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

Abstract

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.

Actinic keratoses show variable histological basal growth patterns – a proposed classification adjustment

“…Additionally, another study claims that the severity of AK dysplasia and expression of p53 are independent of clinical and histological thickness . These results challenge the biological significance of the AK I‐III grading system …”

“…They are diagnosed clinically and commonly classified based on the overall thickness of individual lesions . However, recent studies have shown that the thickness of AK lesions neither correlates with its histological grading nor predicts its dysplastic severity . To overcome the limitation of single lesion evaluation, a new clinical classification, called the ‘actinic keratosis area and severity index’ (AKASI), has recently been proposed.…”

“…Besides this ‘classical’ pathway, another ‘differentiated’ pathway has been reported, suggesting that penetration may possibly be independent of the extent of atypical keratinocytes throughout different layers of the epidermis . Additionally, another study claims that the severity of AK dysplasia and expression of p53 are independent of clinical and histological thickness . These results challenge the biological significance of the AK I‐III grading system …”

Diclofenac Sodium 3% in Hyaluronic Acid 2.5% Gel Significantly Diminishes the Actinic Keratosis Area and Severity Index

“…However, a recent study has shown that it is not possible to draw a correlation from clinical appearance to histology [7]. Furthermore, another study revealed that the thickness of AKs does not predict its dysplastic severity and thus its aggressiveness [6]. Therefore, an assessment tool taking the whole field as well as hyperkeratotic lesions into account was required.…”

“…Recent studies show that the thickness of AK does not predict its degree of dysplasia or correlate with established histological grading systems [6, 7]. Furthermore, a lesion-based classification scheme does not adequately represent the whole area affected by AK.…”