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