S3 guideline "actinic keratosis and cutaneous squamous cell carcinoma" - update 2023, part 2: epidemiology and etiology, diagnostics, surgical and systemic treatment of cutaneous squamous cell carcinoma (cSCC), surveillance and prevention.

Actinic keratosis (AK) are common lesions in light-skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence-based framework for clinical decision making, the guideline "actinic keratosis and cutaneous squamous cell carcinoma" was updated and expanded by the topics cutaneous squamous cell carcinoma in situ (Bowen's disease) and actinic cheilitis. The guideline is aimed at dermatologists, general practitioners, ear nose and throat specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office-based settings, as well as other medical specialties, policy makers and insurance funds involved in the diagnosis and treatment of patients with AK and cSCC. A separate guideline exists for patients and their relatives. In this part, we will address aspects relating to epidemiology and etiology, diagnostics, surgical and systemic treatment of cutaneous squamous cell carcinoma (cSCC), surveillance and prevention.

Keratinocyte Carcinoma Chemoprevention With a Combination of Imiquimod, 5-Fluorouracil, and Tretinoin.

BACKGROUND: The incidence of keratinocyte carcinomas (KCs), comprising basal and squamous cell carcinomas, is rising in the United States. Chemoprevention is one modality by which patients can reduce the incidence of KCs. METHODS: We performed a retrospective review of 327 patients who employed a combination of imiquimod 5% cream, 5-fluorouracil 2% solution, and tretinoin 0.1% cream in a field therapy regimen over the face/ears or scalp for chemoprevention. RESULTS: Patients had dramatically lower odds of having KCs in the treatment location (face/ears or scalp) in the one-year period after field treatment than in the one-year period preceding field treatment (OR=0.06, 95% CI: [0.02, 0.15]). Patients were also at lower odds of having KCs in non-treated areas the year after field treatment than in the year preceding it (OR=0.25, 95% CI: [0.14, 0.42]). Additionally, fewer cryotherapy sessions were performed for actinic keratoses in the treatment areas in the year after treatment (mean=1.5, SD=1.21) than the year preceding treatment (mean=2.3, SD=0.99; t=11.68, P<0.001). CONCLUSIONS: A combination of imiquimod 5% cream, 5-fluorouracil 2% solution, and tretinoin 0.1% cream were effective at reducing the incidence of new KCs for at least one year. Individualized treatment application frequency allowed for increased patient adherence. Prospective studies evaluating combination topical treatments for chemoprevention of KCs are needed to further assess the treatment effects found in this study. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.7334.

Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients.

BACKGROUND: Immunosuppressed organ-transplant recipients have an increased incidence of, and mortality from, skin cancer. Nicotinamide (vitamin B3) enhances the repair of ultraviolet (UV) radiation-induced DNA damage, reduces the cutaneous immunosuppressive effects of UV radiation, and reduces the incidence of keratinocyte cancers (including squamous-cell and basal-cell carcinomas) and actinic keratoses among high-risk immunocompetent patients. Whether oral nicotinamide is useful for skin-cancer chemoprevention in organ-transplant recipients is unclear. METHODS: In this phase 3 trial, we randomly assigned, in a 1:1 ratio, organ-transplant recipients who had had at least two keratinocyte cancers in the past 5 years to receive 500 mg of nicotinamide or placebo twice daily for 12 months. Participants were examined for skin lesions by dermatologists at 3-month intervals for 12 months. The primary end point was the number of new keratinocyte cancers during the 12-month intervention period. Secondary end points included the numbers of squamous-cell and basal-cell carcinomas during the 12-month intervention period, the number of actinic keratoses until 6 months after randomization, safety, and quality of life. RESULTS: A total of 158 participants were enrolled, with 79 assigned to the nicotinamide group and 79 to the placebo group. The trial was stopped early owing to poor recruitment. At 12 months, there were 207 new keratinocyte cancers in the nicotinamide group and 210 in the placebo group (rate ratio, 1.0; 95% confidence interval, 0.8 to 1.3; P = 0.96). No significant between-group differences in squamous-cell and basal-cell carcinoma counts, actinic keratosis counts, or quality-of-life scores were observed. Adverse events and changes in blood or urine laboratory variables were similar in the two groups. CONCLUSIONS: In this 12-month, placebo-controlled trial, oral nicotinamide therapy did not lead to lower numbers of keratinocyte cancers or actinic keratoses in immunosuppressed solid-organ transplant recipients. (Funded by the National Health and Medical Research Council; ONTRANS Australian New Zealand Clinical Trials Registry number, ACTRN12617000599370.).

