Topical photodynamic therapy in the treatment of actinic keratoses and Bowen's disease in transplant recipients

Photodynamic Therapy for the Treatment of Bowen's Disease: A Review on Efficacy, Non-Invasive Treatment Monitoring, Tolerability, and Cosmetic Outcome

Bowen's disease represents the in situ form of cutaneous squamous cell carcinoma; although it has an excellent prognosis, 3-5% of lesions progress to invasive cutaneous squamous cell carcinoma, with a higher risk in immunocompromised patients. Treatment is therefore always necessary, and conventional photodynamic therapy is a first-line option. The aim of this review is to provide an overview of the clinical response, recurrence rates, safety, and cosmetic outcome of photodynamic therapy in the treatment of Bowen's disease, considering different protocols in terms of photosensitizers, light source, and combination treatments. Photodynamic therapy is a valuable option for tumors at sites where wound healing is poor/delayed, in the case of multiple and/or large tumors, and where surgery would be difficult or invasive. Dermoscopy and reflectance confocal microscopy can be used as valuable tools for monitoring the therapeutic response. The treatment is generally well tolerated, with mild side effects, and is associated with a good/excellent cosmetic outcome. Periodic follow-up after photodynamic therapy is essential because of the risk of recurrence and progression to cSCC. As the incidence of keratinocyte tumors increases, the therapeutic space for photodynamic therapy will further increase.

Treatment of nonmelanoma skin cancer with pro-differentiation agents and photodynamic therapy: Preclinical and clinical studies (Review)

Photodynamic therapy (PDT) is a nonscarring cancer treatment in which a pro-drug (5-aminolevulinic acid, ALA) is applied, converted into a photosensitizer (protoporphyrin IX, PpIX) which is then activated by visible light. ALA-PDT is now popular for treating nonmelanoma skin cancer (NMSC), but can be ineffective for larger skin tumors, mainly due to inadequate production of PpIX. Work over the past two decades has shown that differentiation-promoting agents, including methotrexate (MTX), 5-fluorouracil (5FU) and vitamin D (Vit D) can be combined with ALA-PDT as neoadjuvants to promote tumor-specific accumulation of PpIX, enhance tumor-selective cell death, and improve therapeutic outcome. In this review, we provide a historical perspective of how the combinations of differentiation-promoting agents with PDT (cPDT) evolved, including Initial discoveries, biochemical and molecular mechanisms, and clinical translation for the treatment of NMSCs. For added context, we also compare the differentiation-promoting neoadjuvants with some other clinical PDT combinations such as surgery, laser ablation, iron-chelating agents (CP94), and immunomodulators that do not induce differentiation. Although this review focuses mainly on the application of cPDT for NMSCs, the concepts and findings described here may be more broadly applicable towards improving the therapeutic outcomes of PDT treatment for other types of cancers.

Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study

Artificial daylight photodynamic therapy is a near-painless treatment for actinic keratoses, which can be performed indoors using a controlled light dose. Daylight photodynamic therapy is approved only for treatment of grade I-II actinic keratoses. The aim of this study was to evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades. In addition, the study compared the outcomes of artificial and natural daylight photodynamic therapy. This randomized single-blinded split-side comparative study included 60 patients with  ≥ 2 actinic keratoses of the head. Fractional laser pre-treatment was assigned randomly for actinic keratoses on 1 side of the head and, subsequently, the entire treatment area was treated with artificial or natural daylight photodynamic therapy. Fractional laser-mediated daylight photodynamic therapy achieved significantly higher complete clearance (50.0% vs 30.3%, p = 0.04), partial clearance (78.6% vs 50.0%, p < 0.01) and lesion-specific clearance (86.2% vs 70.2%, p < 0.01) than daylight photodynamic therapy alone at the 6-month follow-up. No significant differences were found in the outcomes of artificial vs natural daylight photodynamic therapy or grade I lesions vs grade II-III lesions. Thus, fractional laser pre-treatment appears to significantly increase the efficacy of artificial and natural daylight photodynamic therapy, and to be suitable for treatment of actinic keratoses of all grades.

Advances in Photodynamic Therapy for the Treatment of Actinic Keratosis and Nonmelanoma Skin Cancer: A Narrative Review

Photodynamic therapy (PDT) with photosensitization using 5-aminolevulinic acid (ALA) [including a nanoemulsion (BF-200 ALA)] is approved in the USA for the treatment of actinic keratoses (AKs); another derivative, methyl aminolevulinate, is not approved in the USA but is used in Europe. For AK treatment, the photosensitizer may be applied to individual AK lesions or, depending on treatment regimen, to broader areas of sun-damaged skin to manage field cancerization, although not all products are approved for field treatment. ALA-PDT and photosensitizers have also been used off-label for the treatment of nonmelanoma skin cancers, primarily basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCC). Advantages of PDT include potentially improved cosmesis and patient satisfaction; disadvantages include pain and duration of treatment. Alternative illumination approaches, including intense pulsed light as well as pulsed-dye lasers, have also been used successfully. Pretreating the affected tissue or warming during incubation can help to increase photosensitizer absorption and improve therapeutic efficacy. Combinations of multiple treatments are also under exploration. Reducing incubation time between photosensitizer application and illumination may significantly reduce pain scores without affecting treatment efficacy. Substituting daylight PDT for a conventional illumination source can also reduce pain without compromising efficacy. The objective of this narrative review is to describe current and ongoing research in the use of topical photosensitizers and modified light delivery regimens to achieve improved therapeutic outcomes with less toxicity in patients with AK, cSCC, BCC, and field cancerization.

