Incipient intraepidermal cutaneous squamous cell carcinoma: a proposal for reclassifying and grading solar (actinic) keratoses

Digitally Enhanced Methods for the Diagnosis and Monitoring of Treatment Responses in Actinic Keratoses: A New Avenue in Personalized Skin Care

Non-melanocytic skin cancers represent an important public health problem due to the increasing incidence and the important local destructive potential. Thus, the early diagnosis and treatment of precancerous lesions (actinic keratoses) is a priority for the dermatologist. In recent years, non-invasive skin imaging methods have seen an important development, moving from simple observational methods used in clinical research, to true diagnostic and treatment methods that make the dermatologist's life easier. Given the frequency of these precancerous lesions, their location on photo-exposed areas, as well as the long treatment periods, with variable, imprecise end-points, the need to use non-invasive imaging devices is increasingly evident to complete the clinical observations in the diagnosis and treatment of these lesions, with the aim of increasing accuracy and decreasing the adverse effects due to long treatment duration. This is the first review that brings together all skin imaging methods (dermoscopy, reflectance confocal microscopy, ultrasonography, dermoscopy-guided high frequency ultrasonography, and optical coherence tomography) used in the evaluation of actinic keratoses and their response to different treatment regimens.

Skin Photodamage Lesions in a Bilateral Feline Auricular Primary Fibrosarcoma

As with human species, recent studies also suggest a photoinduced etiopathology for non-epithelial cutaneous tumors in feline species. We report a recent case of a ten-year-old male cat with a white-hair coat and mesenchymal neoplasms of both auricles. Cytology, complete blood count (CBC), serum biochemistry and imaging examinations were performed. After surgery, the samples underwent routinary histopathology and were additionally stained with orcein. A routine analysis yielded values within a normal range and the imaging examination showed no abnormalities, suggesting that the bilateral presentation of neoplasms was primary rather than metastatic. The cytology was inconclusive, but, through histopathology, two well-differentiated fibrosarcomas were diagnosed and histopathological changes related to chronic UV exposure (such as epidermal hyperplasia, stratification disorders, keratinocyte dysplasia and an accumulation of elastotic material) were documented in the skin adjacent to the lesions. An orcein stain succeeded in highlighting elastosis. The elastic fibers lost their regular structure and orientation and appeared to be fragmented, wavy to branched and knotted. A morphometric analysis showed that the amount of elastotic material in the dermis close to the tumors was more than double compared with the more distant areas. Elastosis is considered to be a hallmark of photodamage; thus, an involvement of UV rays in the carcinogenic process of the tumors may be suspected.

Exposome and Skin. Part 2. The Influential Role of the Exposome, Beyond UVR, in Actinic Keratosis, Bowen's Disease and Squamous Cell Carcinoma: A Proposal

Actinic keratosis (AK) is the main risk factor for the development of cutaneous invasive squamous cell carcinoma (SCC). It represents the first sign of severe chronic ultraviolet radiation exposure, which has a clear significant effect. Nevertheless, the skin is exposed to many other exposome factors which should be thoroughly considered. Our aim was to assess the impact of exposome factors other than ultraviolet radiation (UVR) on the etiopathology of AK and Bowen's disease (BD) and progression of AK to SCC and to design tailored prevention strategies. We performed an exhaustive literature search in September 2021 through PubMed on the impact of exposome factors other than UVR on AK, BD and SCC. We conducted several parallel searches combining terms of the following topics: AK, BD, SCC and microbiome, hormones, nutrition, alcohol, tobacco, viral infections, chemical contaminants and air pollution. Notably, skin microbiome studies have shown how Staphylococcus aureus infections are associated with AK and AK-to-SCC progression by the production of chronic inflammation. Nutritional studies have demonstrated how a caloric restriction in fat intake, oral nicotinamide and moderate consumption of wine significantly reduce the number of premalignant keratoses and SCC. Regarding lifestyle factors, both alcohol and smoking are associated with the development of SCC in a dose-dependent manner. Relevant environmental factors are viral infections and chemical contaminants. Human papillomavirus infections induce deregulation of cellular proliferation and are associated with AK, BD and SCC. In addition to outdoor jobs, occupations such as industrial processing and farming also increase the risk of developing keratoses and SCC. The exposome of AK will undoubtedly help the understanding of its etiopathology and possible progression to SCC and will serve as a basis to design tailored prevention strategies.

A multicenter retrospective analysis of the clinical and pathological characteristics of 1188 cases of actinic keratosis in different ultraviolet radiation intensity areas of China

BACKGROUND

Actinic keratosis (AK) is a precancerous disease, caused by ultraviolet radiation (UV).

OBJECTIVE

To analyze the clinical and pathological characteristics of AK in four areas with different ultraviolet radiation intensities.

METHODS

1188 diagnosed AK patients, from January 2000 to July 2015, in dermatology department of four hospitals were collected. The UV intensity of hospital located cities from high to low is Kunming, Yinchuan, Shenyang and Nanjing. The information comes from medical records, and the pathological types and Keratinocyte Intraepithelial Neoplasia (KIN) grades were checked by two experienced pathologists. All information was conducted a retrospective multicenter research.

RESULTS

The patients were mainly middle-aged and elderly female, which was in direct contrast to the majority of men in European. The age of onset in Kunming group was lower than that in Yinchuan Group (p = 0.013) and Nanjing Group (p < 0.01). The course of disease in Kunming group was significantly shorter than that in Nanjing Group (p < 0.001). The lesions were almost located in the exposed area. The proportion of unexposed areas in Shenyang group was significantly higher than that in other groups (p < 0.001). There were statistical differences in pathological morphological classification among the four groups. These differences were not affected by age and gender. The number of KIN III grade patients in Shenyang group was significantly higher than that in other three groups (p < 0.05).

CONCLUSION

The Asian patients were mainly female. The clinical characteristics of AK are closely related to UV intensity, and environmental pollution, lifestyle, religious beliefs and other factors are also related.

