The influence of the location of the lesion on the absolute risk of the development of skin cancer in a patient with actinic keratosis

Anti-tumor effects of tirbanibulin in squamous cell carcinoma cells are mediated via disruption of tubulin-polymerization

Topical tirbanibulin is a highly effective and well tolerated novel treatment option for actinic keratoses (AKs). This study aimed to characterize the mode of action of tirbanibulin in keratinocytes (NHEK) and cutaneous squamous cell carcinoma (cSCC) cell lines (A431, SCC-12) in vitro. Tirbanibulin significantly reduced proliferation in a dose-dependent manner in all investigated cell lines, inhibited migration, and induced G2/M-cell cycle arrest only in the cSCC cell lines analyzed, and induced apoptosis solely in A431, which showed the highest sensitivity to tirbanibulin. In general, we detected low basal expression of phosphorylated SRC in all cell lines analyzed, therefore, interference with SRC signaling does not appear to be the driving force regarding the observed effects of tirbanibulin. The most prominent tirbanibulin-mediated effect was on β-tubulin-polymerization, which was especially impaired in A431. Additionally, tirbanibulin induced an increase of the proinflammatory cytokines IL-1α, bFGF and VEGF in A431. In conclusion, tirbanibulin mediated anti-tumor effects predominantly in A431, while healthy keratinocytes and more dedifferentiated SCC-12 were less influenced. These effects of tirbanibulin are most likely mediated via dysregulation of β-tubulin-polymerization and may be supported by proinflammatory aspects.

Where Artificial Intelligence Can Take Us in the Management and Understanding of Cancerization Fields

Squamous cell carcinoma and its precursor lesion actinic keratosis are often found together in areas of skin chronically exposed to sun, otherwise called cancerisation fields. The clinical assessment of cancerisation fields and the correct diagnosis of lesions within these fields is usually challenging for dermatologists. The recent adoption of skin cancer diagnostic imaging techniques, particularly LC-OCT, helps clinicians in guiding treatment decisions of cancerization fields in a non-invasive way. The combination of artificial intelligence and non-invasive skin imaging opens up many possibilities as AI can perform tasks impossible for humans in a reasonable amount of time. In this text we review past examples of the application of AI to dermatological images for actinic keratosis/squamous cell carcinoma diagnosis, and we discuss about the prospects of the application of AI for the characterization and management of cancerization fields.

Assessment of dermal bioavailability: predicting the input function for topical glucocorticoids using stratum corneum sampling

Predicting the dermal bioavailability of topically delivered drugs is challenging. In this work, minimally invasive stratum corneum (SC) sampling was used to quantify the delivery of betamethasone valerate (BMV) into the viable skin. Betnovate® cream (0.1% w/w BMV) was applied at three doses (2, 5, and 10 mg cm-2) to the ventral forearms of 12 healthy volunteers. The mass of drug in the SC was measured using a validated tape-stripping method (a) after a 4-h "uptake" period, and (b) following a 6-h "clearance" period subsequent to cream removal. Concomitantly, the skin blanching responses to the same doses were assessed with a chromameter over 22 h post-application. BMV uptake into the SC was significantly higher for the 5 mg cm-2 dose compared to those of 2 and 10 mg cm-2. In all cases, ~30% of the drug in the SC at the end of the uptake period was cleared in the subsequent 6 h. From the SC sampling data, the average drug flux into the viable epidermis and its first-order elimination rate constant from the SC were estimated as 4 ng cm-2 h-1 and 0.07 h-1, respectively. In contrast, skin blanching results were highly variable and insensitive to the dose of cream applied. The SC sampling method was able to detect a 50% difference between two applied doses with 80% power; detection of a 20% difference would require a larger sample size. SC sampling enabled quantitative metrics describing corticosteroid delivery to the viable epidermis to be determined.

Evaluation of dermatoscopic criteria for early detection of squamous cell carcinoma arising on an actinic keratosis

BACKGROUND

Advanced squamous cell carcinoma (SCC) can be discriminated easily from actinic keratosis (AK) based on clinical and dermatoscopic features. However, at the initial stage of dermal invasion, SCC might still be clinically flat and discrimination from AK remains challenging, even with the addition of dermatoscopy.

OBJECTIVE

The aim of this study was to investigate the clinical and dermatoscopic criteria that could suggest early invasion and serve as potent predictors to discriminate early SCC from AK.

METHODS

Clinical and dermatoscopic images of histopathologically diagnosed AKs and early SCCs were evaluated for the presence of predefined criteria by 3 independent investigators.

RESULTS

A total of 50 early SCCs and 45 AKs were included. The main positive dermatoscopic predictors of early SCC were dotted/glomerular vessels (odds ratio [OR] 3.83), hairpin vessels (OR 12.12), and white structureless areas (OR 3.58), whereas background erythema represented a negative SCC predictor (OR 0.22).

LIMITATIONS

The retrospective evaluation of images. Moreover, the differential diagnosis included in the study is restricted between AK and early SCC.

CONCLUSIONS

We identified potent predictors for the discrimination of AK and early SCC that may better guide management decisions in everyday clinical practice.

S3 guideline for actinic keratosis and cutaneous squamous cell carcinoma - short version, part 1: diagnosis, interventions for actinic keratoses, care structures and quality-of-care indicators

Actinic keratoses (AK) are common lesions in light-skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence-based framework for clinical decision making, the guideline "actinic keratosis and cutaneous squamous cell carcinoma" was developed using the highest level of methodology (S3) according to regulations issued by the Association of Scientific Medical Societies in Germany (AWMF). The guideline is aimed at dermatologists, general practitioners, ENT specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office-based settings as well as other medical specialties involved in the diagnosis and treatment of patients with AK and cSCC. The guideline is also aimed at affected patients, their relatives, policy makers and insurance funds. In the first part, we will address aspects relating to diagnosis, interventions for AK, care structures and quality-of-care indicators.

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.

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.

Treatment responder analysis in actinic keratosis: can it lead the way to individualized choice of treatment?

BACKGROUND

It is unclear if there are any distinct AK patient populations that might respond best to a given treatment.

OBJECTIVE

To identify if a distinct subgroup of patients with AK might respond better to treatment with ingenol mebutate (IngMeb) versus diclofenac sodium (DS).

METHODS

Complete clearance of AK and mean lesion reduction at end of first treatment course and week 17 were evaluated within subgroups.

RESULTS

502 patients (255 IngMeb; 247 DS) were included in the analysis. At week 17, complete clearance was achieved by more patients treated with IngMeb versus DS within the majority of patient subgroups, including patients with <6 lesions and ≥6 lesions at baseline, aged ≥65 years, males, females, Fitzpatrick skin types II and III, and facial lesions. Mean lesion reduction at week 17 was greater with IngMeb than DS within the same subgroups, and in patients with scalp lesions.

CONCLUSIONS

This responder analysis did not identify any distinct population that responded more optimally than others with IngMeb or DS. More patients achieved complete clearance and higher lesion reduction of AK with IngMeb compared with DS in most subgroups.