Ablative Fractional Laser-assisted Low-irradiance Photodynamic Therapy for Treatment of Actinic Keratoses in Organ Transplant Recipients: A Prospective, Randomized, Intraindividual Controlled Trial

Pain and inferior efficacy are major limiting factors of conventional photodynamic therapy for the field treatment of actinic keratoses in immunosuppressed organ transplant recipients. This prospective randomized controlled study evaluates the efficacy and tolerability of ablative fractional laser system pretreatment combined with low-irradiance photodynamic therapy (18.5 mW/cm2) compared with conventional photodynamic therapy (61.67 mW/cm2) in the treatment of actinic keratoses on the face and scalp in organ transplant recipients, using a red light-emitting diode lamp at a total light dose of 37 J/cm2. Low-irradiance photodynamic therapy combined with Er:YAG pretreatment achieved a significantly superior lesion response rate (mean ± standard deviation 77.3 ± 23.6%) compared with conventional photodynamic therapy (61.8 ± 21.4%; p = 0.025) in intra-individual fields at 3 months without negatively impacting pain (p = 0.777) or cosmetic outcome (p = 0.157).

Consensus-Based Recommendations on the Prevention of Squamous Cell Carcinoma in Solid Organ Transplant Recipients: A Delphi Consensus Statement

IMPORTANCE

There is a paucity of evidence to guide physicians regarding prevention strategies for cutaneous squamous cell carcinoma (CSCC) in solid organ transplant recipients (SOTRs).

OBJECTIVE

To examine the development and results of a Delphi process initiated to identify consensus-based medical management recommendations for prevention of CSCC in SOTRs.

EVIDENCE REVIEW

Dermatologists with more than 5 years' experience treating SOTRs were invited to participate. A novel actinic damage and skin cancer index (AD-SCI), consisting of 6 ordinal stages corresponding to an increasing burden of actinic damage and CSCC, was used to guide survey design. Three sequential web-based surveys were administered from January 1, 2019, to December 31, 2020. Pursuant to Delphi principles, respondents thoroughly reviewed all peer responses between rounds. Supplemental questions were also asked to better understand panelists' rationale for their responses.

FINDINGS

The Delphi panel comprised 48 dermatologists. Respondents represented 13 countries, with 27 (56%) from the US. Twenty-nine respondents (60%) were Mohs surgeons. Consensus was reached with 80% or higher concordance among respondents when presented with a statement, question, or management strategy pertaining to prevention of CSCC in SOTRs. A near-consensus category of 70% to less than 80% concordance was also defined. The AD-SCI stage-based recommendations were established if consensus or near-consensus was achieved. The panel was able to make recommendations for 5 of 6 AD-SCI stages. Key recommendations include the following: cryotherapy for scattered actinic keratosis (AK); field therapy for AK when grouped in 1 anatomical area, unless AKs are thick in which case field therapy and cryotherapy were recommended; combination lesion directed and field therapy with fluorouracil for field cancerized skin; and initiation of acitretin therapy and discussion of immunosuppression reduction or modification for patients who develop multiple skin cancers at a high rate (10 CSCCs per year) or develop high-risk CSCC (defined by a tumor with approximately ≥20% risk of nodal metastasis). No consensus recommendation was achieved for SOTRs with a first low risk CSCC.

CONCLUSIONS AND RELEVANCE

Physicians may consider implementation of panel recommendations for prevention of CSCC in SOTRs while awaiting high-level-of-evidence data. Additional clinical trials are needed in areas where consensus was not reached.

Update: Solar UV Radiation, Vitamin D, and Skin Cancer Surveillance in Organ Transplant Recipients (OTRs)

Although great progress has been achieved during the last decades, the clinical management of organ transplant recipients (OTRs) remains a challenge. OTRs need in general lifelong immunosuppressive therapy that is associated with an increased risk to develop skin cancer and with an unfavorable clinical outcome of these malignancies. Skin cancer prevention measures, including regular full-body examinations, are therefore necessary in OTRs to detect and treat suspicious lesions at an early stage. The frequency of aftercare depends on the individual risk factors of the patient. Patients should apply consistent sun protection with sunscreens and clothing, as well as a monthly self-examination. On the other hand, the need of UVR avoidance increases the risk of vitamin D deficiency, which itself is associated with an increased risk for many diseases, including malignancies. OTRs should therefore be monitored for 25(OH)D status and/or should take vitamin D supplements. It has to be emphasized that an interdisciplinary approach, coordinated by the transplant center, that includes regular skin examinations by a dermatologist, is needed to ensure the best care for the OTRs.

Cutaneous squamous cell carcinoma in the organ transplant recipient

One in twenty solid organ transplant recipients (SOTRs) will develop a highly morbid or fatal cutaneous carcinoma after transplantation. The majority of these cases develop on the head and neck and may require intervention on the part of dermatology, dermatologic surgery, otolaryngology, transplant medicine, radiation oncology, and medical oncology. In this review, we discuss the problem of cutaneous squamous cell carcinoma (cSCC) in SOTRs as well as the prognostic factors and management strategies to care for this population.

Daylight photodynamic therapy for prevention of new actinic keratosis and keratinocyte carcinomas in organ transplants. A cryotherapy-controlled randomized clinical trial

BACKGROUND

Organ transplant recipients (OTR) have a higher risk of actinic keratosis (AK) and keratinocyte carcinomas (KC). There are no clinical trials assessing the effectiveness of daylight photodynamic therapy (DPDT) to prevent new AK and KC in OTR.