High-frequency ultrasound in the diagnosis of the spectrum of cutaneous squamous cell carcinoma: Noninvasively distinguishing actinic keratosis, Bowen's Disease, and invasive squamous cell carcinoma

OBJECTIVE

To evaluate high-frequency ultrasound (HFUS) features for diagnosing cutaneous squamous cell carcinoma (cSCC) as a spectrum of progressively advanced malignancies, including precursor actinic keratosis (AK), Bowen's disease (BD), and invasive squamous cell carcinoma (iSCC).

METHOD

In this retrospective study, 160 skin lesions diagnosed histopathologically (54 AK, 54 BD, and 52 iSCC) in 160 patients were included. The HFUS features of AK, BD, and iSCC were analyzed. The obtained data were evaluated using univariate and forward multivariate logistic regression analyses.

RESULTS

The most significant HFUS features in AK were regular surface (odds ratio [OR], 8.42) and irregular basal border (OR, 6.36). The most significant HFUS features in BD were crumpled surface (OR, 19.62) and layer involvement confined to the epidermis (OR, 3.96). The most significant HFUS features in iSCC were concave surface (OR, 27.06), stratum corneum (SC) detachment (OR, 14.41), irregular basal border (OR, 4.01), and convex surface (OR, 3.73). The characteristics of surface features, basal border, and layer involvement could be valuable HFUS clues in the discrimination of AK, BD, and iSCC.

CONCLUSION

High-frequency ultrasound is valuable for the differentiation of AK, BD, and iSCC, which may allow dynamic and noninvasive monitoring in the spectrum of cSCC.

Different Immunohistochemical Localization of Fatty Acid Binding Protein 5 in Actinic Keratosis Compared with That in Bowen's Disease: A Retrospective Study

ABSTRACT

Actinic keratosis (AK) and Bowen's disease (BD) are common premalignant lesions of invasive squamous cell carcinoma that have different pathogenesis and clinical significance. Fatty acid-binding protein 5 (FABP5) is responsible for keratinocyte homeostasis and differentiation; however, no study has revealed its expression in AK and BD. Our study aimed to investigate the differential expression and significance of FABP5 in these lesions. Patients with pathologically confirmed cases of AK (n = 37) and BD (n = 12) were included in this study. FABP5 immunostaining pattern was assessed in the normal skin, AK and BD lesions, with a focus on the staining patterns of basal cells, atypical keratinocytes, and uninvolved epidermal keratinocytes. All patients with AK showed negative FABP5 expression in the atypical cells in the basal layer, whereas the uninvolved upper layers showed diffuse, strong FABP5 expression, regardless of the grade of AK. All patients with BD showed heterogeneous and diffuse FABP5 expression in atypical cells of all layers of the epidermis. This study is the first to investigate the role of FABP5 in premalignant skin lesions. The unique immunohistochemical localization of the FABP5 can be a helpful diagnostic marker, and altered fatty acid metabolism may be the key in understanding the different pathophysiology of AK and BD.

P53 staining index and zonal staining patterns in actinic keratoses

Actinic keratoses (AKs) are common dysplastic lesions resulting from chronic excessive ultraviolet exposure. Neither the clinical grade of thickness nor the histological grade of dysplasia seems valid predictors of aggressive potential of AKs. Instead, the mutational status in AKs appears to predict well the clinical course. TP53 gene mutations result in a non-functional protein resistant to degradation, thus immunohistochemical staining for p53 can suggest mutation status. Increased p53 was associated with progression from AK to squamous cell carcinoma. To investigate how the intensity of p53 staining (p53 staining index) varies according to body site, histological subtype and grade dysplasia of AKs. Secondly, we sought to investigate the distribution in the epidermal layers of non-functional p53 (zonal staining patterns). p53 staining index was greater than 50% in 90.7% of AKs. p53 staining index was significantly higher in older age (p < 0.0093) and in facial AKs compared to other body areas (p = 0.03). A significant correlation between p53 staining index and grade of dysplasia was observed (p = 0.006) and between p53 staining index and zonal p53 staining pattern (p = 0.003). No significant differences in p53 staining index among the various histological AK types were observed. No correlation between clinical and histological grade. All AKs, independently from their clinical appearance, should be treated but special attention is required for AKs on severely photodamaged skin on the face and in older patients.

Assessment of 5-Aminolaevulinic Acid Photodynamic Therapy (ALA-PDT) in Chinese patients with actinic keratosis: Correlation of dermoscopic features with histopathology

OBJECTIVES

The study examines the changes in dermoscopic features of actinic keratosis (AK) after photodynamic therapy, and delineates the association between AK dermoscopic and histopathological findings.

METHODS

A total of 21 patients (23 lesions) with pathologically confirmed actinic keratosis who received 5-aminolaevulinic acid (ALA) photodynamic therapy (ALA-PDT) were enrolled. The numbers of PDT treatments were: 1, n = 1; 2, n = 2; 3, n = 10; 4, n = 6; 5, n = 2; 6, n = 2). The dermoscopic features before and after the PDT were compared.

RESULTS

There were statistically significant decreases in the positive rates of dermoscopic features including scales (P < 0.001), follicular plugs with whitish halo (P = 0.013), and red pseudonetwork (P = 0.022) among patients treated with ALA-PDT. Dermoscopic feature was significantly associated with pathological grade (P < 0.001). Histopathological hyperkeratosis was significantly associated with dermoscopic red pseudonetwork (P = 0.034) and wavy vessel (P = 0.005). Parakeratosis was associated with wavy vessels (P = 0.001). For vascular hyperplasia in dermal papillae, the significant correlates included scales (P = 0.011), follicular plugs with whitish halo (P = 0.011), red pseudonetwork (P < 0.001); coiled vessels (P = 0.003) and rosette sign (P = 0.004). Wavy vessels was the only feature correlating keratosis pilaris (P = 0.003).

CONCLUSIONS

The findings of the present study support dermoscopy as having potential to be useful for diagnosing and monitoring of actinic keratosis.

