Incidence trends of melanoma of the skin compared with other localisations, in the Norwegian population, 1956-2005
ABSTRACT Increasing incidence rates (IRs) of cutaneous malignant melanoma (CMM) have been associated with increased exposure to ultraviolet radiation (UVR). The aim of this study was to compare the changes over time in IRs of malignant melanoma in anatomical localisations exposed to different levels of UVR in the same population.
All incident cases of melanoma (invasive) diagnosed 1956-2005 were extracted from the database of the Cancer Registry of Norway. The average percentage change of the age-standardised IRs per 5-year period of diagnosis was calculated (loglinear regression) by anatomical localisation (skin, eye, internal organs and external genitalia).
CMM represented 91.7% of the total number of melanomas, while ocular melanoma and melanoma in the internal organs represented 6.2% and 1.2%, respectively. The average quinquennal percentage increase in IRs for CMM and melanoma in internal organs was 23.3% [95% confidence interval (CI) 20.9-25.8] and 14.0% (95% CI 8.2-19.7), respectively. The corresponding analysis for ocular melanoma showed an increase of 1.3% (95% CI -1.5 to 4.2) and a decrease (not significant) for melanoma on male (-8.8%) and female (-2.1%) external genitalia.
A wide variation in IRs and trends between the four anatomical localisations with unlike levels of UVR exposure suggests different causal pathways for melanoma.
- SourceAvailable from: Visalini MuthusamySkin Cancers - Risk Factors, Prevention and Therapy, 11/2011; , ISBN: 978-953-307-722-2
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ABSTRACT: Due to the implementation of the Montreal Protocol, which has limited, and is now probably reversing, the depletion of the stratospheric ozone layer, only modest increases in solar UV-B radiation at the surface of the Earth have occurred. For many fair-skinned populations, changing behaviour with regard to exposure to the sun over the past half century – more time in the sun, less clothing cover (more skin exposed), and preference for a tan – has probably contributed more to greater levels of exposure to UV-B radiation than ozone depletion. Exposure to UV-B radiation has both adverse and beneficial effects on human health. This report focuses on an assessment of the evidence regarding these outcomes that has been published since our previous report in 2010. The skin and eyes are the organs exposed to solar UV radiation. Excessive solar irradiation causes skin cancer, including cutaneous malignant melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma, and contributes to the development of other rare skin cancers such as Merkel cell carcinoma. Although the incidence of melanoma continues to increase in many countries, in some locations, primarily those with strong sun protection programmes, incidence has stabilised or decreased over the past 5 years, particularly in younger age-groups. However, the incidence of non-melanoma skin cancers is still increasing in most locations. Exposure of the skin to the sun also induces systemic immune suppression that may have adverse effects on health, such as through the reactivation of latent viral infections, but also beneficial effects through suppression of autoimmune reactivity. Solar UV-B radiation damages the eyes, causing cataracts and pterygium. UV-B irradiation of the skin is the main source of vitamin D in many geographic locations. Vitamin D plays a critical role in the maintenance of calcium homeostasis in the body; severe deficiency causes the bone diseases, rickets in children and osteomalacia in adults. Although many studies have implicated vitamin D deficiency in a wide range of diseases, such as cancer and cardiovascular disease, more recent evidence is less compelling, with meta-analyses of supplementation trials failing to show a beneficial effect on the health outcomes that have been tested. It continues to be difficult to provide public health messages to guide safe exposure to the sun that are accurate, simple, and can be used by people with different skin types, in different locations, and for different times of the year or day. There is increasing interest in relating sun protection messages to the UV Index. Current sun protection strategies are outlined and assessed. Climatic factors affect the amount of UV radiation received by the skin and eyes, separately from the effect of ozone depletion. For example, cloud cover can decrease or increase the intensity of UV radiation at Earth's surface and warmer temperatures and changes in precipitation patterns may alter the amount of time people spend outdoors and their choice of clothing. The combination of changes in climate and UV radiation may affect the number of pathogenic microorganisms in surface waters, and could have an impact on food security through effects on plant and aquatic systems. It remains difficult to quantify these effects and their possible importance for human health.Photochemical and Photobiological Sciences 11/2014; 14(1). DOI:10.1039/C4PP90033B · 2.27 Impact Factor