Comparison of the site distribution of melanoma in New Zealand and Canada

Abstract

A comparison of the site distribution of cutaneous malignant melanoma in New Zealand and Canada was performed. This series deals with 41,331 incident cases registered between 1968 and 1990 and is the largest to date to evaluate the influence of age and gender on the site distribution of melanoma. Site-specific, age-standardized rates per unit surface area and relative tumour density were assessed by gender and country and differences compared with statistical techniques adapted to this context. The age-standardized rates for all sites were higher in New Zealand than in Canada, the ratio being 3.2 for men and 3.8 for women. Occurrence of melanoma was denser for chronically than intermittently exposed sites in both New Zealand and Canada. The highest incidence rate per unit area was for the ears in men which was more than 5 times the rate for the entire body in each country. For each gender, melanomas were relatively commoner on the trunk and the face in Canada, and on the lower limbs in New Zealand. The variations in the site distribution were similar in each country and consistent with the effect of differential patterns of sun exposure between genders. Our results show that the levels of risk of melanoma between phenotypically comparable populations exposed to different amount of UV radiation vary in a site-specific manner, especially for intermittently exposed sites. This suggests that both environmental conditions and lifestyle factors influence the site distribution of melanoma in these two populations. Although exposure to ultraviolet radiation (UVR) has been identified as the chief environmental risk factor for skin cancer among Caucasians (IARC, 1992), the aetiology of cutaneous malignant melanoma (hereafter referred to as melanoma) is not fully understood. The site distribution of melanoma has been important in generating aetiological hypotheses about the disease. As determinants of the anatomical site distribution have not yet been elucidated, some speculation has occurred about the mode of the carcinogenic process involved (Lee and Merrill, 1970;Green, 1992).Unlike squamous cell carcinoma and, to a lesser extent, basal cell carcinoma which are strongly associated with UVR and frequently observed on heavily exposed sites such as the face and the neck, the back of the hands and the forearms (Pearl and Scott, 1986;Levi et al., 1988;Osterlind et al., 1988;Kaldor et al., 1993), melanoma has long been known to occur commonly on less sun-exposed sites, such as the trunk for men and the lower limbs for women (Lee and Yongchaiyudha, 1971;Davis, 1976;Crombie, 1981). However, when differences in surface area between anatomical parts of the body were considered, risks of the same order of magnitude have generally been reported for melanoma occurring on chronically and intermittently exposed sites, although substantial variation existed between studies (Elwood and Lee, 1975;Elwood and Gallagher, 1983;Pearl and Scott, 1986;Osterlind et al., 1988;Green et al., 1993;Franceschi et al., 1996). The occurrence of melanoma...

Time trend analysis of the skin melanoma incidence of Finland from 1953 through 2003 including 16,414 cases

“…11 The comparison of subsite-specific incidence rates adjusted for body surface shows that skin melanoma incidence rates among both men and women concentrate on the head throughout the registration period as has also been observed in other populations including New Zealand, Canada and Germany. 11,12,22 The skin of the head is more likely to be chronically uncovered and exposed to UV radiation. Interestingly, also basal cell carcinoma of the skin has the highest body surface adjusted incidence rate on the head (including face, lips, eye lids, ears, scalp and neck) in Finland and Germany.…”

Effective exposure to solar UV in building workers: influence of local and individual factors

“…The association between occupational UV exposure and non-melanoma skin cancers, and the causal association between acute recreational exposure and melanoma have partly been postulated from differences in the anatomical distribution of skin cancers (Beral and Robinson, 1981). Although the importance of the anatomical location in the aetiology of cutaneous cancers has been established (Franceschi et al, 1996;Bulliard et al, 1997), exploitation of this variable remains limited, partly because of the lack of precise information on sun exposure of various body parts during at-risk activities.…”

Site-specific occurrence of nonmelanoma skin cancers in patients with cutaneous melanoma

“…trunk) typically have modest levels of sun exposure yet have high melanoma incidence, whereas other highly exposed sites (e.g. hand) have lower melanoma incidence (Green et al, 1993;Bulliard et al, 1997).…”