OBJECTIVES

To determine whether repeated treatments of field cancerization with DPDT are effective in preventing new AK and KC in OTR.

METHODS

A randomized, intra-subject controlled, evaluator-blind, split-face and/or scalp trial, from April 2016 to October 2018. Participants were OTR older than 18 years, 1-year posttransplant, with at least 5 AK on each hemi-face/hemi-scalp. One side received six field treatments with DPDT: two sessions 15 days apart at baseline, two at 3 months and two at 9 months after baseline. Control side received lesion-directed treatment with cryotherapy (double freeze-thaw) at baseline, 3 and 9 months. Total number of lesions (AK and KC) at 21 months, number of new AK and KC at 3, 9, 15 and 21 months and treatment preferences were analysed.

RESULTS

Of 24 men included, 23 were analysed at 3 months; and 21, at 9, 15 and 21 months. Mean (SD) age was 69.8 years (9.2). The total number of lesions at 21 months was 4.7 (4.3) for DPDT and 5.8 (5.0) for control side; P = 0.09. DPDT showed significantly lower means [SD] of new lesions compared to control side at 3 months (4.2 [3.4] vs. 6.8 [4.8]; P < 0.001), 9 months (3.0 [3.3] vs. 4.3 [3.4]; P = 0.04) and 15 months (3.0 [4.6] vs. 4.8 [5.0]; P = 0.02), and non-significant at 21 months (3.7 [3.5] vs. 5.0 [4.5]; P = 0.06). Most participants preferred DPDT.

CONCLUSION

DPDT showed potential effectiveness in preventing new AK and KC in OTR by consecutive treatments of field cancerization. The preference for DPDT could facilitate adherence to the long-term treatment necessary in these patients.

Platelet-Activating Factor as an Effector for Environmental Stressors

Environmental stressors exert a profound effect on humans. Many environmental stressors have in common the ability to induce reactive oxygen species. The goal of this chapter is to present evidence that the potent lipid mediator platelet-activating factor (PAF) is involved in the effects of many stressors ranging from cigarette smoke to ultraviolet B radiation. These environmental stressors can generate PAF enzymatically as well as PAF-like lipids produced by free radical-mediated attack of glycerophosphocholines. Inasmuch as PAF exerts both acute inflammation and delayed immunosuppressive effects, involvement of the PAF system can provide an explanation for many consequences of environmental stressor exposures.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

The Course of Immune Stimulation by Photodynamic Therapy: Bridging Fundamentals of Photochemically Induced Immunogenic Cell Death to the Enrichment of T-Cell Repertoire

Photodynamic therapy (PDT) is a potentially immunogenic and FDA-approved antitumor treatment modality that utilizes the spatiotemporal combination of a photosensitizer, light and oftentimes oxygen, to generate therapeutic cytotoxic molecules. Certain photosensitizers under specific conditions, including ones in clinical practice, have been shown to elicit an immune response following photoillumination. When localized within tumor tissue, photogenerated cytotoxic molecules can lead to immunogenic cell death (ICD) of tumor cells, which release damage-associated molecular patterns and tumor-specific antigens. Subsequently, the T-lymphocyte (T cell)-mediated adaptive immune system can become activated. Activated T cells then disseminate into systemic circulation and can eliminate primary and metastatic tumors. In this review, we will detail the multistage cascade of events following PDT of solid tumors that ultimately lead to the activation of an antitumor immune response. More specifically, we connect the fundamentals of photochemically induced ICD with a proposition on potential mechanisms for PDT enhancement of the adaptive antitumor response. We postulate a hypothesis that during the course of the immune stimulation process, PDT also enriches the T-cell repertoire with tumor-reactive activated T cells, diversifying their tumor-specific targets and eliciting a more expansive and rigorous antitumor response. The implications of such a process are likely to impact the outcomes of rational combinations with immune checkpoint blockade, warranting investigations into T-cell diversity as a previously understudied and potentially transformative paradigm in antitumor photodynamic immunotherapy.

Actualités sur la prise en charge des kératoses actiniques chez les patients transplantés d’organes

Transplant recipients are at high risk of developing actinic keratosis (AK) and skin cancer. For this reason, initiating treatment at an early stage is crucial. Topical and systemic therapeutic options for AK have widely been described in studies of immunocompetent patients. However, little is known about AK management in organ transplant recipients (OTR). Photodynamic therapy (PDT), along with imiquimod, topical NSAIDs and topical 5-fluorouracil have been used on ORT patients in small non randomized studies. Although these studies seem to suggest that PDT offers best results, solid evidence is lacking. Nicotinamide and oral retinoids have also been described as reasonably effective preventive treatments in ORT patients. Management of immunosuppressive drugs is also considered as a key point for reducing the number of AK in ORT patients; an early switch for m-tor inhibitors has been shown to be protective while azathioprine, ciclosporin and tacrolimus have been shown to heighten the risk of developing AKs and skin cancer in this population. © 2019 Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Kératoses actiniques : comprendre et traiter réalisé avec le soutien institutionnel de Galderma International.

