY DESIGN/MATERIALS AND METHODS

Fifty-six male Wistar were separated into seven groups (n = 8), three groups in the experimental period of 7 days and four groups in the experimental period of 14 days, the control group (CONT), tendinitis group (TEND), LED therapy group (LEDT) for both experimental periods, and LED therapy group 7th to 14th day (LEDT delay) for 14 days experimental period. The LED parameters was 22 mW CW of optical output power, distributed in an irradiation area of 0.5 cm(2), with an irradiation time of 170 seconds, the applied energy density was 7.5 J/cm(2) in contact. The therapy was initiated 12 hours after the tendinitis induction, with a 48-hour interval between the irradiations. The histological analysis and inflammatory mediators were quantified.

RESULTS

Our results showed that LED decreases the inflammatory cells influx and mRNA expression to IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF-alpha) in both phase, and cyclooxygenase-2 (COX-2) just in initial phase (P < 0.05).

CONCLUSION

Our results suggest that the anti-inflammatory therapy with low-power LED (880 nm) enhanced the tissue response in all groups. We can conclude that the LED was able to reduce signs of inflammation in collagenase-induced tendinitis in rats by reducing the number of inflammatory cells and decrease mRNA expression of cytokines.

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.

Milestones in the development of photodynamic therapy and fluorescence diagnosis

Many reviews on PDT have been published. This field is now so large, and embraces so many sub-specialties, from laser technology and optical penetration through diffusing media to a number of medical fields including dermatology, gastroenterology, ophthalmology, blood sterilization and treatment of microbial-viral diseases, that it is impossible to cover all aspects in a single review. Here, we will concentrate on a few basic aspects, all important for the route of development leading PDT to its present state: early work on hematoporphyrin and hematoporphyrin derivative, second and third generation photosensitizers, 5-aminolevulinic acid and its derivatives, oxygen and singlet oxygen, PDT effects on cell organelles, mutagenic potential, the basis for tumour selectivity, cell cooperativity, photochemical internalization, light penetration into tissue and the significance of oxygen depletion, photobleaching of photosensitizers, optimal light sources, effects on the immune system, and, finally, future trends.

Sonodynamic therapy of cancer using a novel porphyrin derivative, DCPH-P-Na(I), which is devoid of photosensitivity

To improve the efficacy of sonodynamic therapy of cancer using photosensitizers, we developed a novel porphyrin derivative designated DCPH-P-Na(I) and investigated its photochemical characteristics and sonotoxicity on tumor cells. DCPH-P-Na(I) exhibited a minimum fluorescent emission by excitation with light, compared with a strong emission from ATX-70, which is known to reveal both photo- and sonotoxicity. According to this observation, when human tumor cells were exposed to light in the presence of DCPH-P-Na(I) in vitro, the least phototoxicity was observed, in contrast to the strong phototoxicity of ATX-70. However, DCPH-P-Na(I) exhibited a potent sonotoxicity on tumor cells by irradiation with ultrasound in vitro. This sonotoxicity was reduced by the addition of L-histidine, but not D-mannitol, thus suggesting that singlet oxygen may be responsible for the sonotoxicity of DCPH-P-Na(I). DCPH-P-Na(I) demonstrated significant sonotoxicity against a variety of cancer cell lines derived from different tissues. In addition, in a mouse xenograft model, a potent growth inhibition of the tumor was observed using sonication after the administration of DCPH-P-Na(I) to the mouse. These results suggest that sonodynamic therapy with DCPH-P-Na(I) may therefore be a useful clinical treatment for cancers located deep in the human body without inducing skin sensitivity, which tends to be a major side-effect of photosensitizers.

Interventions for basal cell carcinoma of the skin

BACKGROUND

Basal cell carcinoma (BCC) is the commonest skin cancer. BCCs are slow-growing, locally invasive, epidermal skin tumours which mainly affect white skinned people. The first line treatment is usually surgical excision, but numerous alternatives are available.

OBJECTIVES

To assess the effects of treatments for basal cell carcinoma.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (January 2006), the Cochrane Central Register of Controlled Trials (The Cochrane LIbrary Issue 1, 2006), the Cochrane Database of Systematic Reviews (The Cochrane Library Issue 1, 2006), MEDLINE (2004 to January 2006), EMBASE (2005 to January 2006), the metaRegister of Controlled Trials (February 2006). Cited references of all trials identified and key review articles were searched. Pharmaceutical companies were contacted where appropriate for reviews or unpublished trials.

