Cancer and Sun:
D, Skin Cancer, the Sun, and Dermatologists
Dr. Ralph Moss
should by definition be open-minded. As the celebrated eighteenth century German
poet and philosopher Goethe said, "As soon as anyone belongs to a narrow
creed in science, every unprejudiced and true perception is gone." This week
[late May, 2004] I begin a two-part series on an important event that has recently
been in the news: the firing of a Boston University professor who has written
a book that puts forward ideas that run counter to current medical doctrine.
D and Cancer: A Dermatologist's Dilemma - Part 1
Boston professor of dermatology has been asked to resign because he advocates
moderate exposure to sunlight. Michael F. Holick, MD, PhD, a professor at Boston
University, was asked to resign in April from BU's Department of Dermatology because
of a book he wrote, in which he describes the importance of sunlight in boosting
vitamin D levels. He was also severely criticized for his ties to the indoor tanning
chair Barbara Gilchrest, MD, told the Boston Globe that the book
"is an embarrassment for this institution and an embarrassment for him."
As demanded, Holick resigned his post, but continues to teach and to direct the
medical center's Vitamin D, Skin, and Bone Research Laboratory, without a cut
is a talented, experienced and highly respected researcher. He is a professor
of medicine and physiology, and formerly of dermatology, at Boston University
School of Medicine, and (until 2000) chief of endocrinology, metabolism and nutrition.
Since 1987 he has also been the program director of the University's General Clinical
chair Gilchrest's disapproval of Holick stems from the fact that his statements,
superficially at least, seem to be at odds with the medical profession's consensus
on the damaging effects of sunlight. Dermatologists have been warning the public
for years that sunlight, and specifically ultraviolet A (UVA) and ultraviolet
B (UVB), is implicated in the causation of melanoma, as well as other less deadly
forms of skin cancer.
the causes of melanoma are still far from established, and there remain many
unanswered questions about the exact relationship of sunlight exposure to the
development of skin cancers. Exactly how much ultraviolet light constitutes a
safe level of exposure is a legitimate topic for scientific debate. For example,
according to the American Cancer Society, "We do not yet know
exactly what causes melanoma
but we do know that certain risk factors are
linked to the disease
.Some risk factors, such as smoking, can be controlled.
Others, like a person's age or family history, can't be changed. But having a
risk factor, or even several, doesn't mean that a person will get the disease"
to sunlight, the ACS says this: "The best way to lower the
risk of melanoma is to avoid too much exposure to the sun and other sources of
. Avoid being outdoors in sunlight too long, especially in the middle
of the day when UV light is most intense
this view is not universally held. William B. Grant, Ph.D., who heads the Sunlight,
Nutrition and Health Research Center (SUNARC) in San Francisco strongly disputes
it. "This is not particularly good advice," he told this newsletter.
"There are several papers indicating that occupational exposure to sunlight
reduces the risk of melanoma (Kennedy 2003). "It is having fair skin, a high-fat,
low fruit and vegetable diet, sunburning, etc., that are more linked to melanoma
than total UV exposure."
people can certainly differ over this complex question. Such vague terms as "too
long" or "too much exposure" leave much room for disagreement.
In science, intellectual rigidity is never warranted, especially when it rests
on fundamental confusion about the actual causes of a potentially fatal human
scientific uncertainty, the attack on Dr. Holick has taken on a quasi-moralistic
tone. Some dermatologists, possibly frustrated at the failure of most of their
treatments to reverse advanced melanoma, now regard sun exposure without sunblock
as analogous to promiscuous sex without condoms. But ultraviolet sunlight (particularly
UVB) is not always and absolutely bad for our health. It has essential functions,
too. In particular, it enables our skin to manufacture vitamin D: without sufficient
exposure to sunlight we run the risk of developing the deficiency disease rickets.
