Assessment of Incidence Rate and Risk Factors for Keratoacanthoma Among Residents of Queensland, Australia

Abstract

IMPORTANCE Keratoacanthoma (KA) is a common and generally benign keratinocyte skin tumor. Reports of the incidence rates of KA are scant. In addition, the risk factors for KA are not well understood, although associations with UV radiation exposure and older age have been described. OBJECTIVETo investigate the incidence rate of KA and the risk factors for developing KA. DESIGN, SETTING, AND PARTICIPANTS The study included data from 40 438 of 193 344 randomly selected residents of Queensland, Australia, who participated in the QSkin Sun and Health (QSkin) prospective population-based cohort study. All participants completed a baseline survey between 2010 and 2011 and were ages 40 to 69 years at baseline. Histopathologic reports of KA were prospectively collected until June 30, 2014, through data linkage with pathologic records. Cox proportional hazards models were used to identify risk factors associated with KA while controlling for potential confounding variables. Data were analyzed from January 2 to April 8, 2020. EXPOSURES Demographic characteristics, phenotypes, UV radiation exposure, medical history, and lifestyle. RESULTS Among 40 438 participants (mean [SD] age, 56 [8] years; 18 240 men [45.1%]), 596 individuals (mean [SD] age, 62 [6] years; 349 men [58.6%]) developed 776 KA tumors during a median follow-up period of 3.0 years (interquartile range, 2.8-3.3 years). The person-based age-standardized incidence rate for KA in the age-restricted cohort was 409 individuals per 100 000 person-years (based on the 2001 Australian population). Risk factors after adjustment for potential confounders were older age (age Ն60 years vs age <50 years; hazard ratio [HR], 6.38; 95% CI,, male sex (HR, 1.56; 95% CI, 1.33-1.84), fair skin (vs olive, dark, or black skin; HR, 3.42; 95% CI, 1.66-7.04), inability to tan (vs ability to tan deeply; HR, 1.69; 95% CI, 1.19-2.40), previous excisions of keratinocyte cancers (ever had an excision vs never had an excision; HR, 6.28; 95% CI, 5.03-7.83), current smoking (vs never smoking, HR, 2.02; 95% CI, 1.59-2.57), and high alcohol use (Ն14 alcoholic drinks per week vs no alcoholic drinks per week; HR, 1.42; 95% CI, 1.09-1.86).CONCLUSIONS AND RELEVANCE This is, to date, the first large prospective population-based study to report the incidence rate and risk factors for KA. The high person-based incidence rate (409 individuals per 100 000 person-years) highlights the substantial burden of KA in Queensland, Australia. Furthermore, the study's findings suggest that older age (Ն60 years), male sex, UV radiation-sensitive phenotypes, indications of high sun exposure (eg, previous keratinocyte cancer excisions), smoking, and high alcohol use are independent risk factors for the development of KA.

Keratoacanthoma or cutaneous squamous cell carcinoma revealing a DNA mismatch repair default (Muir‐Torre Syndrome)

“…Generally, KA are benign keratinocyte skin tumours mostly seen in patients over 60 2 . In this young patient with two KA/cSCC, a sebaceoma, and a family history of digestive cancers, a genetic disease, such as a Muir‐Torre syndrome (MTS), was suspected 3–6 .…”

“…Generally, KA are benign keratinocyte skin tumours mostly seen in patients over 60. 2 In this young patient with two KA/cSCC, a sebaceoma, and a family history of digestive cancers, a genetic disease, such as a Muir-Torre syndrome (MTS), was suspected. [3][4][5][6] MTS is a variant of hereditary non-polyposis colorectal cancer or Lynch syndrome, 7 which is an autosomal dominant disorder due to DNA mismatch repair (MMR) default including deleterious germline mutation of MLSH1, MSH2, MSH6 or PMS2.…”

Keratoacanthomas Induced by Cat Scratches in an Elderly Woman

“…Keratoacanthoma commonly erupts on sun exposed areas with signs of actinic damage. In a large prospective study, it was suggested that ultraviolet radiation, older age (≥60 years), male sex, smoking and high alcohol use are independent risk factors for the development of keratoacanthoma [2]. The exact etiology is uncertain but is believed to be multifactorial, including ultraviolet B radiation, genetic susceptibility, carcinogens, immunosuppression and viruses.…”

Patient and Tumour Characteristics of Keratoacanthoma in a Large, Community-based Cohort Study from Queensland, Australia

“…There is a lack of literature on the aetiology of KA. Previous studies by us ( 10 ) and others ( 1 , 2 , 11 – 13 ) suggest that exposure to ultraviolet (UV) radiation plays a major role in development of KA. Other risk factors include male sex, older age, fair skin, smoking and high alcohol use ( 1 – 3 , 10 , 11 ).…”

“…Previous studies by us ( 10 ) and others ( 1 , 2 , 11 – 13 ) suggest that exposure to ultraviolet (UV) radiation plays a major role in development of KA. Other risk factors include male sex, older age, fair skin, smoking and high alcohol use ( 1 – 3 , 10 , 11 ). KA has been reported to be 10–20 mm in size and to most commonly develop on the head, neck and upper extremities ( 14 – 21 ).…”