Photodynamic therapy: A targeted literature review focussing on outcomes and optimisation in solid organ transplant recipients

Squamous cell carcinoma incidence is 65- to 250-fold in solid organ transplant recipients, BCC is 10-fold and in Australia, rates of skin cancer in solid organ transplant recipients reach 70-82% prevalence within the first 20 years; hence, effective, evidence-based treatment of early and precancerous lesions is an essential tool in dermatological patient care. Photodynamic therapy is used to treat a range of conditions including actinic keratoses, squamous cell carcinoma in situ, superficial basal cell carcinoma and nodular basal cell carcinoma. A literature review was undertaken to examine the outcomes of photodynamic therapy in solid organ transplant recipients and methods of optimising outcomes in solid organ transplant recipients. Study sizes were small and protocols varied widely, so meta-analysis was not possible; however, photodynamic therapy appears to be an acceptable treatment for approved indications in solid organ transplant recipients in whom ongoing surveillance is maintained to ensure clearance and detect recurrence. Methods for improving efficacy were also reviewed for this population. Improved outcomes may be achieved by combining photodynamic therapy with other local methods such as 5-fluorouracil or ablative fractional laser.

Therapeutic bronchoscopy in the era of genotype directed lung cancer management

Lung cancer is the leading cause of cancer related deaths. Non-small cell lung cancer (NSCLC) accounts for ~85% of lung cancers. Our understanding of driver mutations and genotype directed therapy has revolutionized the management of advanced NSCLC. Commonly described mutations include mutations in epidermal growth factor (EGFR) & BRAF and translocations in anaplastic lymphoma kinase (ALK) & rat osteosarcoma (ROS1). Drugs directed against these translocations have significantly improved progression free survival individually and have shown a survival benefit when studied in the Lung Cancer Mutation Consortium (median survival 3.5 vs. 2.4 years compared to standard therapy). In a related yet parallel universe, the number of bronchoscopic ablative modalities available for management of cancer related airway obstruction have increased exponentially over the past decade. A wealth of literature has given us a better understanding of the technical aspects, benefits and risks associated with these procedures. While they all show benefits in terms of relieving airway obstruction, symptom control, quality of life and lung function testing, their complication rates vary based on the modality. The overall complication rate was ~4% in the AQuIRE registry. Bronchoscopic therapeutic modalities include rigid bronchoscopy with mechanical debulking, laser, thermo-coagulation [electrocautery & argon plasma coagulation (APC)], cryotherapy, endobronchial brachytherapy (EBT), photodynamic therapy (PDT), intratumoral chemotherapy (ITC) and transbronchial needle injection (TBNI) of chemotherapy. Intuitively, one would assume that the science of driver mutations would crisscross with the science of bronchoscopic ablation as they overlap in the same patient population. Sadly, this is not the case and there is a paucity of literature looking at these fields together. This results in several unanswered questions about the interplay between these two therapies.

Daylight Photodynamic Therapy for Actinic Keratoses

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

Photodynamic therapy is more effective than imiquimod for actinic keratosis in organ transplant recipients: a randomized intraindividual controlled trial

BACKGROUND

Actinic keratoses (AKs) in solid organ transplant recipients (OTRs) are difficult-to-treat premalignancies and comparison of topical therapies is therefore warranted.

OBJECTIVES

In an intraindividual study to compare the efficacy and safety of field treatment with methyl aminolaevulinate photodynamic therapy (MAL-PDT) and imiquimod (IMIQ) for AKs in OTRs.

METHODS

OTRs (n = 35) with 572 AKs (grade I-III) in two similar areas on the face, scalp, dorsal hands or forearms were included. All patients received one MAL-PDT and one IMIQ session (three applications per week for 4 weeks) in each study area according to randomization. Treatments were repeated after 2 months (IMIQ) and 3 months (PDT) in skin with incomplete AK response. Outcome measures were complete lesion response (CR), skin reactions, laboratory results and treatment preference.

RESULTS

The majority of study areas received two treatment sessions (PDT n = 25 patients; IMIQ n = 29 patients). At 3 months after two treatments, skin treated with PDT achieved a higher rate of CR (AK I-III median 78%; range 50-100) compared with IMIQ-treated skin areas (median 61%, range 33-100; P < 0·001). Fewer emergent AKs were seen in PDT-treated skin vs. IMIQ-treated skin (0·7 vs. 1·5 AKs, P = 0·04). Patients developed more intense inflammatory skin reactions following PDT, which resolved more rapidly compared with IMIQ (median 10 days vs. 18 days, P < 0·01). Patient preference (P = 0·47) and cosmesis (P > 0·30) were similar for PDT and IMIQ.

CONCLUSIONS

Compared with IMIQ, PDT treatment obtained a higher rate of AK clearance at 3-month follow-up and achieved shorter-lasting, but more intense, short-term skin reactions.

Skin Cancers in Organ Transplant Recipients

Long-term utilization of immunosuppression in organ transplant recipients (OTRs) leads to decreased immune-mediated tumor surveillance and development of malignant tumors. A delicate balance needs to be maintained in the intensity of immunosuppression to keep the risk of malignancy low without jeopardizing life-saving graft function. OTRs are prone to developing skin cancers that exhibit unique epidemiologic, pathophysiologic, and prognostic characteristics. In this review, we discuss the most commonly reported skin cancers in OTRs: squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Kaposi sarcoma, Merkel cell carcinoma, and malignant melanoma (MM). Tumors in this high-risk population are aggressive and may respond poorly to standard therapies; however, new targeted therapies are promising. Checkpoint inhibitor antibodies have been used for treatment of cutaneous SCC, Merkel cell carcinoma, and MM; epidermal growth factor receptor inhibitors have been used for cutaneous SCC; hedgehog pathway inhibitors have been used for BCC; and BRAF and MEK inhibitors are being used increasingly in the management of MM. Guidelines for dermatologic screening are variable and primarily based on expert opinion. Prospective evidence-based trials by multidisciplinary groups are needed to better define surveillance schedules for pre- and posttransplant cutaneous malignancies.