Correlation of skin cancer and actinic keratosis-related knowledge and sun protection behaviors and sunscreen use among a sample of Jordanian population.

BACKGROUND: The incidence of skin cancer and actinic keratosis has increased worldwide. Measuring the public awareness, attitude, and knowledge about these diseases and the skin protection behaviors are highly important to undertake preventive measures. METHODS: To investigate skin cancer and actinic keratosis-related knowledge, sun protection behaviors, and sunscreen usage among Jordanians, a questionnaire was developed. The questionnaire was provided as a google form to individuals via social media and the data were analyzed using SPSS® 23. RESULTS: A total of 1277 individuals, aged 18-65 years filled the questionnaire. The median melanoma and actinic keratosis knowledge score were 7 (4-9) and 4 (0-9), respectively. The melanoma knowledge was higher among females, those with a medical background, a high level of education, and in the central region, whereas the AK knowledge was higher among those with a medical background. Overall, 75.9% of the participants used sunscreen at least often to prevent sunburn, uneven skin tone, or tanning, 72% were using sunscreen with an SPF of 30 at least. However, 45.3% and 49.2% of sunscreen users did not comply with application, and reapplication times, respectively. Moreover, 58.4% of participants applied less than the recommended amount of sunscreen. CONCLUSION: Our study revealed that public awareness of actinic keratosis is low among Jordanians. Although it was found that a high proportion of Jordanians use sunscreens there are deficits in sunscreen practice indicating an urgent need to design effective interventions to increase awareness of actinic keratosis and correct use of sunscreen via health campaigns or healthcare professions.

Effect of Nicotinamide in Skin Cancer and Actinic Keratoses Chemoprophylaxis, and Adverse Effects Related to Nicotinamide: A Systematic Review and Meta-Analysis.

BACKGROUND: Oral nicotinamide is recommended in individuals with a field of cancerization or with ≥1 previous cutaneous squamous cell carcinoma (cSCC). OBJECTIVE: To evaluate the effect of nicotinamide in prevention of skin cancers. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of nicotinamide. We used Medline, EMBASE, CENTRAL, and Web of Science databases from their inception to October 2020 to search the following concepts: "nicotinamide"; "randomized controlled trial" (validated filters). Two independent reviewers screened titles and abstracts for intervention and study design before searching full texts for eligibility criteria. To be eligible, ≥1 outcome had to be covered. We used a standardized collection grid to complete data extraction in duplicate. The primary outcome was skin cancers (all types). Secondary outcomes were basal cell carcinomas (BCCs); cSCCs; actinic keratoses; melanomas; digestive, cutaneous, and biochemical adverse effects (AEs). Subgroup analyses were planned a priori. RESULTS: We screened 4730 citations and found 29 trials (3039 patients) meeting inclusion criteria. Nicotinamide was associated with a significant reduction in skin cancers compared to control (rate ratio 0.50 (95% CI, 0.29-0.85; I 2 = 64%; 552 patients; 5 trials); moderate strength of the evidence). Heterogeneity was explained by risk of bias. Nicotinamide was associated with a significant reduction in BCCs and cSCCs, and increased risk of digestive AEs. CONCLUSION: Oral nicotinamide should be considered in healthy patients or organ transplant recipients with history of skin cancer (GRADE: weak recommendation; moderate-quality evidence), in particular of BCC and cSCC.

Topical treatment of actinic keratoses in organ transplant recipients: a feasibility study for SPOT (Squamous cell carcinoma Prevention in Organ transplant recipients using Topical treatments).