SELECTION CRITERIA

Inclusion criteria were adults with one or more histologically proven, primary basal cell carcinoma. The primary outcome measure was recurrence at three to five years, measured clinically. The secondary outcome included early treatment failure within six months, measured histologically. Adverse treatment effects included aesthetic appearance and pain during and after treatment.

DATA COLLECTION AND ANALYSIS

Two authors independantly carried out study selection and assessment of methodological quality.

MAIN RESULTS

Twenty seven studies were identified. Only one RCT of surgery versus radiotherapy had primary outcome data at four years, showing significantly more persistent tumours and recurrences in the radiotherapy group as compared to the surgery group, (RR 0.09, 95%CI, 0.01 to 0.69). One study found no significant difference for recurrence at 30 months when Moh's micrographic surgery was compared to surgery for high risk facial BCCs, (RR 0.64, 95%CI 0.16,2.64). One study of methylaminolevulinate photodynamic therapy (MAL PDT) versus cryotherapy found no significant difference in recurrences in the MAL PDT group when compared to cryotherapy at one year (RR 0.50, 95% CI 0.22,1.12). Cryotherapy showed no significant difference in recurrences at one year when compared to surgery on one small study. When radiotherapy was compared to cryotherapy there were significantly fewer recurrences at one year in the radiotherapy group compared to the cryotherapy group.Short-term studies suggest a success rate of 87 to 88% for imiquimod in the treatment of superficial BCC using a once-daily regimen for 6 weeks and a 76% treatment response when treating nodular BCC for 12 weeks, when measured histologically.

AUTHORS' CONCLUSIONS

Overall there has been very little good quality research on treatments for BCC. Most trials have only evaluated BCCs in low risk locations. Surgery and radiotherapy appear to be the most effective treatments with surgery showing the lowest failure rates. Although cosmetic outcomes appear good with PDT, long term follow up data are needed. Other treatments might have some use but few have been compared to surgery. An ongoing study comparing imiquimod to surgery should clarify whether imiquimod is a useful option.

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.

In vitro and in vivo comparison of two different light sources for topical photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) is an effective and safe treatment option for the treatment of actinic keratosis (AK). Incoherent lamps are often used, matching the absorption maxima of ALA.

OBJECTIVES

A comparative trial was performed to evaluate the efficacy of recently developed light-emitting diodes (LEDs).

METHODS

Human epidermal keratinocytes were incubated for 24 h with ALA (100, 200, 300, 400 or 500 micromol L(-1)) and irradiated consecutively using either an incoherent halogen lamp (lambda(em) = 580-750 nm; 24 J cm(-2); 40 mW cm(-2)) or an LED system (lambda(em) = 633 +/- 3 nm; 3, 6, 12 or 24 J cm(-2); 40 mW cm(-2)). Topical ALA-PDT was performed on 40 patients with AK (n = 584) in a symmetrical distribution suitable for two-sided comparison. After incubation with ALA (20% in cream base) irradiation was performed with the incoherent lamp (100 J cm(-2); 160 mW cm(-2)) on one side and the LED system (40 J cm(-2); 80 mW cm(-2)) on the opposite side followed by re-evaluation up to 6 months.

RESULTS

No significant differences between the LED system (3, 6, 12 or 24 J cm(-2)) and the incoherent light source (24 J cm(-2)) regarding cytotoxicity was found in vitro. The complete remission rate yielded in the in vivo investigation was also not significantly different at 6 weeks (P = 0.95), 3 months (P = 0.75) and 6 months (P = 0.61) following therapy. Six weeks following therapy complete remission rates of 84.3% (LED system) and 82.8% (incoherent lamp) were achieved. There was also no significant difference between both light sources regarding pain during light treatment (P = 0.67), patient satisfaction (P = 1.0) or cosmesis (P = 1.0) following therapy.

CONCLUSIONS

These results show the efficacy of an LED system for ALA-PDT both in vitro and in vivo. ALA-PDT with the LED system showed a noninferiority regarding the clinical outcome in the treatment of AK compared with the incoherent lamp.

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.

Ambulatory photodynamic therapy: a new concept in delivering photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) has been shown to be effective in treating Bowen's disease, superficial basal cell carcinoma and actinic keratosis.

OBJECTIVES

To investigate the feasibility of delivering PDT using a portable light-emitting diode device.