Beyond the margins: real-time detection of cancer using targeted fluorophores

Over the past two decades, synergistic innovations in imaging technology have resulted in a revolution in which a range of biomedical applications are now benefiting from fluorescence imaging. Specifically, advances in fluorophore chemistry and imaging hardware, and the identification of targetable biomarkers have now positioned intraoperative fluorescence as a highly specific real-time detection modality for surgeons in oncology. In particular, the deeper tissue penetration and limited autofluorescence of near-infrared (NIR) fluorescence imaging improves the translational potential of this modality over visible-light fluorescence imaging. Rapid developments in fluorophores with improved characteristics, detection instrumentation, and targeting strategies led to the clinical testing in the early 2010s of the first targeted NIR fluorophores for intraoperative cancer detection. The foundations for the advances that underline this technology continue to be nurtured by the multidisciplinary collaboration of chemists, biologists, engineers, and clinicians. In this Review, we highlight the latest developments in NIR fluorophores, cancer-targeting strategies, and detection instrumentation for intraoperative cancer detection, and consider the unique challenges associated with their effective application in clinical settings.

On the in vivo photochemical rate parameters for PDT reactive oxygen species modeling

Photosensitizer photochemical parameters are crucial data in accurate dosimetry for photodynamic therapy (PDT) based on photochemical modeling. Progress has been made in the last few decades in determining the photochemical properties of commonly used photosensitizers (PS), but mostly in solution or in vitro. Recent developments allow for the estimation of some of these photochemical parameters in vivo. This review will cover the currently available in vivo photochemical properties of photosensitizers as well as the techniques for measuring those parameters. Furthermore, photochemical parameters that are independent of environmental factors or are universal for different photosensitizers will be examined. Most photosensitizers discussed in this review are of the type II (singlet oxygen) photooxidation category, although type I photosensitizers that involve other reactive oxygen species (ROS) will be discussed as well. The compilation of these parameters will be essential for ROS modeling of PDT.

Photodynamic Therapy of Non-Small Cell Lung Cancer. Narrative Review and Future Directions

Photodynamic therapy (PDT) is an established treatment modality for non-small cell lung cancer. Phototoxicity, the primary adverse event, is expected to be minimized with the introduction of new photosensitizers that have shown promising results in phase I and II clinical studies. Early-stage and superficial endobronchial lesions less than 1 cm in thickness can be effectively treated with external light sources. Thicker lesions and peripheral lesions may be amenable to interstitial PDT, where the light is delivered intratumorally. The addition of PDT to standard-of-care surgery and chemotherapy can improve survival and outcomes in patients with pleural disease. Intraoperative PDT has shown promise in the treatment of non-small cell lung cancer with pleural spread. Recent preclinical and clinical data suggest that PDT can increase antitumor immunity. Crosslinking of signal transducer and activator of transcription-3 molecules is a reliable biomarker to quantify the photoreaction induced by PDT. Randomized studies are required to test the prognosis value of this biomarker, obtain approval for the new photosensitizers, and test the potential efficacy of interstitial and intraoperative PDT in the treatment of patients with non-small cell lung cancer.

Photodynamic Therapy and Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy among the Caucasian population. Photodynamic therapy (PDT) is gaining popularity for the treatment of basal cell carcinoma (BCC), Bowen's disease (BD) and actinic keratosis (AK). A topical or systemic exogenous photosensitiser, results in selective uptake by malignant cells. Protoporphyrin IX (PpIX) is produced then activated by the introduction of a light source. Daylight-mediated MAL (methyl aminolaevulinate) PDT for AKs has the advantage of decreased pain and better patient tolerance. PDT is an effective treatment for superficial BCC, BD and both individual and field treatment of AKs. Excellent cosmesis can be achieved with high patient satisfaction. Variable results have been reported for nodular BCC, with improved outcomes following pretreatment and repeated PDT cycles. The more aggressive basisquamous, morphoeic infiltrating subtypes of BCC and invasive squamous cell carcinoma (SCC) are not suitable for PDT. Prevention of "field cancerization" in organ transplant recipients on long-term immunosuppression and patients with Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a promising development. The optimisation of PDT techniques with improved photosensitiser delivery to target tissues, new generation photosensitisers and novel light sources may expand the future role of PDT in NMSC management.

Non-melanoma Skin Cancer in Canada Chapter 3: Management of Actinic Keratoses

Background

Actinic keratosis (AK) and cheilitis (AC) are lesions that develop on photodamaged skin and may progress to form invasive squamous cell carcinomas (SCCs).

Objective

To provide guidance to Canadian health care practitioners regarding management of AKs and ACs.

Methods

Literature searches and development of graded recommendations were carried out as discussed in the accompanying introduction (chapter 1 of the NMSC guidelines).

Results

Treatment of AKs allows for secondary prevention of skin cancer in sun-damaged skin. Because it is impossible to predict whether a given AK will regress, persist, or progress, AKs should ideally be treated. This chapter discusses options for the management of AKs and ACs.

Conclusions

Treatment options include surgical removal, topical treatment, and photodynamic therapy. Combined modalities may be used in case of inadequate response. AKs are particularly common following the longterm immunosuppression in organ transplant patients, who should be monitored frequently to identify emerging lesions that require surgery.

Sequential Curettage, 5-Fluorouracil, and Photodynamic Therapy for Field Cancerization of the Scalp and Face in Solid Organ Transplant Recipients

BACKGROUND

Field cancerization with actinic keratoses and squamous cell carcinoma in situ (AK/SCCIS) represents a common therapeutic challenge in solid organ transplant recipients (SOTRs). These patients often show inadequate responses to methods traditionally used as monotherapy (e.g., topical chemotherapy).