D and Internal Cancers
benefits of sunlight and vitamin D for the development of healthy bones have long
been known: a Nobel Prize was awarded for discoveries relating to the importance
of vitamin D as early as
what has only fairly recently been discovered is that, in addition to its role
in bone metabolism, vitamin D may also help prevent a variety of cancers.
I wrote about this in my book Cancer Therapy in 1992. I quoted the
work of San Diego scientists Drs. Cedric and Frank Garland, who argued that colon
cancer could be prevented by sunlight. The Garlands went further, however, showing
that "brief, regular exposure to sunlight was probably beneficial in preventing
melanoma, while either too little or too much exposure was potentially harmful"
(Moss 1992, citing Garland
research on the subject of vitamin D and cancer is now voluminous, with over 3,500
PubMed articles on the topic. The US National Institutes of Health has stated
that "laboratory, animal, and epidemiologic evidence suggest that vitamin
D may be protective against some cancers. Some dietary surveys have associated
increased intake of dairy foods with decreased incidence of colon cancer. Another
dietary survey associated a higher calcium and vitamin D intake with a lower incidence
of colon cancer" (NIH 2004). One randomized trial, published last December,
showed that people who had high vitamin D levels benefitted from calcium supplementation:
the incidence of premalignant adenomas of the colon was reduced by 29 percent
in those who had optimal amounts of both nutrients (Grau 2003).
D (and indirectly, therefore, sunlight) might also convey protection against prostate
cancer. It is certainly true that more full-scale clinical trials need to be done
to test this hypothesis. (PubMed lists 29 such trial articles.) But people are
exposed to sunlight every time they step outdoors; the public needs and deserves
preliminary recommendations from those with the greatest knowledge.
Holick's "crime" is that he has provided an answer that is at variance
with the positions of the professional dermatology associations. Yet he is well
positioned to offer an opinion, as he himself is in the forefront of this research.
He is the author of over 200 PubMed articles on the topic of vitamin D, the first
of which appeared in 1970. The latest, published this March, suggests the scope
and importance of his research: "Vitamin D: importance in the prevention
of cancers, type 1 diabetes, heart disease, and osteoporosis" (Holick 2004).
By contrast, Dr. Gilchrest, although herself well published in dermatology, has
only authored two PubMed papers on vitamin D, one of which she co-authored with
is hard to believe that a policy dispute of this sort would warrant such a gross
violation of academic freedom and intellectual rights. We do indeed live in parlous
times when doctors are removed from high positions for offering carefully reasoned
and well intended advice to the general public on preventing cancer!
is much about sunlight's biological effects that is not known and no one would
argue that the case for increasing ultraviolet exposure has yet been conclusively
proved. But neither is it firmly established that blocking sunlight is entirely
beneficial. In fact, the value of physical or chemical sunscreens is itself in
February 1998, an epidemiologist at Memorial Sloan-Kettering Cancer Center
in New York, Dr. Marianne Berwick, presented a careful analysis of sunscreen use
and skin cancer at the annual meeting of the American Association for the Advancement
of Science (AAAS). She concluded that sunscreens may not actually protect against
skin cancers such as melanoma. In her own words: "We don't really know
whether sunscreens prevent skin cancer." Berwick first looked at four studies
of squamous cell cancer, a skin cancer that is destructive but not frequently
lethal. Two of the studies concluded that sunscreen protected against a precancerous
skin condition while two others reported that sunscreen did not shield people
from this condition.
then analyzed two studies of basal cell carcinoma, another generally non-lethal
skin cancer. Those two studies found that people who used sunscreen were actually
more likely to develop basal cell cancer than people who did not.
then analyzed ten studies of melanoma, the most deadly form of skin cancer. Melanoma
often starts in or near moles on the skin. In five of the ten melanoma studies,
people who used sunscreen were also more likely than nonusers to develop melanoma.
In three of the studies, there was no association between sunscreen use and melanoma.