BACKGROUND: The risk of cutaneous squamous cell carcinoma (cSCC) is significantly increased in organ transplant recipients (OTRs). Clearance of actinic keratoses (AKs) is generally regarded as a surrogate biomarker for cSCC prevention. OTR-cSCC chemoprevention with topical AK treatments has not been investigated in randomized controlled trials (RCTs), although there is evidence that 5% 5-fluorouracil (5-FU) may be chemoprotective in immunocompetent patients. OBJECTIVES: To assess the feasibility, activity and evaluation outcomes relevant to the design of a future phase III RCT of topical cSCC chemoprevention in OTRs. METHODS: OTRs with 10 or more AKs in predefined areas were randomized 1 : 1 : 1 to topical 5-FU, 5% imiquimod (IMIQ) or sunscreen (sun-protective factor 30+) in a phase II, open-label RCT over 15 months. Feasibility outcomes included proportions of eligible OTRs randomized, completing treatment and willing to be re-treated. AK activity [AK clearance, new AK development, patient-centred outcomes (toxicity, health-related quality of life, HRQoL)] and evaluation methodology (clinical vs. photographic) were assessed. RESULTS: Forty OTRs with 903 AKs were randomized. All feasibility outcomes were met (56% of eligible OTRs were randomized; 89% completed treatment; 81% were willing to be re-treated). AK activity analyses found 5-FU and IMIQ were superior to sunscreen for AK clearance and prevention of new AKs. 5-FU was more effective than IMIQ in AK clearance and prevention in exploratory analyses. Although toxicity was greater with 5-FU, HRQoL outcomes were similar. CONCLUSIONS: Trials of topical AK treatments in OTRs for cSCC chemoprevention are feasible and AK activity results support further investigation of 5-FU-based treatments in future phase III trials. What is already known about this topic? Cutaneous squamous cell carcinoma (cSCC) is significantly more common in immunocompromised individuals including organ transplant recipients (OTRs) compared with immunocompetent populations. cSCC chemoprevention activity of sunscreen and 5-fluorouracil-based (5-FU) actinic keratosis (AK) treatments has been demonstrated in randomized controlled trials (RCTs) in immunocompetent populations but not in OTRs. AKs are cSCC precursors and their clearance and prevention are generally regarded as surrogate endpoint biomarkers for potential cSCC chemoprevention activity. What does this study add? SPOT (SCC Prevention in OTRs using Topical treatments) has confirmed that RCTs of OTR-cSCC chemoprevention with topical AK treatments are feasible. It also suggests that topical 5-FU may be superior to 5% imiquimod and sunscreen in AK clearance and prevention. Together with recent evidence from several RCTs in the general population, these data provide a compelling rationale for further studies of intervention with 5-FU-based topical chemoprevention approaches in OTR-cSCC prevention.

Protective effects of sunscreen (50+) and octatrienoic acid 0.1% in actinic keratosis and UV damages.

Actinic keratosis is a form of dysplastic epidermal lesion resulting from chronic and excessive UV exposure with a certain risk of becoming cancerous. Current guidelines advocated the use of sunscreens to prevent photodamage. An efficient photoprotection must involve both primary protective factors such as UV filters and secondary factors (eg, antioxidants) able to disrupt the photochemical and genetic cascade triggered by UVs. An in vitro model of human skin (Phenion FT) was used to assess the photoprotective potential of a sunscreen containing inorganic sun-filters (50+ SPF) and 0.1% octatrienoic acid (KERA'+) after UVA (10 J/cm2) and UVB (25 mJ/cm2) by means of evaluation of the number of sunburn cells (SBCs) and apoptotic keratinocytes. Also resulting alterations in the gene expression of markers involved in apoptosis (Tumor protein 53), inflammation/immunosuppression (IL-6 and IL-8), oxidative stress (oxidative stress response enzyme heme oxygenase 1), remodeling (metalloproteinase 1) and cell-cell adhesion (E-cadherin) were investigated. Gene expression was investigated using quantitative real-time PCR. This work demonstrated that the sunscreen preparations under study (with and without 0.1% octatrienoic acid, respectively) can be distinguished about their ability to prevent UVs-induced damage. Synergism between the inorganic filters and 0.1% octatrienoic acid was found (KERA'+) on all end points analyzed and this effect was found to be statistically significant (p<0.05). Our data revealed that topical application of a sunscreen containing inorganic filters (50+SPF) and 0.1% octatrienoic acid can protect from SBC formation, reduce the number of apoptotic keratinocytes and protect from the main molecular alterations caused by UV radiations.