OBJECTIVE

To describe the clinical outcomes and feasibility of a sequential approach to treatment of field cancerization in SOTRs.

METHODS

Four SOTRs with field cancerization of the scalp and/or face were treated using a sequential approach. Light curettage of hypertrophic lesions was followed by application of 5-fluorouracil 5% cream twice daily for 5 days and photodynamic therapy (PDT) with 1-hour incubation on day 6. Pain level during and after PDT was recorded. Photographs were obtained immediately before and after treatment and at follow-up appointments.

RESULTS

All 4 patients tolerated this approach well and demonstrated excellent responses to treatment with complete or near-complete clinical resolution of AK/SCCIS lesions. Patients remained free of AK/SCCIS based on clinical examination 1 to 6 months after treatment.

CONCLUSION

For SOTRs with field cancerization, sequential therapy represents a viable therapeutic regimen with good tolerability and durable clinical response. This approach warrants further investigation to determine which therapeutic combinations have optimal tolerability and efficacy.

Skin changes following organ transplantation: an interdisciplinary challenge

BACKGROUND

The immunosuppressants used in transplantation medicine significantly elevate the incidence of neoplasia, particularly in the skin. The cumulative incidence of non-melanocytic skin cancer (NMSC) in renal transplant recipients was 20.5% in a study carried out in German centers. Data on more than 35 000 renal transplant recipients in the USA document a cumulative NMSC incidence of over 7% after 3 years of immunosuppression.

METHOD

The authors selectively review publications obtained by a PubMed search to discuss the incidence of, and major risk factors for, skin tumors and infectious diseases of the skin in immunosuppressed patients.

RESULTS

The main risk factors for skin tumors are age at the time of transplantation, light skin color, previous and present exposure to sunlight, and the type and duration of immunosuppressive treatment. Squamous-cell carcinoma (SCC) is the most common kind of skin tumor in immunosuppressed patients. Human herpesvirus 8 and Merkel-cell polyoma virus also cause neoplasia more often in immunosuppressed patients than in the general population. Surgical excision is the treatment of choice. Actinic keratosis markedly elevates the risk that SCC will arise in the same skin area (odds ratio 18.36, 95% confidence interval 3.03-111). Patients with multiple actinic keratoses can be treated with photodynamic therapy or with acitretin. To lower the skin cancer risk, organ transplant recipients should apply medical screening agents with a sun protection factor of at least 50 to exposed skin areas every day. 55% to 97% of organ transplant recipients have skin infections; these are treated according to their respective types.

CONCLUSION

Squamous-cell carcinoma of the skin adds to the morbidity and mortality of transplant recipients and is therefore among the major oncological challenges in this patient group. Structured concepts for interdisciplinary care enable risk-adapted treatment.

Update on topical photodynamic therapy for skin cancer

Topical photodynamic therapy has become an established therapy option for superficial non-melanoma skin cancers with a substantial evidence base. In this update the increased choice in photosensitizers and light sources are reviewed as well as novel protocols to move beyond lesional treatment and address field therapy. Daylight PDT is emerging as an alternative to conventional office/hospital-based PDT that offers the advantage of much reduced pain. Although most studies have assessed efficacy of PDT in immune-competent patients, there is accumulating evidence for topical PDT being considered an option to assist in reducing the skin cancer burden in organ transplant recipients. The fluorescence associated with photosensitizer application can help delineate lesions prior to full treatment illumination and offers a useful adjunct to treatment in patients where diagnostic uncertainty or poor lesion outline complicates clinical care. PDT may also offer significant benefit in delaying/preventing new cancer development and combined with its recognized photo-rejuvenating effects, is emerging as an effective therapy capable of clearing certain superficial skin cancers, potentially preventing new lesions as well as facilitating photo-rejuvenating effects in treated areas.

Intensified fractional CO2 laser-assisted photodynamic therapy vs. laser alone for organ transplant recipients with multiple actinic keratoses and wart-like lesions: a randomized half-side comparative trial on dorsal hands

BACKGROUND

Photodynamic therapy (PDT) is a well-documented treatment for actinic keratosis (AK), but achieves inferior efficacy in organ transplant recipients (OTRs), particularly in acral regions. Ablative fractional laser (AFXL) intensifies the PDT response and may improve the efficacy of AK clearance when used as monotherapy.

OBJECTIVES

To compare the efficacy of a single treatment with AFXL-assisted PDT vs. AFXL alone for difficult-to-treat AKs and wart-like lesions (WLLs) in OTRs.

METHODS

Ten OTRs were included with a total of 680 AKs (severity grade I-III) and 409 WLLs on the dorsal hands. Both hands were initially treated with targeted fractional ablation of thick keratotic lesions followed by AFXL field treatment. Treatment regions were then randomized to (i) PDT (AFXL-PDT) or (ii) no further treatment (AFXL). The primary end point was complete response (CR) at 4 months after treatment; secondary end points were improvement of AK severity grade, overall patient assessment of efficacy and tolerability of treatments.

RESULTS

CR of AKs was significantly higher for AFXL-PDT (73%) compared with AFXL alone (31%) (P = 0·002). AFXL-PDT improved 82% of AKs to lower lesion grades compared with 52% after AFXL alone (P = 0.008). For WLLs, the rate of CR was 37% for AFXL-PDT compared with 14% for AFXL (P = 0·02). Overall assessment showed a preference for AFXL-PDT compared with AFXL (AFXL-PDT, n = 8; AFXL, n = 0; equal, n = 2). Mild pigment changes were observed in four patients (AFXL-PDT, n = 3; AFXL, n = 1). No scarring was observed.

