Non-melanoma skin cancer and solar keratoses II analytical results of the South Wales Skin Cancer Study

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes)

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

An exploratory randomized clinical trial on negative pressure wound therapy for lower limb full-thickness skin grafts of dermatosurgical patients

Full-thickness skin graft (FTSG) reconstructions of lower limbs are especially prone to wound complications. Negative pressure wound therapy (NPWT) enhances wound healing, but no broad evidence exists if it promotes graft take of lower leg FTSGs. In this investigator-initiated, prospective, randomised and controlled trial, 20 patients with ambulatory FTSG reconstruction for lower limb skin cancers were randomised for postoperative treatment with either NPWT, or conventional dressings. As outcomes, adherence of the skin graft 1 week postoperatively, any wound complications within 3 months, including ≥3 weeks delayed wound healing, and the number of additional postoperative visits were compared. In both groups, grafts adhered equally well (p = 0.47); 80% of NPWT-treated and 100% of control group grafts adhered >90%. There was no significant difference in the number of postoperative complications/delayed wound healing (p = 0.65); 70% of patients in the NPWT and 50% in the control group developed a wound complication. Both groups had an equal number of patients with at least three additional control visits (p = 1.0). The study was discontinued after 20 patients were recruited, as no benefit from NPWT was seen. To conclude, the study showed no benefit from NPWT for lower limb FTSGs.

Positive association between actinic keratosis and internal malignancies: a nationwide population-based cohort study

Little is known about the comorbidities in actinic keratosis patients. To evaluate the association of actinic keratosis with certain malignancies. All patients with actinic keratosis (n = 61,438) and age- and sex-matched control subjects (n = 307,190) at a 5:1 ratio were enrolled using data from the Korean National Health Insurance Service between the years 2007 and 2014. In subjects with actinic keratosis, overall cancer incidence was higher than that for controls after income level, habitat, diabetes, hypertension, and dyslipidemia were adjusted (Hazard Ratio [HR] = 1.43 [95% confidence interval 1.38–1.47]). The positive association of specific cancers were observed in the following order: skin cancer (HR = 3.43 [2.47–4.75]), oral cavity and pharyngeal cancer (HR = 1.99 [1.57–2.52]), lymphoma (HR = 1.59 [1.28–1.96]), leukemia (HR = 1.35 [1.03–1.77]), prostate cancer (HR = 1.35 [1.21–1.51]), renal cancer (HR = 1.29 [1.02–1.63]), liver cancer (HR = 1.21 [1.09–1.35]), thyroid cancer (HR = 1.20 [1.05–1.38]), and gastric cancer (HR = 1.13 [1.03–1.23]). Although further research on pathologic mechanism is needed, the implications of a positive correlation between actinic keratosis and internal organ malignancies has great significance.

Non-Melanoma Skin Cancer in Outdoor Workers: A Study on Actinic Keratosis in Italian Navy Personnel

Occupational exposure to ultraviolet radiation is one of the main risk factors for non-melanoma skin cancer (NMSC) development. The most common variants of NMSC are basal cell carcinomas, squamous cell carcinomas, and actinic keratosis (AK). The latter is nowadays considered by most authors as an early squamous cell carcinoma rather than a precancerous lesion. Outdoor workers have a higher risk of developing NMSC because they spend most of the working day outside. The aim of this descriptive study was to assess the prevalence of skin lesions, especially AK, in a professional category of individuals exposed to ultraviolet (UV) radiation: the Italian Navy. From January to June 2016, a questionnaire and a total skin examination of 921 military personnel were administered by medical specialists (dermatologists) in seven different Italian Navy centres. AK was detected in 217 of 921 (23.5%) workers. Older age, outdoor occupation, longer working life, and fair skin seem to promote the development of AK. Of the 217 workers with AK, 187 (86.2%) had lesions in chronically sun-exposed skin areas. Italian Navy personnel have a high AK prevalence. Further studies are needed to investigate occupational hazards and their health effects among outdoor workers to promote protective behaviour and raise awareness of skin cancer.

Predicting keratinocyte carcinoma in patients with actinic keratosis: development and internal validation of a multivariable risk-prediction model

BACKGROUND

Patients with actinic keratosis (AK) are at increased risk for developing keratinocyte carcinoma (KC) but predictive factors and their risk rates are unknown.

OBJECTIVES

To develop and internally validate a prediction model to calculate the absolute risk of a first KC in patients with AK.

METHODS

The risk-prediction model was based on the prospective population-based Rotterdam Study cohort. We hereto analysed the data of participants with at least one AK lesion at cohort baseline using a multivariable Cox proportional hazards model and included 13 a priori defined candidate predictor variables considering phenotypic, genetic and lifestyle risk factors. KCs were identified by linkage of the data with the Dutch Pathology Registry.

RESULTS

Of the 1169 AK participants at baseline, 176 (15·1%) developed a KC after a median follow-up of 1·8 years. The final model with significant predictors was obtained after backward stepwise selection and comprised the presence of four to nine AKs [hazard ratio (HR) 1·68, 95% confidence interval (CI) 1·17-2·42], 10 or more AKs (HR 2·44, 95% CI 1·65-3·61), AK localization on the upper extremities (HR 0·75, 95% CI 0·52-1·08) or elsewhere except the head (HR 1·40, 95% CI 0·98-2·01) and coffee consumption (HR 0·92, 95% CI 0·84-1·01). Evaluation of the discriminative ability of the model showed a bootstrap validated concordance index (c-index) of 0·60.

CONCLUSIONS

We showed that the risk of KC in patients with AK can be calculated with the use of four easily assessable predictor variables. Given the c-index, extension of the model with additional, currently unknown predictor variables is desirable. Linked Comment: Kim et al. Br J Dermatol 2020; 183:415-416.

Épidémiologie des kératoses actiniques

Actinic keratosis is a premalignant skin lesion resulting from proliferation of atypical epidermal keratinocytes. Actinic keratoses are very frequent and their prevalence is increasing. Risk factors for actinic keratosis include intrinsic and environmental factors, particularly exposure to ultraviolet radiation and advanced age. The main factor is the exposition to ultraviolet radiation. Better sun protection decreases the risk of actinic keratosis and also the risk of progression to squamous cell carcinoma, even though not all actinic keratoses progress to invasive squamous cell carcinoma. A diagnosis of actinic keratosis should encourage patients to do an annual dermatological screening of skin cancers. Given the economic cost of actinic keratoses, a global approach of health authorities could be interesting for their management. © 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.

