An updated report on the incidence and epidemiological trends of keratinocyte cancers in the United Kingdom 2013-2018.

Introduction: The most common cancers in the UK are keratinocyte cancers (KCs): the combined term for basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCCs). Registration of KC is challenging due to high numbers and multiplicity of tumours per person. Methods: We provide an updated report on the descriptive epidemiology of trends in KC incidence for the resident populations of UK countries (England, Northern Ireland, Scotland and Wales) using population-based cancer registry and pathology report data, 2013-18. Results: Substantial increases in cSCC incidence in England, Scotland and Northern Ireland can be detected for the period of 2013-18, and the incidence of cSCC also increased in Wales from 2016 to 2018. In contrast, however, the pattern of annual change in the incidence of BCC across the nations differs. In England, the incidence of BCC declined slightly from 2016 to 2018, however, the overall trend across 2013-18 is not statistically significant. In Scotland, the incidence of BCC shows some variability, declining in 2017 before increasing in 2018, and the overall trend across 2013-18 was also not statistically significant. In Northern Ireland, the incidence of BCC increased significantly over the study period, and in Wales, the incidence of BCC increased from 2016 to 2018. One in five people will develop non-melanoma skin cancers (NMSC) in their lifetime in England. This estimate is much higher than the lifetime risk of melanoma (1 in 36 males and 1 in 47 females born after 1960 in the UK), which further highlights the burden of the disease and importance of early prevention strategies. Conclusions: We highlight how common these tumours are by publishing the first ever lifetime incidence of NMSC. Additionally, the first time reporting of the age standardised incidence of KC in Wales further confirms the scale of the disease burden posed by these cancers in the UK. With approximately one in five people developing NMSC in their lifetime, optimisation of skin cancer prevention, management and research are essential.

The menstrual cycle and the skin.

Perimenstrual exacerbations of dermatoses are commonly recognized, yet our knowledge of the underlying pathophysiological mechanisms remains imperfect. Research into the effects of oestrogen on the skin has provided evidence to suggest that oestrogen is associated with increases in skin thickness and dermal water content, improved barrier function, and enhanced wound healing. Research into the effects of progesterone suggests that the presence of various dermatoses correlates with peak levels of progesterone. Dermatoses that are exacerbated perimenstrually include acne, psoriasis, atopic eczema and irritant dermatitis, and possibly also erythema multiforme. Exacerbations occur at the peak levels of progesterone in the menstrual cycle. Underlying mechanisms include reduced immune and barrier functions as a result of cyclical fluctuations in oestrogen and/or progesterone. Autoimmune progesterone and oestrogen dermatitis are the best-characterized examples of perimenstrual cutaneous reactions to hormones produced during the menstrual cycle. In this review, we describe the current understanding of the menstrual cycle, and its effect on the skin and cutaneous disorders.

Obesity, genetics and the skin.

The increasing problem of obesity in childhood is recognized as both a short-term and long-term serious public-health concern. Excess body weight may contribute to psychological morbidity; cancers; metabolic, cardiovascular and musculoskeletal disorders; and dermatological conditions. There is increasing recognition of the role of genetic factors in the aetiology of obesity. Although in the vast majority of cases these influences are polygenic, some obese children suffer from monogenic disorders, which may present with obesity alone. However, more often than not, they generally display other syndromic features. Some of these syndromes have a clear cutaneous phenotype, and these conditions will be the focus of this review.

Recent developments in the specific dermatoses of pregnancy.

During pregnancy, the mother undergoes changes to sustain and enable normal growth and development of the fetus. Common physiological changes include linea nigra, fibroepithelial polyps, striae, spider angioma, palmar erythema and pruritis gravidarum. However, there are some changes that are purely pathological, and these are termed the pregnancy-specific dermatoses (PSDs). The PSDs occur during pregnancy or in the immediate postpartum period. They do not include the various benign conditions or pre-existing dermatoses and tumours that may present or worsen with pregnancy. They do include a number of distinct and identifiable conditions: atopic eruption of pregnancy (AEP), polymorphic eruption of pregnancy (PEP), intrahepatic cholestasis of pregnancy (ICP) and pemphigoid gestationis (PG). These are a heterogeneous group of skin conditions characterized by pruritis and inflammatory changes. In addition, pruritis gravidarum is sometimes considered pathophysiological and thus part of this group, rather than a physiological process. Each of these conditions has a distinct, but not fully understood, pathogenesis. The mechanisms leading to PSD may be a reflection on the hormonal and immunological changes associated with pregnancy. AEP and PEP are benign conditions, and although they can cause distress to the mother, they are otherwise minor. However, ICP and PG are more serious conditions, and both carry the potential for serious risks to both the mother and the fetus. Thus, the pathophysiology of these latter two conditions is considered in more detail in the following article.

Obesity and the skin.

Obesity is a serious global health problem, perhaps the biggest public health issue of our times. Excess body weight may be a factor in carcinogenesis in general, as well as contributing to the pathogenesis of metabolic, cardiovascular and musculoskeletal disorders. Obesity also has many cutaneous features, which form the basis for this review article. Many of these clinical entities are common to the majority of obese patients, e.g. striae distensae, plantar hyperkeratosis and an increased risk of skin infections. However, it may also be associated with poor wound healing, malignant melanoma and an increased risk of inflammatory dermatoses, such as psoriasis, as well as some rarer disorders. Therapeutic interventions for obesity, whether over-the-counter, prescription medicines or surgical interventions, are increasingly commonplace. All of these treatment modalities potentially have dermatological side-effects too.

Dermatological manifestations of inherited cancer syndromes in children.

Various cutaneous signs presenting in childhood, for example café-au-lait macules, may have systemic cancer associations. Indeed, this may be the first manifestation of the underlying cancer predisposition. The syndromes covered in this review fall into four main categories: (i) DNA damage processing defects including Fanconi anaemia, ataxia telangiectasia, Bloom syndrome, Rothmund-Thomson syndrome, constitutional mismatch repair defects and xeroderma pigmentosum; (ii) signalling pathway defects, including naevoid basal cell carcinoma and Costello syndromes; (iii) primary immunodeficiency syndromes; and (iv) syndromes that do not fit this molecular classification, such as X-linked dyskeratosis congenita. This review focuses on the dermatological findings of these conditions. Some of these conditions exhibit a milder heterozygous phenotype and this should be elicited in the family history. Where the dermatological findings are subtle, a targeted family history can provide clues towards making a diagnosis. Nondermatological features of each condition are summarized too, together with molecular testing strategies, which will direct genetic counselling and screening. This review will enable the dermatologist and other clinicians in the early recognition and molecular confirmation of underlying cancer-predisposing syndromes. This allows the possibility of surveillance and prevention strategies to be initiated in a timely manner, in affected children and other at-risk family members.