CONCLUSIONS

AFXL-PDT is more effective than AFXL in the treatment of acral AKs and WLLs in OTRs.

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy (PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960s. In the late 1970s, the underlying mechanism was defined, and Dougherty’s discovery of the first chromophore led to the production and commercialization of Photofrin^®. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen’s disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.

Immune response after photodynamic therapy increases anti-cancer and anti-bacterial effects

Photodynamic therapy (PDT) is a clinically approved procedure for treatment of cancer and infections. PDT involves systemic or topical administration of a photosensitizer (PS), followed by irradiation of the diseased area with light of a wavelength corresponding to an absorbance band of the PS. In the presence of oxygen, a photochemical reaction is initiated, leading to the generation of reactive oxygen species and cell death. Besides causing direct cytotoxic effects on illuminated tumor cells, PDT is known to cause damage to the tumor vasculature and induce the release of pro-inflammatory molecules. Pre-clinical and clinical studies have demonstrated that PDT is capable of affecting both the innate and adaptive arms of the immune system. Immune stimulatory properties of PDT may increase its beneficial effects giving the therapy wider potential to become more extensively used in clinical practice. Be sides stimulating tumor-specific cytotoxic T-cells capable to destroy distant untreated tumor cells, PDT leads to development of anti-tumor memory immunity that can potentially prevent the recurrence of cancer. The immunological effects of PDT make the therapy more effective also when used for treatment of bacterial infections, due to an augmented infiltration of neutrophils into the infected regions that seems to potentiate the outcome of the treatment.

[New developments in photodynamic therapy]

We review new developments in recent years in photodynamic therapy. Since 2009 two new photosensitizers, a self-adhesive 5-aminolevulinic acid (ALA) patch and a nanoemulsion formulation of 5-aminolevulinic acid have been approved for the treatment of actinic keratoses. Pretreatment with ablative fractional lasers enhances penetration of the photosensitizer and enables intensified PDT in acral lesions and in field-cancerized skin. Several clinical trials have demonstrated the skin-rejuvenating effects of photodynamic therapy, while the underlying mechanisms of action have been clarified. The efficacy of photodynamic therapy has been shown in the treatment and prophylaxis of actinic keratoses in organ transplant recipients at high risk for developing skin cancer. We also summarize the results of available studies on daylight-mediated photodynamic therapy.

Spotlighting the role of photodynamic therapy in cutaneous malignancy: an update and expansion

BACKGROUND

Topical photodynamic therapy (PDT) is an option for the treatment of cutaneous malignancy.

OBJECTIVE

To present an update and expansion on a previous review of the use of PDT in the current literature in the treatment of actinic keratoses (AK), superficial and nodular basal cell carcinoma (sBCC, nBCC), squamous cell carcinoma (SCC), Bowen's disease, cutaneous T cell lymphoma (CTCL), malignant melanoma, and its use in chemoprevention.

METHODS

Extensive PubMed search January 2013.

RESULTS AND CONCLUSIONS

We find sufficient evidence to recommend the use of PDT in certain patients in the treatment of AK, Bowen's disease, sBCC, and nBCC. It is especially useful in those with contraindications to surgery, widespread areas of involvement, and large lesions. Not only can it be considered superior to other therapies as far as recovery time, tolerance, and cosmetic outcomes, but it also should be considered, when indicated, as first-line treatment in the above conditions. Investigations continue for the use of PDT in the treatment of melanoma, SCC, chemoprevention, and CTCL.

Efficacy of photodynamic therapy for treatment of basal cell carcinoma in organ transplant recipients

Photodynamic therapy (PDT) is an established treatment for superficial basal cell carcinoma (BCC). Organ transplant recipients (OTRs) are at increased risk of BCC. We investigated the efficacy of PDT in OTRs and compared the recurrence rate to the non-transplanted population. We conducted a retrospective casenote review of all patients undergoing PDT for the treatment of BCC in our centre from 2003 to 2013. Three hundred and twenty-two BCCs from 103 patients underwent PDT during this period. There is no significant difference in BCC recurrence following PDT in OTRs (22.6 %) versus non-transplant patients (15.2 %) (p = 0.18). PDT is an efficacious treatment for BCC in OTRs with no significant evidence of inferiority compared to non-transplanted patients. Our findings require corroboration in a larger study.

IL-17 promotes neutrophil entry into tumor-draining lymph nodes following induction of sterile inflammation

Blood-borne neutrophils are excluded from entering lymph nodes across vascular portals termed high endothelial venules (HEVs) because of lack of expression of the CCR7 homeostatic chemokine receptor. Induction of sterile inflammation increases neutrophil entry into tumor-draining lymph nodes (TDLNs), which is critical for induction of antitumor adaptive immunity following treatments such as photodynamic therapy (PDT). However, the mechanisms controlling neutrophil entry into TDLNs remain unclear. Prior evidence that IL-17 promotes neutrophil emigration to sites of infection via induction of CXCL2 and CXCL1 inflammatory chemokines raised the question of whether IL-17 contributes to chemokine-dependent trafficking in TDLNs. In this article, we demonstrate rapid accumulation of IL-17-producing Th17 cells in the TDLNs following induction of sterile inflammation by PDT. We further report that nonhematopoietic expression of IL-17RA regulates neutrophil accumulation in TDLNs following induction of sterile inflammation by PDT. We show that HEVs are the major route of entry of blood-borne neutrophils into TDLNs through interactions of l-selectin with HEV-expressed peripheral lymph node addressin and by preferential interactions between CXCR2 and CXCL2 but not CXCL1. CXCL2 induction in TDLNs was mapped in a linear pathway downstream of IL-17RA-dependent induction of IL-1β. These results define a novel IL-17-dependent mechanism promoting neutrophil delivery across HEVs in TDLNs during acute inflammatory responses.