Actinic keratoses: review of clinical, dermoscopic, and therapeutic aspects

Actinic keratoses are dysplastic proliferations of keratinocytes with potential for malignant transformation. Clinically, actinic keratoses present as macules, papules, or hyperkeratotic plaques with an erythematous background that occur on photoexposed areas. At initial stages, they may be better identified by palpation rather than by visual inspection. They may also be pigmented and show variable degrees of infiltration; when multiple they then constitute the so-called field cancerization. Their prevalence ranges from 11% to 60% in Caucasian individuals above 40 years. Ultraviolet radiation is the main factor involved in pathogenesis, but individual factors also play a role in the predisposing to lesions appearance. Diagnosis of lesions is based on clinical and dermoscopic examination, but in some situations histopathological analysis may be necessary. The risk of transformation into squamous cell carcinoma is the major concern regarding actinic keratoses. Therapeutic modalities for actinic keratoses include topical medications, and ablative and surgical methods; the best treatment option should always be individualized according to the patient.

The clinical course of actinic keratosis correlates with underlying molecular mechanisms

BACKGROUND

Actinic keratoses (AKs) are common premalignant skin lesions triggered by excessive ultraviolet exposure. The majority of AKs regress or persist, but some progress to squamous cell carcinomas. Biomarkers associated with their persistence, progression and regression have not been characterized.

OBJECTIVES

We performed skin biopsies in patients with extensive actinic damage to identify biomarkers that correlate with clinical progression and regression of AKs.

METHODS

This was an observational study of a cohort of patients with extensive actinic damage. AKs were mapped on a clear plastic template in 26 patients at months 3, 6, 9 and 11. Biopsies were taken from randomly selected, predetermined AKs and were evaluated for p53, E-cadherin, Snail, Slug and Twist. The study is registered at Clinicaltrials.gov: NCT00027976.

RESULTS

p53 exhibited greater expression in clinically apparent AKs (histological score 2·89 ± 1·45) than in regressed AKs (0·75 ± 0·96); P < 0·01. There was also significantly less membrane E-cadherin, the lack of which is a marker of epithelial-mesenchymal transition, in clinically apparent AKs (1·89 ± 1·81) than in sun-exposed skin (3·07 ± 1·75); P < 0·005. The E-cadherin transcription repressors Snail, Slug and Twist were increased in AKs compared with sun-exposed skin. A limitation of the study is that measurement of histological biomarkers was not a primary end point. In addition, patients were allowed to apply sunscreens.

CONCLUSIONS

At the molecular level, loss of E-cadherin and an increase in p53 are linked to the dynamic interplay between the persistence, progression and regression of AKs. What's already known about this topic? Actinic keratoses (AKs) are common dysplastic epidermal lesions that result from chronic and excessive ultraviolet exposure. Biomarkers associated with progression and regression of AK have not been characterized. What does this study add? Decreased E-cadherin and increased p53, Snail, Slug and Twist (E-cadherin transcription factors) were associated with progression from AK to nonmelanoma skin cancer. What is the translational message? Strategies targeting these molecules may be effective in reversing rising skin cancer rates. E-cadherin, p53, Snail, Slug and Twist are potential biomarkers that may be used to assess the efficacy of existing chemopreventive agents.

Prevalence of actinic keratosis in patients attending the dermatology outpatient clinic

Actinic keratoses (AKs) are precancerous epidermal lesions that develop on sensitive, frequently sun-exposed skin surfaces. There are very little data regarding AK prevalance. The aim of this study was to investigate the prevalence of AK and related conditions among patients in a dermatology outpatient clinic.Patients attending our dermatology outpatient clinic between January 1, 2015 and December 31, 2017 were evaluated retrospectively usingan automated system. A total of 54,786 patients aged ≥30 years attending the dermatology outpatient clinic were included in the study. We identified 1375 patients diagnosed with AK.In our study, the AK prevalence was 0.01% for patients between 30 and 39 years of age, 0.45% for patients between 40 and 49 years of age, 1.77% for patients between 50 and 59 years of age, 4.61% for patients between 60 and 69 years of age, 9.38% for patients between 70 and 79 years of age, and 14.57% for patients ≥80 years. AK prevalence was 2.50% among patients of all ages.The exposure to sunlight is excessive due to the geographical location of our country. Due to the tendency of AKs to convert to malignancies, the identification of patients at high risk for AK development and the identification of high-risk anatomical regions are important to establish the basis of effective screening programs to support public health.

Klotho Protein Protects Human Keratinocytes from UVB-Induced Damage Possibly by Reducing Expression and Nuclear Translocation of NF-κB

Background

UV-related skin disease such as actinic keratosis is a major concern in public health. In view of the cell injury induced by UVB, Klotho protein it is an ideal therapy to eliminate UVB-induced cell damages and the associated signaling pathways.

Material/Methods

To gain insights into the potential role of Klotho and the underlying molecular mechanism, we constructed a Klotho-overexpress HaCaT cell line and assessed the protection against UVB insults. The effects of exposure to UVB radiation on the human keratinocyte HaCaT cells, including cell growth, apoptosis, and changes of selected biomarkers, were measured by CCK-8, flow cytometry, Quantitative real-time PCR, and Western blot analysis.

Results

We found that enhanced NF-κB activity was accompanied by decreased expression of the anti-aging protein Klotho upon UVB stimulation, which was further confirmed with in vivo experiments. Overexpression of Klotho was able to considerably alleviate the UVB-induced damages to cells and reversed the UVB-caused biomarker changes to a great extent, which was comparable to the effects of administration of NF-κB inhibitor PDTC, suggesting the inhibition of nuclear translocation and DNA-binding activity of NF-κB. Furthermore, Klotho overexpression was proved to decrease the nuclear expression of NF-κB as much as the treatment with PDTC, which provides support for the direct regulation of NF-κB by Klotho.

Conclusions

Collectively, our work provides new insight into the potential role of Klotho in the context of UVB-induced injuries in human keratinocytes, as well as providing the basis for future study of new therapies against UV-related skin disease.