Actinic keratosis and imiquimod: a review of novel carriers and patents

INTRODUCTION

Actinic keratosis is one of the most common disorder characterized by erythematic and generally attached scaly lesions which are present either alone or in clusters. World Health Organization defines actinic keratosis as a common intraepidermal neoplasm of sun-damaged skin, characterized by variable atypia of keratinocytes.

AREAS COVERED

At the beginning of the 20th century, a new immunomodulator molecule, imiquimod, appears in the market for the treatment of actinic keratosis but suffers from the pitfalls of the conventional approach of dosage form preparation including high dose, poor stability and more side effects. The present article attempts to compile the scatter information related to actinic keratosis and imiquimod at one place. The special emphasis will be made on the information available in various research articles and patents with respect to the efforts made for overcoming shortcomings associated with imiquimod by novel drug delivery or other approaches.

EXPERT OPINION

The conventional drug delivery systems are unsuccessful to improve the actinic keratosis. The patient acceptance and compliance with these treatments are generally poor due to associated side effects, poor cosmetic outcomes and high costs. Therefore, several available and reported novel therapeutic approaches are being developed in order to provide better action.

Photodynamic therapy activated by intense pulsed light in the treatment of actinic keratosis

BACKGROUND

Actinic keratosis (AK), a hyperkeratotic lesion induced by solar exposure, is the precancerous lesion that most frequently develops into squamous cell carcinoma. Cryotherapy, topical fluorouracil 5, topical diclofenac 3% gel and, more recently, ingenol mebutate are used in addition to surgery. However, these treatments have varying degrees of effectiveness and are not always tolerated due to side effects. In recent years, photodynamic therapy (PDT), has asserted itself as a new effective and safe method for the treatment of actinic keratoses with almost no side effects. The aim of this study is to verify whether a third treatment may now be added to the "Conventional -PDT" and "Daylight-PDT": PhotoDynamic Therapy activated by Intense Pulsed Light (IPL-PDT).

METHODS

Thirty-one patients, 24 males and 7 females, in most cases elderly, were included in the trial. As in the previous methods, also in IPL-PDT, 5-methylaminolevulinic acid (MAL) was applied topically for a period of 3 hours. Thereafter, the occlusive dressing and the topical cream, were removed and the neoformation was irradiated with IPL, with a 640 nm filter with variable power. Irradiation was performed in single or multiple sessions, depending on the type of keratosis, to completely cover the lesion and the apparently healthy surrounding areas, i.e. the cancerization field.

RESULTS

Results were evaluated 3, 6 and 9 months after treatment. Treatment achieved a 95% complete clearance rate, with a 5% partial relapse, 9 months after the last treatment.

CONCLUSIONS

The above method is a valid alternative to methods already in use. The results obtained demonstrate the efficacy and tolerability of the treatment described which, due to its versatility and speed of use, is preferable to the methods used so far.

From actinic keratosis to squamous cell carcinoma: pathophysiology revisited

The precursor of most cutaneous invasive squamous cell carcinomas (iSCCs) is intraepithelial UV-induced damage, known as field cancerization, which can eventually transform into actinic keratosis (AK). Although AK is the most common precursor of iSCC, many AKs will either persist in the same stage or regress, while only a few will progress into iSCC. Nevertheless, because the progression of individual AKs cannot be predicted, it has been proposed that all AKs, regardless of the grade, should be carefully monitored and appropriately treated in clinical practice. Modern imaging techniques such as dermatoscopy, reflectance confocal microscopy (RCM) and high-definition optical coherence tomography (HD-OCT) may have potential to monitor the evolution of actinic field damage. Dermatoscopy can be used to differentiate between AK, intraepidermal carcinoma (IEC) and SCC which may help clinicians to diagnose in situ or invasive lesions at an earlier stage. HD-OCT and RCM can be used to detect cellular and histological changes characteristic of subclinical lesions, allowing visualization of previously invisible lesions. As development of invasive AK directly from the cancer field cannot be ruled out, the ideal treatment should be able to eradicate AK lesions and reverse the underlying field cancerization.

Are actinic keratoses really squamous cell cancer? How do we know if they would become malignant?

Actinic keratosis (AK) is a very common skin disease caused by chronic sun exposure. AKs have historically been characterized as being "precancerous" or "premalignant." It is true that these lesions do not possess metastatic potential, because they are confined to the epidermis, but it is not accurate to deem them "premalignant." AK qualifies as a malignant neoplasm, because it also fulfills criteria for malignancy in classic pathology, namely, the capability, or potential, to kill by either destruction of tissue locally or by metastasis widely. In this context, AK is considered now by many a carcinoma in situ and can persist or progress to invasive squamous cell carcinoma (iSCC), which rarely metastasizes. Through this controversy, which speaks to an issue we have been debating for at least a century, we should like to start a constructive debate to reach a unanimous conclusion considering the various theories and points of view in the literature.

Thickness of Actinic Keratosis Does Not Predict Dysplasia Severity or P53 Expression

The severity of dysplasia and expression of p53 in actinic keratosis (AK) is of importance for the transformation to squamous cell carcinoma. It is assumed that it is most important to treat thick AKs as they are believed to be more dysplastic than thin AKs. However, a relation between AK thickness and dysplasia or the expression of p53 has never been demonstrated. The aim of this study was to investigate this possible relation. Sixty-six AKs were included for clinical and histological examination. Prior to performing a punch biopsy, the clinical thickness of each AK was measured objectively using two scale bars with a thickness of 0.5 mm and 1 mm. Subsequently, the thickness of the epidermis, the severity of dysplasia and the expression of p53 were assessed histologically. We found a strong and significant positive correlation between measured clinical thickness of the AKs and the histological thickness of epidermis (p < 0.0001). However, the clinical thickness did not correlate with either the severity of dysplasia (p = 0.7) or the expression of p53 (p = 0.5). In conclusion, thin AKs show the same severity of dysplasia and expression of p53 as thicker AK lesions. Consequently, clinical thickness cannot predict aggressiveness.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