The Preventive Value of Sun Protection.

BACKGROUND: With more than 200,000 new cases per year, skin tumours have been the most frequently reported cancers in Germany for years. We performed a systematic review to summarise the current evidence concerning the preventive value of regular sunscreen use. METHODS: Systematic literature review of controlled and randomised controlled trials were performed in Ovid Embase and Ovid Medline on 21 January 2020. We included studies evaluating the effectiveness of sunscreens on epithelial skin cancer, actinic keratosis or photoageing, or side effects in humans. RESULTS: Five eligible trials, each involving 28 to 1,621 participants from various populations, were identified. All 4 studies on actinic keratoses showed a significant beneficial effect of sunscreens. The 2 studies on squamous cell carcinoma demonstrated significant beneficial effects of sunscreens. The 2 studies on photoageing observed a significant reduction in the sunscreen groups. The 2 studies on basal cell carcinoma reported no significant results, but both studies reported some non-significant protective effects of sunscreen use. Sunscreens as well as vehicles sometimes had side effects affecting skin and eyes. Compared with controls, sunscreens had no significant side effects on vitamin D, bone mass density and mortality. CONCLUSION: The evidence from published controlled and randomised controlled studies is limited. Especially for basal cell carcinoma, further high-quality studies including young populations are required to investigate possible protective effects of modern broad-spectrum sunscreens. The results of this systematic review do not change the current recommendations for UV protection. Sunscreens are recommended as a second-line measure against solar radiation whenever protective clothing and seeking shake are inadequate.

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.

Randomized controlled trial of fractionated laser resurfacing on aged skin as prophylaxis against actinic neoplasia.

BACKGROUNDThe loss of insulin-like growth factor 1 (IGF-1) expression in senescent dermal fibroblasts during aging is associated with an increased risk of nonmelanoma skin cancer (NMSC). We tested how IGF-1 signaling can influence photocarcinogenesis during chronic UVB exposure to determine if fractionated laser resurfacing (FLR) of aged skin, which upregulates dermal IGF-1 levels, can prevent the occurrence of actinic keratosis (AK) and NMSC.METHODSA human skin/immunodeficient mouse xenografting model was used to test the effects of a small molecule inhibitor of the IGF-1 receptor on chronic UVB radiation. Subsequently, the durability of FLR treatment was tested on a cohort of human participants aged 65 years and older. Finally, 48 individuals aged 60 years and older with considerable actinic damage were enrolled in a prospective randomized clinical trial in which they underwent a single unilateral FLR treatment of one lower arm. Numbers of AKs/NMSCs were recorded on both extremities for up to 36 months in blinded fashion.RESULTSXenografting studies revealed that chronic UVB treatment with a topical IGF-1R inhibitor resulted in a procarcinogenic response. A single FLR treatment was durable in restoring appropriate UVB response in geriatric skin for at least 2 years. FLR resulted in sustained reduction in numbers of AKs and decreased numbers of NMSCs in the treated arm (2 NMSCs) versus the untreated arm (24 NMSCs).CONCLUSIONThe elimination of senescent fibroblasts via FLR reduced the procarcinogenic UVB response of aged skin. Thus, wounding therapies are a potentially effective prophylaxis for managing high-risk populations.TRIAL REGISTRATIONClinicalTrials.gov (NCT03906253).FUNDINGNational Institutes of Health, Veterans Administration.

Dopamine Prevents Ultraviolet B-induced Development and Progression of Premalignant Cutaneous Lesions through its D2 Receptors.