Efficacy of Ingenol Mebutate in the Treatment of Actinic Keratoses: A Pre- and Posttreatment Dermoscopic Comparative Analysis

Actinic keratosis (AK) is a common skin lesion in adults which usually occurs on chronically photoexposed areas and considered as a precancerous lesion or a superficial squamous-cell carcinoma. Many classifications have been proposed and its diagnosis is generally clinical but, sometimes, its wide variety of presentations can make diagnosis difficult, even among expert observers. The malignant potential of AKs imposes an early diagnosis and treatment in order to reduce morbidity and mortality, and, for the characterization of photodamaged skin, noninvasive diagnostic techniques, such as dermoscopy, have proved to be useful, while multiple therapeutic strategies, lesion-directed versus field-directed therapies, are available for the treatment of AKs. In this study, we evaluated the efficacy of ingenol mebutate for the treatment of AKs, with a particular focus on patients' compliance, correlating it to clinical and dermoscopic grading, pre- and posttreatment, of these lesions. Fifty-two enrolled patients with AKs received treatment with ingenol mebutate gel (0.015% for face and scalp; 0.05% for trunk and extremities) and multiple dermatological evaluations. End points of the study were complete and partial clearance of clinically visible AKs on day 90. All acquired data were recorded and statistical analyses were performed. Univariate and multivariate analyses were used to identify possible predictive factors. We retrospectively analyzed patient-related and lesion-related factors to identify which variables, among age, gender, lesion site, pain, LSR score, and pretreatment clinical and dermoscopic grading, could independently predict the response to ingenol mebutate treatment. Our findings showed that pretreatment dermoscopic grade II represents an independent predictive factor of the efficacy of ingenol mebutate therapy (OR=14.78, 95% CI: 1.83–119.59, P=0.012) and that response rates differ on the basis of the treated anatomical sites (OR=0.16, 95% CI: 0.03–0.85, P=0.031). Data from this study provide evidence that ingenol mebutate gel is an effective treatment for AK, with relative ease of use, short exposure, and rapid resolution of local reactions, benefits contributing to high adherence of this therapy. Moreover, dermoscopic analysis of skin lesions offers more information than clinical evaluation alone and can be helpful in identifying different groups of AKs, thus selecting the adequate therapeutic choice.

Association between Height and Actinic Keratosis: A Nationwide Population-based Study in South Korea

The association between actinic keratosis (AK) and anthropometric measures has not been investigated. This study aims to evaluate the associations between anthropometric measures and the incidence of AK in South Korea. We analyzed clinical data from individuals aged over 20 years who received a health examination arranged by the national insurance program between 2005 and 2008. Newly diagnosed AK was identified using claims data from baseline to the date of diagnosis or until December 31, 2015. The incidence of AK was highest among the elderly (aged over 60 years) and showed a male bias. The risk of AK increased with greater height. The quintile with the greatest height had an increased risk of AK compared with the quintile with the lowest height (hazard ratio = 1.28, 95% confidence interval: 1.24-1.33) after adjustment for age, sex, income, smoking status, alcohol consumption, hypertension, dyslipidemia, myocardial infarction, congestive heart failure, and chronic obstructive pulmonary disease. This study showed a positive association between the incidence of AK and human height. However, it is unclear whether these findings can be generalized to Koreans who have not received an examination or to populations in other countries.

Phosphoinositide 3-Kinase-Dependent Signalling Pathways in Cutaneous Squamous Cell Carcinomas

Cutaneous squamous cell carcinoma (cSCC) derives from keratinocytes in the epidermis and accounts for 15–20% of all cutaneous malignancies. Although it is usually curable by surgery, 5% of these tumours metastasise leading to poor prognosis mostly because of a lack of therapies and validated biomarkers. As the incidence rate is rising worldwide it has become increasingly important to better understand the mechanisms involved in cSCC development and progression in order to develop therapeutic strategies. Here we discuss some of the evidence indicating that activation of phosphoinositide 3-kinases (PI3Ks)-dependent signalling pathways (in particular the PI3Ks targets Akt and mTOR) has a key role in cSCC. We further discuss available data suggesting that inhibition of these pathways can be beneficial to counteract the disease. With the growing number of different inhibitors currently available, it would be important to further investigate the specific contribution of distinct components of the PI3Ks/Akt/mTOR pathways in order to identify the most promising molecular targets and the best strategy to inhibit cSCC.

Increased number of mast cells in the dermis in actinic keratosis lesions effectively treated with imiquimod

Actinic keratosis (AK) is a cutaneous cancer in situ which develops as a result of excessive exposure to ultraviolet (UV). Toll-like receptor (TLR)7 agonist imiquimod is a topical immune response modifier and is effective for the treatment of non-melanoma skin cancers. Recently, the diagnostic role of the dermatoscope has been reported in the course of treatment of AK. In addition, mast cells are now considered to contribute to both the innate and adaptive immune systems in topical imiquimod therapy. We assessed the effect of imiquimod treatment by dermatoscopic and immunohistochemical findings in 14 patients with a total of 21 AK lesions. With the dermatoscope, though the mean erythema score was not significantly different between the cured lesions and the unresponsive lesions, the erythema/red pseudo-network ("strawberry") pattern was decreased significantly in the cured lesions. By immunohistochemistry, the number of Ki-67-positive proliferative cells in the epidermis was decreased and that of CD117-positive mast cells in the dermis was increased in the responding lesions. To the best of our knowledge, this is the first study demonstrating that the number of mast cells in the dermis was increased in AK lesions effectively treated with imiquimod. Our present result suggests that mast cells may contribute an antitumor effect in human skin treated with topical imiquimod.

The continued use of sunscreen prevents the development of actinic keratosis in aged Japanese subjects

It is well known that the trigger for actinic keratosis (AK) mainly depends on UV exposure. We evaluated the effects of long-term use of sunscreen on the histopathological and dermoscopic changes of AK in aged patients. Eighteen months use of sunscreen produced no change in the number of actinic keratoses or the advancement of histological grade. Although a significant decrease was not observed in the number of positive cells of p53, Ki-67 and COX-2 of the subjects who used sunscreen for 18 months, the downward tendencies of these proteins were observed. The continued use of sunscreen decreased the number of CD31-positive vessels significantly using the Chalkley method, and a significant improvement in scaling and vessel dots was found by dermoscopic study. Moreover, a relationship was found in the amount of sunscreen use and the number of actinic keratoses. Considering these results, it was thought that application of sunscreen reduces the risk of advancement of AK to higher grade AK and squamous cell carcinoma.

