Uncovering the Controversies
Which Cloud Sunscreen
There is much confusion surrounding the protective benefits of sunscreen.
A noted dermatologist provides insight on this important segment.
THE PROTECTIVE benefit of sunscreens from UV radiation, a known carcino- gen, is well established. However,
important questions still surround sunscreens and several key ingredients.
HAPPI recently sat down with Steven Q.
Wang, MD, director of Dermatologic Surgery and Dermatology, Memorial Sloan-Kettering Cancer Center at Basking Ridge,
NJ, to discuss the controversies surrounding sunscreens.
Happi: Regular sunscreen use has proved
effective at reducing the development of
both squamous cell cancers (SCC) and actinic keratoses. Have there been any studies that show a statistically significant
protective benefit of sunscreen against either basal cell carcinoma (BCC) or malignant melanoma?
Wang: The evidence currently available indicates that regular sunscreen use provides
prolonged protective benefit in preventing
However, while there is no demonstrated benefit of regular sunscreen use in
reducing the incidence of BCC development, a trend toward reduced incidence of
BCC tumors among sunscreen users has
Furthermore, current data has demonstrated that sunscreens do not increase the
risk of melanoma, but clinical evidence for
its protective benefits remains inconclusive.
However a publication in the Journal of
Clinical Oncology in 2010 featured a study
from Australia in which the investigators
showed a 50% reduction of melanoma in
individuals who used sunscreens.
One important limitation of all the
available clinical and epidemiological evidence, however, is that most of the studies
were conducted during the 1970s and
1980s when only sunscreens with low SPF
and little to no UVA protection were available. Modern sunscreens have corrected
these shortcomings. However, long-term
studies using these newer sunscreens are
not yet available. Moreover, it may take
many years or decades to determine the
potential protective effects of improved
sunscreen formulations. Thus, it is reasonable to conclude that in conjunction with
better education, future studies using these
sunscreens in a corrective manner may
demonstrate a preventive effect for BCC
Happi: What about vitamin D? Does sunscreen use impair vitamin D production?
Wang: Considerable overlap exists between the UV absorption profiles of sunscreens and the action spectrum for vitamin
D synthesis. In theory, correct usage of sunscreens should significantly reduce vitamin
D levels. However, this is not the case in
practice. In fact, several studies have
demonstrated that sunscreens are rarely
applied correctly, in the right dosages and
with appropriate frequency.
Therefore, under real-world conditions,
it is likely that the improper use of sunscreen and/or increased exposure time results in normal production of vitamin D
among sunscreen users. It is important to
note that the level of cutaneous vitamin D
production from UVB exposure is also influenced by seasons, latitude, obesity level
Hence, after considering all these factors, we dermatologists prefer dietary sup-plementation, instead of prolonged UV