Expression of Minichromosome Maintenance Proteins in Actinic Keratosis and Squamous Cell Carcinoma

Minichromosome maintenance (MCM) proteins are a group of proteins involved in DNA replication and cell-cycle regulation. Because they are associated with DNA through G1 into S phase, MCM proteins are potentially specific indicators of cell proliferation that could be valuable markers of dysplasia, and preinvasive and invasive malignant tumors. To analyze MCM protein expression patterns in actinic keratosis (AK), Bowen disease (BD), and cutaneous squamous cell carcinoma (SCC), we performed immunohistochemical staining of MCM2, -5, and -7 on tissue microarray blocks from 91 AK, 50 BD, and 174 SCC samples. The distribution and semiquantitatively assessed number of positive cells were analyzed in relation to the type of the lesion and the SCC prognostic parameters (grade, diameter, and thickness). Basal expression of all 3 proteins was observed more frequently in AK, whereas the distribution in BD was predominantly diffuse (P<0.001). All 3 proteins showed peripheral distribution in most well-differentiated SCC and diffuse distribution in poorly differentiated tumors (P<0.001). Using the 50% cut-off value, there was a statistically significant difference among AK, BD, and SCC (P<0.001). In addition, all MCM proteins showed highly significant differences (P<0.001) between well-differentiated SCC and both moderately and poorly differentiated SCC. The diffuse distribution and 50% cut-off value of positive cells revealed statistically significant associations of all MCM proteins with SCC thicker than 6 mm. Our results suggest a role for MCM proteins in the progression of in situ keratinocytic lesions and their association with high-risk features in SCC.

Photodynamic therapy of the surface form of basalioma and actinic keratosis with the topical administration of methyl aminolevulinate

Goal. To assess the efficacy of the photodynamic therapy with the external use of methyl aminolevulinate as a photosensitizer with further irradiation with visible red light with the wavelength of 630 nm in the treatment of patients suffering from a surface form of basalioma and actinic keratosis. Materials and methods. The study involved 28 patients diagnosed with the surface form of basalioma and 34 patients diagnosed with actinic keratosis. They underwent treatment by the photodynamic therapy method using a LED lamp radiating visible red light with the wavelength of 630 nm, with the total dose of irradiation equal to 37 J/cm2. All patients also underwent a confocal in vivo laser scanning microscopy of lesions at the baseline and after 7, 30, 90 and 180 days of treatment. Results. Absolute regression of abnormal lesions was observed in 25 (91%) patients diagnosed with the surface form of basalioma and 30 (88.9%) patients diagnosed with actinic keratosis after 30 days of treatment. No signs of the diseases were revealed in these patients after examination by the method of confocal in vivo laser scanning microscopy. Conclusion. The photodynamic therapy with the local administration of methyl aminolevulinate with further irradiation with visible red light with the wavelength of 630 nm is an efficient method of treatment of the surface form of basalioma and actinic keratosis.

A prospective randomized exploratory study comparing the efficacy of once-daily topical 0.5% 5-fluorouracil in combination with 10.0% salicylic acid (5-FU/SA) vs. cryosurgery for the treatment of hyperkeratotic actinic keratosis

BACKGROUND

Actinic keratoses (AKs) are clinically significant and require therapy. Efficacy of low-dose (0.5%) 5-fluorouracil with 10% salicylic acid (5-FU/SA) has been shown in randomized comparative trials of hyperkeratotic lesions of various grades.

OBJECTIVES

To evaluate the efficacy, tolerability and safety of low-dose 5-FU/SA topical solution vs. cryosurgery in patients with moderate/severe (grade II/III) hyperkeratotic AKs (NCT01358851).

METHODS

In an exploratory, open, randomized study, patients with histologically confirmed moderate/severe hyperkeratotic AKs on the face/forehead or bald scalp received 6 weeks of once-daily topical 0.5% 5-FU/SA, or up to two cryosurgery treatments (3 weeks apart). Histological outcomes were determined from punch biopsies. Clinical, cosmetic and tolerability outcomes were also assessed.

RESULTS

Sixty-six patients received treatment (33 per arm). The baseline total number of lesions was 266 (8.1/patient) in the 0.5% 5-FU/SA and 263 (8.0/patient) in the cryosurgery group. Most (74.5%) lesions were grade II (grade III, 25.5%). Mean change in lesion count from baseline to Day 98 was -5.2 and -5.7 lesions per patient for 0.5% 5-FU/SA and cryotherapy groups respectively. Histological AK clearance rates on Day 98 were 62.1% and 41.9% respectively. At 6-month posttreatment follow-up, recurrence of cleared lesions (no clinically visible lesions in treatment area) occurred in 39.4% of 0.5% 5-FU/SA and 84.8% of cryosurgery patients. Drug-related adverse events (AEs), including local skin reactions considered 'severe' by the investigator, were reported in 24.2% of 0.5% 5-FU/SA and 6.1% of cryosurgery patients. All drug-related AEs were skin reactions.

CONCLUSIONS

Although the study was not powered to explore statistical differences in clinical efficacy between treatments, a short (6-week) schedule of topical treatment with 0.5% 5-FU/SA achieved greater histological clearance and lower recurrence of grade II/III hyperkeratotic AKs than cryosurgery. AE incidence across both treatment groups was relatively low and AEs were generally mild or moderate. Clinical trials.gov identifier: NCT01358851.

Actinic keratosis: a clinical and epidemiological revision

Actinic keratoses are benign intraepithelial skin neoplasms constituted by atypical proliferation of keratinocytes that may evolve to squamous cell carcinoma. They develop in photoexposed skin areas; they are induced mainly by ultraviolet radiation and are considered cutaneous markers of chronic exposure to sunlight. They develop mainly in adults and older, fair skinned individuals, and are the fourth most common cause of dermatologic consultation in Brazil. Damage to the apoptosis pathway in photoexposed epithelium favors cellular proliferation and the permanence of the lesions. In this revision, the authors assemble the main epidemiological data regarding this disease and suggest that strategies to identify risky phenotypes, early diagnosis, adequate treatment, clinical follow-up, stimulus to skin self examination, photoeducation and photoprotection should be promoted with the aim of avoiding the progression to malignancy and also the prevention and the diagnose of concomitant neoplasms also induced by ultraviolet radiation.