Prevalence of actinic keratosis among dermatology outpatients in Spain

BACKGROUND

Actinic keratoses (AKs) are common skin lesions associated with an increased risk of developing squamous cell carcinoma. Few studies in Europe have focused on AK prevalence.

AIM

To determine the point prevalence of AKs in a dermatology outpatient population in Spain, to describe the clinical characteristics of these lesions and to characterise the profile of AK patients.

METHODS

Observational, cross-sectional, multicentre study conducted in 19 hospitals (dermatology outpatient services) around Spain. A total of 204 consecutive patients per hospital who were ≥45 years old were screened for the presence of AKs.

RESULTS

3877 patients were assessed and the overall AKs prevalence was 28.6%. Prevalence was significantly higher in men than women (38.4% vs. 20.8%, p<0.0001) and increased with age for both sexes (45.2% in 71-80 years). Scalp and ear lesion locations were significantly more frequent in men (51.9% vs. 2.7% and 16.9% vs. 2.4%, respectively, p<0.0001 both cases) and the cheek, nose and neckline in women (46.3% vs. 34.0% [p<0.0001], 43.0% vs. 24.8% [p<0.0001] and 5.3% vs. 1.8% [p=0.002]). Men showed a significantly higher frequency of ≥2 affected areas than women (42.7% vs. 20.3%, p<0.0001). Among patients with AK lesions, only 65% confirmed that they were the reason for the visit to the clinic.

CONCLUSIONS

Approximately a quarter of the dermatology outpatient population in Spain aged ≥45 years old have AKs, with the prevalence rate being highest in men and in older age groups. AK is underdiagnosed and a proactive strategy is needed for the diagnosis and early treatment of these lesions.

Evaluation of Resource Utilization and Treatment Patterns in Patients with Actinic Keratosis in the United States

OBJECTIVE

To compare health care resource utilization and treatment patterns between patients with actinic keratosis (AK) treated with ingenol mebutate gel (IngMeb) and those treated with other field-directed AK therapies.

METHODS

A retrospective, propensity-score-matched, cohort study compared refill/repeat and adding-on/switching patterns and outpatient visits and prescriptions (health care resource utilization) over 6 months in patients receiving IngMeb versus those receiving imiquimod, 5-fluorouracil, diclofenac sodium, and methyl aminolevulinate or aminolevulinic acid photodynamic therapy (MAL/ALA-PDT).

RESULTS

The final sample analyzed included four matched treatment cohort pairs (IngMeb and comparator; n = 790-971 per treatment arm). Refill rates were similar except for imiquimod (15% vs. 9% for imiquimod and IngMeb, respectively; P < 0.05). MAL/ALA-PDT treatment repetition rates were higher than IngMeb refill rates (20% vs. 10%; P < 0.05). Topical agent add-on/switch rates were comparable. PDT had higher switch rates than did IngMeb (5% vs. 2%; P < 0.05). The IngMeb cohort had a significantly lower proportion of patients with at least one AK-related outpatient visit during the 6-month follow-up than did any other cohort: versus imiquimod (50% vs. 66%; P < 0.0001), versus 5-fluorouracil (50% vs. 69%; P < 0.0001), versus diclofenac sodium (51% vs. 56%; P = 0.034), and versus MAL/ALA-PDT (50% vs. 100%; P < 0.0001). There were significantly fewer AK-related prescriptions among patients receiving IngMeb than among patients in other cohorts.

CONCLUSIONS

Results based on the first 6 months after treatment initiation suggested that most field-directed AK therapies had clinically comparable treatment patterns except imiquimod, which was associated with higher refill rates, and PDT, which was associated with significantly more frequent treatment sessions and higher switching rates. IngMeb was also associated with significantly fewer outpatient visits than were other field-directed therapies.

A randomized trial comparing simultaneous vs. sequential field treatment of actinic keratosis with ingenol mebutate on two separate areas of the head and body

Background

Actinic keratoses (AKs) are precursors to invasive squamous cell carcinoma and can progress if untreated. Limited data support the use of ingenol mebutate to treat AKs on more than one area of the body simultaneously.

Objective

To investigate safety, efficacy and treatment satisfaction when treating separate areas simultaneously or sequentially with different concentrations of ingenol mebutate gel.

Methods

In this phase IIIb study (NCT01787383), patients with clinically visible, non‐hyperkeratotic AKs on two separate treatment areas (face/scalp and trunk/extremities) were randomized to simultaneous or sequential treatment with ingenol mebutate gel (0.015% and 0.05%). Endpoints included composite local skin response (LSR) score 3 days after first application, complete AK clearance and percentage reduction in AKs at week 8.

Results

There were no statistically significant differences between simultaneous (n = 101) and sequential (n = 98) groups in composite LSR score (10.4 vs. 9.7), complete clearance (52.7% vs. 46.9%) or percentage reduction in AKs (83.4% vs. 79.1%). Mean composite LSR scores on face/scalp and trunk/extremities were similar for both groups. Adverse event (AE) incidence was comparable between groups, the most common treatment‐related AEs being pruritus and pain at the application site.

Conclusion

Treating AKs with ingenol mebutate simultaneously or sequentially gave similar results in terms of tolerability (LSR score, AEs) and efficacy (complete clearance). Therefore, the physician and patient can select the most convenient treatment regimen, with confidence in achieving a similar outcome.

How to treat actinic keratosis? An update

Actinic keratosis (AKs) is one of the most common skin lesions leading to an increased risk of developing squamous cell carcinoma and other skin malignancies. The lesions principally arise as a result of excessive ultraviolet (UV) exposure. AKs may regress spontaneously, remain stable or evolve to invasive squamous cell carcinoma. The risk of squamous cell carcinoma is significantly increased patients with more than 5 AKs. The main mechanisms involved in the formation of AK are inflammation, mutagenesis, oxidative stress, impaired apoptosis, immunosuppression, disregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been correlated with the formation of some AKs. As an individual ages, his skin is exposed to increasing cumulative amounts of UV light and other environmental insults. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also the surrounding area. In this area undetectable preclinical AK lesions or dysplastic cells may be present. The whole affected area is known as the 'field'. Therefore, management is divided into lesion-directed and field-directed therapies. Currently, the therapies in use are lesion-directed cryotherapy and/or excision, and field-directed topical agents: 5-fluorouracil, diclofenac, photodynamic therapy, imiquimod, and ingenol mebutate. Combining lesion- and field-directed therapies showed good results and several novel therapies are under investigation. Treatment is variable and personalized, what makes a gold standard management algorithm difficult to design. This review aims to describe the rationale behind the available treatment options for AKs based on current understanding of pathophysiology and epidemiology.