Although the role of dopamine (DA) in malignant tumors has been reported, its function in premalignant lesions is unknown. Herein we report that the stimulation of DA D2 receptors in endothelial cells in ultraviolet B (UVB)-induced cutaneous lesions in mice significantly reduced the tumor number, tumor burden, and malignant squamous cell carcinoma in these animals. DA D2 receptor agonist inhibited VEGFA-dependent proangiogenic genes in vitro and in vivo. However, the mice pretreated with selective DA D2 receptor antagonist inhibited the actions of the agonist, thereby suggesting that the action of DA was through its D2 receptors in the endothelial cells. To our knowledge, this study is the first to report DA-mediated regulation of pathogenesis and progression of UVB-induced premalignant skin lesions. PREVENTION RELEVANCE: This investigation demonstrates the role of dopamine and its D2 receptors in UVB induced premalignant squamous cell skin lesions and how DA through its D2 receptors inhibits the development and progression of these lesions and subsequently prevents squamous cell carcinoma of the skin.

Repetitive Daylight Photodynamic Therapy versus Cryosurgery for Prevention of Actinic Keratoses in Photodamaged Facial Skin: A Prospective, Randomized Controlled Multicentre Two-armed Study.

Actinic keratoses are a chronic condition in ultraviolet-damaged skin, with a risk of progressing to invasive skin cancer. The aim of this study was to investigate the preventive potential of field-directed repetitive daylight photodynamic therapy for actinic keratoses. A randomized trial was performed, including 58 patients with ≥5 actinic keratoses on photodamaged facial skin, who received either 5 full-face sessions of daylight photodynamic therapy within a period of 2 years or lesion-directed cryosurgery. Primary outcome was the mean cumulative number of new actinic keratoses developed between visits 2 and 6 (visit 6 being a follow-up). This outcome was lower after daylight photo-dynamic therapy (7.7) compared with cryosurgery (10.2), but the difference did not reach significance (-2.5, 95% confidence interval -6.2 to 1.2; p=0.18). Several signs of photoageing (fine lines, pigmentation, roughness, erythema, sebaceous gland hyperplasia) were significantly reduced after daylight photodynamic therapy, but not after cryosurgery. Significantly less pain and fewer side-effects were reported during daylight photodynamic therapy than during cryosurgery. This study found that repetitive daylight photodynamic therapy had photo-rejuvenating effects. However, the prevention of actinic keratoses by this therapy could not be proven in a statistically reliable manner.

Evaluation of the Use of Capecitabine for the Treatment and Prevention of Actinic Keratoses, Squamous Cell Carcinoma, and Basal Cell Carcinoma: A Systematic Review.

Importance: Certain patient groups, such as solid organ transplant recipients (SOTRs), have a significantly increased risk of developing skin cancers. The chemotherapeutic drug capecitabine has been used off label as a chemopreventive modality to suppress the development of precancerous skin lesions and squamous cell carcinomas (SCCs). Objective: To systematically review published studies on the use of capecitabine for the treatment and prevention of precancerous and cancerous skin lesions, with a focus on cutaneous SCC. Evidence Review: For this systematic review, a literature search was performed using the PubMed and Embase databases in December 2019 for all articles published between January 1, 1998, and December 31, 2019, using the search term capecitabine paired with each of the following terms: actinic keratosis, actinic keratoses, squamous cell carcinoma, and basal cell carcinoma. Articles on the use of capecitabine for the treatment and prevention of actinic keratoses (AKs), SCCs, and basal cell carcinomas (BCCs) were selected for inclusion. Findings: Sixteen publications met the criteria for inclusion, with 8 case reports describing the inflammation of AKs in patients with solid organ cancer treated with capecitabine (2 patients with breast cancer and 6 patients with colorectal cancer). One case report and 1 case series of 4 patients investigated the use of capecitabine for the treatment of advanced or widespread cutaneous SCCs. A total of 6 publications (3 case reports and 3 case series) described the use of capecitabine to prevent development of SCCs in SOTRs. Of these case series, 2 studies found a significant reduction in SCC incidence rate during treatment with capecitabine compared with before treatment. Adverse effects, such as fatigue, nausea, vomiting, diarrhea, elevated creatinine level, hand-foot syndrome, hyperuricemia, weight loss, anemia, and cardiomyopathy, limited the duration of chemoprevention in several patients. Conclusions and Relevance: Capecitabine treatment may be associated with a decrease in the incidence of SCCs in SOTRs. Capecitabine treatment may also be associated with a decrease in AK and BCC incidence. However, practitioners must weigh this benefit against the risk of adverse effects for each patient individually. Further investigation with a prospective clinical trial is warranted.