In the final two studies, people who used sunscreen seemed to be protected (Berwick
recently, L.K. Dennis of the University of Iowa reviewed the topic in the Annals
of Internal Medicine. Again, he found that sunblocks offered no protection:
"No association was seen between melanoma and sunscreen use," he and
his colleagues wrote (Dennis 2003).
Berwick's was a factual presentation. But the dermatology profession's response
to her analysis was as unmeasured as its response to Dr. Holick. The American
Academy of Dermatology promptly denounced the Memorial Sloan-Kettering
researcher's conclusions. In March 1998 the Academy issued a press release calling
her message "misleading and confusing."
Ceilley, MD, a Des Moines dermatologist and a past president of the Academy, called
Berwick "a numbers cruncher," not a doctor, according to an article
in Science News. Incidentally, Dr. Ceilley, has only one PubMed article on the
topic of melanoma, dating from 1980 (Elmerts 1980). Dr. Berwickthe Sloan-Kettering
"numbers cruncher"has 81 such publications.
going to have millions more cases of skin cancer in the next decade" if people
forgo sunscreen, Dr. Ceilley proclaimed (Fackelmann 1998).
D and Cancer: A Dermatologist's Dilemma - Part 2
week I wrote about the firing of Boston University dermatologist, Michael F. Holick,
MD, PhD. Dr. Holick was sacked for suggesting, in his book The UV Advantage,
that people seek out a few minutes of unblocked sunlight a couple of times per
week. The goal is to boost the skin's production of vitamin D, thereby reducing
the risk of contracting various diseases, including cancer. The ancient grandmotherly
advice to "get a little color in your face" may not be all wrong!
is commonly believed that exposure to sunlight leads to skin cancer, including
deadly melanoma. No one believes this more ardently than leaders of the dermatology
profession. For example, a leading dermatologist, Roger Ceilley, MD, has proclaimed,
"We're going to have millions more cases of skin cancer in the next decade"
if people forgo sunscreen (Fackelmann 1998).
the relationship may not be that simple. There is evidence that a moderate amount
of unblocked sunlight is actually beneficial to most people, reducing the risk
of many diseases including, paradoxically, melanoma itself. For example,
in often-cited research on US Navy personnel in San Diego, researchers from the
University of California School of Medicine found that more melanoma occurred
among desk workers than among sailors who worked outdoors (Garland 1990).
a ten-year period, 1974-1984, the researchers identified
176 cases of melanoma
among active-duty white male Navy personnel. The risk of melanoma was then determined
for occupations that were grouped into three categories of sunlight exposure:
(1) indoor, (2) outdoor, or (3) indoor and outdoor.
with the US civilian population, Navy personnel in indoor occupations had a higher
age-adjusted incidence rate of melanoma (10.6 per 100,000). But persons who worked
in occupations that required spending time both indoors and outdoors had the lowest
intriguing finding was that incidence rates of melanoma were higher on the trunk
of the body than on the more commonly sunlight-exposed head and arms. This alone
calls into question the notion that exposure to sunlight equals increased rates
UC San Diego researchers concluded that there was a protective role for brief,
regular exposure to sunlight. They also pointed to laboratory studies showing
that vitamin D suppresses the growth of malignant melanoma cells in tissue culture.
They suggested that vitamin D could inhibit previously initiated melanomas from
becoming clinically apparent (Garland
ideas such as these have made some dermatologists very angry indeed.
Boni E. Elewski, MD, current president of the American Academy of Dermatology,
has argued that even a few minutes of sunlight exposure can be dangerous, and
that people can get all the vitamin D they need through supplements. This is a
strange recommendation indeed, since orthodox doctors usually urge the laity to
shun food supplements. (Incidentally, I can find no published scientific papers
by Dr. Elewski on the topic of vitamin D.)
dermatologists' vehement opposition to the idea, it is not at all clear that small
amounts of unblocked sun exposure could be a significant cause of melanoma. As
even the Skin Cancer Foundation states, "Epidemiologic studies have suggested
that intense intermittent exposure resulting in sunburn, especially in childhood,
is most likely to lead to melanoma development." (Skin Cancer Foundation
2004) But full-blown intermittent sunburn is not at all the same thing as getting
a bit of sun on a winter afternoon in the northern latitudes.
course too much of a good thing can be dangerous. But the essential point that
Holick makes is that by moderately increasing our exposure to sunlight, we can
probably decrease our risk of many forms of cancer, as well as diabetes, seasonal
affective disorder (SAD), multiple sclerosis, and other illnesses.