Clinical, dermoscopic and immunohistochemical assessment of actinic keratoses and evaluation of the effectiveness of diclofenac therapy with immunohistochemical analysis

Actinic keratoses (AKs) is a keratinocytic neoplasm that typically develops on the face of elderly patients. Little is known regarding the clinical, dermatoscopic and immunohistochemical assessments of AK using topical diclofenac therapy. We sought to determine these assessments and evaluate the efficacy of topical diclofenac gel in AK. In this prospective, open-label study, 44 patients with 66 AKs were treated for 12 weeks with topically applied diclofenac (3% gel in 2.5% hyaluronic acid). Immunohistopathologic analyses were performed before and after diclofenac treatment using epidermal stem cell markers such as Cytokeratin 15 (CK15), Cytokeratin 19 (CK19) and p63, in addition to proliferation markers (Bcl-2, Ki-67). Diclofenac gel was found to be effective in AK, including the hyperkeratotic type. Surprisingly, complete remission was observed at a significantly higher rate in Grade 3 lesions (p = 0.017). However, imunohistochemical and histopathologic examinations revealed that 12-week treatment periods may not be sufficient to fully cure AK. The immunohistochemical analyses revealed no change in the expression levels of CK15, CK19 and Bcl-2 following diclofenac therapy. However, the expression of Ki-67 (p = 0.042) and p63 (p = 0.030) exhibited a significant decrease after therapy. Dermatoscopy is an effective method for diagnosis of AK, and topical diclofenac sodium gel was found as an effective additional treatment modality. Since positive histopathological findings were detected in some patients even with significant remission, a 12-week treatment period should be extended even in patients presenting with positive clinical response. Importantly, anti-proliferative effects of diclofenac were demonstrated by decreased Ki-67 and p63 expression levels.

The importance of early diagnosis and treatment of actinic keratosis

Chronic, long-term sun exposure results in genetic changes in epidermal keratinocytes and the development of various skin lesions ranging from actinic keratosis (AK) to skin cancer. AK lesions may first appear as rough, scaly spots on sun-exposed skin, and, although most individual AK lesions do not become invasive cancers, the majority of invasive squamous cell carcinomas originate from AK. Genetic analysis demonstrates that ultraviolet radiation-induced mutations and changes in gene expression are present in squamous cell carcinoma, AK, and clinically normal-appearing perilesional sun-exposed skin, which supports the progressive nature of keratinocyte transformation. The presence of certain clinical features, such as large size, ulceration, or bleeding, suggests an increased risk of disease progression. The risk is also increased by evidence of extensive solar damage, advanced age, and immunosuppression. Early diagnosis and consideration for treatment are indicated to clear actinically damaged sites and diminish the risk of invasive squamous cell carcinoma.

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.

Imiquimod 3.75% cream (Zyclara) for the treatment of actinic keratoses

INTRODUCTION

actinic keratosis is a premalignant disease with a high incidence and is a strong predictor for the development of squamous cell carcinoma. Various treatment options have been established over recent years, including topical treatment with imiquimod, 5-fluorouracil, diclofenac or photodynamic therapy, cryotherapy and surgical procedures.

AREAS COVERED

this review covers basic and clinical experiences with imiquimod 3.75% for topical treatment of actinic keratosis of the face and balding scalp and its comparators with special focus on imiquimod 5%. It also covers pharmacology of imiquimod 3.5% and its contribution to the current treatment options of actinic keratoses.

EXPERT OPINION

imiquimod 3.75% is an interesting, safe and well-tolerated treatment option for actinic keratoses of the face or balding scalp especially in respect of compliance, as it is indicated for daily use for a shorter time period (2 times, 2-week cycles) and approved for use on larger areas compared with imiquimod 5%. Data from current trials indicate lower efficacy compared with imiquimod 5% cream when applied three times a week for 16 weeks or for two 4-week cycles with a 4-week no-treatment interval, but indicate similar efficacy when compared with a twice-weekly schedule for 16 weeks. An additive effect was observed when combining cryosurgery followed by imiquimod 3.75%.

Cyclin-dependent kinase 2 (CDK-2) expression in nonmelanocytic human cutaneous lesions

Lesions originating from different types of skin cells differ significantly with respect to their pathologic importance. The aim of this work was to examine as to what extent the differences in the origin are reflected in expression levels of CDK-2 and to investigate whether CDK-2 expression might be considered as potential marker useful for diagnostics and assessment of invasiveness of human nonmelanocytic lesions. We conducted comparative immunohistochemical studies of expression of cyclin-dependent kinase 2 (CDK-2) in 16 benign epithelial skin lesions, 11 precancerous lesions, 19 cases of basal cell carcinoma (first such study), 14 squamous cell carcinomas (SCCs), and 7 fibromas. Development of benign epithelial skin lesions was not associated with considerable increase of the CDK-2 expression. Increase of the CDK-2 level was observed in precancerous lesions, and the expression was strongest in SCCs. The level of CDK-2 may be related to invasiveness of skin cancers, as squamous cell carcinomas expressed the enzyme significantly stronger than basal cell carcinomas. Higher percentage fraction of CDK-2 positive cells observed in SCC compared with precancerous lesions may be useful for histopathologic diagnostics of this cancer. Moreover, strong immunohistochemical CDK-2 staining of the cancer cells present deep in dermis may facilitate their detection in histopathologic examinations.

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.

Effect of dosing frequency on the safety and efficacy of imiquimod 5% cream for treatment of actinic keratosis on the forearms and hands: a phase II, randomized placebo-controlled trial

BACKGROUND

Clinical studies in cutaneous conditions other than actinic keratosis (AK) have revealed that the safety and efficacy profile of imiquimod is influenced by dosing frequency.

OBJECTIVES

To evaluate dosing frequency response of imiquimod 5% for treatment of AK.