[Effects of an unconventional skin cancer prevention campaign : Impacts on the sun protection behavior of outdoor workers]. / Effekte einer unkonventionellen Hautkrebs-Präventionskampagne : Auswirkungen auf das Sonnenschutzverhalten von Außenberufstätigen.

BACKGROUND: The disease burden of actinic keratoses and keratinocyte carcinoma can be reduced by primary and secondary prevention. However, these measures are often poorly received, especially among the high-risk group of outdoor workers. OBJECTIVES: The aim of this follow-up study was to investigate whether an improvement in sun protection and awareness of skin changes could be observed among the study population, especially outdoor workers, one year after a prevention campaign focusing on this topic. MATERIALS AND METHODS: In 2017, all participants who initially participated in a study at the Bavarian Central Agricultural Festival 2016 and agreed to participate in the follow-up study were contacted by mail and received the same questionnaire and evaluation questions regarding possible behavioral changes. RESULTS: A total of 400 people took part in the follow-up study (response rate 52.8%). Of the 240 outdoor workers, 45.0% said they were more conscious of protecting themselves from the sun and 68.8% said they were more aware of skin changes. About 85.0% of outdoor workers indicated that they would consult a dermatologist earlier and 65.8% desired further prevention campaigns regarding skin cancer and sun protection. CONCLUSION: Overall, the majority of participants reported that they had improved sun protection behavior and awareness of skin changes after the intervention. Based on the participants' self-disclosure, especially outdoor workers tended to use sun protection measure more frequently. These findings underline the importance of target group-oriented awareness and prevention campaigns to reduce the burden of skin cancer.

Photodynamic therapy for the prevention and treatment of actinic keratosis/squamous cell carcinoma in solid organ transplant recipients: a systematic review and meta-analysis.

Solid organ transplant recipients (sOTR) are at an increased risk of developing cutaneous cancers, especially squamous cell carcinoma (SCC). Photodynamic therapy (PDT) for the prevention and treatment of actinic keratosis (AK)/SCC in sOTR is increasingly prescribed given the increase in solid organ transplantations performed worldwide. PDT has added advantages of superior cosmetic outcomes and good safety profile compared to conventional surgical methods and other topical therapies. We aim to evaluate the role of PDT in the prevention and treatment of AK/SCC in sOTRs. The Cochrane Library, PubMed and EMBASE database were searched. Articles reporting PDT outcomes amongst sOTR with or without AK/SCC at baseline were selected. We classified the studies into two categories: (i) PDT as prevention measure and (ii) treatment of AK/SCC in sOTR. Primary outcome for the prevention category was 3-year incidence of AK/SCC and complete response (CR) of lesions after PDT exposure in the treatment category. Secondary outcomes were cosmesis and adverse reaction in both categories. Pooled results were expressed as risk difference (RD) with corresponding 95% confidence interval (95% CI). Twelve out of 641 articles met our eligibility criteria, out of which four RCTs reported the preventive effect of AK/SCC and another five RCTs reported the treatment effect of PDT in sOTR. One RCT did not report absolute number of lesions at baseline/end of study for results to be pooled in the quantitative analysis. The remaining three studies were cohort studies reporting treatment and preventive effect of PDT in sOTR. PDT group had a lower incidence as a preventive measure with pooled RD of 0.14 (95% CI 0.08-0.19). The CR in PDT was higher in the treatment group with a pooled RD of 0.77 (95% CI 0.6-0.94) and 0.50 (95% CI 0.22-0.79) in predivided lesional areas and number of lesions, respectively. In conclusion, PDT is efficacious for prevention and treatment of AK/SCC in sOTRs.

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.