Interested readers should take a look at the maps of disease distribution and
mortality at the website of the SUNARC Foundation of San Francisco at http://www.sunarc.org
these maps clearly show is that, as a general rule, the death rates for breast,
colon and ovarian cancer, as well as incidence rates for multiple sclerosis, decrease
as one moves south. For example, the breast cancer death rate in the south is
about half of what it is in the north and northeast. Dr. William B. Grant, founder
of SUNARC, has published a paper in the journal Cancer, in which he argues that
these differences are due to sunlight and vitamin D (Grant 2002).
he is correct, then this is very good news indeed for the "worried well."
Brief but regular sunlight exposure could turn out to be a healthful measure that
is easy to implement, cost-free and accessible to almost all. And ironically,
despite the fervent objections from photophobes in the medical profession, it
might even decrease the risk of melanoma.
the moral climate these days has become polluted by dogmatism, bigotry and petty-mindedness.
Science is supposed to be an island of rationality in a sea of intolerance. Yet
intolerance is rearing its ugly head here as well.
advocating even a few minutes of exposure to Old Sol these days is enough to get
you black balled by your profession, regardless of prior accomplishments. "Any
group, organization, or individual that disseminates information encouraging exposure
to UV radiation, whether natural or artificial, is doing a disservice to the public,"
Elewski menacingly told The Scientist (www.biomedcentral.com). Read
that sentence over. This is what we've come to in America, circa 2004. One would
have to go back to the McCarthy era or to the 1930swhen (to paraphrase the
poet W.H. Auden) "intellectual disgrace stared from every human face"to
find an equivalent.
is much in this current debate on sunlight that is reminiscent of the longstanding
feud over dietary fat. First, Dr. Robert Atkins was excoriated by almost the entire
medical profession as a fraud and a quack. Then there was a grudging admission
that his diet may work sometimes, but for reasons other than those he postulated.
Now, after the public in its millions has deserted the orthodox position on weight
loss, the medical profession is running full tilt to catch up. Recently I awoke
to the following headline: "Longest scientific study yet backs Atkins diet."
Two clinical trials conducted at the Philadelphia VA hospital and at Duke University,
published in the prestigious Annals of Internal Medicine, have found that subjects
on the Atkins diet shed significant amounts of weight without harmful effects
on blood fats and sugars (Coghlan 2004).
purpose here is not to weigh the merits and demerits of the Atkins low-carb diet.
Rather it is to point out that all too often science is ruled not so much by
cool reason as by pride and prejudice. The reaction to Dr. Holick's research
is a case in point.
sunlight (and those who advocate moderate exposure) is a manifestation of dogma
rather than science. Perhaps a certain narrowness of vision is an inevitable result
of professional over-specialization. Dermatologists spend their days looking for
melanoma, an insidious and deadly disease. After a while, they begin to see UV
exposure (which is indisputably dangerous when carried to extremes) as the sole
source of this evil. Dermatologists are not asked to worry about non-cutaneous
forms of cancer, or about diabetes, seasonal affective disorder (SAD), or any
of the other illnesses that may be prevented by judicious UV exposure. They just
care about skin disease. As the old saying has it, to the hammer, everything
looks like a nail'.
