CLINICAL REPORT
77
Incidence and Regression of Actinic Keratoses in Organ Transplant
Recipients
Zainab JIYAD 1,2 , Louise MARQUART 3 , Peter O’ROURKE 3 and Adele C. GREEN 1,4
Cancer and Population Studies Group and 3 Statistics Unit, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia,
Institute of Cardiosvascular and Cell Sciences (Dermatology Unit), St George’s University of London, London, and 4 CRUK Manchester
Institute and Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, UK
1
2
Actinic keratoses (AKs) are highly dynamic lesions
and AK activity has been shown to be associated with
squamous cell carcinoma (SCC). We sought to explore
risk factors which may affect the 12-month turnover of
AKs in organ transplant recipients (OTRs). The num-
ber of incident AKs, regressed AKs and net change in
AK counts were calculated. Negative binomial regres-
sion and Poisson regression models were used to es-
timate rate ratios (RR) for these 3 outcomes. Among
150 renal and 89 liver OTRs, those who spent > 50%
of a typical weekday in the sun had a lower rate of AK
regression than those who spent minimal time in the
sun during a typical weekday. Age, parents’ country
of origin, hair colour, skin cancer history and recent
AK treatment were all significantly associated with AK
turnover. Clinically, these risk factors may be used to
monitor OTRs at increased risk of SCC.
Key words: actinic keratosis; incidence; regression; solar kera-
tosis; squamous cell carcinoma.
with longer duration of immunosuppression (12). In a
recently published study, we showed that the variability
of AKs in a 12-month period is associated with an in-
creased risk of SCC (13). Specifically, we identified an
association between AK incidence, net gain of AK and
SCC development. However, despite this association,
there is very limited literature exploring risk factors
affecting the rates of incidence and regression of AKs
and thus our aim was to explore this in further detail.
We wanted to explore if there were modifying factors
that would enable targeted surveillance of AK affected
patients beyond simply counting numbers of AK present.
The ultimate aim is to reduce the incidence of SCC. We
examined the impact of phenotype, sun exposure and
various immunosuppression-related risk factors as well
as the total number of incident AKs, regressed AKs and
overall net gain/loss in AK counts in a high-risk immu-
nosuppressed population.
Accepted Aug 29, 2017; Epub ahead of print Aug 30, 2017
Acta Derm Venereol 2018; 98: 77–81.
Corr: Zainab Jiyad, Cancer and Population Studies Group, QIMR Bergho-
fer Medical Research Institute, Locked Bag 2000 Royal Brisbane Hospital,
Brisbane, Queensland 4029, Australia. E-mail: [email protected].
uk
A
ctinic keratoses (AKs) are common sun-induced le-
sions, a small proportion of which are pre-cancerous
and progress to squamous cell carcinoma (SCC) (1).
Studies based on histopathological analysis have estima-
ted that approximately 70% of SCCs develop from AKs
(2, 3). AKs are highly dynamic lesions that frequently
develop, regress and recur in a relatively short period
of time (4–6). As such, investigating AK turnover is a
challenging process that necessitates regular follow-up at
short intervals and detailed mapping. As many as 74% of
AKs present at initial examination may have regressed by
12 months (5), with the risk of regression of a single AK
estimated to be between 15–63% per year (7). However,
following regression, a substantial number of AKs will
subsequently recur (4, 5, 8).
Risk factors for AKs that have been identified in pre-
valence studies in general populations are increasing age,
male sex, European ancestry, high cumulative sun expo-
sure and baldness (9–11). In organ transplant recipients
(OTRs),