METHODS

This was a phase II, multicentre, randomized, double-blind, placebo-controlled study. Adults with > or = 10 but < or = 50 clinical AKs, one of which was histologically confirmed, were randomized (4:1) to 2-6 packets of imiquimod or placebo cream applied to the dorsum of the forearms and hands once daily 2, 3, 5 or 7 times per week for 8 weeks. The primary endpoint was complete clearance of AKs in the treatment area at 8 weeks post-treatment.

RESULTS

One hundred and forty-nine (94 men and 54 women) white subjects, with a mean +/- SD age of 71 +/- 10.2 years, were enrolled. Twenty-eight subjects (18.8%) discontinued from study: 0%, 3.1%, 6.9%, 30.0% and 33.3% withdrew for local skin reactions or adverse events in the combined placebo, and in the imiquimod 2, 3, 5 or 7 times per week groups, respectively. Seven serious adverse events occurred; none was related to the study drug. Median baseline lesions ranged from 38 to 40 for the treatment groups. Complete clearance was achieved in 0%, 3.2%, 6.9%, 3.3% and 6.7% of subjects, and partial clearance (> or = 75% lesion reduction) in 0%, 22.6%, 24.1%, 20.0% and 36.7% of subjects for the placebo and imiquimod 2, 3, 5 or 7 times per week regimens, respectively.

CONCLUSIONS

Imiquimod 5% applied more frequently than 3 times per week to AKs was not well tolerated. Complete clearance rates were low; however, partial clearance rates increased with increased dosing frequency (P = 0.002).

Photodamage in feline skin: clinical and histomorphometric analysis

The purpose of this study was to investigate clinical and histomorphometric features of cat skin under long-term solar exposure. Ear skin of 34 Domestic Shorthair cats that were chronically exposed to sun was classified as follows: group 0, normal (n = 13); group 1, initial stage of photodamage (PD) (n = 10); group 2, advanced stage of PD (n = 11). Histologic sections were examined independently by 2 pathologists, and epidermal thickness, adnexal unit area, and dermal cellularity were assessed by morphometry. A positive correlation was obtained between age, degree of edema and sclerosis in the upper dermis, telangiectases, squamatization of basal keratinocytes, and epidermis thickness and the degree of PD. The area occupied by adnexal structures in the dermis diminished with increased PD. Dermal sclerosis and edema best separated the 3 groups. The results indicated a high level of skin hypersensitivity to sun rays in cats. The findings may be useful for clinical testing and in general veterinary pathology and dermatology.

Open-Label Study to Assess the Safety and Efficacy of Imiquimod 5% Cream Applied Once Daily Three Times per Week in Cycles for Treatment of Actinic Keratoses on the Head

Background:

Local skin reactions are common during imiquimod treatment of actinic keratosis (AK). Cyclical application of imiquimod may improve tolerability while maintaining efficacy.

Objective:

To assess the tolerability of imiquimod and clearance rate of AK lesions after imiquimod application.

Methods:

Imiquimod 5% cream was administered three times per week for 4 weeks followed by 4 weeks of rest (cycle 1) to AK lesions on the head. If AK lesions remained visible at the end of cycle 1, a second treatment cycle was instituted.

Results:

Fifty percent (30 of 60) of patients experienced complete clearance of AK lesions, and 75% (30 of 40) of patients experienced partial clearance of AK lesions after imiquimod treatment at the end of cycle 2. Moreover, 77% of patients who achieved complete clearance had no visible AK lesions 12 weeks post-treatment. Imiquimod was well tolerated.

Conclusion:

Imiquimod cycle therapy may be a safe and effective treatment option for AK lesions.

Pathology and pathobiology of actinic (solar) keratosis - an update

Actinic keratosis is a UV light-induced lesion and develops mostly in fair-skinned patients being susceptible to solar damage. The term actinic keratosis (AK) describes clinically ill-defined reddish to reddish-brown scaly lesions on erythematous base in areas damaged severely by sunlight. The term does not imply anything about the biology or histopathology. Actinic keratoses (AKs) have been recognized as precursor of cancer or of precancerous lesions in the past but today they are considered as an early in situ squamous cell carcinoma (1,2) and are categorized in several classifications with subdivisions into three grades depending on the amount of atypical keratinocytes in the epidermis.(3-6) The incidence of development of AK in caucasians increases with age, proximity to the equator and outdoor occupation. Australia has the highest skin cancer rate in the world. AKs are discovered in up to 40-50% of the Australian population older than 40 years.(7) AKs are the most common malignant lesion of the skin.(8-12).

Actinic keratosis is an early in situ squamous cell carcinoma: a proposal for reclassification

The term actinic keratosis (AK) describes a sun-induced, clinical erythematous lesion covered with scale, but does not provide an understanding of the biology or histopathology of the lesion. Consequently, several classification systems for AK have been suggested, but as yet no consensus has been reached. These systems strive to correlate the pathological and clinical features to better provide physicians with the most accurate information to enable correct decisions to be made regarding treatments, Prognosis and metastatic potential. AK is a clinical description that has a histological diagnosis consistent with squamous cell carcinoma (SCC) in situ. We recommend an AK classification system that describes these lesions as squamous cell carcinomas (SCCs), using the terminology 'early in situ SCC Type AK I', 'early in situ SCC type AK II' and 'in situ SCC Type AK III', there by giving clinicians better guidance for diagnosis and specific treatment recommendations.

Low prevalence of p53, p16(INK4a) and Ha-ras tumour-specific mutations in low-graded actinic keratosis

BACKGROUND

Ultraviolet radiation induces DNA damage and is the major risk factor for the development of non-melanoma skin cancer (NMSC). Different mutation rates of p53, p16(INK4a) and Ha-ras in cutaneous squamous cell carcinoma (SCC) and the earlier stage actinic keratosis (AK) have been reported.

OBJECTIVES

To assess the presence of missense mutations in hotspot exons of p53, p16(INK4a) and Ha-ras in low-graded AK.