Question of Sponsorship
of the animus against Prof. Holick stems from his friendly relationship with the
Indoor Tanning Association (ITA), a society that represents people
working in that burgeoning industry. Holick is said to have unveiled his new book
during a meeting of the ITA, which has also hired a publicist to promote it and
has contributed $150,000 to his research.
his association with the ITA may have been professionally unwise, Holick has denied
that his research is influenced by any financial conflict. I have no reason to
believe otherwise. It is unlikely that a distinguished and accomplished researcher
would compromise his honesty for a few grants. One needs to look at the totality
of the man's accomplishments. To me, these all add up to an honest lifelong search
for the truth.
there is something hypocritical in this criticism of Dr. Holick. Of course, it
would be better if all research could be independently funded, thereby eliminating
the need for researchers to go cap in hand to those who have a vested interest
in the outcome of their research. But it certainly seems ironic that leading dermatologists
should rebuke Holick so roundly for his ties to the indoor tanning industry when
in truth most medical research today is supported by interested parties of one
kind or another. Imagine what would happen if all researchers with ties to the
pharmaceutical industry were asked to resign. There would be hardly any top doctors
left in America's medical schools and research laboratories. Are dermatologists
willing to accept that funding of research from, say, the chemical sunscreen industry
should also be prohibited? I haven't heard those sentiments expressed by those
who are now harrumphing over Dr. Holick's connections to indoor tanning.
Case of Dr. Healy
we in for a new round of medical McCarthyism? Dr. Holick's case is similar to
that of another medical professor who was also recently fired for unorthodox views.
Dr. David Healy was removed from his post by the University of Toronto's Centre
for Addiction and Mental Health (CAMH), after he wrote a book that was highly
critical of the pharmacological approach to mental illness (Kendall 2004).
stated the following: "Scientific progress in psychiatry has been stalemated
because Big Pharma's marketing efforts have overwhelmed the field." This
powerful statement points to a far more serious and pervasive problem than Dr.
Holick's grant from the tanning lobby.
there are still a few encouraging signs of elementary fairness in American medicine.
Some vitamin D experts have rallied to Holick's side and have agreed that he should
not have been forced to resign. "If he was fired for his opinion, which is
based on science, then it would appear to be a violation of the principles of
academic freedom," said James Fleet, PhD, who studies nutrition and vitamin
D at Purdue University. Whether small amounts of sunlight can boost vitamin D
intake without raising the risk of cancer "is an issue worth debating,"
Fleet has said.
Reinhold Vieth, PhD,of the University of Toronto, who has worked with vitamin
D since 1974, said that the shunning of Dr. Holick represents a "narrow-minded"
approach to health. "It's like a horse with blinkers, and the only thing
they [the orthodox dermatologists, ed.] see is melanoma."
Holick's response has been rather mild-mannered. He has said that he was "disappointed"
and "surprised" when asked to step down simply on account of the fact
that his opinions differed from those of some of his colleagues. "If you
don't follow that party line, then they'll make every effort to squelch everything
you have to say," he said.
year another 1.3 million Americans will develop life-threatening cancers. Nearly
600,000 will die. Dr. William Grant, founder of the SUNARC Foundation, estimates
that 47,000 of those deaths will result from internal cancers that could have
been prevented by adequate UVB exposure and consequent vitamin D synthesis (Grant,
a recent leading article in Fortune magazine has pointed out, the war on cancer
has so far been a failure.
simply cannot afford to throw away such accomplished and creative scientists as
Michael Holick. In my opinion, Dr. Gilchrest and Boston University should reverse
this misguided decision, pin a medal on Dr. Holick's labcoat, and get down to
the business of finding innovative ways of preventing this terrible disease. The
public deserves nothing less.
order a copy of Dr. Holick's book, The UV Advantage, click
Dermatology Department at Boston University invites the public to send comments,
suggestions and concerns. Those wishing to comment on the case of Dr. Holick should
have received copies of dozens of letters so far and urge those of you who have
not yet expressed your opinion on this matter to do so now. I would appreciate
receiving a copy of any of your comments and letters and with your permission
may print some of them in a future issue.
W. Moss, PhD
References associataed with the above article, click
here to read the original at Dr. Moss's site.
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