Primary care review of actinic keratosis and its therapeutic options: a global perspective

Actinic keratosis (AK) is a common skin condition caused by long-term sun exposure that has the potential to progress to non-melanoma skin cancers. The objective of this review is to examine the therapeutic options and management of AK globally, particularly in Australia, Canada, and the United Kingdom. Despite its potentially malignant nature, general awareness of AK is low, both in the general population and in the primary health care setting, especially in countries with low incidence. There is no standard therapeutic strategy for AK; it is treated through a variety of lesion-directed or field-directed therapies or a combination of both. A variety of treatment options are used depending on the experience of the primary care physician, the pathology of the lesion, and patient factors. Studies have shown that the physicians do not always use the optimal treatment option because of a lack of knowledge. The higher incidence of AK in fair-skinned people in Australia has resulted in well-established management strategies and guidelines for its treatment, compared with countries with lower incidence. It is essential to raise the awareness of AK because of its potential to progress to invasive squamous cell carcinoma. Primary care physicians are often the first to see this condition in their patients and are perfectly placed to educate the public and raise awareness. It is therefore desirable that their education and knowledge about AK and its treatment are up to date.

Ultraviolet radiation-induced non-melanoma skin cancer: Regulation of DNA damage repair and inflammation

Exposure to ultraviolet (UV) radiation is associated with approximately 65% of melanoma cases, and 90% of non-melanoma skin cancers (NMSC), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). While the incidence of most other malignancies has either stabilized or declined, that of NMSC has increased and is developing even in younger age groups. NMSCs account for nearly 15,000 deaths, 3.5 million new cases, and more than 3 billion dollars a year in medical costs in the United States alone, representing a major public health concern. As sun protection efforts have not been proven effective, targeted chemoprevention strategies are much needed. Skin carcinogenesis by DNA damage is considered a predominant paradigm for UV toxicity. Exposure to UV radiation can activate various oncogenes while inactivating tumor suppressor genes, resulting in inappropriate survival and proliferation of keratinocytes that harbor these damages. Moreover, increasing evidence demonstrate that inflammatory responses by the immune cells within the tumor microenvironment also contribute significantly to skin tumorigenesis. Initiation and progression of skin carcinogenesis mediated by UV radiation involve complex pathways, including those of apoptosis, proliferation, autophagy, DNA repair, checkpoint signaling, metabolism, and inflammation. In this review, we highlight the recent advances in two of these key molecular processes that result in UV-mediated skin carcinogenesis. In particular, we discuss 1) pathways that regulate DNA damage repair and 2) the regulation of the inflammatory process its crosstalk with DNA repair potentially leading to non-melanoma skin carcinogenesis.

Prevalence of actinic keratosis among dermatology outpatients in Austria

BACKGROUND

Actinic keratoses (AKs) are common precursors of squamous cell carcinomas (SCCs) of the skin making them an important public health issue with information on their prevalence widely lacking.

OBJECTIVES

To define the prevalence of AK in dermatology outpatients in Austria and to identify more accurately the target population for AK screening, treatment and prevention.

METHODS

Each of the 48 randomly selected Austrian office-based dermatologists simultaneously screened 100 consecutive patients (aged ≥ 30 years) for the presence of AK.

RESULTS

In total, 4449 evaluable patients showed an overall AK prevalence of 31·0%, which was higher in men (39·2%) than in women (24·3%) and increased with age in both sexes. AK distribution among sun-exposed body sites and extent of disease varied with sex and region.

CONCLUSIONS

In Austria, AKs are common among dermatology outpatients, who have access to professional education and treatment. Investigations regarding the efficacy of routine AK screening in dermatology outpatients for the prevention of invasive SCC is warranted.

Actinic keratosis: rationale and management

Actinic keratoses (AKs) are common skin lesions heralding an increased risk of developing squamous cell carcinoma (SCC) and other skin malignancies, arising principally due to excessive ultraviolet (UV) exposure. They are predominantly found in fair-skinned individuals, and increasingly, are a problem of the immunosuppressed. AKs may regress spontaneously, remain stable or transform to invasive SCC. The risk of SCC increases for those with more than 5 AKs, and the majority of SCCs arise from AKs. The main mechanisms of AK formation are inflammation, oxidative stress, immunosuppression, impaired apoptosis, mutagenesis, dysregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been implicated in the formation of some AKs. Understanding these mechanisms guides the rationale behind the current available treatments for AKs. One of the main principles underpinning the management of AKs is that of field cancerization. Wide areas of skin are exposed to increasing amounts of UV light and other environmental insults as we age. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also large areas where crops of AKs may appear. The skin between lesions is exposed to the same insults and is likely to contain as-yet undetectable preclinical lesions or areas of dysplastic cells. The whole affected area is known as the ‘field’. Management is therefore divided into lesion-directed and field-directed therapies. Current therapies include lesion-directed cryotherapy and/or excision, and topical field-directed creams: 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy and ingenol mebutate. Combining lesion- and field-directed therapies has yielded good results and several novel therapies are under investigation. Treatment is variable and tailored to the individual making a gold standard management algorithm difficult to design. This literature review article aims to describe the rationale behind the best available therapies for AKs in light of current understanding of pathophysiology and epidemiology. A PubMed and MEDLINE search of literature was performed between January 1, 2000 and September 18, 2013. Where appropriate, articles published prior to this have been referenced. This is not a systematic review or meta-analysis, but aims to highlight the most up to date understanding of AK disease and its management.

Management of actinic keratosis: a practical report and treatment algorithm from AKTeam™ expert clinicians

BACKGROUND

Actinic keratoses (AK) are common photo-induced cutaneous lesions that may progress to invasive squamous-cell carcinoma and serve as a risk marker for skin cancer. Although numerous studies present the various therapeutic options for AK, publications that can be used to pragmatically guide dermatologists in their daily practice are limited. National and international guidelines have been published, however, they are based on clinical trials with highly selected patient populations and do not always capture the range of patients seen in everyday practice.

OBJECTIVE

The objective of this expert panel of French dermatologists was to present an analysis of AK geared towards everyday practice, to express an informed opinion about most recent treatments, and to propose a treatment algorithm for AK for daily practice in France.