PATIENTS/METHODS

Cryo-biopsies of 75 sun-exposed AK lesions and 75 sun-shielded areas of normal skin from 75 AK patients were analysed to identify mutations in p53 (exons 7 and 8), p16(INK4a) (exon 2) and Ha-ras (exon 1) using polymerase chain reaction (PCR) followed by direct sequencing. As a representative subset of the specimens, ten mutation-negative AK were also micro-dissected in order to exclude the possibility that additional mutations were undetected.

RESULTS

Eight missense and one nonsense point mutations were found in the 75 AK lesions examined (12%), of which seven (9%) were tumour-specific (i.e. present in AK lesions only) and two (3%) were p16(INK4a) mutations (i.e. also detected in normal skin). Three of the tumour-specific mutations (42%) were cytosine (C) to thymine (T) transitions at pyrimidine-rich sequences. Tumour-specific mutations were identified in 1% of p16(INK4a) (exon 2), 1% of Ha-ras (exon 1) and at a higher rate of 7% in p53 (exons 7 and 8), including one nonsense mutation.

CONCLUSIONS

The evaluation of a large number of AK specimens in this study have found a low gene mutation rate in low-graded AK lesions. p53 mutations rather than p16(INK4a) and/or Ha-ras mutations may be an early event in the development of AK to cutaneous SCC.

Fluorescence diagnosis in keratinocytic intraepidermal neoplasias

BACKGROUND

As different tissue types have distinct capabilities to accumulate protoporphyrin-IX, fluorescence diagnosis with aminolevulinic acid-induced porphyrin (FDAP) could be used to discriminate between different tissue types.

OBJECTIVE

Protoporphyrin-IX accumulation and proliferation were studied in cutaneous squamous (pre)malignancies to see whether FDAP could be used to discriminate between different stages of keratinocytic intraepidermal neoplasia or proliferative status.

METHODS

FDAP was performed in 14 patients (86 lesions) and biopsy specimens were taken, on which (immuno)histochemistry was performed for histopathologic classification and assessment of Ki67-antigen expression. Stratum corneum thickness was also measured.

RESULTS

The fluorescence ratio (lesional:nonlesional skin) showed neither significant differences between the different keratinocytic intraepidermal neoplasia stages, nor between different levels of Ki67-antigen expression. Macroscopic fluorescence intensity and stratum corneum thickness were negatively correlated.

LIMITATIONS

Relatively few malignancies were biopsied.

CONCLUSIONS

With FDAP we were not able to discriminate between keratinocytic intraepidermal neoplasia lesions or proliferative activity. However, hyperkeratosis appeared to be an important determinant in variations in macroscopic fluorescence intensity.

Vehicle-controlled, randomized, double-blind study to assess safety and efficacy of imiquimod 5% cream applied once daily 3 days per week in one or two courses of treatment of actinic keratoses on the head

BACKGROUND

Imiquimod has been investigated as a safe and effective therapeutic option for the treatment of actinic keratosis (AK).

OBJECTIVES

To evaluate imiquimod vs. vehicle applied three times a week for 4 weeks in one or two courses of treatment for AK on the face or balding scalp.

PATIENTS AND METHODS

Patients diagnosed with AK were enrolled in this multicentre, vehicle-controlled, double-blind study conducted in Europe. Twenty study centres enrolled a total of 259 patients in this study. Patients applied the study drug for 4 weeks, entered a 4-week rest period and if they did not have complete clearance, they then entered a second course of treatment.

RESULTS

Patients in the imiquimod group had an overall complete clearance rate of 55.0% (71/129) vs. a rate of 2.3% (3/130) for the vehicle group. There was a high rate of agreement between the clinical assessment and histological findings with respect to AK lesion clearance. At both 8-week post-treatment visits, the negative predictive value of the investigator assessment was 92.2% for clinical assessments vs. histological results.

CONCLUSIONS

A 4-week course of treatment with three times weekly dosing of imiquimod 5% cream, with a repeated course of treatment for those patients who fail to clear after the first course of treatment, is a safe and effective treatment for AK. The overall complete clearance rate (complete clearance after either course 1 or course 2) is comparable to the 16-week treatment regimen, while decreasing drug exposure to the patient and decreasing the overall treatment time.

Photodynamic therapy using aminolaevulinic acid for patients with nonhyperkeratotic actinic keratoses of the face and scalp: phase IV multicentre clinical trial with 12-month follow up

BACKGROUND

Actinic keratoses (AKs) are the most common epithelial precancerous lesions, especially among individuals with light complexions. AKs are believed to progress to in situ squamous cell carcinoma (SCC) and potentially, to invasive SCC. AKs and invasive SCCs share certain histopathological features and both share genetic tumour markers and p53 mutations. Given these facts, the treatment and management of AKs are integral components to quality dermatological health care.

OBJECTIVES

Topical aminolaevulinic acid-based photodynamic therapy (ALA-PDT) has been extensively studied over the last several years. This study seeks to characterize further the efficacy and safety of ALA-PDT by extending previous work to: (i) assess the long-term recurrence rate of AKs that have resolved after ALA-PDT; (ii) to characterize the histopathology of treated AK lesions that do not completely respond to ALA-PDT or recur in long-term follow up; (iii) to characterize the histopathology of untreated clinically diagnosed AK lesions in the study population at baseline; and (iv) to evaluate ALA-PDT in darker skin types than previously studied.

METHODS

Patients enrolled in this study had six to 12 discrete AK lesions, either on the face or the scalp. Individual AK lesions designated for treatment were graded as either grade 1 (lesions slightly palpable and more easily felt than seen) or grade 2 (moderately thick AKs, easily seen and felt). Patients with grade 3 (very thick and/or hyperkeratotic) lesions were excluded. For each subject, two lesions at baseline were randomized to biopsy, and were not followed as part of the study while the remaining lesions (target lesions) were treated with ALA-PDT (baseline and month 2, if required) and followed for 12 months.

