Keratinocyte cancer (KC), formerly known as non-melanoma skin cancer, comprises basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC).
In Australia, KCs accounted for an estimated 939,000 treatments in 2015, although they cause only about 560 deaths annually. Keratinocyte cancers accounted for 8% of all health spending on cancer (excluding cancer screening) in Australia in 2008–2009, and Medical Benefits Schedule reimbursements for KC diagnosis, treatment and pathology cost an estimated $703 million in 2015. Thus, these mostly non-fatal cancers represent a large public health problem with disproportionately high costs.
Moreover, the predilection of KCs for the head and neck means that their treatment is often clinically complex, with cosmetic ramifications for affected patients. Keratinocyte cancers are traditionally treated by surgical excision (see: Surgical treatment). A 2002 national survey found that over 70% of BCCs and the majority of cSCCs, regardless of body site, were excised. The main non-surgical treatments are cryotherapy for upper and lower limb lesions, electrodessication and curettage (see: Cryotherapy and electrodessication and curettage), and topical agents like imiquimod (see: Topical treatments and photodynamic therapy).
The environmental cause of most BCCs and cSCCs is exposure to solar radiation. This inference is supported by evidence from numerous epidemiological studies showing that KCs rarely develop in dark-skinned populations, who are far less sun-sensitive than white populations, and that white populations living in regions with high levels of ambient solar ultraviolet (UV) radiation have especially high KC rates. Compared with people born in Australia, immigrants from high-latitude UK show lower incidence rates, and their age of arrival in Australia is inversely proportional to their KC risk. Strong positive associations between childhood sun exposure and BCC suggest that UV radiation received early in life increases BCC risk in adulthood.
Less than 1% of skin cancers in Australia are attributable to other factors. These include immunosuppression, exposure to ionising radiation, exposure to arsenic, human papillomavirus (HPV) infection, and cigarette smoking.
Skin cancers can be prevented by sun protection. While KC eradication among Australians is not feasible, there is emerging evidence for the success of skin cancer awareness and prevention campaigns that commenced in the early 1980s with the aim of reducing the rates of both KC and melanoma, particularly among vulnerable and high-risk groups like children and outdoor workers (see: Prevention of keratinocyte cancer (UV protection strategies, chemoprevention and vitamin D). Since the introduction of these campaigns, sun protection behaviour has improved among Australians. Stabilisation of incidence rates of KC in Australians younger than 60 years was first seen around 2002, and decreasing incidence has recently been reported among young adults.
Primary prevention is known to be cost effective in reducing the large health expenditure on skin cancer, but ongoing substantial investment in sun protection campaigns is needed to maintain the trend of decreasing incidence in KC into the future and across all age groups (see also: Economics of keratinocyte cancer).
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