The majority of skin cancers are caused by exposure to ultraviolet (UV)
radiation in sunlight. Cumulative lifetime exposure to sun is associated with
basal-cell and squamous-cell cancers. More serious melanomas are more
likely to be associated with intermittent but intense exposure (infrequent or periodic
sunburn) (Albino et al 1997, Balch et al 1997). Use of sunscreens that
block UV radiation or more prudent exposure (e.g. sitting in the shade, covering
more of the body with clothing) should reduce or eliminate most skin cancers.
Estimates range up to 78% of lifetime basal-cell and squamous-cell skin
cancers that could be prevented by regular use of sunscreens rated at SPF 15 or
greater during childhood and adolescence (Stern et al 1986).
Efforts have been made to increase knowledge about the risks of sun exposure
and skin cancer, but the results have not been encouraging. Surveys suggest
that fewer than half of sunbathers use sunscreen, and that of those who do,
fewer than half use sunscreens that convey adequate protection (Bak et al
1992, Banks et al 1992). Educational interventions have increased awareness
and knowledge of skin cancers, but there is little evidence of associated behavior
change (Katz&Jernigan 1991, Mermelstein&Riesenberg 1992, Hughes et
al 1993). Beliefs persist that tanning makes people look healthy and more attractive,
that exposure to the sun is good for health, and that the risks of skin
cancer are outweighed by these more immediate factors (e.g. Baum & Cohen
1998, Grob et al 1993, Maducdoc et al 1992, Miller et al 1990, Keesling &
Friedman 1987). Some intensive intervention programs have produced evidence
of short-term behavior change (Girgis et al 1993, Lombard et al 1991).
However, long-term behavior change is usually not evaluated and there is little
evidence that these programs achieve measurable reductions in skin cancer
morbidity (Baum & Cohen 1998).