RESULTS

Of the 110 patients enrolled, 101 completed the study. The target AK lesions in the per-protocol population clearing completely in the first and second months following a single ALA-PDT treatment (baseline) were 76% and 72%, respectively. Sixty per cent of the patients received a second ALA-PDT treatment, limited to the target AKs still present at month 2. The percentage of treated target lesions that cleared completely peaked at 86% at month 4 then decreased gradually over time to 78% at month 12. The overall recurrence rate for all lesions that were noted to be cleared at some visit during the 12-month period was 24% (162/688). Of the 162 recurrent lesions 16 were lost to follow up, seven spontaneously cleared and 139 were biopsied. With respect to the lesions biopsied, 91% (127/139) were diagnosed histopathologically as AK, with the balance of lesions being SCC (nine of 139: 7%), basal cell carcinoma (one of 139: 0.7%) and other non-AK diagnoses (two of 139: 1%). The recurrence rate for histologically confirmed AKs was 19%. The clinical diagnosis of AK by investigators appeared to be accurate, with 91% (200/220) of the untreated clinically diagnosed AK lesions being histopathologically confirmed to be AK (AK, 142/220: 65%; advanced AK, 29/220: 13%; macular AK, 29/220: 13%). Despite concentrated efforts to recruit patients with Fitzpatrick skin types IV-VI, the distribution was as follows: I, 11%; II, 36%; III, 41%; IV, 11%; V, 2%. The demographics of this study population are typical of a patient population with AK.

CONCLUSIONS

ALA-PDT was shown to be an effective and safe therapy for the treatment of AKs of the face and scalp in skin types I-V, with an acceptable rate of recurrence over 12 months of histologically confirmed AKs of 19%. Phototoxicity reactions were all expected, nonserious and had essentially resolved after 1 month post-treatment independent of skin type.

Actinic cheilitis: histologic study of the entire vermilion and comparison with previous biopsy

BACKGROUND

Actinic cheilitis (AC), is the very superficial, incipient form of actinically induced squamous cell carcinoma of the lower lip. Few studies of actinic cheilitis analyzed the entire lip vermilion searching for microscopic areas of progressing carcinoma.

METHODS

Twenty patients with biopsy proved actinic cheilitis presenting with diffuse clinical changes were submitted to vermilionectomy of lower lip. Surgical specimens were sectioned every 3 mm, studied histopathologically and findings were compared with the biopsy. Histological findings were classified as 'AC', carcinoma in situ (CIS), superficially invasive squamous cell carcinoma (SISCC), and invasive squamous cell carcinoma (ISCC).

RESULTS

Comparison between biopsies and most severe changes on vermilionectomies revealed coincidental changes in 10 cases (50%), more severe changes on biopsy occurred in two cases (10%) and in eight cases (40%) the changes on vermilionectomy were more severe. SISCC was diagnosed in nine cases (45%): of these, two had been detected on biopsy, six had shown a milder aspect on biopsy, and in one biopsy had shown ISCC. Foci of discontinuous areas of SISCC were detected in four cases (20%).

CONCLUSIONS

These findings suggest that cases of AC presenting with poorly demarcated lesions may bear severe histopathological changes irregularly distributed along the vermilion.

Aneuploidy and proliferation in keratinocytic intraepidermal neoplasias

Cutaneous squamous (pre)malignancies can be classified according to the keratinocytic intraepidermal neoplasia (KIN) classification. Aneuploidy can be seen as the result of chromosomal aberrations leading to altered DNA content and has been strongly associated with malignancy. Hyperproliferation is also strongly associated with tumorigenesis. The aim of the study was to analyse the presence and the amount of aneuploidy and proliferation in the progression from intraepithelial neoplasm to microinvasive carcinoma (miSCC). For this purpose, nuclei were isolated from 116 formalin-fixed KIN lesions from 68 patients in which DNA content was measured by flow cytometry. Proliferation was assessed by immunohistochemical staining for Ki67 as well as by flow cytometry. Aneuploidy was increasingly found in higher KIN lesions, but not in normal skin. However, in miSCC aneuploidy was relatively less frequently found. DNA indices (mean +/- SE) of KIN III-lesions (1.57 +/- 0.05) were significantly lower compared with KIN I/II lesions (1.71 +/- 0.05). Ki67 expression was strongly positively correlated with KIN grade, and proved to be a good adjunct in the classification of KINs. Thus, aneuploidy occurred more frequently in higher KIN lesions, indicating cumulative damage during KIN progression. The lower frequency of aneuploidy in miSCC compared with KIN III may point at alternative routes towards invasive carcinoma besides serial progression through all three KIN stages. Ki67 expression appears a valuable marker in the classification of KINs.

Immune-mediated changes in actinic keratosis following topical treatment with imiquimod 5% cream

Background

The objective of this study was to identify the molecular processes responsible for the anti-lesional activity of imiquimod in subjects with actinic keratosis using global gene expression profiling.

Methods

A double-blind, placebo-controlled, randomized study was conducted to evaluate gene expression changes in actinic keratosis treated with imiquimod 5% cream. Male subjects (N = 17) with ≥ 5 actinic keratosis on the scalp applied placebo cream or imiquimod 3 times a week on nonconsecutive days for 4 weeks. To elucidate the molecular processes involved in actinic keratosis lesion regression by imiquimod, gene expression analysis using oligonucleotide arrays and real time reverse transcriptase polymerase chain reaction were performed on shave biopsies of lesions taken before and after treatment.

Results

Imiquimod modulated the expression of a large number of genes important in both the innate and adaptive immune response, including increased expression of interferon-inducible genes with known antiviral, anti-proliferative and immune modulatory activity, as well as various Toll-like receptors. In addition, imiquimod increased the expression of genes associated with activation of macrophages, dendritic cells, cytotoxic T cells, and natural killer cells, as well as activation of apoptotic pathways.

Conclusion

Data suggest that topical application of imiquimod stimulates cells in the skin to secrete cytokines and chemokines that lead to inflammatory cell influx into the lesions and subsequent apoptotic and immune cell-mediated destruction of lesions.