Nicotinamide reduces photodynamic therapy-induced immunosuppression in humans

BACKGROUND

The immune suppressive effects of topical photodynamic therapy (PDT) are potential contributors to treatment failure after PDT for nonmelanoma skin cancer. Nicotinamide (vitamin B(3) ) prevents immune suppression by ultraviolet radiation, but its effects on PDT-induced immunosuppression are unknown.

OBJECTIVES

To determine the effects of topical and oral nicotinamide on PDT-induced immunosuppression in humans.

METHODS

Twenty healthy Mantoux-positive volunteers received 5% nicotinamide lotion or vehicle to either side of the back daily for 3 days. Another group of 30 volunteers received 500 mg oral nicotinamide or placebo twice daily for 1 week in a randomized, double-blinded, crossover design. In each study, methylaminolaevulinate cream was applied to discrete areas on the back, followed by narrowband red light irradiation (37 J cm(-2) ) delivered at high (75 mW cm(-2) ) or low (15 mW cm(-2) ) irradiance rates. Adjacent, nonirradiated sites served as controls. Delayed-type hypersensitivity (Mantoux) reactions were assessed at treatment and control sites to determine immunosuppression.

RESULTS

High irradiance rate PDT with vehicle or with placebo caused significant immunosuppression (equivalent to 48% and 50% immunosuppression, respectively; both P < 0·0001); topical and oral nicotinamide reduced this immunosuppression by 59% and 66%, respectively (both P < 0·0001). Low irradiance rate PDT was not significantly immunosuppressive in the topical nicotinamide study (15% immunosuppression, not significant), but caused 22% immunosuppression in the oral study (placebo arm; P = 0·006); nicotinamide reduced this immunosuppression by 69% (P = 0·045).

CONCLUSIONS

While the clinical relevance of these findings is currently unknown, nicotinamide may provide an inexpensive means of preventing PDT-induced immune suppression and enhancing PDT cure rates.

Use of photodynamic therapy for treatment of actinic keratoses in organ transplant recipients

Solid organ transplant recipients are predisposed to actinic keratoses (AK) and nonmelanoma skin cancers, owing to the lifelong immunosuppression required. Today, increasing numbers of organ transplants are being performed and organ transplant recipients (OTRs) are surviving much longer. Photodynamic therapy (PDT) is proving a highly effective treatment modality for AK amongst this susceptible group of patients. Following an overview of the pathogenesis of AK amongst OTRs, the authors review current safety and efficacy data and how this relates to the role of PDT for the treatment of AK in OTRs.

Biomodulatory approaches to photodynamic therapy for solid tumors

Photodynamic Therapy (PDT) uses a photosensitizing drug in combination with visible light to kill cancer cells. PDT has an advantage over surgery or ionizing radiation because PDT can eliminate tumors without causing fibrosis or scarring. Disadvantages include the dual need for drug and light, and a generally lower efficacy for PDT vs. surgery. This minireview describes basic principles of PDT, photosensitizers available, and aspects of tumor biology that may provide further opportunities for treatment optimization. An emerging biomodulatory approach, using methotrexate or Vitamin D in combination with aminolevulinate-based PDT, is described. Finally, current clinical uses of PDT for solid malignancies are reviewed.

Therapeutic options to decrease actinic keratosis and squamous cell carcinoma incidence and progression in solid organ transplant recipients: a practical approach

BACKGROUND

Solid organ transplant recipients (SOTRs) have a 50 to 250 times greater risk of squamous cell carcinoma (SCC) than the general population and experience higher rates of invasive and metastatic disease. These greater risks are a product of the tumorigenic effects of their immunosuppressive medications. As the number of transplantations and the life expectancy of SOTRs increase, SCCs are becoming a major source of morbidity and mortality.

OBJECTIVE

To present a practical approach for busy practicing clinicians to the care of SOTRs who are developing SCCs. Topics include assessment and treatment of new and neglected SOTRs; the dermatologist's role with the transplantation team; and practical considerations in the choice of topical agents, systemic agents, and immunosuppressive therapy manipulation.

METHODS AND MATERIALS

An extensive literature search of the understanding of SCC pathophysiology and treatment in SOTRs was conducted.

RESULTS

Presented here is a logical, concise guide to the care of SOTRs who are developing actinic keratoses and SCCs.

CONCLUSION

Proper assessment of patients, understanding therapeutic alternatives and their application, and early institution of preventative and adjuvant therapies can help to decrease skin cancer-related morbidity and mortality in SOTRs.

Photodynamic therapy for basal cell carcinomas in organ-transplant recipients

The incidence of nonmelanoma skin cancer is significantly increased in recipients of solid-organ transplants. Photodynamic therapy (PDT) is a well-documented treatment option for superficial and selected nodular basal cell carcinomas (BCCs) in immunocompetent patients, but there are few reports describing PDT of BCCs in organ-transplant recipients (OTRs). We report a study of 18 OTRs with BCC on the head and trunk, who were treated with PDT, using methyl aminolevulinate as photosensitizer. There was only one recurrence during a total follow-up period of 407 months. PDT seems to be an effective treatment option for BCC in immunosuppressed OTRs.