METHODS

A prototype diode array, comprising 37 AlGaInP diodes cast in epoxy with a diffuser, and driven by a battery pack, was designed and constructed. A pilot study was carried out in five patients with histologically proven Bowen's disease who were referred for PDT with 5-aminolaevulinic acid. They were all treated in the hospital-based dermatology PDT suite such that each received the same level of supervision as patients receiving PDT with nonambulatory light sources. Patients recorded pain levels. In accordance with our usual practice, patients received two treatments at a 4-week interval.

RESULTS

Four of five patients were clear at follow-up (range 6-13 months, median 9). Pain was classified as none or mild in 80% of treatments and moderate in the remainder.

CONCLUSIONS

There are many potential benefits of ambulatory PDT, including the possibility of a much higher patient throughput, and allowing effective treatment at home. This pilot study provides early promising data of the safety and efficacy of this approach.

Photodynamic therapy systems and applications

Photodynamic therapy (PDT) is a form of photochemotherapy requiring the simultaneous presence of a photosensitiser, activating light of the proper wavelength and molecular oxygen in order to produce a localised therapeutic effect thought to be due to high-energy singlet oxygen generation. Neither drug nor light alone are effective as therapeutic agents and thus PDT treatment methods should be looked upon as true, necessary, drug and device combinations ('systems'). Selectivity of treatment is imparted by a combination of factors, including accumulation of photosensitiser by the target lesion and targeted application of activating light. The most common systemic side effect of systemically administered photosensitisers is cutaneous photosensitivity of varying periods of time. Local toxicities depend on the area of treatment. Sources of light which have been used in PDT include lasers, arc lamps, light-emitting diodes and fluorescent lamps. PDT has been used for a wide variety of clinical applications. In 1995, the first PDT system, using porfimer sodium (Photofrin, Axcan Pharma, Inc.), lasers and fibre optic light delivery methods, developed by QuadraLogic Technologies, was approved in the US for endoscopic palliation of malignant dysphagia caused by oesophageal cancer. A topical PDT system, aminolevulinic acid HCL (Levulan Kerastick) and the large-area BLU-U PDT Illuminator, was developed by DUSA Pharmaceuticals, Inc. for the treatment of actinic keratoses of the face and scalp and approved in the US in 2000. Topical PDT has applicability to a wide variety of skin cancers and precancerous conditions. In 2001, Novartis launched the systemically administered verteporfin (Visudyne) laser-based PDT system in the US as the first pharmacologic treatment for age-related macular degeneration. Development programmes are continuing to investigate PDT for the potential treatment of a variety of diseases, yielding therapeutic results with minimal toxicity.

Effectiveness of different light sources for 5-aminolevulinic acid photodynamic therapy

Many medical applications, including photodynamic therapy for cancer (PDT), involve the use of lasers. However, the coherence of laser light is not necessary for PDT, and attempts have been made to construct non-coherent light sources for PDT, which are relatively inexpensive, stable and easy to operate, require simple maintenance but differ fundamentally from the lasers in their output characteristics. In the present work we compared two clinically used lamps, CureLight1, which is a broadband source (560-740 nm) based on a filtered halogen lamp, and CureLight2, which is a narrowband source based on light-emitting diodes (LEDs), with respect to several parameters of crucial significance for PDT efficiency in vivo: (a) depth of action in tissues, (b) heating effects, (c) pain generation, (d) photodegradation of PpIX in solution, in cells and in mouse skin and (e) photo-inactivation of cells in vitro. We conclude that CureLight2 (LED), relative to CureLight1 (halogen) has deeper PDT action in tissue, similar efficiency for bleaching PpIX in mouse skin, better efficiency for bleaching PpIX in cells and solutions and good efficiency for inactivating cells in vitro. CureLight2 gives less heating of the tissue and less pain in unsensitised human skin. All these differences are related to difference in the spectra of the lamps. Thus, PDT light sources with emissions that are visually similar have significantly different photobiological properties.

Interventions for basal cell carcinoma of the skin: systematic review

OBJECTIVES

To assess the effects of treatments for basal cell carcinoma.

METHODS

Systematic review of randomised controlled trials.

MAIN OUTCOME MEASURE

Recurrence of basal cell carcinoma at three years or beyond, assessed clinically.

STUDIES REVIEWED

Randomised controlled trials of interventions for histologically confirmed basal cell carcinoma (published and unpublished material; no language restrictions).

