CLINICAL REPORT
351
ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Assessing the Concordance of Actinic Keratosis Counts on Digital Photographs with Clinical Examination in Organ Transplant Recipients
Zainab JIYAD 1, 2, Peter O’ ROURKE 3, H. Peter SOYER 4, 5 and Adele C. GREEN 1, 6
1
Cancer and Population Studies Group and 3 Statistics Unit, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, 2 Institute of Cardiosvascular and Cell Sciences( Dermatology Unit), St George’ s University of London, London, United Kingdom, 4 Dermatology Research Centre, The University of Queensland, School of Medicine, Translational Research Institute, Brisbane, Queensland, 5 Department of Dermatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia, and 6 CRUK Manchester Institute and Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom
Actinic keratoses( AKs) are common lesions that are usually diagnosed clinically. We sought to examine the accuracy of AK counts on digital photographs when compared with clinical examination counts. Skin sites of renal transplant recipients were examined clinically and on digital photographs by independent dermatologically-trained examiners. Specificity, sensitivity and Kendall’ s tau-b correlation coefficient were calculated based on exact photographic AK counts as well as counts with ± 1 AK tolerance. When 138 skin sites with 305 clinical AK counts were examined for total count ± 1 AK, the sensitivity and specificity of photography was 95 % and 100 %, respectively. There was significant positive correlation between AK counts on photographs and clinical examination( T b
= 0.537) and correlation was even higher for total count ± 1 AK( T b
= 0.758). The results show moderate to strong concordance between AK counts on digital photographs and on clinical examination.
Key words: actinic keratosis; actinic keratosis counts; digital photographs; actinic keratosis diagnosis; virtual diagnosis.
Accepted Oct 3, 2016; Epub ahead of print Oct 4, 2016 Acta Derm Venereol 2017; 97: 351 – 353.
Corr: Adele C. Green, Cancer and Population Studies Group, QIMR Berghofer Medical Research Institute, Locked Bag 2000 Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia. E-mail: adele. green @ qimrberghofer. edu. au
Actinic keratoses( AKs) are acquired lesions that develop as a result of chronic sun exposure( 1). AKs frequently arise on white Caucasian skin and are a common presentation to dermatologists, with one study showing an estimated $ 920 million dollars annual spend on AK treatment in the USA alone( 2).
Although histopathology can be used to diagnose AK, the high prevalence of AK, its often benign natural history, and practical and aesthetic limitations mean that in reality, the diagnosis is largely a clinical one( 3, 4). AKs usually appear as red scaly papules or plaques that vary in size and shape. However, they are notoriously heterogeneous lesions and can appear hypertrophic, atrophic, pigmented or as cutaneous horns( 5). The validity of the clinical diagnosis of AK has therefore often been questioned and studies have shown a positive predictive value ranging from 74 – 81 % when compared with histopathology( 6, 7). In addition, several studies have examined the reliability of measurement techniques to evaluate AKs. Weinstock et al.( 8) reported poor reliability in the direct counting of AKs, although a refined technique by Atkins et al.( 9), where only AKs greater than 0.5 cm were counted, showed good correlation between assessors.
The potential for using digital photography in the diagnosis of AK presents exciting possibilities such as applications in teledermatology and use in large clinical or epidemiological studies. In a small reliability study of 6 participants that compared AK counts on digital photographs with clinical counts, it was found that photographic counting was not a reliable alternative to clinical examination( 10). A further study that looked at automated photographic detection of AKs based on erythema showed sensitivity of the technique ranging from 40 – 53 %( 11).
Against this background, the aim of the present study was to provide a detailed evaluation of the consistency of AK counts on digital photographs with clinical examination in renal transplant recipients, using defined areas of skin and a much larger study population than in previous studies.
METHODS Study population
The Skin Tumours in Allograft Recipients( STAR) study recruited organ transplant recipients residing in Queensland, Australia. Eligible participants were White Caucasian renal, liver or lung transplant recipients over the age of 18 years, who were at least one year post-transplantation. Details of eligibility and exclusion criteria have been described extensively elsewhere along with full details of STAR study protocol and primary outcomes( 12, 13). The study in full was approved by the QIMR Berghofer Human Research Ethics Committee( project P1481) and all participants provided written consent. For the purposes of this sub-study, only renal transplant recipients were evaluated.
Data collection
At baseline, all recruited participants underwent a full skin examination by one of several dermatologically-trained physicians. AKs were identified as erythematous papules or plaques with white to yellow scale and a consensus meeting was held at the outset of the study to establish a clear clinical definition( 5). All AKs identified clinically were recorded on a body map and total numbers were summarised per skin site. In addition, high-quality photographs of the face, arms and hands( Fig. 1) of participants
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2017 Acta Dermato-Venereologica. doi: 10.2340 / 00015555-2540 Acta Derm Venereol 2017; 97: 351 – 353