METHODS

Over a 12 month period, six expert dermatologists in the field of AK (AKTeam(TM) expert panel) met regularly to formulate an opinion about treatment in everyday practice compared with the analysis of the literature and guidelines published since 1990.

RESULTS

Definitions, terminology, diagnosis and risk factors were summarized. Data from the literature and current practices related to the initial evaluation, indications for biopsy, therapeutic indications, therapeutic options and effectiveness, monitoring and prevention were discussed. A pragmatic treatment algorithm was formalized according to current data available. This practical algorithm distinguishes between different clinical situations depending on the number of AK, their hyperkeratotic or suspicious nature, and includes cryotherapy, curettage-electrocoagulation, 5% 5-fluorouracil, 3% diclofenac sodium, 5% imiquimod, 150 and 500 μg/g ingenol mebutate, lasers, photodynamic therapy and surgery.

CONCLUSION

This up-to-date expert opinions about AK and its treatment provide a management strategy and practical treatment algorithm for AK for French dermatologists to use.

Clinical and pathological study of 328 cases of actinic keratosis in eastern chinese patients

BACKGROUND

Actinic keratosis (AK) is prevalent and has been widely studied in fair-skinned populations. However, this is not the case in eastern countries. AK in Asians has not been so thoroughly investigated.

OBJECTIVES

To analyse the clinical and pathological features of a relatively large number of cases of AK diagnosed in older Chinese patients.

METHODS

Case histories of 328 patients with pathologically diagnosed AK were analysed retrospectively. Their demographic, clinical, pathological and treatment data were collected for analysis of associated factors.

RESULTS

Lesions were usually distributed on the face, especially the cheeks and temples. The most frequent pathological type was hypertrophic. Only 34% of the cases had been diagnosed correctly as AK before biopsy; many were mistaken for seborrhoeic keratosis.

CONCLUSIONS

Most patients were elderly females and there was a higher incidence of lesions on the face, and a lower incidence on the extremities and trunk; this finding contrasts with previous investigations in fair-skinned people.

Prevalence of actinic keratosis and its risk factors in the general population: the Rotterdam Study

Limited data are available on the prevalence and risk factors of actinic keratoses (AKs). Within the Rotterdam Study, full-body skin examinations were performed among participants aged 45 years or older to estimate the age- and sex-standardized prevalence of AK and its associated risk factors. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for associations between risk factors and the presence of 1-3, 4-9, and ≥ 10 AKs. Of the 2,061 inspected cohort members (mean age 72 years), 21% had 1-3, 9% had 4-9, and 8% had ≥ 10 AKs. AK prevalence was 49% (95% CI: 46-52%) for men and 28% (26-31%) for women. Male gender, older age, light pigmentation status, severe baldness, skin wrinkling, and high tendency for sunburn were significantly associated with extensive actinic damage (≥ 10 AKs) in the multivariate analyses. Especially bald males were at an increased risk of severe actinic skin damage (adjusted OR=7.0 (3.8-13.1)). The prevalence of AK is very high, especially among elderly bald males. The prevention and management of AK is a true challenge for patients, physicians, and health-care policymakers.

Clinical findings using ingenol mebutate gel to treat actinic keratoses

Actinic keratosis (AK) is a common ultraviolet light-induced skin lesion found on sun-exposed skin areas generally in older, fair-skinned people. It is part of a disease continuum observed in photodamaged skin that may lead to invasive squamous cell carcinoma. The presence of AK is associated with an increased risk of all skin cancers, as it is visible evidence of the carcinogenic effects of cumulative ultraviolet exposure. AKs are treated with lesion- and field-directed methods. Field-directed methods treat both the visible and subclinical lesions present in photodamaged skin, but treatment regimens are often lengthy and associated with poor tolerability because of vigorous local inflammatory reactions. Ingenol mebutate gel was recently approved by the Food and Drug Administration for topical treatment of AK. It induces cell death preferentially in transformed keratinocytes and promotes an inflammatory response that kills remaining tumor cells. In human studies, ingenol mebutate achieved high clearance rates of AK on the trunk or extremities and face or scalp after once-daily application for 2 or 3 consecutive daily treatments, when measured by complete or partial clearance of lesions. The localized inflammatory skin responses were generally mild to moderate and resolved in approximately 2 weeks on the face or scalp and 4 weeks on the trunk or extremities.

Prevalence and awareness of actinic keratosis: barriers and opportunities

Actinic keratoses (AKs) are common skin lesions that appear after long-term exposure to ultraviolet radiation. The presence of AKs is associated with an increased risk for development of nonmelanoma skin cancer. AKs vary widely in clinical and histologic presentation, which contributes to inadequate identification and presents challenges for consensus classification. Clinically adequate reduction in AK prevalence requires a multifaceted approach. There is a reasonable need to increase awareness and knowledge about AK, including symptoms, prevention, and associated risk of nonmelanoma skin cancer, especially among the public at large. Safe and effective treatment strategies are needed to optimize clearance of AKs, ideally to prevent progression to invasive cutaneous neoplasia.

Prevalence and risk factors of actinic keratoses in Germany--analysis of multisource data

BACKGROUND

In Europe, only few and inconsistent data on the prevalence and treatment of actinic keratoses (AK) are available.

OBJECTIVES

To determine the prevalence of AK in Germany, to identify potential predictors and to estimate the number of AK cases treated in dermatological practices.

METHODS

In a multiple-source approach, prevalence was assessed from whole-body examinations in a cohort of 90 800 employees and from nationwide statutory health insurance (SHI) data of 2008. The number of cases documented in dermatological offices was estimated from statistics of a SHI Physicians Association.

RESULTS

Standardized prevalence of AK from dermatological examinations was 2.7%; the rate increased with age (11.5% in the group 60-70 years) and was higher for men (3.9%) than for women (1.5%). Significant associations were also identified for skin phototype I, sunburns in childhood and solar lentigines. Vitiligo and a history of melanoma were also, but not significantly, associated with AK. In the SHI data analysis, standardized AK prevalence was 1.8%. Age-specific rates were below 1.5% up to 60 years and rose to 8.2% (13.2% in men) in the group 80-89 years. The prevalence from these large data sets--which is at the lower limit of studies from other countries--suggests about 1.7 million estimated AK cases in Germany. In 2011, AK accounted for 8.3% of the hundred most frequently treated dermatological outpatient diagnoses. The proportion of AK cases has risen almost continuously over the last 10 years, compared to other dermatological conditions. Estimated annual number of AK cases documented by dermatologists in Germany is about 1.7 million.