RESULTS

25 studies were identified, covering seven therapeutic categories. Only one study of surgical excision versus radiotherapy contained primary outcome data, which showed significantly more persistent tumours and recurrences in the radiotherapy group compared with surgery (odds ratio 0.09, 95% confidence interval 0.01 to 0.67). One study compared cryotherapy with surgery, with inconclusive results at one year. In a comparison of radiotherapy with cryotherapy, significantly more recurrences occurred at one year in the cryotherapy group. Preliminary studies suggest a short term success rate of 87-88% for imiquimod cream in the treatment of superficial basal cell carcinoma, although this cream has not been compared with surgery. No consistent evidence was found for the other treatment modalities.

CONCLUSIONS

Little good quality research has been done on the treatments used for the most common cancer in humans. Most trials have included only people with basal cell carcinoma occurring at low risk sites. Only one trial measured recurrence at four years; recurrence rates at one year should be interpreted with caution. Surgery and radiotherapy seem to be the most effective treatments; surgery showed the lowest failure rates. Other treatments might have some use but need to be compared with surgery.

Topical treatment strategies for non-melanoma skin cancer and precursor lesions

The ability to manage non-melanoma skin cancers and pre-malignant lesions with topical pharmacologic agents is highly compelling. This article examines currently available products and discusses their emerging roles and limitations. These include fluorouracil, diclofenac sodium, imiquimod, and photodynamic therapy.

Topical photodynamic therapy in clinical dermatology

The growing incidence of cutaneous malignancies each year necessitates the development of new and more effective methods for both the diagnosis and the treatment of cancerous lesions, while assuring better cosmetic results and improving patient satisfaction. With that in mind, the use of topical photodynamic therapy (PDT) has been explored in the treatment as well as the diagnosis of various cutaneous malignancies. Using the intrinsic cellular haem biosynthetic pathway and principles of photoillumination, topical PDT carries the goal of selectively targeting abnormal cells, while preserving the normal surrounding structures. This paper will discuss the various applications and data on the use of topical PDT in dermatology.

A Review of Laser and Photodynamic Therapy for the Treatment of Nonmelanoma Skin Cancer

BACKGROUND

The role of laser and light sources used alone and in conjunction with photodynamic therapy (PDT) for the treatment of nonmelanoma skin cancers (NMSCs) remains unclear. PDT is a newly accepted treatment option for actinic keratoses (AKs) with clearance rates comparable to 5-flourouracil. The purpose of this study was to review literature pertaining to the use of light-emitting technologies and PDT for the treatment of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and AKs.

METHODS

A National Library of Medicine PubMed Internet search of English-language journals was performed using the terms laser, PDT, BCC, SCC, and AK. The search encompassed all English-language clinical trials on human subjects from the mid-1960s to the present using laser and light source therapy and/or topical aminolevulinic acid. Articles were excluded if they contained fewer than 10 patients, had a follow-up time of less than 1 month, used intravenous photosensitizers, or were review articles.

RESULTS

A total of 20 papers were included for review (10 for BCC, 4 for AK, and 6 for SCC). Follow-up for these patients ranged from 1 to 36 months. Clearance rates were reported up to 100% for superficial BCCs, AKs, and SCC in situ, and lower (8%) for more invasive SCC. Recurrence rates ranged from to 0% to 31% for superficial BCCs, 16% to 31% for AKs, 0% to 52% for SCC in situ, and 82% for invasive SCC.

CONCLUSION

Precise PDT and laser clearance and recurrence rates for superficial and nodular BCC and SCC treated with laser and PDT are not yet known. From the available data, it appears that PDT may be capable of achieving clearance rates comparable to radiation therapy for BCC. However, with current technology, PDT treatment of BCC remains inferior to surgical excision and Mohs surgery, for which recurrence rates have been reported to be less than 10%. The reported clearance rates currently limit the usefulness of PDT and laser therapy. However, multiple treatments and the use of penetration enhancers may significantly increase the efficacy of 5-aminolevulinic acid-PDT. With regard to SCCs, the risk of metastatic disease restricts the use of laser and PDT. Studies are currently underway with new light sources, photosensitizers, and various therapeutic regimens. At this time, because the reported recurrence rates are significantly higher than those achieved with standard therapies, laser and PDT should be reserved for only those patients who cannot undergo surgical therapy for BCC and SCC.