Acta Dermato-Venereologica 99-4CompleteContent | Page 13

404 CLINICAL REPORT Modifiable Risk-factors for Keratinocyte Cancers in Australia: A Case-control Study Lina Maria SERNA-HIGUITA 1 , Simone L. HARRISON 2 , Petra BUTTNER 2 , Margaret GLASBY 2 , Beverly A. RAASCH 2 , Angelika IFTNER 3 , Claus GARBE 4 , Peter MARTUS 1 and Thomas IFTNER 2,3 Department of Clinical Epidemiology and Applied Biostatistics, 3 Institute for Medical Virology, University Hospital Tübingen, Tübingen, Germany, 2 Skin Cancer Research Unit, College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, Queensland, Australia, and 4 Division of Dermato-Oncology, Department of Dermatology, University of Tübingen, Tübingen, Germany 1 Keratinocyte cancer is the most common malignancy in Caucasians. The aim of this study was to investi- gate risk-factors responsible for development of kera- tinocyte cancer in Australia. A case-control study was conducted, including 112 cases of squamous cell car- cinoma (SCC), 95 cases of basal cell carcinoma (BCC) and 122 controls. Freckling during adolescence (SCC: odds ratio (OR) 1.04, p < 0.01; BCC: OR 1.05, p < 0.01), propensity to sunburn (SCC: OR 2.75, p = 0.01, BCC: OR 2.68 p = 0.01) and high cumulative sun-exposure (SCC: OR 2.43, p = 0.04; BCC: OR 2.36 p = 0.04) were inde- pendent risk-factors for both SCC and BCC. This study provides further evidence that a sun-sensitive phe- notype and excessive sun-exposure during adulthood contribute to the risk of developing keratinocyte can- cer. Wearing a hat, long-sleeved shirts, and sunscreen did not significantly reduce the risk of keratinocyte cancer in this study. Key words: risk factor; keratinocyte cancer; sunscreen; basal cell cancer; squamous cell cancer. sunlight; Accepted Dec 13, 2018; E-published Dec 13, 2018 Acta Derm Venereol 2019; 99: 404–411. Corr: Lina-Maria Serna-Higuita, Department of Clinical Epidemiology and Applied Biostatistics, University Hospital Tübingen, Silcherstraße 5, DE- 72076 Tübingen, Germany, and Thomas Iftner, Institute of Medical Vi- rology, University Hospital Tübingen, Elfriede-Aulhorn Str. 6, DE-72076 Tübingen, Germany. E-mails: [email protected]. de; [email protected] K eratinocyte cancer (KC) arises from the malignant transformation of squamous epithelial cells compri- sing the epidermis (1). KC includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) (1, 2). Al­ though KC rarely causes death (3), surgical excision can cause significant morbidity, especially on highly-visible areas, such as the face, ears and neck (4). KC is the most common malignancy in Caucasians (2, 5). The incidence of KC has increased worldwide by 3–8% annually (6, 7). Australia has the highest reported incidence of KC (8, 9), with the most extreme incidence rates recorded in North Queensland (10, 11). A popula- tion-based study conducted in Townsville between 1996 and 1997 found that the age-standardized incidence rates per 100,000 inhabitants for BCC were 2,058.3 for men and 1,194.5 for women, and for SCC were 1,075.7 for men and 517.7 for women (10, 11). doi: 10.2340/00015555-3107 Acta Derm Venereol 2019; 99: 404–411 SIGNIFICANCE This study examined the complex interplay between en- vironmental and host risk-factors for keratinocyte cancer. The results show that increasing age, lower academic qua- lifications, freckling during adolescence, solar lentiginous, propensity to sunburn and high-cumulative sun-exposure increase the risk of keratinocyte cancer. The increasing incidence of KC may be explained mainly by high levels of sun-exposure (7) despite the implementation of campaigns in Australia to induce a be- haviour change in favour of sun protection and reduce sun exposure (12–14). However, the complex interplay bet- ween sociodemographic and environmental risk-factors and the uptake of the various forms of photoprotection is not fully understood. Exposure to solar ultraviolet radiation (UVR) is a well-established risk-factor for KC (15). Several studies have found modifiable risk-factors for KC other than UVR (16); including diet (17), alcohol consumption (17), cigarette smoking (18–20), and infection with human papilloma virus (21). However, the individual contribution of each factor is not clear, and data on interactions between sun-exposure, host-factors and other potential risk-factors for KC are limited (22), and may explain some inconsistencies in the published literature (2). The identification of modifiable risk-factors for KC may lead to more effective preventive strategies to reduce the incidence of KC, particularly in high-risk populations. The present study was designed to eluci- date the relationship between environmental and host risk-factors in Caucasian patients from Australia who develop KC. METHODS Eligible cases (n = 442) in this case-control study consisted of adults (18–76 years) from the population of Townsville (latitude 19.3°S), North Queensland, who had an incident of BCC or SCC during 2004 to 2009. Cases were patients who presented for treat- ment at the Townsville Hospital or the surgeries of local surgeons, a dermatologist and general practitioners in Townsville. Only patients with histological diagnosis of in situ or invasive SCC or BCC of at least 5 mm diameter on the body or 10 mm diameter or This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2019 Acta Dermato-Venereologica.