CONCLUSIONS

Actinic keratosis is a frequent condition in higher age groups and more prevalent in men; a relevant need for health care is evident. Predictors and risk factors for AK are easy to identify in the population, which could also help to detect groups with special need for preventive measures.

Comprehensive candidate gene study highlights UGT1A and BNC2 as new genes determining continuous skin color variation in Europeans

Natural variation in human skin pigmentation is primarily due to genetic causes rooted in recent evolutionary history. Genetic variants associated with human skin pigmentation confer risk of skin cancer and may provide useful information in forensic investigations. Almost all previous gene-mapping studies of human skin pigmentation were based on categorical skin color information known to oversimplify the continuous nature of human skin coloration. We digitally quantified skin color into hue and saturation dimensions for 5,860 Dutch Europeans based on high-resolution skin photographs. We then tested an extensive list of 14,185 single nucleotide polymorphisms in 281 candidate genes potentially involved in human skin pigmentation for association with quantitative skin color phenotypes. Confirmatory association was revealed for several known skin color genes including HERC2, MC1R, IRF4, TYR, OCA2, and ASIP. We identified two new skin color genes: genetic variants in UGT1A were significantly associated with hue and variants in BNC2 were significantly associated with saturation. Overall, digital quantification of human skin color allowed detecting new skin color genes. The variants identified in this study may also contribute to the risk of skin cancer. Our findings are also important for predicting skin color in forensic investigations.

The role of ingenol mebutate in the treatment of actinic keratoses

Actinic keratoses (AK) are the most common premalignant pathology seen in dermatological practice and represent a burgeoning burden upon health services. Increasingly recognized is the damage to surrounding, perilesional skin, forming the premise for field-directed therapy. Ingenol mebutate gel is a novel agent for field-directed treatment of AK, requiring only 2 or 3 days of application. Following an overview of existing treatment modalities, the authors review recent trials and safety data pertaining to the use of ingenol mebutate gel and discuss its role in the treatment of AK.

Functional protein pathway activation mapping of the progression of normal skin to squamous cell carcinoma

Reverse phase protein microarray analysis was used to identify cell signaling derangements in squamous cell carcinoma (SCC) compared with actinic keratosis (AK) and upper inner arm (UIA). We analyzed two independent tissue sets with isolation and enrichment of epithelial cells by laser capture microdissection. Set 1 served as a pilot and a means to identify protein pathway activation alterations that could be further validated in a second independent set. Set 1 was comprised of 4 AK, 13 SCC, and 20 UIA. Set 2 included 15 AK, 9 SCCs, and 20 UIAs. Activation of 51 signaling proteins, known to be involved in tumorigenesis, were assessed for set 1 and showed that the MEK-ERK [mitogen-activated protein (MAP)/extracellular signal-regulated (ERK; MEK)] pathway was activated in SCC compared with AK and UIA, and that epidermal growth factor receptor (EGFR) and mTOR pathways were aberrantly activated in SCC. Unsupervised two-way hierarchical clustering revealed that AK and UIA shared a common signaling network activation architecture while SCC was dramatically different. Statistical analysis found that prosurvival signaling through phosphorylation of ASK and 4EBP1 as well as increased Bax and Bak expression was higher in AK compared with UIA. We expanded pathway network activation mapping in set 2 to 101 key signaling proteins, which corroborated activation of MEK-ERK, EGFR, and mTOR pathways through discovery of a number of upstream and downstream signaling molecules within these pathways to conclude that SCC is indeed a pathway activation-driven disease. Pathway activation mapping of SCC compared with AK revealed several interconnected networks that could be targeted with drug therapy for potential chemoprevention and therapeutic applications.

Actinic keratosis: facts and controversies

Actinic keratoses are common lesions that are generally clinically diagnosed. Although currently most actinic keratoses are treated, whether this is truly necessary is debated. Treatment of all actinic keratoses is advocated because preliminary evidence indicates that actinic keratoses may progress to squamous cell carcinomas. Some also consider actinic keratoses equivalent to squamous cell carcinoma.

Life course sun exposure and risk of prostate cancer: population-based nested case-control study and meta-analysis

There is currently no means of primary prevention for prostate cancer. Increased exposure to ultraviolet-radiation may be protective, but the literature is inconclusive. We investigated associations of life course exposure to sunlight with prostate cancer. The study design was a UK-wide nested case-control study, based on 1,020 prostate specific antigen-detected cases and 5,044 matched population controls and a systematic review with meta-analysis. Men with olive/brown skin (OR = 1.47; 95% CI: 1.00 to 2.17), men who burnt rarely/never (OR = 1.11; 0.95 to 1.29) and men with the lowest levels of intense sun exposure in the 2 years prior to diagnosis (OR = 1.24; 1.03 to 1.50) had an increased prostate cancer risk. However, amongst men with prostate cancer, spending less time outside was associated with a reduced risk of advanced cancer (OR = 0.49; 0.27 to 0.89) and high Gleason grade (OR = 0.62; 0.43 to 0.91), and men who burnt rarely/never had a reduced risk of advanced cancer (OR = 0.71; 0.47 to 1.08). The meta-analysis provided weak evidence that men with the lowest (versus highest) sunlight exposure had an increased prostate cancer risk (4 studies, random-effects pooled relative risk = 1.13; 0.98 to 1.29) and higher advanced or fatal prostate cancer risk (6 studies, random-effects pooled relative risk = 1.14; 0.98 to 1.33). Our data and meta-analyses provide limited support for the hypothesis that increased exposure to sunlight may reduce prostate cancer risk. The findings warrant further investigation because of their implications for vitamin D chemoprevention trials.

Ultraviolet B regulation of transcription factor families: roles of nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1) in UVB-induced skin carcinogenesis

Prolonged and repeated exposure of the skin to ultraviolet light (UV) leads not only to aging of the skin but also increases the incidence of non-melanoma skin cancer (NMSC). Damage of cells induced by ultraviolet B (UVB) light both at the DNA level and molecular level initiates the activation of transcription factor pathways, which in turn regulate the expression of a number of genes termed the "UV response genes". Two such transcription factor families that are activated in this way are those of the nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) families. These two transcription factor families have been identified to be involved in the processes of cell proliferation, cell differentiation and cell survival and therefore play important roles in tumorigenesis. The study of these two transcription factor pathways and the cross-talk between them in response to UVB exposure may help with the development of new chemopreventive strategies for the prevention of UVB-induced skin carcinogenesis.

Cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia

Patients with chronic lymphocytic leukemia are at heightened risk for the development of cutaneous malignancies, especially squamous cell carcinoma. These tumors portend a worse prognosis than is typically seen in immunocompetent patients. Patients with chronic lymphocytic leukemia who develop squamous cell carcinoma are more likely to develop multiple tumors, recurrences after treatment, and regional or distant spread of their tumor. Evaluation of the literature substantiates the ominous nature of squamous cell carcinoma in patients with underlying lymphocytic malignancies.

Skin cancer chemoprevention: strategies to save our skin

There are over 1 million cases of skin cancer diagnosed yearly in the United States. The majority of these are nonmelanoma (NMSCs) and are associated with chronic exposure to ultraviolet light (UV). Actinic keratosis (AK) has been identified as a precursor for SCC, but not for BCC. AKs are far more common than SCC, making them excellent targets for chemoprevention. Cancer chemoprevention can prevent or delay the occurrence of cancer in high-risk populations using dietary or chemical interventions. We have developed strategies that have rational mechanisms of action and demonstrate activity in preclinical models of skin cancer. Promising agents proceed to phase I-III trials in subjects at high risk of skin cancer. UV light induces molecular signaling pathways and results in specific genetic alterations (i.e., mutation of p53) that are likely critical to skin cancer development. UVB-induced changes serve as a basis for the development of novel agents. Targets include inhibition of polyamine or prostaglandin synthesis, specific retinoid receptors, and components of the Ras and MAP kinase signaling pathways. Agents under study include: epigallocatechin gallate (EGCG), a green tea catechin with antioxidant and sunscreen activity, as well as UVB signal transduction blocking activity; perillyl alcohol, a monoterpene derived from citrus peel that inhibits Ras farnesylation; difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase and polyamines; retinoids that target retinoid X receptors and AP-1 activity; and nonsteroidal anti-inflammatory agents that inhibit cylooxygenase and prostaglandin synthesis. We performed a series of Phase I-II trials in subjects with multiple AK. For example, a phase II randomized trial of topical DFMO reduced AK number, suppressed polyamines, and reduced p53 protein. Our goal is to develop agents for use in combination and/or incorporation into sunscreens to improve chemoprevention efficacy and reduce skin cancer incidence.

Multiple nonmelanoma skin cancer in an exposed Australian population

BACKGROUND

Patients with nonmelanoma skin cancer (NMSC) frequently develop multiple skin cancers. The study presents incidence rates and rates of excision of NMSC for a population living in a high-risk environment for skin cancer.

METHODS

Between 1997 and 1999 a prospective population-based study collected information on all histologically confirmed NMSCs in Townsville, Australia.

RESULTS

Of the 6708 patients recorded with NMSC, 38.5% had multiple lesions. Yearly age-standardized incidence rates (per 100,000 inhabitants) of basal cell carcinoma (BCC) were 1444.8 for men, 942.7 for women, and of squamous cell carcinoma (SCC) were 805.0 for men, and 423.6 for women. Compared to incidence rates, age-standardized rates of lesions of BCC were 2.1 times higher in men, 1.6 times higher in women, and of SCC were 1.8 times higher in men and 1.4 times higher in women.

CONCLUSIONS

The occurrence of multiple NMSCs compromises results of short-term studies on incidence. Further discussions on the most appropriate strategies to describe the real burden of NMSC are warranted.

Chemoprevention of human skin cancer

The incidence of skin cancer has been rising in recent years with significant effects on public health. Primary prevention has proven inadequate in impacting the incidence of skin cancer, thus stimulating the development of chemopreventive strategies. The majority of skin cancer chemoprevention studies focus on occurrence of new nonmelanoma skin cancers (NMSC) in individuals with a previous NMSC, or on reduction in the number of premalignant skin lesions such as actinic keratoses (AK). Dysplastic nevi, a likely precursor of melanoma, are also potential targets for chemoprevention strategies. Premalignant lesions are especially attractive as endpoints since they are more common than frank cancer, resulting in reduced sample size, length, and cost of clinical trials. Development of new agents that affect the pathogenesis of skin cancer will be discussed, from elucidation of molecular targets to implementation of trials designed to determine the effects of chemopreventive interventions on human skin cancer.

Prostate cancer risk: associations with ultraviolet radiation, tyrosinase and melanocortin-1 receptor genotypes

Exposure to ultraviolet radiation may reduce prostate cancer risk, suggesting that polymorphism in genes that mediate host pigmentation will be associated with susceptibility to this cancer. We studied 210 prostate cancer cases and 155 controls to determine whether vitamin D receptor (VDR, Taql and Fokl variants), tyrosinase (TYR, codon 192 variant) and melanocortin-1 receptor (MC1R, Arg151Cys, Arg160Trp, Val92Met, Asp294His and Asp84Glu variants) genotypes are associated with risk. UV exposure was determined using a questionnaire. MC1R Arg(160)/Arg(160) homozygotes were at increased risk (P = 0.027, odds ratio = 1.94) while TYR A2/A2 homozygotes were at reduced risk of prostate cancer (P = 0.033, odds ratio = 0.48). These associations remained significant after correction for UV-exposure. Stratification of cases and controls by quartiles of exposure, showed that the protective effect of TYR A1A2 (P = 0.006, odds ratio 0.075) and A2A2 (P = 0.003, odds ratio 0.055) was particularly strong in subjects who had received the greatest exposure. Our data show for the first time, that allelism in genes linked with skin pigment synthesis is associated with prostate cancer risk possibly because it mediates the protective effects of UV. Importantly, susceptibility is associated with an interaction between host predisposition and exposure.

Basal cell carcinoma of the nail unit: a case report

Basal cell carcinomas (BCC) of the foot are rare. A review of the English literature found only 23 cases of BCC reported in the foot, none of which involved the nail unit. The nail unit, which is composed of the nail bed and nail-folds, is an exceedingly atypical site for basal cell carcinomas. A case of BCC of the proximal nail fold of the hallux which was treated with Mohs Micrographic Surgery (MMS) is presented.